Conseil Permanent International pour l'Exploration de la Mer CHARLOTTENLUND SLOT - DANEMARK
ANNALES BIOLOGIQUES VOLUME NO. 23
REDIGE PAR H. T AMBS-L YCHE
1966
En Commission chez ANDR. FRED. H0ST & FILS COPENHAGUE
Prix: kr. 55.00 Janvier !968
TABLE OF CONTENTS
Page
Preface, by H. TAMBS-LYCHE 7
Part I. HYDROGRAPHY
Distant Northern Seas Some regularities in the distribution of phosphates and oxygen in the Davis Strait summer and winter 1965-V. S. ZLOBIN, M. F. PERLYUK, N. G. SAPRONETSKAYA ...... I3 Danish hydrographical observations in West Greenland waters 1966 P.M. HANSEN ...... 20 The Oceanic Polar front in the waters off the East Coast of Greenland in August 1966- G. DIETRICH, J. M. GrESKES ...... 20 Hydrographic conditions in Icelandic waters in June 1966- S. A. MALMBERG ...... 23 Water temperature of the Norwegian Current in 1966 - V. V. PENIN, L. R. SOLONITSINA ...... 27 Thermal conditions in the Barents Sea in 1966- L. I. BoROVAYA 29
Near Northern Seas ...... 33 Surface temperature and salinity observations at English sampling stations during 1966- D. J. ELLETT, S. R. JONES, G. READ 33 Hydrographical conditions in the North Sea in March 1966 and 1967- E. MITTELSTAEDT ...... 49 Polish hydrographical observations in the North Sea in summer and autumn 1966- J. FILARSKI ...... 60 Hydrography of the south-eastern North Sea 1966, Danish observations -H. THOMSEN...... 65 Hydrography of the Skagerak and the Kattegat area 1966, Swedish observations- A. SVANSSON...... 65 Hydrography of the Kattegat area 1966, Danish observations - H. THOMSEN ...... 67
Baltic-Belt Seas ...... 68 Danish observations in the Great Belt and the Baltic 1966 - H. THOM- SEN ...... 68 Polish hydrographical observations in the southern Baltic in 1966 - A. GLOWINSKA ...... 68 Observations at Swedish lightships and the central Baltic 1966 - S. H. FoNsEuus ...... 74 Some peculiarities in the oceanographical regime of the Baltic in 1966 - M. V. KALEIS, N. B. ALEXANDROVSKAYA, E. A. YULA . . . . . 78 Page Part II. PLANKTON AND BENTHOS
Distant Northern Seas The continuous plankton recorder survey: plankton in the Irminger Sea region during Ig66 - R. S. GLOVER, G. A. RoBINSON ...... 84 Plankton investigations from Aberdeen Ig66 in the Distant Northern Seas area- J. H. FRASER ...... 85 Sebastes in continuous plankton records in Ig66- G. T. D. HENDERSON 85
Near Northern Seas ...... 86 The continuous plankton recorder survey. Plankton around the British Isles during Ig66- R. S. GLOVER, G. A. RoBINSON ...... 86 Investigations from Aberdeen in Ig66- D. D. SEATON, J. H. FRASER go Chlorophyll a and zooplankton standing crop J. A. ADAMS, I. E. BAIRD 92
Baltic-Belt Seas ...... 94 Investigations on zooplankton in the western part of the Gdansk Bay - K. SruDZINSKI ...... 94
Atlantic Area ...... 96 Scottish plankton investigations in the Atlantic area in Ig66 - j. H. FRASER ...... 96
Part III. THE FISH
Gadoid Fish
Cod g8 Danish investigations on cod in West Greenland waters Ig66 - P.M. HANSEN ...... g8 The spawning stock of Icelandic cod in Ig66- G. P. NrzOVTSEV . 102 Scottish investigations of the North Sea cod stock in Ig66 - D. F. S. RAITT ...... I04 German investigations on the stock of cod in the western Baltic in Ig66 - R. KANDLER ...... I05 Stock condition and distribution of cod in the eastern Baltic in Ig66 - I. A. LABLAIKA, D. V. UzARS ...... Io6
Haddock ...... Io8 Soviet investigations on young haddock of the 0, I, II and III age-groups in the Barents Sea- Z. P. BARANOVA ...... I08 Scottish investigations on the Faroe stock of haddock Ig66- R. JONES, D. G. CROSS ...... IIO Scottish investigations on the west coast stock of haddock, Ig66- R. JoNES, D. G. CRoss ...... III Scottish investigations on the North Sea stock of haddock, Ig66- R. jONES, D. G. CROSS ...... II2 German investigations on the haddock of the North Sea in Ig66 - G. WAGNER ...... II3 -s-
P2ge Whiting ...... rq Scottish investigations on the west coast stock of whiting, rg66- J. HISLOP, D. G. CROSS ...... rq Scottish investigations on the North Sea stock of whiting, rg66 - J. HISLOP, D. G. CROSS ...... rr6 German investigations on the whiting of the North Sea in rg66 - G. WAGNER ...... rrS German investigations on whiting in the western Baltic in rg66 - R. KANDLER ...... rr8
Blue Whiting ...... rrg Results of Soviet investigations on ;l1icromesisti%s poutasso% m the North-east Atlantic in rg66- V. K. ZILANOV .. rrg
Herring ...... 122 Introduction, by G. HEMPEL ...... 122 The Icelandic herring fishery in rg66 - J. jAKOBSSON 124 Soviet investigations on the age composition of the White Sea herring in the north-western White Sea in rg65-rg66- B. M. TAMBOVTSEV 129 Norwegian small and fat herring investigations in rg66- 0. DRAGEST.iND 130 Norwegian adult herring fisheries rg66 0. DRAGESUND ...... 132 Norwegian herring tagging experiments and tagging returns- 0. DRA- GESUND, S. HARALDSVIK ...... 136 Survey of the German commercial herring fisheries in rg66 K. ScHu- BERT ...... 138 The Norwegian herring fisheries in the North Sea and Skagerak rg66 - S. HARALDSVIK ...... I43 Scottish herring fisheries rg66- G. McPHERSON, A. SAVILLE 149 Scottish fisheries on adolescent herring, rg66- A. SAVILLE . 159 Herring trawling off the west coast of Scotland rg66 - I. G. BAXTER r6o The English herring fisheries in rg66 - R. .J. WooD, W. G. PARNELL 163 0-group herring on the English east coast- R. J. WooD ...... 167 Growth data for herring of the Southern Bight, derived by back-calcu- lation on scales - T. D. ILES ...... r68 The German oil-herring fishery in rg66- P. F. MEYER-WAARDEN . . IJI The herring fisheries of the Netherlands in rg66 - J. J. ZIJLSTRA, K. H. PosTuMA ...... r7r The Swedish herring fisheries in the North Sea, Skagerak and Kattegat in rg66 - H. HoGLUND ...... 173 The Polish herring fishery in the southern Baltic from 1957 to rg66 - J. POPIEL, K. STRZYZEWSKA ...... I75 Herring investigations in the north-eastern Baltic in rg65-rg66 - L. RANNAK, E. 0JAVEER ...... I79 Baltic herring in the seas around Finland in rg66 - VEIKKO SJOBLOM r8r
Sardine ...... r85 Sprat The English sprat fisheries- P. 0. JoHNSON r85 -6-
Page Scombriform Fish 192 Mackerel Norwegian mackerel investigations in 1966- A. REVHEIM 192 English mackerel tagging in 1966- G. C. BoLSTER 195 Netherlands mackerel fishery in the North Sea in 1966- J. J. ZIJLSTRA, K. H. PoSTUMA ...... 195
Salmon and Trout . . . 198 Danish Research on Atlantic salmon in the West Greenland waters 1966 - P. M. HANSEN ...... 198 British investigations on salmon and sea trout 1966- A. SwAn\ . . . 198 German investigations on salmon and trout 1966- F. THUROW . . . 199 Status of the Baltic salmon stocks in the Latvian rivers 1956-1966 - B. R. EVTUHOV A ...... 202
Other Fishes ...... 204 Danish observations on halibut, catfish, capelin, lumpsucker and redfish in West Greenland waters 1966- P.M. HANSEN ...... 204 Soviet investigations on young redfish (S. mentella and S. marinus) in the Barents Sea in 1966/67 - T. S. BERGER ...... 204 The age composition of the plaice stocks exploited by the Dutch fishing fleet in 1966- J. F. DE VEEN ...... 206 The age composition of the Dutch sole landings in 1966- J. F. DE VEEX 208 Quantitative fishing of flatfish with the standard trawl in the Kiel Bay 1966 - R. KANDLER ...... 209
Rare Fishes 211 Rare fishes recorded by the Marine Research Institute in Reykjavik during 1966- G. JoNSSON ...... 2rr Scottish records of rare fishes- 1964- B. B. RAE, S. F. PIRIE 2rr Scottish records of rare fishes - 1966 - B. B. RAE, S. F. PIRIE 212 English observations on rare fishes in 1966- R. W. BLACKER . 212 Non-indigenous demersal species caught in the western Baltic 1966 R. KANDLER ...... 213
Shellfish 214 Crustacea Danish observations on crustacea in West Greenland waters 1966 - P. M. HANSEN ...... 214
APPENDIX
Report on the joint meeting on Atlanto-Scandian herring distribution, held at Akureyri 12.-14. June 1966 ...... 215 -7-
PREFACE
There are very few changes in the arrangement of contributions to this volume as compared with the last one. As mentioned in the preface to Volume 22, however, a rearrangement following the Council's new committee system has been under consideration for some time. In October 1967, the Council passed the following resolution concerning the Annales biologiques: "Area chairmen's summaries should in the future not be included, but experts - not necessarily chairmen - should be invited to write summaries on herring and cod." In accordance with this, there are no area chairmen's summaries in the present volume. A summary on demersal fish in the distant northern seas, which had already been written by professor G. V. NrKOLSKY, has been incorporated in the comments on the following pages, and is hereby gratefully acknowledged. As in later years, professor G. HEMPEL has written a summary of the contributions to the herring chapter. He could take into consideration some contributions presented to the Statutory Meeting of the Council in October 1967, which could not be included in the present volume. They will eventually be printed in Volume 24. It is regretted that it has not been possible this year to include a summary on cod. By joined efforts of all concerned, it has been possible to speed up the production of this volume quite considerably, and possibilities are now available for a further shortening of the production time for the next volume. This has inevitably caused some inconvenience for contributors, staff and printers, but it is believed that the result justifies the effort, and the editor wishes to thank all concerned. A nnales biologiques and Statistical News Letters are to some extent complementary, and wherever possible, references have been inserted in the text of the present volume. Because of the earlier appearance of this volume, however, this has not always been possible, and general reference is therefore given to the following numbers of Statistical News Letters (issued, in print, or under preparation), where basic and detailed statistical data relevant to the information presented in this volume will be found: No. 34: Herring. North Sea. Nominal Catch and Fishing Effort rg66. No. 35: Herring. Stock Record Data. rg66. No. 36: Nominal Catch and Fishing Effort by months rg66, as reported on STAN A forms. No. 37: Demersal species. Nominal Catch and Fishing Effort. Stock Record Data. rg65. The observations, reported for rg66 in the present volume may be very briefly summarized as follows:
Hydrography West Greenland waters were characterized by relatively high temperatures both at the surface and in near-bottom layers. In East Greenland waters the course of the Polar Front was determined in August (p. 20-22). While drift-ice in Icelandic waters was further off the Icelandic coast than usual, the East Icelandic current was more pronounced, and the southern boundary of the 0°-isotherm reached about 30 n.m. farther south than the average for the period rgso-rg6o. The Atlantic influx north of Iceland was in June abnormally low, and the extension of Arctic waters north-east of Iceland was abnormally high. Soviet investigations in the Norwegian Sea throughout the year showed the temperatures to be generally low, for some localities and times even lower than in 1965. The negative anomalies were, however, greater in the summer than towards - 8 - the end of the year, and they were more pronounced in the northern than in the southern part of the area. Due to extreme cooling and slackening of the influx of heat from the Norwegian Sea, temperatures in the Barents Sea in January-April were the lowest ones observed during the last 30 years. In spite of somewhat intensive heating of the upper layers during the summer, temperatures at the bottom remained very low, and 1966 must in the whole be registered among the coldest years in the Barents Sea. Detailed observations around the English coasts showed temperatures to be at or above normal throughout the year in the south-western English Channel and in parts of the Celtic Sea, while salinities were largely normal. In the central North Sea temperatures were generally low during the first part of the year and near to normal later on. Salinity values were mostly below normal. German investigations in March confirmed this picture and gave details on an advance of Atlantic water towards south-east, and of an influx of relatively warmer water through the British Channel. Bottom temperatures were below normal in March. Polish investigations in May to October added further details. Low salinity water from the Skagerak penetrated further south-west than in previous years. Danish light-ship observations in the south-eastern North Sea also showed low salinities throughout the year. Swedish reports show that a sharp cooling of deeper layers in Skagerak took place in March with a gradual rise later in the year. In Kattegat both salinity and temperature were on the low side during the year, except a rather high salinity at the surface in September. In the Great Belt and at the entrance to the Baltic, temperatures were below normal, and extremely high salinity was observed in March. Polish observations show a rather complicated hydrographic pattern in deeper layers in the southern Baltic. The most conspicuous features were an influx of high salinity water in March-April, and another one of relatively warmer wate::- with lower salinity in the fall. Surface temperatures were below normal during the first part of the year, but tended to be above normal during the summer.
Stagnation of deep water lead to formation of H 2S in the Gotland Basin. The inflow in the autumn cut off part of the stagnant layer and lifted it, so there was during the autumn months found two layers with H 2S, separated by a layer with oxygen. There was no supply of oxygen, however, to the deeper layers of the northern Baltic. Latvian observations confirmed that the r965j66 winter was severe and added new details to the description of deep water conditions.
Plankton and Benthos The most striking feature of the phytoplankton cycle in the Irminger Sea was a very abundant crop in October and November in the eastern part. This was accompagnied by a high number of copepods in the same months. The number of Sebastes larvae was rather low (p. 85). For plankton production around Iceland and in the Norwegian Sea, see Appendix (p. 217 f.). Details of plankton production and distribution around the British Isles are given on pp. 86-90. The general impression is that the abundance was higher than usual for many species. There was a late peak in the abundance in September to November, and there was a marked increase in the numbers of Clione and Spiratella which for many years had been scarce in the area. For the first time data are this year given separately for Calanu.s finmarchicu.s and C. helgolandicus (with 8-year-means). Scottish investigations confirmed the picture given by the Plankton Recorder Surveys, and added further details, f.i. records of biogeographically interesting species (p. 91). There was no marked penetration of oceanic water into the northern North Sea in the first half of the year, but there was some inflow by Septe::nber. No information was available on plankton in the Baltic during 1966, but there is (pp. 94-95) a survey of the plankton in the Gdai1sk Bay during 1958-64. -g-
The Fish Cod Danish investigations in vVest Greenland waters show the rich year-classes rg6o and rg6r to be predominating in the catches. The rg63 year-class, which last year seemed to be poor, is now apparently richer, probably due to recent transport by the current from East Greenland. The following year-classes, up to the rg66 one, seem to be rather poor. Fishing in Icelandic waters was mostly based upon the rg56, rg58 and rg6o year-classes, and first-time spawners made up 85% of the spawning population. Soviet investigations in the Barents Sea showed the rg63 year-class to be good in sub-area IIb and of medium strength in area I. The rg64 year-class was very abundant all over the Barents Sea, while the rg65 one was extremely scarce. Scottish investigations on the North Sea cod stock show an overall increase in catching rates in rg66 as compared with the two previous years. While the effect of the strong rg6r year-class is ebbing out, the rg64 one also seems to be above average, and the rg65 one is promising. In the western Baltic, the rg65 year-class seems to be weaker than the rg64 and rg63 ones. The rg66 year-class looks promising, but it was too early for definite conclusions. The catches of cod in the eastern Baltic were very good in rg66, and the spawning concentrations were not spread over such a wide area as last year. The bulk of the catches was made up of the good rg63 year-class and the very good rg64 one. The rg65 year-class also looks promising.
Haddock Soviet investigations in the Barents Sea confirmed that the rg63 and rg64 year classes were of average strength, while the rg65 one seems to be rather poor. The catching rates in the Faroese waters continued to increase in rg66. In North Sea catches, the strong rg62 year-class was still very well represented, and the rg66 one looks promising, although it was too early for definite conclusions.
Whiting The dominating rg62 year-class caused higher catching rates than the year before both in the North Sea and at the west coast of Scotland. While the rg63 and rg64 year-classes are in these waters below average, the rg65 one is good and available data indicate that the same is the case with the rg66 one. In the southern North Sea, German investigations found the rg64 year-class to be good, and this was also the case with the rg66 one both in the North Sea and the Skagerak. In the western Baltic, where the stock of small whiting depends upon an influx from the north, the fluctuations in abundance are very great. It was obvious, however, that smaller quantities of the 0-group invaded the Kiel Bay in rg66 than the year before.
Blue Whiting Information from Soviet investigations in the North-east Atlantic is given on pp. rrg-r2r. Dense concentrations were found only in the southern part of the ?-Jorwegian Sea and west of Great Britain. Young fishes (r2-r6 em) were mainly found west of Spitsbergen and near the Hebrides; fishes of 35 em length were found south-west of Iceland and west of the British Isles. Large shoals of spawning and pre-spawning ones were found on the Porcupine Bank where spawning took place from the end of February with a maximum in the middle of March. Herring Reference is given to the Introduction chapter by professor G. HEMPEL on p. 122 f., and to the Appendix (pp. 215 ff.). -10-
Sprat This year information on English sprat fisheries only are available. A detailed survey of the development of those fisheries since 1958/59, with an analysis of mean length for age in different areas, and an account of the recruitment year by year to the Wash and Thames fisheries is found on pp. 185-191. Mackerel In later years, a Norwegian purse-seine fishery has developed in parts cf the North Sea and Skagerak. Some details on the development of the fisheries, taggings and biology are given on pp. 192-195. Six year olds were the most abundant age group in the catches in 1966. English taggings are reported on p. 195, Dutch ones on p. 197. In Dutch catches the 1958 year-class (8 years old) was still dominating; the 1963 year-class seems to be of moderate strength. Salmon and Sea-Trout Danish research in West Greenland waters is reported on p. 198, together with a summary of recaptures of fishes tagged in Canada and USA (II3) and Europe (17). British reports on investigations in some rivers include also tagging data. In this connection, reference is also given to the recently published "Report of the ICES-ICNAF Joint Working Party on North Atlantic Salmon, 1966" ('=::oop. Research Reports, Ser. A No.8). The German landings of salmon from the Baltic were the lowest since 1956. probably due chiefly to a change in the stock. A change of the gear used has at the same time lead to the catching of smaller fish than before, with a decline in the average length as a result. Tagging experiments show a tendency for salmon released in the Kiel Bay to migrate in a northerly direction, both towards the Kattegat and further, and towards the Baltic proper. There is this year a report on the development of the stocks of salmon in Latvian rivers during the last 10 years. The stock is at present relatively low. Redfish Danish tagging experiments at West Greenland is reported on p. 204. Soviet investigations in the Barents Sea show that young redfish had a more southern distribution than usual, and they were also found farther east. The 1966 year class was dominating, and young redfish were eaten in great quantities by cod in winter. Information on planktonic Sebastes larvae is given on p. 85. Plaice Dutch investigations in the southern part of the North Sea showed that catches were composed of different populations, and this made the age-group pattern somewhat difficult to interprete. In catches representative of the stock as a whole, however, the 1961 and 1963 year-classes were well represented. The recruitment of plaice to the western Baltic was poor in 1966, and catches have been declining, although they are still above the average for 1950-59. Sole Dutch catches of soles in 1966 showed the 1963 year-class to be very dominant in the catches (more than go% in the first quarter of the year). This unusual age distribution is thought to be an after-effect of the severe winter 1962/63. Others There are notes on halibut, capelin and lump sucker (p. 204), dab and flounder (p. 210), and lists from Iceland, Scotland, England and Germany on catches of rare fishes (pp. 2II-213). The only information this year on shellfish concerns Danish observations in \Vest Greenland waters. HANS TAMBS-LY,:HE PART I. HYDROGRAPHY
- r3-
Distant Northern Seas
Some Regularities in the Distribution of Phosphates and Oxygen in the Davis S:?rait Summer and Winter 1965 (Figures r-4; Tables r-6) Studies on the distribution of phosphates and oxygen throw light on processes of photosynthetical activity of phytoplankton, on its biomass in water layers and on productivity of various areas. The Davis Strait is situated in an area with a heightened primary productivity (rr) *, so studies on the distribution of biogenic elements in the Strait are of great interest to scientists. Soviet scientists (7) participating in the investi gations under the NORWESTLANT I in the period from ro. to 21. April r963 determined phosphate and oxygen concentrations. In the outlet from the Strait the concentration of phos phates varied in the surface layer between 0.5 and 0.75 fLg-at.jl, at the layer of roo m phosphates were stable at the level of r.o fLg-at.jl. Dissolved oxygen in the 0-m layer and in the areas with an intensified photosynthesis increased to 8 ml/1 in coastal areas making up 7.0-7.5 mljl in the cen 70° 60° 5QO tral part of the Davis Strait. Oxygen concentration Figure r. Hydrological stations on standard sections of the at the depth of room was J.O ml/1 on an average. Davis Strait. In April-May r963 English scientists studied the vertical distribution of phosphates and oxygen In April-June r963 German scientists found south of Greenland (4). that the increase of phosphate concentrations with During these investigations it was found that depth off West Greenland was more intensive in phosphate concentrations to the depth of roo m r955 than in r963, thus in r955 the content of remained on the level of r.o r1g-at.jl over an phosphates at the depth of roo m was 0.97 [Lg-at./1 extensive ocean area, the content of oxygen in the while in r963 it made up o.86 [Lg-at.jl. In r963 photic layer being 6.5-7.0 mljl. the expenditure of phosphates was more intensive According to data from Norwegian scientists in the 0-50 m layer while in r955 the decrease the concentration of phosphates off the West of phosphate (from the depth of roo m towards Greenland coast in April-May r965 varied from the the surface) showed a linear relation and smaller analytical zero (close to the Greenland coast) values of expenditure (3). to 0.5-0.75 fLg-at.fl. (in the surface layer of the Davis Strait) and between 0.5 and r.o [Lg-at.jl The distribution of inorganic phosphorus on (in the roo m layer). Section 8 a from the Wolf Island (Labrador) to The content of oxygen in the ro m layer in the the Cape Farewell (Greenland) observed in June same areas varied between 8.5 and ro.o mlfl and r962 shows that its concentration in surface layers between 7.0 and 7·5 mljl at the roo m layer (6). (o-200 m) reached 1.2 [Lg-at.jl increasing to In spring-summer r963 Canadian scientists 1.3 fLg-at.jl at a depth of rooo-2500 m (r). carried out investigations in the Baffin Bay and The material available clearly shows the found phosphates concentration in the upper occasional character of investigations carried out roo m layer varying from 0.25 fLg-at.jl (on the in the Davis Strait, the lack of data on seasonal surface) to 1.25 fLg-at.jl (in deeper layers). fluctuations in the content of phosphorus and The content of oxygen varied more, from 5.5 ml/1 oxygen and the fact that no general regularities in the east (in deep waters) to 9.0 ml/1 in the west were revealed in the vertical distribution of (in surface layers) (5). biogenic elements. This, however, is imperative *) References on p. 19. for the purpose of making perspective forecasts -14-
Table I. Comparison of phosphates content in various waters at different depths in 1965 Section ro A Section II A SectionS A SectionS A SectionS A Section q A Depth July 30. May-z. June June July December June A B A B C D E C D E D E D E o.69 0.2S o.q 0.71 0.66 o.so o.s2 LOS I. IS o.sr 0 ± ± ± + ± ± ± ± ± ± 0.04 0.00 0-34 0.003 0.06 o.oS 0.06 o.oS 0.04 0.04 0.0! 0.13 0.04 0.71 0.17 o.sz O.I6 0.76 o.6S LI I 0-73 0.67 o.69 , LIS o.s6 o.s5 20 ± + ± ± ± ± ± ± ::;:: ± 0.04 0.02 0.36 O.OI 0.06 0.02 0.06 0.13 0.06 0.02 O.OI 0.20 0.04 LOS o.6o o.6S o.S2 0.9s 0-74 0-97 o.S3 LII LI7 r.q o.S7 so ± ± ± + ± + ± + ± ± O.IO o.os 0.26 0.07 o.os 0.07 0.04 0.03 0.06 0.03 0.02 o.oz O.I6 0.04 LI9 LOS o.S7 0.96 o.S7 L03 LIO o.Ss !.12 LIO I.I2 LI9 0.94 LIO roo ± ± + ± ± ± ± ± ± + 0.04 0.06 o.os 0.04 0.09 0.02 0.02 0.04 0.06 0.02 O.OI 0.04 o.z6 0.03 L06 L35 LIS , LI3 LOO LI6 o.9S I.I6 r.z5 LI9 LI6 200 ± ::r: ± ± ± ± ± ± o.os 0.04 0.02 0.02 0.00 0.02 o.os 0.02 0.03 0.04 0.02 L32 LZ4 LIZ LZ3 LI4 !.22 1.32 LOI 1.24 soo _L ± ± ± ± ± _L ± ± 0.00 0.03 0.00 0.02 0.04 0.02 O.OI 0.00 O.OI L3I LI9 L25 1.36 I.OO 1.27 Soo _L ± ± ± ± + 0.04 0.00 0.02 0.04 0.00 O.OI 0 99-99-9% 99-99-9% <95% 9S-99% 95-99% <9S% <95% <9S% <95% >99-9% 99-99-9% <95% 20 9S-99% <95% <9S% <95% <9S% <9S% <9S% 95-99% so <9S% <9S% <9S% 95-99% <9S% <95% roo <95% 95-99% 9S--99% <9S% <95% <95% <9S% 99-99-9% >99-9% zoo 9S-99% 9S-99% 95-99% <95% soo <9S% <9S% >99-9% Soo 95-99% >99-9%
o.S3 0-35 o.s6 o.2S 0.76 o.6o o.n 0.64 0.66 o.6S I.IO I.I6 0.70 *) ± ± ± ± + ± ± ± ± ± ± _L ± 0.06 0.02 0.3Z 0.03 0.06 0.04 0.06 0.06 o.o9 0.04 0.03 O.OI 0.16 0.04 A - Canadian Current B- mixed West Greenland Current *) Weighted mean value in the o-som layer. C- cold West Greenland Current D - Labrador Current E - Atlantic Current for the hydrochemical conditions and primary Methods productivity of water masses in the Strait. In rg6s-rg66 sections in the Davis Strait were We made an attempt to study the seasonal investigated during the 49th cruise of the RV. fluctuations in the concentration of biogenic "Topseda", 23rd and 24th cruises of the RV. elements in the Davis Strait by comparing data "Sevastopol" and the rst cruise of the RV. in summer and winter, as well as to find the "Novorossisk". Figure r shows the location of general criterions to estimate the expenditure of stations on standard sections. phosphorus and generation of oxygen in the water Sampling of seawater to determine the content column during the photosynthesis. of phosphates and oxvgen was made with N ansen -15- Hydrography Dist. N. Seas
0.3 0.5 0.7 0.9 9 10
100
300
500
2 700
900 3 2 3 1 H(m) H(m)
Figure 2. Vertical distribution of phosphates and oxygen in summer (June-July, I965) on: I - Section Sa 2- Section Ioa 3 - Section I 3a
bottles from the following standard depths: o, 20, Preliminary estimation shows that fluctuations 50, roo, 200, 300,500, 8oo m and sometimes rooo m. in the concentration values are subject to the law Hydrochemical determinations were made in of distribution. accordance with instructions developed for the Correlation analysis can be made by the follow MGG programme (g). ing two methods: of correlation lattice and a The content of phosphates was determined by tabular one (with number of variants < 25). visual colorimetry analysis after the method of The correlation coefficient was determined by Deniges-Atkins from a sample of roo ml. A solution the following equality: of KH2P04 (o.68o g of KH2P04 in r l of water) was used as a main standard solution. Distilled water was used, and the concentration was 31 mg Pjm3 . Oxygen determination was made by the iodo where ~xy = (x · Y) -X1Y1 x =~n ·x metric method of ·WINKLER. Close attention was n 1 X paid to the statistical treatment of the observations, x2= ~nx·x2 to the derivation of certain mathematical relations ~xx= x2 -xi and to the estimation of correlation relationships. n Y1 = ~ny·y ~yy= :>'2 -y2 1 Series were compared by the method of "Student" Y2= ~ny·y2 n x-y t= where The mean-root-square error of the correlation m" 2 nx + ny vt(;i-~~):-~~~i-=Yl ------~--- was calculated by the approximate equality: 1-·~2 x and y are means of the two series compared, m'1] == v1~--! ~(xi -x)2 are sums of the squares of deviations, ~ (yi-:Y)2 To estimate the correlation coefficient the nx and ny are number of observations in the mequa. l" 1tv 'I ;;:, 3 was use d . series compared. " mY[ (ro) -I6-
a) b) c) 0.3 0.5 0.7 0.9 1.1 03 0.5 0.7 0.9 1.1 0.4 0.6 O.B 1.0 1.2 1.4 100
300
5 00
700 1 2 900 3 2 2 H(m) H(m) H(m) Figure 3. Vertical distribution of phosphates on Sections a) Sa, b) roa, c) 13a in winter and summer: r -December 1965 2- June 1965 3- July 1965
Average data on vertical distribution of phospha To characterize the content of phosphates in these tes and oxygen were subjected to further mathe waters, Sections 8a, Ioa, II a, I3a and I4a in June matical treatment with derivation of a correspond July I965 were made. The results of the observations ing relationship between the concentration of are given in Tabler. As is seen from Table I, reliable the biogenic element and its distribution in water differences to 0-4I [Lg-at.jl were registered in the layers: phosphate content of the surface layer on Section Ioa in the waters of the Canadian and West Green cp-fpo~ ± cr = 1 (h) land Currents. Marked differences to 0.36 [Lg-at./1 Co2= I (h) (z.8) are also observed in cold waters of the West Greenland Current and in the waters of the Labra dor Current. Phosphate Content Comparison of weighted mean values in the Content of phosphates and that of some other layer of active photosynthesis (o-so m) enables biogenic elements to a certain degree depend on us to make a supposition based upon these differen the hydrological features of an area and on photo ces. Apparently, in summer the change in the synthetical activity of warm- and cold-loving concentration of phosphates in water masses of forms of phytoplankton. different origin is conditioned by the intensity of the photosynthesis of the main groups of phyto It is known that movements of water masses plankton. of the Canadian, Labrador and East Greenland currents and of the cold branch of the West The unreliable character of fluctuations in the Greenland Current as well as movements of waters content of phosphates in the zoo-soo m layers of Atlantic origin may be fairly well traced in the in the cold, mixed and warm waters also proves Davis Strait. this suggestion. In Table I are given data obtained on Section 8 a Table 2. Phosphates content (in [Lg-at.jl) in the Davis Strait in December I965. As is seen from the correspond on sections roa and na in December 1965 ing columns of the table no reliable differences in IO a ua the content of phosphates were found in the Depth No. of No. of (m) observa- Cp-jpo~ ± cr observa- Cp-jpo~ ± cr tions tions Table 3· Phosphates distribution (in [Lg-at.jl) in the 0-50 m 0 s o.So±o.o3 5 o.So±o.o2 layer on sections Sa and roa 20 s o.S3±0.03 5 o.So±o.oz Month, 1965 Section Sa so s o.S3±0.05 5 o.S2±o.o2 Section roa roo 7 0.94±0.05 3 o.S6±0.02 June ...... 0,73 0.41 200 6 I.09±o.oS 3 !.04±0.03 July ...... o.6S 0.52 soo 5 1.33 ±0.03 2 1.22 ±0.07 December ...... 1.12 o.S3 Soo 2 I.35 ±0.03 !.34±0.03 January ...... r .oS - IJ- Hydrography Dist. N. Seas Table 4· Comparison of oxygen content in various waters at different depths in 1965
Section 10 A Section rr A Section 8 A Section 8 A Section 8 A Section 14 A Depth July July June July December June A B A B C D E C D E. D E D E 7.88 8.36 8-46 7.70 8.o6 7-47 8.o8 7-51 8.19 7-57 8.91 7.60 0 + ± ~' --·- -+ + :r: ± ± + 0. I I 0.13 o.ro 0.!2 0.!2 0,03 O.IO 0.23 O.IO 0.10 0.03 o.r6 0.07 8.24 8.19 7·76 8.36 7-45 7·74 8.44 7.00 8.19 7-38 7-56 _).. 20 I ' ± ::1: + + ± .,-' ::r: o.I8 o.o9 0.02 o.o8 o.q o.ro O.IO 0.21 0.14 0.08 0.02 o.r6 0.07 7-94 7-87 8.I8 7-90 7-63 7-90 7-25 7-40 7.66 7.1 I 8.rs 7-15 7-19 so ± + .,' ± ± ± +- _L ::r::' ± O.II 0.06 0.!2 o.q 0.20 o. r6 o.o5 0.08 0.02 0.22 o.o9 0.06 7.6r 7.28 7-90 7-I7 7-40 7-56 7-07 7-22 7-32 6.9+ 7-99 6.99 7·85 6.87 roo ± + +- ~ -L- ± ± o.o9 0.06 0.06 o.rz O.IO 0.06 0.06 o.r8 o.8r 0.0+ 7· 0 7 6.82 6.88 6.79 6.80 7-13 6.80 200 -1- + + ± ± o.I6 0.13 o.os O.IO 0.00 0.03 O.I4 0.06 0.05 0.2! 0.04 5·77 6.68 6. I I 6.70 6.52 6.60 6.6r 6.56 6.71 soo ::r::' --r' 0.00 o.os 0.00 o.os 0.00 0.06 0.03 0.04 0.05 7.02 6.62 6.39 6.6r 6.72 8oo ± ± ± 0.00 0.07 0.00 0.05 0 99-99-9% <95'% 99-99-9% <95% 99-99-9% <95% 99-99-9% 99-99-9% <95% 99-99-9% 99-99-9% <95% 99-99-9% <95% 20 >99-9% 95-99% >99-9% 99-99-9% <95% <95% <95% <95% <95% so >99-9% 99-99-9% 99-99-9% 99-99-9% <95% 100 99-99-9% 95-99%, <95% <95% >99-9% 95-99% >99-9% 95-99% 99-99-9% 95-99% 200 <95% <95% <95% 95-99% soo >99-9~1~) 99-99-9% <95% <95% 8oo <95% <95% 8.33 7-90 8.31 8.26 7.66 8.II 7-39 7·74 8.17 7-37 8.30 7-45 *) ~ ± -+ ± -r' ± ± :r' 0.13 0.09 0.05 0. I I 0.13 O.II o.o8 0.20 O.IO 0.09 0.02 0.18 0.07 A - Canadian Current B- mixed \Vest Greenland Current *) Weighted mean values in the o-50 m layer. C- cold \Vest Greenland Current D - Labrador Current E - Atlantic Current
Labrador Current and Atlantic waters in winter. content of phosphates in the 0-50 m layer may By December the concentration of phosphates in be due to the hydrolysis of organic remnants and the surface layer increased to r.o8-r.r5 tLg-at.jl. to vertical circulation in winter. In Table 2 are given results of observations on When comparing the southern section with a the content of phosphates on Sections ro a and more northern one, 8a and roa for example II a in winter. (Table 3), it should be noted that the expenditure As is evident from Table 2 there occurs an of phosphates in the o-50 m layer was more equalization of phosphorus concentrations in surface expressed on Section roa while other conditions and deep layers of the Strait. Increase in the were similar on both sections. - r8-
a) b) c) 7 8 9 10 11 6 7 8 9 10 6 7 8 9 10 100
300
500
700
900 2
H(m) H(m) Figure 4· Vertical distribution of oxygen on Sections a) Sa, b) roa, c) r3a in winter and summer: r -December 1965 2- June 1965 3- July 1965
Apparently, the more intensive expenditure of in all layers investigated on Section 8 a in the phosphates can be explained by more expressed waters of the Labrador Current and Atlantic development of cold water forms of phytoplankton waters. in the cold northern waters. Correlation between values of the content of phosphorus and oxygen (Table 5) in the o-rooo m Oxygen Content layer shows a close relation between these biogenic In the period of photosynthesis there is observed elements on all sections. an increase in the content of oxygen simultaneous Studies of the vertical distribution of phosphates with the fall in content of phosphates. and oxygen enabled us to reveal some regularities In June-July rg65 investigations were carried common to summer and winter and to represent out to study oxygen distribution in water masses them as emperical formulas. The most charac of the Davis Strait, observations were made on teristic types of their distribution curves are given the same sections on which the distribution of in Figures 2, 3 and 4· phosphates was studied. Results of these investiga Figures 2 and 3 clearly show that in summer the tions are presented in Table 4· content of phosphates gradually decreases from As is seen from Table 4, reliable differences in the the surface to the depth of 50 m, in deeper layers content of oxygen in the o-m layer were registered the decrease of ions of phosphoric acid becomes a only when extremely different water masses were linear function of the depth. compared, for example cold waters of the Labrador In winter the concentration of phosphates by Current and waters of Atlantic origin. As a rule layers can be expressed by a linear function. An these differences disappear with depth. In winter, anomaly is observed in the oxygen content (Figure reliable differences in oxygen content are observed 4) in the upper o-50 m which indicates either an intensified hydrolysis with oxygen consumption Table 5. Correlation indices between phosphates and oxygen or undersaturation with oxygen depending on in the o-1000 m on some sections of the Davis Strait 1965 characteristics of the current in winter. Section, Yj ±m·c, Equation of cr cr max Month relationship It should be noted that in summer the content of phosphates regularly decreases from the northern Sa, Dec. o.S2±0.04 02= I.OI P-S-46 ±o.S9 :r:' 2.67 Sa, June o.Sr To.o3 o2 =o.73P-S.o5 ±I.02 + 3-06 sections to southern ones, while the content of Sa, July o.65±o.o6 o2 =0.43P-7.55 ±I.79 ± 5·37 oxygen in the photic layer increases synchronously roa, Dec. ..L o.SS±o.o3 o2 =o.S2P-7.67 ±r.rs ..L. 3·45 in the opposite direction. roa, May o.S9±o.o3 o2 = 0-49 P-S.oS ±0-43 ± I.29 roa, July 0.60±0.07 o2 =o.3oP-7.74 ±2.9S ± S.94 In Table 6 are given empirical equations derived rra, Dec. 0.91 ±o.o3 o2 =o.62P-7.82 ±L4I ± 4-23 from the curves of the distribution of phosphates rra, June o.S5±o.o3 o2=o.36P-7.78 ±2-36 ± 7-0S and oxygen by depth which characterize their 13a, o.S8±0.02 o =o.3r P-7.55 June 2 ±2-44 ± 7-32 vertical distribution in the summer and winter r3a, July o.78::'::o.o8 o =o.79P-S.26 ±3-76 ±rr.rS 2 of rg65. qa, June 0.73 ±0.04 o2 =0.29P-7-47 ±2.62 ~ 7.86 -H)- Hydrography Dist. N. Seas Table 6. Empirical equations of curves of vertical distribution of phosphates and oxygen
Phosphorus P/Po4 [Lg-at.jl Oxygen 0 2 ml/l Depth for Depth for Section, which the which the month formula is Formula formula is Formula used (m) used (m) SA December, 0-IOO y 1 = I.120 + 0.0003 • X ::i::O.OO ro-200 y 1 = 942.S · x-1.270 + 7.So9 ±0.04 I965 zoo-Soo Y2= I.2I3 + 0.0002 ·X ±O.OI 2oo-Soo y 2 = 6.953 -o.ooo7 · x ±o.or SA January, o-soo y = r.oSs + o.oooo6 · x =~0.02 I966 36-354 SA July, I965 20-Soo y 0.370 xOA07 + I-442 :_::0.02 zo-Soo y = 6.541 =0.15 X
44-222
x o.4sa "-~--- SA June, I965 20-Soo y 0-336 T I -370 c::o.oo zo-Soo y = 6.595 ±0.23 + X
SA June-July, X 40.177 ±0.19 zo-Soo y = -!co.oi 20-Soo y 6.5S1 'T I965 I = r6.r75 T 0.7S4 X X
Io A December, X o-soo y o.Sro + 0.001 X =.::o.oz 50-710 y = ±0.12 I965 -1.649 + o.15S · x X Io A June, 1965 2o-6S7 Y= zo-6S7 y = 10.04. x-O.lS3 + 3-039 ±0.10 37.IS4 + o.6So ·X
X Io A July, 1965 2o-6Sr y = ------:J:o.os 20-704 y = o.S345 . x-0.199 + 10-447 ±o.os 27.I53 + 0.667 'X IO A June-July, X zo-soo y = - -- :2:0.05 20-694 y = o.os4. x-0.031 + 2S.S95 ±o.os I965 36-97S + o.66o · x II A 30. May to 2. June, I965 20-Soo Y = o. I+ I . x0.548 + L494 ±o.o4 20-Soo y = 13.22 . x-0.537 + 6.093 ±0.23 496 I3 A June, I965 20-Soo y = 0.209 · x0· + 1.429 ±o.o1 20-Soo y = I0.49. x-0.572 + 6.304 ±o.oS I3 A July, I965 20-Soo y = 0.270 · x0·139 + 2.9IO ±0.03 20-Soo y = o.o36 . x-o.o1s + 37-30 ±o.o6 I3AJune-July, 196520-Soo y = 0.244. x0.430 + I.S04 ±o.or 2o-Soo y = 7-034. x-0.401 + 6.017 ±o.os
In the same table are g1ven values of errors a more detailed analysis of the processes related arising while using the formulae. to the productivity of the photic layer and will An analysis of the curves (Figures z, 3 and 4) serve as a reliable basis to forecast the reproduction as well as the functions of Table 6 show that the of primary substances in the sea. decrease of phosphates and generation of oxygen V. S. ZLOBIN, M. F. PERLYUK, is observed mainly in the photic layer. As a rule N.G.SAPRONETSKAYA the content of oxygen and phosphorus in layers PINRO, 6 Knipovich Street, Murmansk, 'CSSR. deeper than rso ill is independent of the season. References Reliable differences in the concentrations of biogenic elements are observed only in extremely r. CoRWIN, N. & D. A. :YlcGrLL, 1963. "Nutrient distribution in the Labrador Sea and Baffin Bay". Woods Hole, different water masses. As a rule mixed waters Collected Reprints, Contr. 1370. are characterized by mean values of concentration 2. DEMIDOVICH, D. P., I. A. MARON & E. Z. SHUVALOVA, of phosphates and oxygen as compared with cold 1962. "Numerical methods of analysis". Fizmatgiz, and warm water masses. Moscow. 3· GrLLBRIGHT, :YI., 1964. "German national report. B. Plank In winter the differences in the phosphorus ton. b) Phytoplankton". ICNAF. Ann. Meet., 1964. content between extremely differing water masses Doc. No. 23, Serial 1318. disappear. 4· LEE, A., J. CORLETT& J. FRASER, 1964. "U.K. National Report" NORWESTLANT Surveys 1-3, April to July. Analytical expressions of correlation relation 1963. ICNAF. Ann. Meet., 1964. Doc. No. 27. Serial 1322. ships of phosphorus and oxygen as well as functional 5- Pu.TFORD, R. F., 1964. "Preliminary Report on the Ca relations found in the vertical distribution of nadian program on chemical oceanography". ICNAF. biogenic elements allow us to make in the future Ann. Meet., 1964. Doc. No. 55· Serial 1351. -20-
6. H.eport on i'orwegian Participation in ~ORWESTLANT, 9- STRICKLA;">;D, J. H. D., I957· "Standard methods of sea April 1963. 1C~AF. Ann. :Vleet. 1964. Doc. ~o. 25. water analyses". Fish. Ecs. Bel. Can. Pacific Oceanogr. Serial 1320. Group, I. 7· l{ossov, V. V., A. G. KrsLYAKov, E. N. VoRONTSOvA & ro. URBAKH, V, Y., 1964. "Biometric methods". ~auka, E. A. PAvSTIKS, I96+ "Eeport on the USSH. partici 1\Joscow. pation in the investigations under the NORWESTLANT I I. YOLKOVI:-ISKY, Y.V. & 1\f.V. FEDOSOY., I96+ "Formation program in 1963". IC~AF. Ann. :Vleet., 1964. Doc. ~o. 26. o£ the primary production in Antarctic waters". Serial r 32 I. Okeanologicheskie issledovaniya. Sbornik statci. Hazclcl 8. EUDNEv,K.:\I.&N. E.PALY, 1964.''0ceanographic methods programmy :\IGG (13), '\[osCo\\·. 115-22 pp. in fisheries in ,·cstigations''. ATLANTN1 H.O, 1\:aliningrad.
Danish Hydrographical Observations in West Green 1958). Surface temperature and salinity were land Waters rg66 recorded continuously during the cruise. Due to Like in previous years "Adolf Jensen" and the length of this survey, from 12. August to "Tornaq" have made annual observations especially 2. September rg66, the data cannot be regarded in ICNAF Division rD. "Dana" carried out as completely synoptic. However, the data presented hydrographic work from the end of June to the in the Figures 5 and 6 were obtained from continu beginning of August in the Irminger Sea and ous runs towards and from the coast, moving in the Davis Strait. The hydrographic material is gradually to the south. Over small stretches, treated by Mr. FREDE HERMANN. therefore, the data may be regarded as quasi synoptic. Temperature observations at the entrance to the Godthab Fjord showed a special strong inflow From the data the following features may be of warm water near the bottom in November and observed: r) A narrow limit between cold an slightly saline January. The winter rg65-66 was unusually mild and no temperatures below zero were observed East Greenland water, and warm and highly in the surface. In the first months of the year saline Atlantic water exists. This limit is the the temperatures were above normal. Later the so-called Polar Front. temperatures were normal. 2) Temperature and salinity show essentially the same course of the Front. In the Davis Strait the temperatures were rather 3) Some meandering can be observed in this Polar high in the deep water west of Fylla Bank. In Front, but due to the large difference in time July very high temperatures were measured in not much significance can be attached to these depths below 300 m west of the fishing banks. For meanders as far as the total course of the Front instance temperatures of more than 4.5°C were is concerned. found north of Store Hellefiske Bank. In Disko 4) A good correlation seems to exist between the Bay temperatures about 3.5°C were measured on general course of the Polar Front and the edge the prawn grounds. It is I.5° above the normal of the shelf as represented by the line of rooo temperature. metres depth in the figures. There seemed to be an inflow of cold Polar 5) The course of the Front seems to be a continua water in the southern part of the area in August. tion of the Polar Front as reported by DIETRICH P.M. HANSEN (rg58). Gronlands Fiskcriundersogelser, 6) A good correlation is apparent between the Jxgersborgalle r B, Charlottenlund, Denmark. location of the Polar Front and the course of the main body of the East Greenland Current The Oceanic Polar Front in the Waters off the East as reported by DIETRICH (1957). Coast of Greenland in August rg66 G. DIETRICH, J. M. GIESKES (Figures 5-6) 1nstitut fi.ir '\Icercskuncle dcr Gniversitat Kicl In the summer of rg66 a cruise was made with Hohenbcrgstrasse 2, Kiel, Germany. R. V. "Meteor" along the East Coast of Greenland, References mainly for a survey of the bottom topography DIETRICH, G., 1957. "Schichtung unci Zirkulation der of this region. It consisted of go cross-sections lrminger See im Juni 1955". Ber. clt. wiss. Kommn :\Ieeres- forsch., 14 (4). normal to the shelf edge at a distance of 3-4 DIETRICH, G., 1958. "The Oceanic Polar Front in the nautical miles. This cruise was similar to a survey waters round Greenland and Iceland in August 1956". by R. V. "Gauss" in August rg65 (DIETRICH, Annis. bioi., Copenh., 13: 33-4- -21- Hydrography Dist. N. Seas
II I 530
~~iL------7~~~~------t------~60° N
Figure r. Surface temperatures along the Greenland coast - August rg66. -22-
Figure ~ Surface salinities along the Greenland coast - August rg66. -23- Hydrography Dist. N. Seas
69~r5_o-,---,--,--,--~2ro_o-,----,---,--,---IT5_o--,-~--,--,---ITO_o_,_--,--,--,--~5o
l°C,20m 4-11/6,1966 0 30
0 68° 0 0 40 zo 0 50 60 0 0 • 0 0 0 l<
0 ./e\ I > 5 o\
• HYDROGRAPHIC STATION
o BT STATION
Figure 7· Temperature, 20m- June rg66.
25° 20° 15° I 0° 5° 69°r--,---,--,,--,--~-~--,--,---,-~~-,---,--,--r--~--,--,--,---,-~
S%o,20m 4-11/6, 1966 •
68°
···················· ...
. ·· ... ·.""' . 34.6
.· .. • !• "~~,~~~. 347 ··... <34.4 >34.7
Figure 8. Salinity, 20m- June rg66.
Hydrographic Conditions in Icelandic Waters drift-ice limit and the distribution of temperature in June rg66 and salinity at zo m. Figures g-II show the (Figures 7-13) vertical distribution of temperature and salinity A hydrobiological survey was carried out in the (in sections) off Kogur, Siglunes and Langanes-NE waters north and north-east of Iceland during (for location see Figure 7). Figure rz shows the 4.-II. June. Figures 7-8 show the location of location of the 0°C isotherm at 50 m. Figure 13 the stations (hydrographic and BT stations), the shows t-S diagrams for all hydrographic observa- 24-
ST 25 26 27 28 29 30 0 m . 30 . zo
100
-/0 !" '- ;o oo
300 t° C 4/6, 1966
400 0 n.m. 50
26 27 28 29 30 342 0 . m .
>35.1
200
300 4/6, 1966
400L-_____J ______L ______~----~L------L~----~------~----~~ 0 n.m. 50 Figure g. Section north-northwest of Kogur a) Temperature, b) Salinity. tionsin theuppermost zoom (with temperatures be and rzoW (Soviet observation). Thus, drift-ice low 2° C) within latitudes 67 to 69oN and longitudes was farther off the Icelandic coast than normally II to I5°W made in June in the years 1950, 1952, found. 1953, 1954, 1955, 1956, 1957, 1958, 1964, 1965, and In June a tongue of Atlantic water WC > 4°; 1966, in July 1948 and 1949 and in August in 1951. S Ofoo > 35 Ofool had reached the area off Skagata No hydrographic observations were made in the (zo 0 W), and the temperature and salinity distribu above-mentioned area in the years 1959-63. tion off Kogur was about normal. In the coastal The main features of the 1966 hydrographic area from Siglunes and eastward along the North conditions were as follows: Coast, the North Icelandic Winter Water WC = The drift-ice was observed at 67°45'N and 1-3°; S Ofoo = 34.8-34.9 Ofoo) dominated through 24ooo'W (75 n.m. NNW of Kogur) and at JI 0 N out the water column. Temperatures in the surface -25- Hydrography Dist. N. Seas 41 42 43 44 45
500
5-6/6, 1966
0 n.m. 50 100
40 41 42 43 44 45 0 . . : . m : . :34.8 . . 34.6 • 347~ /'9 34.8~ ~ 34.9- >34.9
500
S 0/oo 5-6/6, 1966
0 n.m. 50
Figure ro. Section north of Siglunes a) Temperature, b) Salinity. 55 56 57 58 zo 100 1%2· z
54 56 58
34.6 -....___:______
34.7 34.8--..---
200 34.9~
300L_____ L_ ____ L_ ____ L_ ____ ~~--L-----L_ ____L_ ____ L_ ____ L_ ____ L_ ____ ~----~----~----~--' 0 n.m. 50 100 Figure I I. Section north-east of La.nganes a) Temperature, b) Salinity.
2 •• 1948-1958 •• D \ 0 1964 1965 0 • 'e- • 1966 • o• r•c • ·~ 67° • d- o:> o•c ISOTHERM, 50m •• c 5-11/6, 1966 0 0 d -i 0 • co• • • 0 0 • • • J_• -I • Figure I2. The position of the 0°-isotherm at 50 min June • • ••• 1966. •
layers ranged from 3 to soc and 0 to 3oC in the -2.~----~----~~----~~~ deeper layers, which is approximately r 0 below 33.5 340 34.5 350 s %. normal. The surface layers were r--2° warmer Figure I3. t-S diagrams at 67-69°Njrr-I5°\Vin June I950, than in rg6S but the deeper layers about ro colder. 1952, 1953, 1954, 1955, I956, I957, I958, I964, 1965, 1966; In the oceanic area north-east of Langanes the in July I948-I949 and in August I95I. influence of the cold East Icelandic Current was more pronounced than normal, with temperatures with the exception of those in rg6s. The southern below - r°C at roo m, whicb are the lowest boundary of the 0°C isotherm at so m was in values found in this area during the period rg48--66, June rg66 located about 30. n. m. farther south -27 Hydrography Dist. N. Seas than the average for the period rgso-6o. In the 10 t-S diagrams shown in Figure 13 all observations made in the years 1948-58 were found within a relatively narrow range, with salinities between 0.2 34-72 Ofoo and 34-92 Ofo0 , but during the years 0+-~----~==~~~~--~~------ rg64-66 there has obviously been an increase of -0.2 the Polar water component in the Arctic water of the East Icelandic Current. This is indicated -0.6 by salinities of 34-5-34-7 Ofoo or even lower, as -1.0 found in 1965 (MALMBERG, 1967). On the whole it can be concluded that in the first -1.4 half of June rg66 the temperatures in the upper most zoo m north and north-east of Iceland were 1960- 1962 -<>- 1964 -·-· 1965-- 1966 ..,_ below normaL The Atlantic influx north of Iceland Figure q. The eastern branch of the Norwegian Current, was abnormally low and the extension of Arctic June, o-200 m layer. F.S. = The Faroe-Shetland ChanneL water north-east of Iceland was abnormally high. S. A. MALMBERG The data obtained in February on the section Hafranns6knastofnunin, Skl!lagata 4, Reykjavik, Iceland. along 65°45'N and 67°30'N are insufficient to calculate the mean. The temperature of the eastern References and western branches of the Norwegian Current :\lALlV!BERG, Sv. A., 1967. "Hydrographic conditions in was also lower than in rg65. Icelandic waters in June 1965". Annis. bioi., Copenh., 22: 17-23- In March rg66, the water temperature on the STEFANSSON, U., 1962. "North Icelandic \Vaters". Rit. Fisk section along 63ooo'N was higher than in March ideildar, 3- of the cold years rg63 and rg65. Though the o-zoo m layer of the Norwegian Current was characterized by a small positive temperature anoma Water Temperature of the Norwegian Current ly, a great negative anomaly of 0.56° remained in rg66 in the zoo-soo m layer (Table g). (Figure q; Tables 7-11) In January rg66, the average temperature of Table 7- Average temperature anomalies of the Norwegian the o-zoo m layer of the Norwegian Current on Current along 63°00'N in January 1959/1966 the section along 63ooo'N was 0-40° below the Layers in m o-50 0-200 200-500 mean calculated for the eight-year period I959/Ig66 Date 6 yo 6 yo 6 yo (Table 7). The negative anomaly, thus, proved to be 22.-26. January 1966 -0-47 -0-40 -0.12 the greatest over that period. A cold "temperature 18.-22. January 1965 -0.11 -O.II +o.53 10.-q. January 1964 -0.15 -0.18 +o.os wave" had reached the central Norwegian Sea by 16.-20. January 1963 -0.20 -0.21 -0-49 June, and the rate of anomalies' transport amounted 18.-21. January 1962 +o.o6 +o.oz -0.21 to 3 miles a day. 1.- 5- January 1961 +0-49 +o.sr +o.zs 7.-15. January 1960*) +o.Sz +o.55 +0.19 In the middle of January rg66, the negative tem 16.-22. January 1959 -0-41 -0.21 -0.20 perature anomaly, its absolute value being less Mean 7-74 7-70 5-89 than in the southern sea, occurred at 67°30'N in the eastern branch of the Norwegian Current. Table 8. Average temperature anomalies of the Norwegian The temperature of the East-Icelandic Current Current along 63°00'N in February 1959/1966 was in January rg66 0.2° above that observed in Layers in m o-50 0-200 200-500 the cold rg65. Date 6 yo 6 yo 6 yo In February rg66, the Norwegian Current at 18.-20. February 1966 -0.18 -0.22 -o.66 63°oo'N was also the coldest in the period. 14.-16. February 1965 *) -0.10 -0.19 -0-42 Temperature deviations from the February mean 5-- 9- February 1964 -0.02 -o.o6 -0-31 11.-15. February 1963 -0.14 -0.10 -0.21 (Table 8) were -0.22° and -o.66° in the o-zoo m 3-- 4· February 1961 +o.15 +o.29 +o.44 and zoo-500 m layers respectively. A sharp 7.-15. February 1960 +o.42 +0-34 +0.27 cooling of the whole water strata indicated a 13.-15. February 1959 -0.10 -0.09 +o.87 considerable decrease in the heat advection by Mean 7-50 7-46 5-77 the Norwegian Current. *) The means are interpolated -28-
On the sections along 65o45'N and 67o3o'N the Table 9· Average temperature anomalies of the Norwegian temperature anomaly of the eastern branch in the Current along 63°00'N in March 1959/1966 o-200 m and 200-500 m layers did also turn Layers in m o-so 0-200 200-jOO Date To To To out to be negative. The waters of the western 6 6 6 II.-17. March 1966 -j-0.17 ·f-O.I I -0.22 branch were o.8° and 0.2° colder in the o-200 m 8.-q. March r965 -0.30 --0.32 ---0.96 layer of the same latitudes than in March 1965. 5-- 8. ~larch 1964 *) +0.27 ..!..0-33 - 1-0.67 24--27. March 1963 --0-40 -0-43 -I.04 The deviation of the average temperature from zo.-zs. March 1962 --0-44 --0.25 -0.25 the mean in the o-200 m layer of the eastern I6.-I8. March I96o -f-0.)7 +o.38 .J-0.41 branch in 67°30'N amounted to -0.72° in April I I.-IS. :\I arch 1959 -i-0.23 -f-0.27 -!-- 1.20 1966 (Table 10). In JanuaryjAprilrg66, the absolute :\Tean 7·43 7-27 5- 2 4 value of the negative temperature anomaly of the Table 10. Average temperature anomalies of the Eastern eastern branch in the 0-200 m layer was consider Branch of the Norwegian Current along 67°30'N in April ably greater on that section (than at 63°00'N 1959/1966 Layers in m o-50 0-200 and 65°45'N) where the cooling of the water was To To more intensive. Date ro.-17. April 1966 ...... --0.59'"' -0.72 Consequently, a sharp cooling of the whole basin 18.-23. April 1965 ...... ·--0. 72 ···--0.69 in the winter/spring period of 1966 resulted from q.-19. April 1964 -'-0.23 _L0.3I ----o.r.; both the inflow of very cold waters from the south I0.-17. April 1962 ...... ---0.27 28. April-2. :\Iay I96I ...... L0.37 -j-0.34 and anticyclonic weather being predominant over 27.-28. April I96o ...... +o.SI -!··0.82 the whole Norwegian Sea from January to April. 24.-25. April I959 ...... -,-o. rS ..!..0.09 In the southern sea waters were less cooled than ?vi can 6.so 6.y) in the central and northern areas. Table rr. Average temperature anomalies of the East-Ice Waters flowing in May 1966 into the Norwegian landic Current along 65° 45'N in November 1959/1966 Layers in m o-so 0-200 Sea through the Faroe-Shetland Channel had the 0 Date 6 To 6 T lowest temperature for the period since 1959. 20.-27. :"\ovcmber I966 ...... -0.33 ··-0.25 In May, the lowest temperatures were observed 26.-28. Xovember I965 ...... --0.89 -0.83 in the eastern branch of the Norwegian Current 26.-29. November I964 ...... -0.69 ---0. I I q.-2r. November I962 ...... -0-40 -f---0.02 on the sections along 65 ° 45'N, 67o3o'N and 69°20'N I2.-I9- November I96I ...... -i- r.og -[-o.58 from 500 m up to the surface. In the western 26.-27. November I96o ...... -f-I.I7 -1-o.;z branch, however, a certain rise of the water 27.-28. November I959 ...... -~o.os ----0.12 temperature, especially in the 200-500 m layer, ?vican ...... 4.20 3· I r was appreciable. Thus, the average temperature of *) The means arc interpolated the 200-500 m layer in the western branch and -0.9° on the section along 72°5o'N in the 200- in mixed waters was 0.5° to 0.6° higher at that 500 m layer. time than in the warm 1960. The temperature of Waters with the positive temperature anomaly the East-Icelandic Current increased simultane in the o-200 m layer (0.47°) were observed in the ously. Norwegian Sea only in the Faroe-Shetland Channel. In June 1966, the temperature anomaly of the In the middle of June 1966 the influx of waters eastern branch of the Norwegian Current on the to the north across the Channel proved to be section along 63°0o'N 65° 45'N and 67°3o'N was considerable and amounted to 18.23 km3 per hour. close to the mean in the o-50 m layer, and was In June 1966, the temperature anomaly of the -0.2° or -0.3° in the o-200 m layer. The influx western branch of the Norwegian Current was of warm waters to the north across the section close to the mean only on the sections along along 67o3o'N amounted to 13.52 km3 per hour 65° 45'N and 67°3o'N in the o-50 m and o-200 m in the first half of June and was the same as in layers. The average temperatures of the western cold years (the 1000 m level was taken as the zero branch on the sections from 69°20'N was 0-4 to surface). I.1° below the mean, and thus proved to be the The negative anomaly was sharply rising north lowest over the whole period investigated. wards from 69°2o'N to 78ooo'N. The temperature In June 1966, the negative temperature anomaly anomaly of the eastern branch on the section along of the whole water strata was typical of the thermal 72°5o'N was -0.93° and -r.18° in the o-50 and regime of the Norwegian Sea and its branches, o-200 m layers respectively (Figure 14), and ranged except the southern part of the sea, where the between -~0.2° on the section along 65°45'N and temperature was somewhat above the mean. -29- Hydrography Dist. N. Seas On the Cape LanganesjJan JVIayen section the Current were warmer (0.56° in the 0-50 m layer temperature of the northern branch of the Irminger and 0.58° in the o-200 m layer) than in the same Current rose considerably against rg65, but the period of rg65. The temperature anomaly of this temperature anomaly remained negative and made current was -0.25° in the o-200 m layer, whereas up -O.J 0 in the o-200 m layer. The waters of the in November rg65 it was -0.83° (Table II). East-Icelandic Current were also warmer in all InN ovember rg66, the temperature of the eastern the sections. branch in the section along 67°30'N was 0.5° and In July rg66, a further fall occurred in the that of the western branch o.8° lower than at the temperature of the eastern and western branches same time in 1964. of the Norwegian Current (0-4° to 0.7° in the In December rg66, waters with low temperatures central sea as compared with the previous cold were transported into the Norwegian Sea through years). The chilling of the northern Norwegian the Faroe-Shetland Channel. The mean temperature Sea was especially pronounced, and the temperature of the 0-200 m layer in this channel was found anomaly there was -I.6°. to be the lowest for the period under investigation. The temperature of the East-Icelandic Current Thus, in the autumn-winter months of rg66 the in the o-200 m layer was 0.3° to o.8° lower than temperature anomaly of Atlantic waters remained the last years and that of the northern branch of negative as before, but its absolute value rose the Irminger Current was too low for that month somewhat as compared with those of the summer (it was r.6 to 2.1 lower than that registered in rg6o anomalies. The temperature anomaly of the East and rg64). Icelandic Current being below the mean, its value On the whole, the heat content of the waters was less than in previous months. in the Norwegian and Greenland Seas was low in the summer of rg66. Only in the extreme south V. V. PE)!E, L. R. SoLONITSI::-IA of the sea a certain rise was encountered in tempe PlNEO, Knipovich Street 6, Murmansk, 1' S S R rature and salinity of the waters of the Norwegian Current in comparison with the last year and the Thermal Conditions in the Barents Sea in rg66 mean. The hydrological conditions of the western Nor (Figures 15-20; Tables 12-13) wegian Sea in the autumn of rg66 were characterized In the winter of rg65-66, eastern winds prevailed by relatively high water temperatures, while great over the Barents Sea and air temperatures were negative temperature anomalies were found in the on an average 4-8° beneath normal. The distribu same months of rg65. tion of temperature on the surface and near the In October rg66, the o-200 m layer of the East bottom was similar to that in abnormally cold Icelandic Current on the Jan JVIayenjCape Langanes years. section of those along 67o3o'N and 65o45'N was In January, the boundary of relatively warm warmer than in October rg65 by 0-36°, o.67o and waters (with a temperature over 2°C} in the o.87o respectively. bottom layer ran along 35°E, the most western The o-200 m layer of the eastern and western position observed during 25 years of investigations. branches of the Norwegian Current on the section The stream of the warm JVIurman Current in the along 65o45'N was, on an average, 0.8° cooler as eastern sea was outlined by the I 0 -isotherm. compared with October rg65. Figure 15 illustrates the position of the 2°-isotherm In 65°45'N the waters of the East-Icelandic on the bottom in various years.
Table 12. \Vater temperature anomalies in the o-200 m layer on standard sections of the Barents Sea in rg66 Sections Months Jan. Feb. '\Tar. Apr. :\'lay June July Aug. Sept. Oct. Nov. Dec. North-Cape/Bear Island (J1°33'N 25°02'E- 73 o3s'N 20° 46'E) ...... -I. I -r.s -r.s -r.s -r.G -I.+ -0.6 -0.3 -o.; -o.g -0.] -o.s -I.O East of the Bear Island along 74°3o'N (26°50'- 3I 0 2o'E) ...... -I.O -1.0 -1.3 -!.6 -I.+ -0.] -0.+ -o.s -0.+ -o.; -o.g -o.g Along the 1\:ola Meridian (70°3o'-72°3o'N) ...... -1.2 -1.2 -1.4 -r.s -r.6 -1.3 -I.+ -1.3 -1.3 -r.; -I.+ -I. I -I.+ Kharlov section (68°51'N 37°2o'E-69°39'N 38oo4'E) -!.5 ice ice ice -2.3 -2.0 -2.4 -r.S Kharlov section (69°39'N 38°0-f'E-71°0-f'N 39°25'E) -1.3 icc icc ice -2.-f 2.2 2.0 I.3 30" 40" 49° (Figure r6 b) .The vertical distribution of temperature in winter on standard sections of the Barents Sea is shown in Figure rg a, b, c. Thus, due to sharp cooling of the water and to \ slackening of the heat influx from the Norwegian \. Sea, the general thermal conditions in the Barents " . " .. Sea in January--April happened to be the lowest '" · ...... \ _,....) : for the last 30 years. Negative anomalies of water \ I : ~ I . temperature all over the sea in winter were about ( : \ . r.so (Tables rz and 13). (_) In summer, eastern winds prevailed over the Barents Sea, the air temperature wac: z--6° 0 (in May--June) and I (in July--August) below normal. 68"30''------~-----l--~~----~~~----~ The seasonal rise in surface water temperatures Figure 15. The position of the 2°-isothcrm near the bottom was more intensive than usual. However, the in January. temperature in the active o--so m layer remained ..... mean years, ----- 1963, ----- 1966. far beneath normal, except for the south-western part In December--April, weather conditions led to of the sea where in July--August it was very close to a very intensive fall of water temperatures in the the long-term mean (Table 13). In the period of the Barents Sea. In April the surface temperature most intensive warming up in summer, the distribu reached its minimum and the edge of floating ice tion of water temperatures at the surface was was found at an extremely western position similar to that in ·reasonably cold years. This (Figure r6a). In May, the extension of the area fact is fairly well illustrated by the position of with relatively warm waters was markedly reduced. the 8° -isotherm during a number of years. (Figure Bottom water temperature recorded in the southern 17). In the summer, there was more drifting ice sea in the same period was 2° lower than in the in the Barents Sea than normal. The northernmost reasonably warm rg6o and its distribution over position of the edge of the ice was recorded in the area was similar to that in the cold year rg63 October.
Fit;urt: r6. The Position of the edge of ice and the distribution of water temperature: a) on the surface in April 1966; b) on the bottom in ::viay ----- rg6o, ----- rg66. 31- Hydrography Dist. N. Seas 30° .::,.a· 49" Sea was characterized by an intensified inflow of 74. cold waters of the Nadezhdinsko-Medvezhinskoe "' \ Current. Waters with a bottom temperature below roC extended as far as to J2°N. Warm Atlantic \ waters were met with close to the Norwegian \ shore and formed a somewhat warmer belt along \ the Continental Slope. Vertical distribution of water temperatures on the sections in the Barents 7'2: Sea in summer is shown in Figure 19 d, e, f. Thus, in spite of relatively intensive heating (due to solar radiation) of the surface layer in July to early in August the temperature in the '--- ....._ o-zoo m layer was considerably below normal on all standard sections, with the exception of the section North Cape/Bear Island where negative anomalies fell to 0.6 to O.J 0 (Table rz). In autumn-winter, the seasonal decrease of
6s·~------''-----"---_L_-----"'="'------' water temperature in the Barents Sea was irregular 30' and more intensive than in September-October. Figure I7. The position of the 8°-isotherm on the surface \Vater temperatures on the surface in October in August...... 1960, ----- 1963, -.-.-. 1964, --- 1966. was on an average 3-4° lower than in the cold 1963. Drifting ice in the Barents Sea was much Bottom water temperatures remained very low more abundant than usual, the edge of the ice at that time and corresponded to the temperatures being found 6o-8o miles further to the south observed in the coldest years. In July, the stream than usual. (Figure zo a). of the warm Murman Current into the eastern sea In the autumn of 1966, the distribution of was outlined by the 0°-isotherm. The boundary temperatures near the bottom was similar to that of waters with a temperature above 2°C was in the most severe years (Figure 20 b). In the area along the Kola Meridian. The water temperature in of the Bear Island cold waters penetrated 40-60 a narrow coastal zone increased slightly (Figure r8). miles further to the south-west than in the cold The hydrological regime in the western Barents 1963. In the Western Deep waters with a tempe-
Figure rS. Distribution of water temperatures near the bottom in July 1966. -32-
9 8 7 6 5 9 s 7 6 5 4- 3 2 rvvI\ L .
. 200
250
300
A D
4DO- l_l ~.0 ~ na ut. -miles ~ 34- 5 6 7 g w 11 12. ~3 1~ 2. 14- I 0
0'
j• -150
200
-250
-300 8 E
~0 -na.ut.mifes ~0 na1.1t. mdes 4oo 11 10 g 8 7 G 5 4 3 2. 11 iO 9 7 6 5 4
Figure rg. Vertical distribution of water temperatures on sections: North Cape/Bear Island: A -in winter, D-in summer; East of the Bear Island along 74°3o'N: B-in winter, E- in summer; Along the Kola :vreridian: C - in winter, F--in summer. 33- Hydrography Dist. N. Seas/Near N. Seas
20° 30° 400 ~oo 30° 40' 2.0 7S' A B
Figure zo. Ice edge position and distribution of water temperatures in October: A) on the surface; B) on the bottom. rature above roc were registered only to the Bear (Tables 12 and 13). Island latitude, whereas in 1963, they were traced Thus, in 1966, the general thermal conditions up to 77°3o'N. in the Barents Sea, as illustrated by the distribution Water temperatures in the o-200 m layer in of temperatures on the surface and near the the Barents Sea in the end of 1966 remained far bottom, was on the whole as in the coldest years. below normal, and only in November-December, there appeared in the western sea some tendency L. I. BoRovAYA towards a decrease of the negative anomalies PINRO, Knipovich Street 6, Murmansk, U S S R.
Table 13. Water temperature anomalies in the o-50 layer on standard sections of the Barents Sea in 1966 Sections Months Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. North Cape/Bear Island (71°33'N Z5°02'E- 73035'N 20°46'E) ...... -1.3 -1.7 -1.3 -!.2 -1.7 -1.7 -0.3 -O.I -0.7 -o.6 -0.3 -0.4 -0.9 Along the Kola Meridian (70°3o'-72°3o'N) ...... -0.9 -1.2 -1.8 -1.7 -1.5 -1.4 -o.8 -0.9 -r.o -1.8 -1.3 -r.o -1.3
Near Northern Seas
Surface Temperature and Salinity Observations at six lightvessels. The positions of these routes and English Sampling Stations during rg66 the names and station numbers used to refer to them are shown in Figure 2r. In general, observations (Figures 21-49; Table 14) were taken at weekly intervals on all routes Surface sampling for temperature and salinity except NewhavenjDieppe and BristoljFinisterre, by merchant ships and lightvessels for the Fisheries where sampling took place two to three times Laboratory, Lowestoft continued during 1966. A per month. Gaps in the data occurred in various short examination of the main changes observed months when ships were re-fitting and also during is given here. the whole of June, when a strike stopped sailings In the North Sea, English Channel and Celtic Sea on most routes. The cargo vessel on the Folkestonej observations were made on seven routes and by Boulogne route was withdrawn from service in 34-
mean anomalies have then been plotted, as in Figures 23 to 46. Two further diagrams, Figures 47 and 48, show the extremes of temperature observed at each station in the course of the year and the earliest date at which these temperatures were attained. To provide a comparison with sea temperature and salinity variations in areas ad jacent to the coast, Figure 49, drawn from values 55' published by the British Meteorological Office (1966-67), shows the monthly mean air tempe rature anomalies for five land areas of England and \iVales and the percentage of the normal monthly rainfall over each. Rainfall has been 53' plotted on an inverted scale, to facilitate comparison with the salinity anomalies of Figure 22. In the monthly mean anomaly charts (Figures 23 52' to 46) no attempt has been made to draw isopleths 1 i · .· M·.. id LB.jrJ,.. ow· •.·. G'llloper L:.. of equal anomaly. A certain degree of inhomogeneity Cork-zj 4F1shguard 56 78 9~~·...... · .. ·······.·.··.:::.:' · .· .. · ..• · • · ·~1 •• · .. Varne i/,2Folkestone exists between different routes, due to varying ) ' ~:~vo·ir--Boulogne dates and frequencies of sampling, and tbis makes 3 Seven Stone_s•• l~ ~~~ea;pe;o ~·./ , detailed interpretation inadvisable. In addition, 50 some stations fall within ICES atlas regions where the means are less complete than in adjoining LV & . s.i76·~·~3~~;~\oelr~e ~ ~~···· ...... ·.·.····::·· regions, or within coastal regions where the means are largely dependent upon discontinued series of observations at fixed points otber than those at which we are making the comparison. Despite Figure 21. Position of routes and stations mentioned in the the relative crudity of the results the general text. trends of temperature and salinity changes during the year are apparent from the diagrams, and a August and was not replaced. Lightvessels normally discussion of these follows. sampled at four-day intervals, and at the Lynn January (Figures 23 and 24). Cold south to east Well and Mid-Barrow lightvessels, where tidal winds blew across the British Isles for much of changes are large, observations of temperature the month and rainfall was below average (Me and salinity were taken at both high and low teorological Office, 1966-67). The influence of water on observing days. this weather can be seen in the negative mean Table 14 presents the monthly mean values of temperature anomalies at the surface of the temperature and salinity, and their anomalies eastern English Channel and the North Sea, from the 1905-1954 monthly means (ICES, 1962), *pecially in the German Bight and over the for the six lightvessels shown in Figure 21 and also Dogger Bank. for three stations in the Irish Sea, i.e. the Morecambe In the western English Channel water with a Bay and Liverpool Bar lightvessels and Bardsey positive salinity anomaly persisted at the northern lighthouse. Responsibility for sampling at these stations of the BristoljFinisterre route, as it had latter stations was taken over by the Fisheries done since the previous September (RAMSTER and Laboratory from the University of Liverpool ELLETT, 1967). Less saline water from the Brest during the spring of 1966. Anomalies for these peninsula covered the southern stations. three stations are from the 1935-1961 means Salinities were high in the eastern English computed by HuGHES (1966). Figure 22 shows the Channel at stations awav from the French coast, lightvessel anomalies diagrammatically. where coastal water a:'ppears to have moved In order to present the results of the merchant offshore under the influence of the southerly to ship sampling in a concise form the observed easterly winds. The high salinities probably values of temperature and salinity at each of the represent the water of Atlantic origin which stations of the routes have been meaned by months advected into the eastern Channel during late and compared with the regional means given in November and early December 1965 (RAMSTER the ICES atlas (ICES, 1962); the resulting monthly and ELLETT, 1967). - 35 -- Hydrography Near N. Seas Table 14· Monthly mean temperatures and salinities at English and ·welsh lightvessels in 1966 and their anomalies from the 1905-1954 means Jan. Feb. :Yiarch April May June July Aug. Sept. Oct. Nov. Dec. Seven Stones Lightvessel Temperature °C ... . IO.I 10.2 IO.] II.O I2.2 I4.6 14·6 I2.8 II.6 Anomaly ...... 0.0 +o.6 -i-I.3 +r.2 -1-r.2 +r.4 +r.3 -f-r.o +o.6 +o.s Salinity 0loo ...... 35-40 35·34 35-34 35-29 35-29 35-22 35.2I 35-2I 35-27 35-35 35-25 Anomaly ...... +o.I5 +o.o8 +o.o8 +o.o3 +o.o6 -o.o2 -O.OI -f-0.03 -f-o.o6 -f-o.og -f-O.OI V arne Lightvessel Temperature °C ... . 8.] 8-4 8.8 g.I IO.] I3-4 I 5-4 I6.5 I6.g I6.2 !2.5 IO.O Anomaly ...... +o.6 -f-I.I +r.7 -1-r.2 -f-o.g -1-I.I -1-o.g +o.4 -f-0.] -f-I.4 -f-0.3 -\-0.2 0 Salinity I 00 •••••••• 35-30 35-26 35-06 35-I3 35·08 34-95 34-89 34-8I 34·78 34·78 34·63 34·83 Anomaly ...... +o.z8 -f-0.27 -l-0.07 +o.Ig +o.Io -o.oi -O.IO -0.I3 -O.I7 -0.20 -0.39 -0.I9 Galloper Lightvessel Temperature oc ... . 8.6 8.2 8.6 8.4 I I.2 I3.6 I5·7 I6.6 I7.3 r6.2 I2.6 8.7 Anomaly ...... +r.6 -f-2.3 +z.s -f-o.8 -f-r.I +o-4 -0.2 -o.s -f-o.8 +z.o -l- I.5 -f-0.3 0 Salinity j 00 •...... 35-24 35-20 35.I2 34-75 34-97 34-83 34-76 34-74 34-72 34·73 34-67 34-52 Anomaly ...... +0.35 +o-48 +o.43 +o.Io -1-o.38 -1-0.27 -0.05 -O.I4 -O.I9 -o.I6 - 0 -34 -0.45 lVIid-Barrow Lightvessel Temperature °C ... . 3·8 5.8 ].I 7·3 I I.5 14·7 I6.7 I6.g I].O 14·5 8-4 6.8 Anomaly ...... ~2.8 -0.2 -I.O -0.3 + I.4 + I.3 -f-o.g 0.0 -f-0.] +o.6 -2.6 -r.6 Salinity 0 loo ...... 33-53 34-36 34-06 34-24 34-34 34·57 34-53 34·58 34-60 34-52 34·39 34-I7 Anomaly ...... -I.04 -0.20 -0.36 -0.07 -0.12 -f-O.II -O.IO -O.II -0.21 -0.27 -0-43 -o.5r Smith's Knoll Lightvessel Temperature °C ... . 6.2 4-5 5-9 6.2 8.4 I I.4 14·4 I5.3 I 5-4 14·8 I I. I ].8 Anomaly ...... +o.z -0-4 -l-o.8 -0.2 -0-4 -0-4 -0.2 -0.9 -0-4 -f-o.g +o-4 -0.3 0 Salinity I 00 .••..••• 34-39 33-91 33-93 33-5I 33-82 33-97 34-08 34-09 34.I5 34-21 34-41 33-94 Anomaly ...... -0.03 -0.38 -0.23 -0.64 -0.32 -0.2I -o.o5 -0.03 -O.I3 -O.I7 -0.07 -0.53 Lynn Well Lightvessel Temperature oc .... 3·6 4-3 5.2 6.o 9-9 I3·4 I5.3 r6.8 I3.2 8.6 5·6 0 Salinity I 00 ••.•••.• 3!.74 3!.74 3!.90 32·37 32-58 33-06 33-29 33·58 33-33 32-92 32.60 JV!orecambe Bay Lightvessel*) Temperature oc ... . 6.0 6.3 9-9 I3.8 I5.4 rs.6 I 5-5 13.6 I0-4 7·3 Anomaly ...... -I.O -1-o.s -r.4 -0.7 o.o -o.s -I. I -O.I +o-5 +o.3 -0.2 0 Salinity I 00 .•..•... 32.09 32-14 32.08 32.63 32-35 32·35 32.95 32.86 32-5I 32-59 33-54 Anomaly ...... -0.14 -f-o.o6 -O.OI +0.32 -0.3I -0-44 +o.ro -f-o.oz -0.27 -O.I3 -f-o.g6 Liverpool Bar Lightvessel*) Temperature °C ... . 4·9 5·2 6-4 6.2 9-3 14-4 I6.8 I6-4 IS-9 I3.6 9-4 7·0 Anomaly ...... -0.6 +o.z +o.8 -r.8 -r.8 o.o +o.4 -0.6 +o.3 -f-o.8 -0.2 -O.I 0 Salinity I 00 •••••.•• 32.IO 32.64 31.82 32.23 32.55 31.78 31.81 32.2! 32·34 32.62 32 -75 32.0I Anomaly ...... +o.3I +o.go +o.3o +o.67 +o.73 -0.34 -0-4I 0.0 +o.rr -f-0.4I -f-0.]3 -f-O.I2 Bardsey Lighthouse*) Temperature °C ... . ].2 ].2 8.3 8-4 9-5 I2.8 I3.7 14·5 I5.6 14·6 II.3 9·5 Anomaly ...... -1.2 -o.s +o.4 +o-4 -o.8 -1-o.5 -o.5 -0.] +o-4 +o-7 -0-4 -0-4 0 Salinity I 00 •••••••• 34-33 34-63 34-30 34·5 I 34-53 34.6I 34-59 34·67 34-65 34-65 34-4I Anomaly ...... +o.o6 -1-0.34 o.o -i-O.I9 +0.22 +o.27 +o.24 -f-0.26 +o.28 -f-0.36 +o.rz *) Anomalies from I935-I96I means
Stations 2 and 3 of the Folkestone;Boulogne (2.5°C). On the following day the sea froze along route fell to their lowest temperature for the the coast to the south of North Foreland (Meteoro year on 21. January, and the Varne lightvessel's logical Office, rg66-67), and the Lynn Well light annual observed minimum occurred on 17. January vessel also recorded its minimal temperature (Figure 47). Although no observations are available (2.8°C) on this day (20. January). for the NewhavenjDieppe route between mid Off the coast from the Firth of Forth to the February and the end of March it seems likely River Humber high salinity anomalies may have that the year's minimal temperatures at all stations resulted from a westward movement of the main on the route were observed on rg. January, the axis of Atlantic water inflow into the North Sea. day on which temperatures at the Mid-Barrow Similarly, large negative salinity anomalies in the lightvessel were also at their lowest for the year German Bight and off the Danish coast probably JFMAMJJASOND JFMAMJJASOND +2
+ 1 ;-' ,_:::
-2 -2 ~ ·l=~- . -=--- ··r=)GA~ 5 -OJ -O / :.._____. GALLOPER L.V. o ... ~ SEVEN STONES LY VARNE LY MID-BARROW L.V. 6'
JFMAMJJASOND JFMAMJJASONO JFMAMJJASONO +2
+ 1 + 1 +1
-2 -2
+0·1
~:"'1 0 :-h~.------,;=.;::---~- -05 LIVERPOOL BAR L.V SMITHS KNOLL LV. BARDSEY LH. o ··O·····o MORECAMBE BAY L.V.
Figure 22. Monthly mean temperature and salinity anomalies at.lightvessel stations. reflect a westward movement of coastal waters February (Figures 25 and 26). Winds were mainly in these areas. The large positive salinity anomalies south to south-westerly during the first and last obtained consistently throughout the year at the ro days of the month, with an intervening period of north-easternmost stations of the LeithjCopen easterlies. Mean air temperatures were well above hagen route are difficult to account for. They are normal in southern England, and rainfall was very possibly artefacts produced by differences between heavy over the whole of the British Isles. In north the station positions and the positions of the east England the total rainfall was 224% of the observations upon which the mean values are normal February total. based, the area being one in which large salinity Sampling on the LeithjBremen and Newhaven/ gradients occur. Dieppe routes is representative of the first part Sampling on the LeithjBremen route was inter of the month only. The BristoljFinisterre anomalies rupted between mid-February and the last week shown in the figures are from one voyage made of March. It seems likely from the records of the on 2. to 3· February, when the ship's track was adjacent HulljHanstholm route that the observed displaced westwards from its normal route. Tempe minimal temperatures shown in Figure 47 at station rature anomalies for these three routes are thus 7 on r6. January and at stations 4 and 5 on 29. Janu biased negatively because of the early date of the ary are higher than the true minima for the year. observations within the month. -37- Hydrography Near N. Seas s' 10'
0·8 0 0 ·44 0 0 ·38 -0·5 -·04 -03 ·DB 0·1 ·09 -0-5 ·07 0·1 -05 ·14 -·49 -OB -·02 0·1 -0·8 ·24 ·09 -oz ·1B -06 -7·4 -08 -07 -08 ·12 -70 ·12 -06 -7-7 ·09 -52 -09 -72 ·02 -·02 -oz ·OB -0-7 ·16
5%, Anomaly Jan 1966
Figure 23. Monthly mean temperature anomalies, January Figure 2+. :\Ionthly mean salinity anomalies, January rg66. rg66.
10' 5' 10'
O·S 1·17 -08 -0·9 -29 -08 ·19 -03 -OJ 0·0 ·02 ·03 -0·7 -7-7 ·12 ·22 ·OS -77 ·19 -74 ·23 ·OS -O-J ·01 -07 -05 -23 -·77 -0!, ·OS -77 -07 ·03 -07 -07 -·54 -05 -07 -·05 -·74 -ot. ·04 -Ot. ·09
53'
S %, Anor.1aly Feb 1966
Figure 25. T\1onthly mean temperature anomalies, February Figure 26. Monthly mean salinity anomalies, February rg66. rg66. -38-
0·1 28 -0·5 -0·5 --12 04 -·09 0·6 -o 4 ·10 0·1 -04 ·09 ·32 -07 -77 0·3 - 75 ·15 -72 -oz -o4 -06 -09 0·4 55' -08 -0·4 0·8 1·0 -72 ·03 -64 0·1 0·7 ·00 -08 0·1 -26 -02 ·31
53' 53'
T'C Anomaly Mar 1966
Figure 27. :VIonthly mean temperature anomalies. M.arch Figure 28. Monthly mean salinity anomalies, March rg66. rg66.
Off the coasts of southern Eire aud Wales large Low temperatures were found over all the negative salinity anomalies appeared in juxtaposi North Sea, with the exception of the area im tion to large positive anomalies at stations 5 and mediately to the east of the Firth of Forth and 6 of the CorkfFishguard route. The first seem to the entrance to the Skagerak. Nevertheless, originate from land run-off and the second from salinities were above normal values except for the north-eastward movement of Atlantic water stations in the German Bight (from observations in the Celtic Sea. The year's observed minimal taken during the first south-westerly wind period temperatures at all stations on this route were of the month, as noted above) and on the Dogger recorded during February, although at some Bank. This distribution of anomalies suggests that stations the same temperatures recurred during low-salinity water from the German Bight and the course of March and April. Dutch coast may have moved westwards under Temperatures rose in the eastern English Chan the influence of the January winds and northwards nel, the area most affected by meteorological during February, dividing the inflow of Atlantic conditions over the surrounding coasts. The south water between the deeper waters to east and west westerly winds appear to have advected high of the Dogger Bank. Minimal observed temperatures salinity water of Atlantic origin into the area, for for the year were encountered at all stations on the Varne lightvessel and the FolkestonejBoulogne the HullfHanstholm route on 20.-21. February, route, at which stations sampling continued although the temperature at station 7 had normally throughout the month, show continuing previously been recorded on 12. February. Stations large positive salinity anomalies. There is little r and 7 of the LeithjCopenhagen route also reached evidence of the existence of much low salinity minimal temperatures during this period, on I7. coastal water resulting from excess land run-off. r8. February. The annual minimal temperature at station I of Notably low salinities were observed at the the FolkestonefBoulogne route was observed on Smiths Knoll lightvessel from February to June, r8. February. probably due to the eastward extension of English -39 Hydrography Near N. Seas
5' 10'
-0·4 1-45 -OJ -OJ ·24 -08 -o6 -os -11 -0·4 ·07 -0-3 ·11 -14 ·15 -10 -12 -31 -7·4 ·22 -!.9 -09 -10 ·12 I -12 -13 -07 -12 -16 -1-5 -0 6 -23 ·20 -05 -17 -75 -0-3 -06 -30 -11 ·07 -09 -01
53'
Figure 29. :Monthly mean temperature anomalies, April 1966. Figure 30. :VIonthly mean salinity anomalies, April 1966.
coastal water moving northwards along the East February. Rainfall was very low in eastern and Anglian coast. This station's annual temperature southern Britain. minima of 4.2°C was recorded on 13. February. At the Seven Stones lightvessel temperatures At the Galloper lightvessel both temperature and were high and salinity values were still somewhat salinity anomalies in February were large, as they had been in January. In an earlier investigation above normal, as in February. The CorkjFishguard route recorded positive temperature anomalies at (ELLETT and BAXTER, 1965) it was shown that the monthly temperature means in spring for region all stations, and Atlantic water occupied the eastern part of the route, reducing the magnitude No. 217 of the ICES atlas, in which this lightvessel is situated were biased in favour of the 18 years of the positive salinity anomaly observed at of observations taken further inshore at the stations 5 and 6 in February, but raising the Edinburgh lightvessel, and an examination of the anomalies at stations 7 to 9 to values well above salinity records for the area confirms that this normal. is also true of the monthly salinity means. Thus No NewhavenjDieppe observations were avail the Galloper temperature anomalies should be able during March. Those taken on the Folkestonej regarded as being too large in winter and too Boulogne route show a period of high salinity small in summer and the salinity anomalies as values during the time of the south-westerly winds, being somewhat too high throughout the year. followed by a decrease to lower values at the end It is intended to compute new means for comparison of the month, due to fresher water spreading with the 1967 data. northwards from the French coast. March (Figures 27 and 28). After a week of south Increased advection into the northern North westerly winds most of the North Sea and English Sea as a result of the north-westerly winds seems Channel experienced north-westerlies for the remain likely to have caused the rise of temperature to der of the month. Mean air temperatures were above normal values on the eastern and western above normal, but to a lesser degree than in sections of the LeithfCopenhagen route, as these 5' 10' 5'
-0·3 3-13 0·0 1·06 0·1 --86 0·3 --og -07 -07 0·0 ·07 0·3 ·10 -04 ·08 --72 -02 0·2 - 74 0·0 -07 1\06 ·04 -SJ -04 ·09 -06 -04 -77 ·00 -08 55° ~ --70 -72 0·3 ! -73 ·24 0·1 -57 -74 0·3 i 02 ·39 -72 ·14 -06 ~ ·05
53' 53'
52'
T'C Anomaly ~ S%, Anomaly May 1955 4s' Li-'.____[ _ __L___jl-='~s::···:...,L____L_J____j__-"-:1,---'--M-ay-'--19_55-'--__JI ~ 8' s' o' Figure 31. :VIonthly mean temperature anomalies, May Figure 32. :VIonthly mean salinity anomalies, May rg66. rgGG. were associated with continuing positive salinity southerly component of the wind over the western anomalies. On the HulljHanstholm route, however, Channel during the first three weeks of the month. temperature anomalies had decreased in magnitude, All temperatures in the eastern English Channel but were still negative at six stations and not were high, but the anomalies shown for the New much above normal at the remaining three. Salinity havenjDieppe route are positively biased, relating values were notably low over the central section to a single crossing at the end of the month; at this of this route. Negative salinity anomalies on the time the east to south-east wind regime had been Leith/Bremen route, based on two crossings of broken and low-salinity water had spread north the route during the last week of the month, wards from the French coast. Nevertheless, salinities suggest that outflow from the north German rivers and temperatures were high during the month in may have been responsible for the generally low the Straits of Dover, as the Varne and Folkestone/ salinities in the central and eastern part of the Boulogne observations show. North Sea. The year's minimal observed temperature at April (Figures zg and 30). This, like February, the Galloper lightvessel was recorded on 5. April. was another very wet month. Mean air temperatures The large negative salinity anomaly at the Smiths were below normal, especially in northern England Knoll lightvessel suggests that the heavy rainfall and Scotland. From April 5. to rg. winds were increased the volume of English coastal water mainly easterly over the North Sea and south-east off the East Anglian coast. Temperatures at this to south over the western English Channel. After station became lower than normal during this this they were largely westerly or south-westerly month and remained so until October. over the whole of Britain. Temperatures at all stations in the North Sea, At the Seven Stones lightvessel and on the with the exception of station z of the Leith/ Cork/Fishguard route temperatures and salinities Copenhagen route, were below normal and salinity remained high, with anomalies retaining similar values remained generally low, as in the preceding values to those of March. This reflects the greater month. Minimal annual observed temperatures - 4I- Hydrography Near N. Seas
SJ'
". "'}\,. S'/, Anomaly
"8' Ll_LI _j__J.___jj-;:'~,;::: . :ell_·. _~_j_···_. _._L_~_J__L;-_j_J_un_J_19_66..J..__j 1.8' s' o' Figure 33· Monthly mean temperature anomalies, June Figure 3-t· Monthly mean salinity anomalies, June 1966. 1966. occurred at stations 2 to 4 and station 6 of the in mid-Channel, although coastal water occupying LeithjCopenhagen route during the early part of the four southern stations of the NewhavenjDieppe the month, and the temperature at station I on route at the end of April had spread further north 3· April equalled the minimum recorded there in in early May, probably because of reduced advection February. Minima appear also to have occurred from the western Channel, and mean salinities at at stations I to 3 of the LeithjBremen route, all stations on this route became less than the although the incomplete records of February and normal values for May. March preclude certainty upon this point. In the North Sea temperatures rose to normal May (Figures 31 and 32). Winds were more values on the LeithjCopenhagen route. Anomalies variable over England and Wales than in previous on the HulljHanstholm and LeithjBremen routes months, but on the whole were from between west represent crossings from the first half of the month and south. Mean air temperatures and rainfall only. It seems likely that the low surface tempe for the month were close to normal values. ratures off the mouth of the River Humber resulted The figures show little change in the values of from the low air temperatures over the north-east the anomalies at the Seven Stones lightvessel and coast of England during the previous month, when on the CorkjFishguard route, except for the water with the same order of positive salinity reappearance of negative temperature and salinity anomaly was found off the Firth of Forth. On the anomalies in coastal water along the southern Dogger Bank the large negative temperature and coast of Eire. salinity anomalies of April generally decreased, May anomalies for the Newhaven/Dieppe route but off the Danish coast water of low salinity was were obtained from two crossings made during present. The observations indicate that this water the first fortnight of the month. On the Folkestonej came from the German Bight. Boulogne route one crossing only was made, on j'Vtne. (Figures 33 and 34). vVind direction was IO. May. High-salinity water which was sampled variable during the month, but westerlies and on this route at the end of April was still present south-westerlies predominated. Mean air tempe- 42 -
5' 10'
2·19 -03 ·43 0·3 ·06 0·6 ·84 -OJ -07 ·02 -1-D5 0·2 ·12 0 1 -·07 -·88 -0-2 ·03 -05 -D-2 -34 -04 -01 -77 -04 -·73 -07 -0-2 -02 -07 0·6 -·17 -11 -36 0·0 --75 -72 -DB ·02 -07 ·03
53' 53'
52'
T'C Anomaly Jul 1966
Figure 35· Monthly mean temperature anomalies, July Figure 36. Monthly mean salinity anomalies, July rg66. rg66. ratures and rainfall for the month were above the the month. Mean air temperatures were notably average values. below normal and rainfall was above average in Apart from one crossing of the CorkfFishguard east and south-east England, although below aver route in the first week of the month only light age in the south-west. vessel data are available, due to a strike which Temperatures were high on the BristolfFinisterre prevented British ships from sailing. and Cork/Fishguard routes. Low-salinity water In the south-west the Seven Stones lightvessel occupied the last three stations of the latter route, recorded its largest monthly positive temperature and at three other stations the year's observed anomaly and its first monthly negative salinity maximal temperatures were recorded (Figure 48). anomaly for the year. The Varne lightvessel anomalies suggest that In the eastern English Channel a single crossing the eastern English Channel remained warmer than of the NewhavenfDieppe route during the second normal and that the water of near-normal salinity half of the month showed high temperatures and encountered at station 2 of the NewhavenjDieppe low salinities, suggesting a low advection rate for route in May reached the Straits of Dover in June. Atlantic water from the western Channel. This is In the Southern Bight temperature and salinity supported by the fact that the situation persisted, anomalies at the Galloper lightvessel declined, but with very similar salinity anomalies, throughout the Mid-Barrow lightvessel had its only positive the rest of the year, although rainfall over south monthly salinity anomaly for the year. Rather low east England was more nearly normal during the salinities and temperatures continued to be observed second half of rg66. At the Varne, Mid-Barrow at the Smiths Knoll lightvessel during June. and Galloper lightvessels salinity anomalies became negative and remained so to the end of the year, a }%ly (Figures 35 and 36). Winds were mainly significant change for the latter, which had observed from between west and north-west except for four positive values during all preceding months (see days of north-easterlies during the third week of Figure 22). The close agreement between conditions -43- Hydrography Near N. Seas
0' 5' 10'
-04 -06 1·24 2·00 ·17 0·2 -·72 -06 -03 ·12 -58 ·05 0·3 -02 0·0 --03 ·35 -05 ·22 -07 -77 -·05 -25 -07 -73 -·08 -72 -26 -08 -07 --o3 -7 4 -0 4 0·4 ·03 -·08 -·77
Figure 37· Monthly mean temperature anomalies, August Figure 38. Nlonthly mean salinity anomalies, August 1966. 1966. in the Straits of Dover and those at the Galloper route than in July, and salinity values were below a few weeks later have been remarked npon in a normal over the northern half of the route. The commentary on the rg65 sampling (RAMSTER and year's maximal observed temperatures at stations r ELLETT, 1967), and the rg66 observations offer a to 8 were recorded on zr. and zz. August. On the further example. CorkfFishguard route temperature anomalies de Apart from the area offshore from the Firth clined slightly, and the lower-salinity water off of Forth, temperatures in the North Sea were the Welsh coast in July was replaced by an mostly at or a little below normal. The distribution apparently stronger Atlantic inflow. Four further of salinity anomalies suggests that the main stations attained annual temperature maxima Atlantic inflow may have been diverted to the during the last week of the month. eastern part of the LeithfCopenhagen route. Values In the eastern Channel temperatures were some on the other two North Sea routes show little sign what above normal, but no water of salinity of its southward penetration. greater than 34.8r0fo0 was present on the Newhavenf Many North Sea stations recorded their highest Dieppe route. The salinity situation in this area temperatures of the year during July (Figure 48), was very similar to that in the preceding month, although in several cases the same values recurred with apparently minimal advection from the west. during the course of the following two months. The inshore stations of the NewhavenfDieppe These early maxima arose because of a cool period route recorded their highest observed temperature in August which kept surface temperatures at or for the year during August. At the Varne lightvessel below their July values. a temperature of 17.0°C was observed on zr. and August (Figures 37 and 38). Wind direction was zg. August, and the same maximal value was very variable during the month. Mean air tempe attained at intervals during the succeeding months ratures were again low and rainfall above average. until 13. October. In the western English Channel temperature Temperatures were below normal at most stations anomalies were less high on the BristolfFinisterre in the North Sea; around the Dogger Bank and 5' 10'
-01 0·2 0·0 -34 -114 0·4 ·49 -01 -·64 0·0 ·DB 0·1 0·7 ·00 ·33 0·1 -03 -0-2 -05 0·1 -07 -13 0·3 -0·4 -·02 -02 55' -·04 -0-1 -02 -o2 --02 _. 0·1 12 0·1 0·1 -09 -·43 -0-8 -73 -OJ --16
53' 53'
52'
Figure 39· :\Ionthly mean temperature anomalies, Septem Figure 40. l\Ionthly mean salinity anomalies, September ber rg66. rg66. off the Humber anomalies exceeded-r.0°C. From ratures were high. On the Cork/Fishguard route the salinity anomalies it appears that Atlantic high temperatures and above average salinities influence was confined to the area north of 56°N. were observed in St. George's Channel. The two Advection of water of Atlantic origin down the stations nearest to the \V'elsh coast attained their east coast of England appears to have been at a observed temperature maxima for the year early minimum and, as with the eastern English Channel, in the month. little change occurred in the values of the negative In the eastern Channel the situation of the salinity anomalies during the remaining months previous two months persisted. Temperatures of the year in the area south of 55 °N. remained above normal and salinities well below During August maximal annual temperatures the means for September. No FolkestonejBoulogne were observed at several stations on the Leith/ values are available for this month, nor for the Copenhagen and LeithjBremen routes; at the remainder of the year. Observed maximal tempe Smiths Knoll lightvessel the year's observed ratures for the year occurred at stations 2 and 3 maximum was recorded on 2I. August. of the NewhavenjDieppe route on 7· September September (Figures39 and4o). During the first half and at the Galloper lightvessel on 13. and IJ. Sep of the month winds were mainly from south-west tember. to west, but during the second half they were Temperatures were close to normal over most of chiefly light and variable. Mean air temperatures the North Sea with the exception of the area were a little above normal, taken over the month immediately to the east of the Firth of Forth, which as a whole, and rainfall was below average over was somewhat warmer than normal, and the area eastern and southern England. between the Dogger Bank and the Humber, where In the south-western Channel one crossing of negative anomalies persisted. Salinities were gene the BristoljFinisterre route during the second half rally low, as in August, but water with a positive of the month showed that water of rather low salinity anomaly was present on stations 2 to 4 of the salinity was to be found in mid-Channel; tempe- LeithjCopenhagen route and station 2 of the -45- Hydrography Near N. Seas 0' 5'
1·2 0·8 ·28 1-2 ·09 H -29 1·0 1·0 ·09 -·47 1·3 H 0·5 ·00 --06 -·09 1-2 ·04 0·9 0·1 -06 ·01 1·0 -·79 -·08 0-8 -02 -·05 0·7 55' -·02 0·4 0·5 1·2 -·04 -·07 -27 0·5 0·7 -·11 --66 0·2 -·19 0·7 -·76
Figure 4r. Monthly mean temperature anomalies, October Figure 42. Monthly mean salinity anomalies, October rg66. rg66.
LeithjBremen route, suggesting that some advection tions, with higher values to the south. This of Atlantic water was occurring at these stations. presumably reflects the changing wind regime. Again, no evidence of penetration of this water On the CorkfFishguard route coastal water of low to the area offshore from the Humber is apparent salinity caused large negative anomalies at stations in the salinity anomalies of stations r to 3 of the r to 3 near the southern coast of Eire. Positive HulljHanstholm route. The year's observed tempe salinity anomalies were maintained on the western rature maxima at stations r and 2 of this route side of St. George's Channel and temperatures over occurred on ro. September, and at the Lynn Well the larger part of the route were more than I°C lightvessel on r. September. above normal. October (Figures 41 and 42). Wind directions October anomalies for the NewhavenjDieppe were variable for the first II days of the month. route refer to one crossing in the fourth week of From ro.-21. October winds were largely from the month. It seems probable that we can accept the south-east to the south-west and for the rest them as a reliable guide to conditions during the of the month from between north-west and north month, since they agree with other observations east. Rainfall was well above average, especially in the Straits of Dover and Southern Bight in in south-east England. Mean air temperatures for maintaining similar values to those of September, the month were near normal in northern and save for the decreasing temperature anomalies in western England and above normal in the east French and English coastal waters. and south-east. In the North Sea temperatures were above Temperature anomalies on .the BristoljFinisterre normal at all but one station, a notable contrast route were the highest of the year. During the with all previous months of the year. Negative first half of the month salinities were high at salinity anomalies persisted, as they had done stations 2 and 3 and low at the central stations of from July, over the LeithjBremen route and at this route. During the second half, however, lower stations r to 5 of the HulljHanstholm route. salinities occurred at the northern five sta- Positive salinity anomalies on the Leith/ Copenhagen 0' 5' 5' 10'
1·6 1·92 1·1 ·31 1-3 ·07 1·9 -17 1-0 1·2 -10 -·05 0·9 0·9 1-2 -07 --25 1-7 ·08 0-7 0·6 ·06 0·8 -72 1·5 0·9 -77 -03 55' 1-2 55' ·07 0·4 1-7 -·07 -OB 1·5 --50 0·5 1-0 ·07 -92 0·2 --7l 0·6 -·55
Figure 43· Monthly mean temperature anomalies, Novem Figure 44- Monthly mean salinity anomalies, November ber rg66. rg66. route during all these months demonstrate that only at stations r to 4 in early December, and it there was no decrease in salinity of the Atlantic seems possible that a reversal of flow may have water entering the northern North Sea, and thus takm place at the surface of St. George's Channel it seems that the negative salinity anomalies, under the influence of the northerly winds of highest near the coasts, must have been due to November. Little modification occurred in the excessive run-off following the unusually wet pattern of both temperature and salinity anomalies spring and summer months. in the eastern Channel; negative salinity anomalies at the Varne and Galloper lightvessels increased November (Figures 43 and 44). Winds were from north-east to north-west for many days of the somewhat during the month. month. Mean air temperatures were more than All North Sea stations had positive temperature I°C below the normal over most of England and anomalies during November, many of them greater Wales. Rainfall was rather less than average. than +r°C. This is surprising for a month with Stations on the Bristol/Finisterre route retained chiefly northerly winds and, in view of the continu positive temperature anomalies, but of a lesser ing low salinity anomalies over much of the area, degree than those of the previous month. Salinities cannot be ascribed to warm Atlantic inflow. rose to normal values and above at all stations on Further investigation will be needed to reveal the the route. The large positive November temperature cause of this. anomalies for the Cork/Fishguard route are biased December (Figures 45 and 46). Winds were positively, being obtained from a single set of generally west to north-west until the last week observations made on z. and 3· November. The of the month when they became west to south-west. negative salinity anomalies resulting from this South-east and south-west England had higher single crossing should probably be greater in order mean air temperatures than normal, and east to be representative of true conditions during the and north-east England had roughly average mean month. Water of salinity greater than 35%0, which air temperatures. Rainfall was above average over occupied stations 3 to 8 in October, was present much of England and Wales. 47- Hydrography Near N. Seas 0' 50 10'
0-8 1-82 0-4 -·05 -0-7 ·00 0-4 -77 ·50 0-3 0-0 -12 -13 0-3 ·09 1-0 0-3 -76 0-4 -36 0-2 -06 -77 0-3 ·02 0-1 -0-5 ·00 -·07 -07 -77 -70 -03 -·70 -06 0-1 --77 -7-0 2-0 -75 -23 -04 --73 -07 --70
53' 53'
52'
Figure 45- Monthly mean temperature anomalies, Decem Figure 46. Monthly mean salinity anomalies, December ber rg66. rg66.
One crossing only of the BristolfFinisterre route temperatures at the Galloper were near normal, was made, this being during the first week of the suggesting that an eastward movement of coastal month. The temperature anomalies for this route water was influencing conditions at this station. shown in Figure 45 were derived by comparing The warm temperatures of the North Sea in the observed values with interpolations from the November declined to near normal values in November and December means, and show that general. Three crossings between Hull and Hanst the temperatures at this time were close to, or holm during the second half of the month observed slightly below, normal. The low-salinity water temperatures below normal over much of the route, found in mid-Channel in November was still present. probably resulting from strong cooling over the On the CorkfFishguard route all temperatures were Dogger Bank. High salinities due to Atlantic above normal; water of salinity greater than 35°/00 influence existed at the western stations of the was confined to stations I to 3 by the end of the LeithjCopenhagen and Leith/Bremen routes, but month, at which time a tongue of low salinity off the Humber and in the German Bight much water appeared on stations 7 and 8 of the route, coastal influence continued. supporting the suggestion of an southwards flow in the middle of St. George's Channel. Summary In the eastern English Channel the situation of the previous five months persisted although In the course of Ig66 monthly mean temperature salinity had risen at stations I to 3 of the New and salinity anomalies from the I905-I954 havenfDieppe route, somewhat decreasing the large monthly means were largely within the limits negative salinity anomalies at these stations. ± I.5°C in temperature and +o-3°/00 to -0.5°/00 Evidently no great increase in advection occurred, in salinity. as salinity anomalies on this route in January I967 In the south-western English Channel tempe were similar to those of December. Varne and ratures were at or above normal for the whole of Galloper lightvessel salinities remained low, but the year and in the northern Celtic Sea similar 15·4 4·2 15·2 7/8 4·2 18/2 15·2 8/8 5·1 2/4 15-() 25/7 54 12/3 14·5 6/8 9 14·9 27/8 5·B~ BIB ~ 3·6 15·4 12/2 30/7 3·0 15·1 ~ -- 20/2 24/7 9/40~ 4·0 3·5 ~21/2 55' 2911 3·7 4·6 13/2 3·6 16/1 3·7 14/2 5·0 5·0
53' 53'
TEMP.•c
Figure 47· Minimum temperatures observed during rg66 Figure 48. Maximum temperatures observed during rg66 (Earliest date given where values were observed on more (Earliest date given where values were observed on more than one occasion). than one occasion). above-normal temperatures prevailed in offshore negative values in December. During a period of waters. July to November were notably warm cold air temperatures in the third week of January months in these two areas. Salinities were very the year's minimal surface temperatures were high in Atlantic water on the CorkjFishguard observed at many stations in the area. route in February, and were low in November and Temperatures in the central North Sea were December when this water was absent from St. generally low in January and February and also George's Channel. Only in January and September from April to August. April mean temperatures were negative salinity anomalies of value greater were more than r°C below normal at many stations. than -o.ro0fo observed on the BristoljFinisterre 0 March, September, October and December had route, but observations are lacking for the months near normal temperatures and only November was of May to June. It seems reasonable to assume appreciably warmer than average. Salinity values that water in the south-western approaches main were generally rather low in March, April and July tained normal salinity values throughout the year. and were consistently low in the German Bight, In the eastern English Channel observations on over the Dogger Bank and off the Humber from the NewhavenjDieppe route showed much change August to December. Off East Anglia, at the in the conditions of advection of Atlantic water Smiths Knoll lightvessel, coastal influence kept to this area. High advection at the beginning of salinity values below normal throughout the year. the year decreased during the spring and was at a minimum for the last six (or possibly seven) months D. J. ELLETT, S. R. JoNES, G. READ of the year. This change is also reflected in salinity Fisheries Laboratory, Lowestoft, England. anomalies at the Galloper lightvessel in the Southern Bight. Temperature anomalies were greater than References +roc at many stations in the eastern Channel ELLETT, D. J. and G. C. BAxTER, rg65. "Surface tempe from February to July, after which they decreased ratures in the southern North Sea, January-March to normal values in November and to slightly rg63." Annis bioi., Copenh., 20: 28-39. -49- Hydrography Near N. Seas
J ,F M AM J J A S 0 N 0 +2 .., +1 + 1 --" -2 -2 50 o" 50 ~ 100 ~ 100 ~ 150 200 SW ENGLAND AND S.WALES • E. ENGLAND JFMAMJJASON JFMAMJJASONO +2 +2 + 1 50 ~ 100 -H-+-t--:--r--++-1----"- ~ 150 200 NW ENGLAND AND N. WALES Figure +9· Monthly mean air temperature anomalies and percentage of normal rainfall for a number of districts of England and \Vales. HuGHES, P., rg66. "The temperature and salinity of the 22. March rg67 the R. V. "Anton Dohrn" carried surface waters of the Irish Sea for the period 1947-61." out routine investigations in the North Sea. In both Geophys. J. R. astr. Soc., IO: 421-35. ICES, rg62. "Mean monthly temperature and salinity of cases the main task was to get an insight into the 1 the surface layer of the North Sea and adjacent waters stock of herring, particularly the young herring ). from 1905 to 1954." ICES Service Hydrographique, The range of investigations is shown in Figure 50 Charlottenlund Slot. Meteorological Office, rg66-67. "}Ionthly ·weather Report, and sr. Beside the biological work, temperature and rg66." 83: r-rg2. salinity measurements have been taken. The result EAMSTER, G. M. and D. J. ELLETT, rg67. "Surface tempe of the hydrographical observations is seen from rature and salinity observations at English sampling 2 Figures 52 to 6r ). One recognizes clearly the close stations, rg65." Annis bioi., Copenh., 22: 32-40. relationship between the hydrographical conditions and the wind conditions. In February rg66 easterly Hydrographical Conditions in the North Sea in winds prevail over the North Sea veering to south March 1966 and 1967 west at the end of the month. Early in March (Figures 50-63) high air pressure extends over Great Britain cau From ro. to 27. March rg66 and 27. February to sing persistent winds from north to north-west. 1) In March rg67 R.V. "Clione", R.V. "Explorer" and R.V. 2) In March rg66 the surface dates refer to 0 m, in March "\Villem Beukelsz" participated in the enterprise. rg67 to 5 m. -50- Figure so. I{oute and hydrographic stations of R.V. "Anton Dohrn", ro. to 27. March rg66. Under their influence warm Atlantic watermasses and a following cross circulation of seaward advance to south-east and displace the winterly shifting coastal water. water of the North Sea covering a large part of the Corresponding to the relatively warm winter of Dogger Bank. (Figures 52 to 55). rg66/67 and the strong inflow of Atlantic water Through the Channel as well, warm water masses, the North Sea over the Dogger Bank was masses enter the North Sea. A part of this water in March rg67 about 2° warmer than in March is separated by cross circulation running offshore. rg66. Compared with the monthly mean of 52 years It moves as a warm water isle with the currents (ToMCZAK and GoEDECKE, rg62), the bottom tem in the western German Bight mixing gradually perature of the central North Sea was in March with the surrounding cold water. rg66 predominantly too low, in March rg67 Whereas there were no persistent gales in the predominantly too high. Because of the slight late winter of rg66 over the North Sea, stormy stratification of the North Sea in March the same winds from westerly directions prevailed in Feb applies to the surface temperature. ruary and March rg67. In March rg67 they caused warm Atlantic water to advance eastward E. MITTELSTAEDT over the Dogger Bank, (Figures 56 to 59). In the Deutsches Hydrographisches Institut, north the isotherms and isohalines indicate a Bernhard Nocht Strasse 78, 2. Hamburg 4, Germany. fairly strong influx into the Skagerak water (Figures 6o and 6r). Simultaneously the cold Bal tic current of low salinity flows at the surface Reference along the Norwegian coast towards south-west in creasing its meridional component in the western ToMCZAK, G. and E. GoEDECKE, rg62. "Monatskarte der Temperatur der Nordsee, dargestellt fur verschiedene Skagerak. Tiefenhorizonte". Deutsches Hydrographisches Institut, Similar to the preceding year a warm-water isle Hamburg. has been formed by an influx of Channel water (See pp. 51-59 for Figures 51-63). - sr- Hydrography Near N. Seas 70 so go 10° 51' 56° 56° 55° 55° 54° 54° 53° 53° 3 2 Figure sr. Route and hydrographic stations of R.V. "Anton Dohrn", 27. February to 22. March I967. -52- Figure 52. Bottom temperature. 10. to 27. March 1966. r Figure 53· Bottom salinity, ro. to 27. March 1966. -53- Hydrography NearN. Seas Figure 54- Surface temperature, ro. to 27. ·March rg66. Figure 55· Surface salinity, ro. to 27. march rg66. -54- s• g• 57" 5s• 5s• 55• 55• 54° 54° 53° 53° 3 5" s• 7 Figure 56. Bottom temperature, r. to 22. March 1967. -55- Hydrography NearN. Seas 57" ss• ss• ss• ss• 54. 54° 53" 53° 3. 2. ,. 30 ,. s• 7. 10 Figure 57· Bottom salinity, 27. February to 22. March 1967. - s6- 59" 51' 55" ss• ss• 55" i I 54° 54° i +-·. ~~-~~~ 53° t•c 53° SURFACE 1.3.-22.3.1967 3 0 6 7 10 Figure sS. Surface temperature, I. to 22. March I96]. -57- Hydrography Near N. Seas 57" 56' ,I 56'1' 55'1 1 54' 54' I 53' : 53' 27.2."22.3.1967 Figure 59· Surface salinity, 27. February to 22. iYiarch 1967 -58- 50 100 150 200 250 300 350 400 450 500 Figure 6o. Section across the Norwegian Channel in the Figure 61. Section across the Norwegian Channel in the western Skagerak, 14. March 1967. central Skagerak, 15. March 1967. Figure 62. Bottom temperature anomalies, March 1966. -59- Hydrography Near N. Seas 57" ss• 56" ss• ss• 54. 54° 53° 53° z• 10 0 10 30 70 a• g• 1o• Figure 63. Bottom temperature anomalies, March 1967. - 6o- Polish Hydrographical Observations in the North Sea by the Sea Fisheries Institute at Gdynia concern in Summer and Autumn 1966 the following periods and areas: r) 26. May to 25. June in the area (Figures 64-82) 57°30' to 6oooo'N; Hydrographical observations carried out in rg66 oo 0 oo' to os 0 oo'E 698 697 696 695 • • • • 60° e694 702 7Q1 700 6~9 5~2 693 El • • 59° 703 704 705 691• 736 690 689 • • • • 735• 734• •737 715 709 '708 707 • 688 o754 ®713 6717 •716 .706 8 58° 753 '746 745 738 714 712 718 755 756 710 .729 •• •711 • e747 744 •750 • 719 752 739 758 757 • • Cl751 727 728 731 732 759o 760~;po •760 8 8 8 •775 748 .743 740 774 57° 762 761 749 • • 0 721 767 763• •726 e742 •741 •773 ••766 ..725 764• e765 •768 •722 e724 e769 e770 e771 •772 56° 55° Figure 64. Distribution of stations in rg66. - 6r _ Figure 6 5· S urface te mpcraturcs • J une rg66 Figure 66 . S urface te mperatures ' J uly rg66 10 oo . 10 oo 2" --:-:----~. 10 20 s 40 10 3;0 Figure 68. Bottom tern peratures , J une rg66. - 6z- 1" oo 10 20 3" 40 10 o· 10 20 y 40 so , " ;:r •I ~ CiV'159o I I 5801 ~8~ I I 57° ,60 r 56 I !\ Figure 6g. Bottom temperatures, July rg66. Figure 70. Bottom temperatures, September-October rg66. II )35 <35 Figure 7I. Bottom salinity, June rg66. Figure 72. Bottom salinity, July rg66. -63- Hydrography Near N. Seas m o,--69~.3------~~--~------~~~F9· 20 60 350--J 100 34,8 c-----35 140 34,6 58° 160 34.6 r 220 260 56° Figure 74· T-section along 6o 0 oo'N between oz 0 -04°E Figure 73. Bottom Salinity, September-October rg66. 2) 12. July to 3· August in the area 55o3o' to 58ooo'N; 01°0o'W to 04°0o'E 3) 13. September to 10. October in the area 56ooo' to 58o3o'N; ooooo' to 05°oo'E The analysis of the temperature and salinity data resulted in the following statements: Figure 75· T-section along 59°0o'N between 00°-03°30'E r. The temperature of surface water during the first cruise was lower as compared with the distribu- tion of long-term mean isotherms in the same season and area. The difference amounted to about 2°. The result of measurements made during the second cruise revealed that in the area under consideration the surface temperatures did practi cally not deviate from the long-term mean values, and in comparison with the same period in 1965 they were somewhat higher. During the last cruise the surface temperatures did not differ from the mean values. Computed for the same time they were also higher than in 1965. 2. The temperature of the bottom waters was lower in 1966 in comparison with the long-time Figure 76. T-section along 58°3o'N between oo 0 30'-o5°E 200 T°C 250 IX-X·1966 Figure 77- T-section along s8°00'N between 00°-04 °E :;::::::::::·:·:·:·:·:·:·:·.·.·.·...... , Figure So. T-section along s8°oo'N between OI 0 VV-03°E 60 100 140 180 220 T°C Vl-1966 260 that the more diluted waters coming from the Skagerak and the Belts reached 2°5o'E in the mean values and showed differences amounting western direction and 56°3o'N southwards, thus, for June to about -0.36°, and for July to about they extended farther in a south-western direction -0.75°. Temperatures like those in rg66 had than in previous years. previously occurred in 1956 and 1958. In relation 4- Within the bottom layer the Atlantic water to rg65 the bottom waters were characterized by which in June extended from 6o 0 N to 57°30'N, lower temperatures. afterwards shifted more southwards, so that in 0 3- Salinity values of the surface waters in the July it formed a wedge between I E and 3°E as central and western parts of the sea did not show far as 56o4o'N. any deviations worth mentioning, and during the The observations from September-October whole period of investigation they remained at the indicated that a regression of that Atlantic water mean leveL In the eastern part of the sea the to the north had taken place. At the same time occurrence of the 34°/00 and 33%o isohalines proved two wedges were formed by the 35%0 isohaline, one of them in 57°:)o'N between the meridians Figure Sz. T-section along 57°oo' N between or 0 \V 05°E ~~ ~-~~~~----~-~~---~---~--~-·---· -65- Hydrography Near N. Seas 0 I vV and roE and another one beyond 58°N Hydrography of the Skagerak and the Kattegat Area between 4oE and 5°E. Simultaneously a small lens 1966, Swedish Observations formed by the 35°/00 isohaline was observed at (Figures 83-84; Table 16) 5J 0 N ooo3o'E. Table r6 presents monthly mean values of tem J. FILARSKI perature and salinity at the light5hip "Fladen", Sea Fisheries Institute, Al.Zjednoczenia I, Gdynia, Poland. substituting the values from the lightship "Vinga", References which were used earlier in this publication but Deutscher Wetterdienst: "Einzelveroffentlichungen zur ceased by the end of rg65. Striking features are a) Klimatologie des Nordatlantischen Ozeans". No. 39. low bottom temperatures throughout the year FRAHM, G., I956. "Hydrographic conditions of the German b) low surface temperatures during winter and c) Bight in I956". Annls bioi., Copenh., 13: 76. high temperature but low salinity in the surface layers during the autumn months. Hydrography of the South-eastern North Sea 1966, At this occasion it is interesting to study the Danish Observations deviations of temperature and salinity at "Fladen" (Table 15) during many years; this can be done in Figure 83. In the South-eastern North Sea the lightvessel The mean values rgz6-52 referred to were taken "Vyl" recorded low salinities throughout the year from Koczy (1954). with exceptionally low salinities in May. Tempera Figure 84 shows the temperature variations at tures ranged from low to normal. some stations at the deepest part of the Skagerak. H. THOMSEN The figure is part of a larger figure published by Meteorologisk Institut, Gamlehavealle, Charlottenlund, SVANSSON (rg66) completed by the latest measure Denmark. ments. Not only Swedish data have been used but Table 15. Monthly means of salinity and temperature at surface and bottom at the lightvessel "Vyl" (55°24'4N, 7°33'5E) for a longer series of years, and deviations from these means (From the Danish Meteorological Institute, Nautical Department) Month Jan. Feb. March Apr. :VIay June July Aug. Sept. Oct. Nov. Dec. Salinity Surface Mean I93I-39, 1946-60 33·0 33.I 32.8 32·5 32.6 32·7 32·5 32.6 32.6 32·7 32·9 33·0 Deviation 1966 ...... -0.6 -0.9 -0.7 -0.6 -I.7 -I.O -0.6 -0.7 -0.3 -0.9 -O.I Bottom (20m) Mean I931-39, 1946-6o 33·4 33-4 33·2 33·0 33·1 33·1 32.8 32·9 32.8 32·9 33.2 33·3 Deviation 1966 ...... -0.6 -I.1 -0.4 -0.6 -r.5 -o.5 -0.5 -0.4 -0.3 -0.7 -0.9 Temperature Surface Mean 1931-39, 1946-6o 4·3 2.9 2.8 5·0 9.0 12.9 15.6 16.8 I6.o 13.1 9·7 6.7 Deviation 1966 ...... -I.7 -I.7 -0.2 -I.1 -0.3 o.8 -0-4 -0.9 -0.6 0-4 0.2 Bottom (20m) Mean 1931-39, 1946-6o 4·7 3.2 3·0 4-7 7·5 Io.6 q.1 16.o 16.0 13·5 !0.2 7·1 Deviation 1966 -I.7 -r.8 -0.3 -I.O -o.5 0.5 0-4 -0.2 -o.s 0.3 0.2 The lightvessel was withdrawn from December 19th 1966 to January 3rd 1967. Table 16. Monthly means of salinity and temperature in 1966 at surface and bottom at the lightship "Fladen" with deviations from means 1926-52 Month Jan. Feb. :VI arch April May June July -~ug. Sept. Oct. Nov. Dec. Salinity Surface (23.5) (22.0) 18-4 16.8 19.0 20.9 20.8 23.8 20.7 18.7 zo.s 20.6 Deviation -o.6 +o.s -2.5 -r.8 -0.6 +o.3 +o.7 +z.-t -2.8 -4.6 -3·3 -I.1 Bottom 40 m (33·7) (30.1) 33·9 34-5 33·8 33-4 33·4 33-4 33-4 33·7 33·5 33·5 Deviation .. +o.3 -3.8 -0.2 +o-4 -0.2 -0.1 +o.z ±o +o.I +-0.2 ±o -o.I Temperature Surface (5.9) (-J-.2) 3·9 4-4 5-2 6.8 9.0 II.O rr.s II.O 8.I 7·I Deviation .. -2.2 -o.8 -I.9 +o-4 +z.z +o.3 -0.3 -0.3 +o.8 -j-0.2 +r.o -o.5 Bottom 40 m (o.I) (L3) 3·0 9·5 I5.0 17.0 16.7 14·3 1I.7 7·3 -1-·7 8.I Deviation .. -o.5 -o.8 -I. I -0.9 -I. I - l. I -0.9 -0.9 -0.6 +o.7 -0.2 -0.7 -66- Fladen Lightship N 57.13' E 11.51' Temperature Deviations from Means 1923-52 ·c 4 3 2 +1 0~~~~-+~~~~~~~-+~~~r+-r~H---~-+~~~~~~~~~~~~++~~~ 4 1951 I 52 I 53 I 54 I 55 I 56 I 57 I 58 I 59· 1 60 I 61 I 62 I 63 I 64 I 65 I 66 I ·c 4 3 2 +1 3 4 0/oo S Fladen Lightship N 57.13' E 11.51' 6 Salinity Deviations from Means 1923-52 5 4 3 2 +1 OH4++~~H-~++~~~-H~~~~~~~~~-+~~-+~++~~~~~~~-14H+-~A-~+- -1 2 3 4 5 0 /ooS 1951 I 52 I 53 I 54 I 55 1 56 I 57 I 58 I 59 I 60 I 61 I 62 I 63 I 64 I 65 I 66 I 4 3 2 +1 o~~~~~~~~++ti4-+--1-~-+~~*-+*-+~--~~~-++-~~~~~~~~~H1-+~+ -1 2 3 40 m 4 Figure 83. Hydrography Near N. Seas T·c + M6, N 58.10' E og• 30' also Norwegian ones. The figure displays a sudden o N 58.08' E og•n · cooling of the deeper layers in March (as for the mechanism, see LJOEN, rg65). By now the tem x Other positions 8 perature at 6oo m has risen to 4.5°C but is still far from 6°C which seems to be a more normal 200 m temperature at this depth. 00 7 0' A. SVANSSON 0 o 0 xoo Kungliga Fiskeristyrelsen, H ydrografiska Avd., 6~--~---4~--+-~~----~--~--~--- Box 1038, Goteborg 4, Sweden. References 5 KoczY, F. F., 1954- "Monthly average values of hydro graphical observations on Swedish lightships 1923 to 1952." Fishery Board of Sweden, Series Hydrography, Rep. No.5· 300m LJOEN, R., 1965. "On the exchange of deep waters in the 7 Skagerak." ICES, Doc. CM 1965jN: 157 (mimeogr.). 00' 0 0' 0 ;xo: ' SvANSSON A., 1966. "Long-Term variations of subsurface .1' \ o\o~ oo,! 6 temperatures in the Skagerak." ICES, Doc. CM 1966/ N: 19 (mimeogr.). 5 Hydrography of the Kattegat Area 1966, Danish Observations 1961 62 63 64 65 66 67 (Table 17) Ice conditions Due to the early winter ice formations were 7r- 400 m o' reported from fjords and sheltered waters already '0 6 0~0 ;·: at the beginning of the year. By the middle of 00 ,o 0 0' '0 January some ice was also reported from the ' . 0 offing, and during the first part of February the 5r- o, ice cover increased quickly and reached a maximum '· by 17. February. At that date the sheltered 4r- fairways were covered by heavy landfast ice, and in the offing drift-ice of varying closeness was 7r 600 m reported to cover the sea from the Skaw to Riigen M0n-Falsterbo. In the subsequent period the ice •• 0 6 0 disappeared quickly and by I4· March all waters round Denmark were free of ice. "' • o0 5 OO,POO Salient features of the variation of the surface . salinity were high salinities in September and 4r- . . ..0 • unusual low salinities in November. Temperatures . ranged from low to normal throughout the year. 3r- H. THOMSEN Meteorologisk Institut, Gamlehavealle, Charlottenlund, Figure 84- Denmark. -68- Table 17. Monthly means of salinity and temperature at surface and bottom at the lightvessel "Anholt Nord" (S6°SI'zN, II 0 48'rE) for a longer series of years, and deviations from these means (From the Danish Meteorological Institute, Nautical Department) Month Jan. Feb. :\I arch April May June July .i\ug. Sept. Oct. Nov. Dec. Salinity Surface ?dean 1931-60 23-7 23.6 21.3 20-4 r8.2 r8.6 19.6 19-9 20.j 21.8 22.! 23-3 Deviation 1966 -2.3 I.9 0.1 -r.8 -0.6 I.O 0.2 3·3 -1.9 -3-5 0.9 Bottom (30m) Mean 1931-60 ...... 33·0 33·0 33.2 33·6 33·6 33-5 32.9 32.6 32.6 32-7 33.1 33-0 Deviation 1966 0.5 0.7 -0.9 0.0 -0.6 -0.3 -0.6 -0.2 -0-4 -0.1 -o.5 Temperature Surface Mean 1931-60 ...... 2-4 I.2 I.7 4·7 9-9 14·5 r;.5 17.8 IS-4 11.6 7·8 4·9 Deviation 1966 -2.2 -0.1 -I.6 -o.; 0.2 -0.2 -I.O -I.2 0.2 -o.5 0.2 Bottom (30 m) Mean 1931-60 ...... 6.7 j.2 4-6 4·7 4·9 6.s 9.6 !2.) 13·4 12.9 1I.O 8.7 Deviation 1966 ..... -0.9 -0.7 -1.1 -o.8 -0.2 0-4 0.3 -0.9 -0.2 0.5 -o.s From 9· February until 5· :\'larch the lightvessel was withdrawn on account of ice. Baltic-Belt Seas Danish Observations in the Great Belt and the Baltic Polish Hydrographical Observations in the Southern 1966 Baltic in 1966 (Tables 18-2o) (Figures 85-88; Table 21) Regarding ice conditions: see p. 67. The mean This contribution takes into account the obser salinities at "Halsskov Rev" lightvessel for the vations made by the Sea Fisheries Institute as well month of March were the highest recorded since as those made by the State Institute for Hydrology the lightvessel was established in 1923. Also at and Meteorology at Gdynia. "Gedser Rev" the salinities were high in March. In January the surface temperatures in the Due to the early and cold winter the temperatures Gdansk Deep and adjacent areas ranged between were far below normal in January, and low tem 2° and roc. The lowest winter temperatures (oo peratures prevailed throughout the year. to r 0 C), somewhere even lower than 0°, were H. THOMSEN observed in the second half of February. In the Meteorologisk Institut, Gamlehavealle, Charlottenlund, same month the surface waters in the Bornholm Denmark. Basin showed values from -o-4oC to about r°C. Table r8. Monthly means of salinity and temperature at surface and bottom at the lightvessel "Halsskov Rev" (55°20'zN, II0 02'7E) for a longer series of years, and deviations from these means (From the Danish Meteorological Institute, Nautical Department) :VIonth Jan. Feb. March April May June July Aug. Sept. Oct. Nov. Dec. Salinity Surface Mean 1931-60 17-5 16.7 14·5 q.6 12.4 13-7 q.o q.o 15-4 16.7 15.8 17-4 Deviation 1966 -2.6 7·3 -I.9 -0.3 -I.3 r.6 -0.1 z.s -4-5 -2.4 o.8 Bottom (ISm) Mean 1931-60 ...... 20.6 20.3 19-4 2I.6 22.] 26.9 25-7 24.0 22.3 21.1 19-7 20.8 Deviation 1966 -3-7 9-1 -4-3 4·4 0.1 I.5 I.1 2.) -2.9 4·8 I.3 Tem-perature Surface Mean 1931-60 ...... 2.3 1.4 I.9 4·8 9-3 13.8 16.9 17.3 15-3 11.6 7·8 +6 Deviation 1966 -r.s 0-4 -I.9 -0.1 0.0 -0.1 -1.1 -I.2 0.4 -0.3 0.4 Bottom (ISm) Mean 1931-60 ...... 3·3 2.3 2-4 4·5 6.9 8.; 11.4 13.6 q.1 11.9 8.7 s.6 Deviation 1966 ..... -2.1 I.O -r.8 -r.8 -I.1 -I.7 -I.6 -1.2 0.5 I.9 0.4 From q. February until 3· March the lightvessel was withdrawn on account of ice. - 6g- Hydrography Baltic-Belt Seas Table 19. Monthly means of salinity and temperature at surface and bottom at the lightvessel "Gedser Rev" (54°27'2N, I2°Io'8E) for a longer series of years, and deviations from these means (From the Danish :VIeteorological Institute, Nautical Department) Month Jan. Feb. :\1arch April May June July Aug. Sept. Oct. Nov. Dec. Salinity Surface Mean 193r-6o 12.0 rr.5 10.2 9.8 8.9 9.2 9·5 9.6 ro.s rr.6 II.3 !2.2 Deviation 1966 -1.2 r.s -IA -0.3 -0.6 0.0 -0.3 I.+ -2.6 -r.6 0.0 Bottom (rs m) :\'lean 193r-6o ...... q.r q.r 13.9 1+·5 14·+ 14·7 q.S I5·5 r6.o 15·7 13.8 I+-4 Deviation 1966 ..... -I.+ 3·0 -r.S 2.9 2.5 o.S -!.2 3·3 1.2 2.0 -0.] Temperature Surface "\~lean 1931-60 ...... 2-4 I.+ !.7 4·1 S.o !2.9 r6.3 r6.7 I5.I rr.S 8.2 +·9 Deviation 1966 ..... -I.O -0.3 -I.? -I.O -r.6 -o.S -r.s -1.2 -o.S -0.9 -0.2 Bottom (ISm) :\'lean 1931-60 ...... 3·0 I.] r.S 3·5 6.r IO.I 13.2 14·6 I+·+ !2.3 8.9 5·5 Deviation 1966 -I.3 -0.6 -r.5 -2-4 -2.5 0.5 -I.O -1.2 O.I 0.6 -0.4 From rz. February until 4· "\~larch the lightvessel was withdrawn on account of ice. Table 20. Monthly means of salinity and temperature at Christians0 (55°I9'N, I5°I2'E) for a longer series of years, and deviations from these means (From the Danish "Yleteorological Institute, Nautical Department) "Ylonth Jan. Feb. :\I arch April ::\1ay June July _1\ug. Sept. Oct. Nov. Dec. Salinity Mean r898-r930 ].0 ].0 ].0 ].0 ;.o 7-2 7·4 J.2 ].0 7·0 ].I ].0 Deviation 1966 ..... 0.6 0.5 0.5 0.5 0.3 0.3 0.2 0.4 o.6 0.] 0.5 0.7 Temperature Mean r898-1930 .... 3·3 2.1 r.S 3·0 6.r II.O rs.z r6.o I{.I II. I S.r 5·5 Deviation 1966 ..... -I.9 --2.0 -I.+ -2.1 -2.0 -0.2 0.] 0.0 -0.9 0.4 -O.I -o.r In March the negative values disappeared all over deeper waters of the Arkona Sea showed a very the southern Baltic, and the highest ones were complicated isotherm pattern, indicating three slightly above 2°C. successive intrusions of outside waters. The first occurred in August and brought in relatively warm The highest temperatures in May amounted to water with somewhat higher salinity from the about rr°C and in August they ranged between west. The second one came apparently from the I4° and rg°C, the lowest temperatures were east as it was carrying water of low temperature recorded in the western part of the sea and the and salinity at depths near to 40 m. At the same highest ones in the Gdansk area. About mid time, however, the third intrusion started at the November the cooling process at the surface 0 bottom. The new waters showed temperatures resulted in temperatures of go to J C. gradually increasing to over rroc in November. In the Arkona Sea, represented by the station at The last intrusion involved a water layer of consider I5°0I'N I4°02'E, (Figures Ss a and ss b) the winter able thickness so a complete temperature inversion temperatures below I°C reached the bottom. A took place. The salinity distribution, however, distinct thermic discontinuity layer was observed did not show any marked changes. as late as in June. As a result of winter cooling, The salinity conditions in the Arkona Sea are temperatures lower than 5°C remained around represented in Figure 85 b. There was an influx of 30 m depth probably till the end of June. The bottom water with salinity values higher than highest summer temperatures at the surface did r60fo in March-April, and the salinity increased not exceed r6°C. 0 in comparison with February, by about 6°/00. The warm top water layer with temperatures From March on, the salinity at the bottom above 14oc descended only slightly below zo m remained higher than I4%o till the end of the year. depth at the end of August. The second, but smaller, increase in salinity was In the third decade of November about 7·5oc observed in August. The bottom influxes were was observed. In the second half of the year the accompanied by a general increase in salinity -JO- a) Month Date 0 10 10 20 30 40 E 50 ..c -O.b) ~ 0 7.61'/n --7.74/7.69'/,. --,7.52'/\ -- 7.45'/u -- 7.42'/.,-7.43'/~ --.-----7.79'/., I I I 10 I 7.79 \ __ .... -- .... , ,..' 7.5'~· --- ...... ____ .... 20 30 40 50 Figure S5. Temperature and salinity in the Arkona Sea in rg66. within the whole water layer of the Arkona Sea, whole year for some other regions of the southern as is evident from the simultaneous rise of the Baltic in the same way as Figure 85. entire set of isohalines. The Bornholm Deep is represented by the The following figures (86 to 88) represent the station at 55°20'N I5°45'E. Because the hydro temperature and salinity conditions during the graphical data were scarce, the author completed 3 Table 21. The oxygen content (in ml/l) and the phosphate content (as mg/P2 0 5/m ) of the bottom waters in the most important areas of the southern Baltic in rg66 Arkona Deep Bornholm Deep Date depth m 02 PzOs Date depth m 02 P205 4· February ...... 45 S.66 25 r. February ...... g3 I.20 170 r6. February ...... S7 I.r5 rg. "March ...... 44 6.g5 rS. "March ...... gs 0.7r So r. April ...... 45 7.g6 3r. "March ...... S7 0.67 23. June ...... 44 4.Sg 20 23. June ...... go 0.21 rro I. September ...... 47 I.3g 65 30. August ...... go o.rg 23. November ...... 45 3·03 22. November ...... g5 I.42 r6o Slupsk Furrow, western part Gdansk Deep, southern part Date depth m 02 PzOs Date depth m 02 PzOs S. February ...... ss 3·73 55 25. January ...... r07 4·52 70 r7. February ...... Sr 3·4g rS. February ...... ro6 z.so r7. "March ...... go 5-23 70 ro. :March ...... 107 I.35 70 2. April ...... Sz 4.6r 3· April ...... ro6 I.42 7· April ...... rro r.6S 55 24. June ...... ss 6.52 25 24. May ...... 105 2.42 roo 27. August ...... rro 0.5g roo go 22. November • 0 •••• gr 3·53 So r6. November ...... r07 2.52 -JI- Hydrography Baltic-Belt Seas a) Month ~------~----~----,-----,------r-.~--r-~--~~~.-~--~~~--.-~--.-~X7.1~1--, Date 0 10 20 30 40 50 60 70 80 8.64 90 8.06 8.46 8.05 9" 8.45 7.98 9.02 E .c 100 ~b) Cl 0 7.57, 7.44 7.38 7.19 723 7.21 7.18 7.34 7.'t6 J 10 I I I J 20 I I I I I 30 I I I / / I \ -" 40 ' .... ------7.5.,•• - 6·t •• ------50 60 70 80 90 1649 16.08 16.20 100 Figure 86. Temperature and salinity in the Bornholm Deep in rg66. them by data obtained for the station at 55or8'N The winter water with temperatures below 3°C I5°58'E. The diagram (Figure 86a) shows that the remainded at a depth of about 45 m till September. winter cooling of the surface water was rather At the beginning of the year, bottom temperatures, strong and the summer surface temperatures were about 8.5°C were observed. Afterwards a slight not very high this year. decrease in temperature to about soc took place, -72- a) Month Date XII 0 10 20 30 40 50 50 60 ,.) 70 rr 80 5.68 2.30 2.20 90 5.38 7.67 E ..ca.. Cl> 0 b) 7 32 '-----7r .67 - ·--7.56-7.38--7. 27----7. 39---- 716. -.7 25 ------743. ----l 0 1 1 I I I 17.5"/ .. I I 10 I I I I I I / I I I 20 I I I I I I I I I I I I / 30 I I / / ----- / '-' ' / 40 ---- ''--7.5·/•. - _.. / 50 60 70 S>13"1•• 80 90 13.57 Figure 87. Temperature and salinity in the western part of the Slupsk Furrow in rg66. but in November a new influx of warm water was The most conspicuous features of the temperature recorded with temperatures amounting to g.r°C and salinity conditions were the autumnal warm at 8o m depth. The salinity, however, increased water influx at the bottom of the Deep and the but slightly (by about o.rs%0 , Figure 86 b). During relatively high temperature of the bottom waters the whole year the bottom salinity remained almost during the whole year. The last influx seemed to be the same, within the ranges r6-49%o to r6.o60fo0 . related to the one which had taken place in the The surface salinity kept below 7-5°/00 , except Arkona Deep in August. for the beginning and the end of the year. The next diagram (Figure 87) shows the annual 73- Hydrography Baltic-Belt Seas a) XII 0 10 20 30 40 30 50 60 70 80 90 100 E .c. 110 g. b) 0 0 7·56-7·59-7·68 ... 7·44--7·16-7·21------7·29-7·18------7·29----l 10 20 r I 30 I I I I I 40 I I / I I 50 I I I // \ / \ ... __ _/ 60 70 80 "'-.. 90 11 100 12 ---12.00 12.29 12.03 11 Figure 88. Temperature and salinity in the southern partof the Gdansk Deep in rg66. thermic and salinity changes in the western part layer was somewhat lower than in the Bornholm of the Slupsk Furrow, represented by the hydro Deep, as even negative temperatures were found. graphical station at 55°I3'N IJ0 03'E. Values less than roc reached 5o-6o m depth and The February temperature in the top water lasted till the first days of April. -74- Temperatures of I to Z°C, characteristic of Observations at Swedish Lightships and in the the winter water, did not disappear until June. Central Baltic 1966 The cooling rate at the surface in the autumnal (Figures Sg-gr; Tables 22-23) months did practically not differ from that in the The observations at the Swedish lightships in Bornholm Deep. The thermic conditions at the the Baltic show some deviations from the long-time bottom, however, were particular. salinity and temperature means (Koczv, 1954). In February the bottom temperature amounted At "Falsterborev" the salinity deviations are small, to soc but shortly afterwards there occurred a but the temperature deviations show unusually rapid fall till June, when only z.z°C was measured. cold water both at the surface and the bottom, This cold bottom water, passed quickly by and especially during the spring. At "Havringe" the was replaced by new warm waters showing in salinity deviations are almost negligible, but the November a temperature about 7.5°C. surface temperatures have been unusually high The changes in salinity within the bottom layer during June and July and instead unusually low were frequent. The salinity oscillated three times during August and September. At the bottom the 0 water has been colder than normally throughout during the year from a value less than rz / 00 to over I3Dfoo· The last increase in salinity was the whole year, except in December, when the connected with the influx of warmer waters at temperatures were normal again. "Svenska Bjorn" the year's end and seemed to be closely related shows a positive salinity deviation through the to the water occupying the level of about 65 m whole year. The surface temperatures have been depth in the Bornholm Deep at the same time. high in June and July as at "Havringe" and correspondingly low during August-November. In the Gdansk Deep (Figure 88 a and 88 b) the Conditions were again normal in December. The station at 54o5o'N rgozo'E, the surface temperature bottom temperature was low during the latter in February was negative involving waters down part of the year, especially in September, but to about 6o m depth. The temperatures of o to roc of the winter water disappeared about mid-March_ 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Values of I to Z°C were observed as late as in September, forming the temperature minimum near the lower boundary of the isohalinic top GOTLAND DEEP water layer. In the first decade of May the surface F81 temperatures were very low this year as they were MAY 11.1966 all over the Baltic, but later on the warming 100 process was rather quick and resulted in the area of the Gdansk Deep in temperatures of about IJ.J°C in the first decade of August. At the bottom a high temperature (J.J 0 C) was found in January as a result of the warm water influx into the 200 Bornholm Deep in the autumn of rg65. It gradually S'/,, decreased to 4.8°C about mid-November. The surface salinity decreased in March to less 2 3 4 5 6 7 8 than J.5Dfoo and remained so until the end of the year. The mean depth of occurrence of the 80fo 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 0 0 isohaline in rg66 was 67 m, thus the isohaline top } water layer this year was thicker as compared with ./ FARO DEEP \'-...... _ 0 ml/L the long-term value. The bottom salinity oscillated 2 F 80 around rz0fo and the rz0fo isohaline appeared and '. "">'<-""'-...... 0 0 .· \ \ MAY 10.1966 disappeared several times within the water layer from 95 m depth to the bottom. 100 j \ ( \ t'C The Table zr shows data concerning the oxygen . and phosphate contents of the bottom water at = \ ' \ POt;-P'-., \ the stations, the positions of which were given above. )..lgA/L '1\ S'/oo ,· 200 A. GLOWINSKA 2 3 4 5 6 7 8 Sea Fisheries Institute, Al. Zjednoczenia r, Gdynia, Poland. Figure Sg. 75- Hydrography Baltic-Belt Seas 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 both in the bottom water and at the 175 m level at o~,_,_.,,,~.. -.-.-.-.-.-..,-.-.- F 8r in August and November. Obviously a small . ______] inflow of denser water has occurred, which has lifted up the stagnant water-layer from the bottom to the 175 m level. The inflow has been so small that the old stagnant water has not been driven 100 out over the sills to the northern Baltic. The stagnation has continued at the 175 m level and the new bottom water has again stagnated and H 2S has been formed there. A layer with oxygen containing water has remained between the two stagnant layers. \Vhen this oxygen has been exhausted, the two stagnant layers will grow 5'/,, together, filling the whole Gotland Deep with stagnant sulfide containing water. 2 3 4 5 6 7 8 The above described development of the stagna 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 tion in the southern and central Baltic has prevented 0~.-.-.-.-.-.-~~-.-.-.-.~-.~--.-~ the oxygen supply of the deep water in the northern t•c /--- ~------_) Baltic proper and the conditions have grown 1 worse there as well. In the Landsort Deep this is \:::;;;;\ ·········· .. ·· ::~£::. reflected as a continuous decrease of the oxygen values below roo m during the year. In November 100 .: c" the oxygen is almost completely exhausted in the /0 2ml/L \ \ 5'/oo deep water and values below o.r mlfl are recorded "·-lI ...._po-· 4- P.,ug A/L between rso m and 440 m. +++ I ·-...... ~ ++++++++++il++++++.++-+d-+ H S S A/L , I " +++++++ +++ 2 - J.l9 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ~- H 5 ml/L 1 ·"-. ++++++++.,.++++ 200 2 0~,_,-.,,,-,~-,-.-.-.-.-.-.-.-.- 1 2 3 4 5 6 7 8 ) I 0 ml/L Figure go. '--. ---- 2 GOTLAND DEEP "~\:< .... ········ F 81 returned to almost normal m December. At NOV . 21. 1966 ,. ) " "Finngrundet" the salinity deviations were small. 100 ··..• i \ The surface temperatures show the same pattern ../ \ \ t•c as at "Havringe" and "Svenska Bjorn". The __.·· " \ Sml/L"-\ bottom temperature was extremely low during the . / H2. '1-. .tt+++++++++++++~ 1 "-. PO=- P)lg AIL summer but the conditions returned to normal in ++++++++++-t-H' \ \ 4 October-December. 200: \ \ Due to the severe ice conditions in the Baltic _+++++++++++-t-+++/++++~~~++ H2S-S pgA/L \ H 5 l/L I --~~~++++ +++++++-t-++++++ no winter expedition was carried out with "Skage ·, 2 m --~ rak". The Swedish observations during spring, 1 2 3 4 5 6 7 8 summer and autumn do not show any significant 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 changes of the hydrographic conditions in the Arkona Basin. No inflow of importance seem to have occurred during rg66. In the Bornholm Basin FARO DEEP this has led to decreasing oxygen values in the F 80 deep water. During December there has, however, NOV. 20.1966 been a small improvement of the oxygen conditions. 100 5'/oo As predicted in the previous report (FoNSELIUS, 1967), the lack of inflows of new water has led to stagnation and hydrogen sulfide formation in the deep water of the Gotland Basin during rg66. The Figures 8g, go and gr show the development of the stagnation in the Gotland Basin at F 8r and F So. It is remarkable that hydrogen sulfide can be found Figure gr. -?6- Table 22. Monthly means of salinity and temperature in 1966 at surface and bottom at Swedish lightships with deviations from the 30-year means, at ,Hiivringe, from ro-year means :VIonth Jan. Feb. :\larch April :Viay June July Aug. Sept. Oct. Nov. Dec. "Finngrundet" Surface Salinity ...... s.z s.z j.2 5-4 5-5 5·5 j.6 5·+ Deviation -0.3 -0.2 -o.r -i-o.z +o.z +o.r +o.3 ±o Bottom 30m Salinity ...... j.6 5-7 5-7 5·7 5·5 5·5 5·6 5·6 Deviation ... . -O.I -O.I ±o -O.I -0.2 -0.2 -o.r -o.r Su•·face Temperature .. Io.6 I6.2 I2.9 ro.o -f.8 z.s 9-I Deviation .... +3-3 +2-+ -2.7 -2.! -0.3 -o.s ·j- 3· I Bottom 30m Temperature .. I.O 0.9 r.6 2.9 6.5 4·7 2.6 z.S Deviation .... -3-5 -+-3 -3-7 -2.9 ±o -0.4 -0.3 -0.7 "Svenska Bjorn" *) Surface Salinity ...... (6.8) 6.2 6.0 5-9 5-9 6.2 6.6 6.2 Deviation +o.6 +o.s +o.s +o-4 +o-3 +o.r +o.s +o-3 Bottom 30m Salinity ...... (?-I) 7·0 6.7 6.8 7·3 7·0 7-I 6.8 6.8 6.9 Deviation ... . --t-o.S +o-7 +o.5 +o.6 +I. I +o.7 +o-7 -'-o.5 -f-o.s +o.6 Surface Temperature .. (r.z) I r.7 I6.8 I3.0 I0.3 7·2 5·+ 8.6 Deviation .... -1.2 +z.8 +z.I -2.8 -2.8 -r.8 -!.2 +r.7 Bottom 30m Temperature .. (I.S) r.s +-5 4·3 4·6 6.0 j.6 4·2 +-2 Deviation .... ,o.9 -I.2 ±o -I.? -2.6 -2.0 -o.8 -0.3 -0.4 ''Havringe" *) Surface Salinity ...... (6.6) 6.2 6.3 6.I 6.5 6.6 6.6 6.9 6.9 6.s Deviation -0.-f -0.4 -0.2 -0.3 +o.r +o.r -o.r -'-o.r -o.r -0.2 Bottom 40 m Salinity ...... (6.9) 7·0 6.9 7·4 7-5 7·5 7·2 7-+ 6.9 7-2 Deviation ... . -0-+ ±o -0.3 -t-o.z +o-3 +o.2 -o.r +o.r -O.j -0.1 Surface Temperature .. (o.7) 4-I 12.4 I 7.2 I0.7 8.-f 4-2 8.8 Deviation .... -r.5 -1.2 + I.4 +r.7 -2-+ -!.2 +o.z +LS Bottom 40 m Temperature .. (r.2) 0.7 2.3 r.8 2.3 +·5 -f.O -f.I 2.8 Deviation .... -r.8 -2.2 -r.s -z.s -2.-f -2.9 -r.5 -r.s +o.z -I.O '' F alsterborev'' * *) Surface Salinity ...... 8.I (8.4) 7-6 7·3 7-+ 7.6 7-9 7·7 7·8 8.8 7·9 Deviation -O.I +o.6 +o.r -O.I -O.I -0.3 ±o -0.7 -o.s +o-5 :±:o Bottom IO m Salinity ...... S.r (8.7) 7·7 7·3 7·5 7·6 8.o 8.8 7·8 7·8 9·4 8.o Deviation ... . -0.-f +o-9 +o.r -0.2 -o.I -o.s -0.2 +o.6 -0.9 -o.5 +o.g -o.r Surface Temperature .. 0.9 (r.o) I.5 s.z I2.0 Ij.6 Ij.2 13-9 II.2 7-9 j.O 8.2 Deviation .... -2.0 -I.O -2.2 -2.6 -0.4 -0.2 -I.3 -o.8 -0.5 -O.j -o.r -0.9 Bottom IO m Temperarure .. I.O (r.I) r.s j.I I I.5 I3.8 q.6 13-9 II.3 7-9 5·0 7·9 Deviation .... -I.9 -0.9 -2.I -2-+ -0.3 -o.S -I. I -0.7 -OA -0.5 -o.r -o.g *) I-IS. January **) ro-3r. March -n- Hydrography Baltic-Belt Seas Table 23. Arkona Deep 55°00'N l4°0j'E Depth Temp. pH P04-P Alkal. NO~-N NO:;--N NH;-N m oc p.g-at.jl mvaljl (J.g-at./1 [.J.g--at./1 p.g-at./1 7· May 000 3·72 7·67 9.38 8.20 0 !.45 0 O.IO oro 3·23 7·65 9.16 8.24 0 !.53 0 0.06 030 2.00 7·84 9·23 8.r6 0 !.55 0 O.I I 045 1.99 14-21 6.ro 7.80 o.og I.83 O.+O o.o8 23. August 000 rs.38 7·70 6.6! 8.r8 O.I I 0 0 8.85 oro 15.39 7·73 6.5+ 8.20 o.o9 0 0 s.6o 030 6--12 8.36 5.84 7·55 0.34 0.62 O.I7 6.55 045 8.35 r6.o9 2.!6 7·34 I.OO 3-40 0.!2 7·70 15. November 000 8.79 7·73 7-48 7·97 O.IO r .5r oro 8.79 7-72 7·+5 8.09 O.II I.5I 030 8.8r 7·7I 7·+6 8.ro O.I5 LSI 0+5 r2.56 I7.8I !.24 7-22 2.04 r.89 Bornholm Deep 55°I5'N I5°59'E 7· May 000 2.+5 7·27 9·57 8.rs 0 I. 53 0 O.IO s.67 oro 2.41 7· 2 7 9.7! 8.r8 0 !.41 0 0.12 7·3I 030 2.33 7.28 9·57 8.13 0.06 !.49 O.IO 0.12 8.28 050 I.I7 7·55 9·29 8.oo 0.03 !.54 O.IO 0-40 7·2+ 070 2.-fO 13.06 7-43 7·77 0.37 !.73 2.10 O.IO 6-40 090 8.rs r6.27 0.33 7.15 !.20 !.95 2.:20 0.38 3.88 24. August 000 I5·3+ 7·35 6.52 8.22 0.07 !.55 0 0 s.6s oro 15.53 7·33 6.51 8.26 0. I2 r.s6 0 0 6-45 030 4.86 7.-fi 7·94 8.oo 0.2 r I. 57 0 0 s.so 050 2.42 8.8r 6.8r 7.80 0-47 r.6s o.6o 0 3·65 070 5·58 14·36 4.19 7·59 o.8o I.83 2.20 0.07 2.12 o8o 7·69 I5.9I o.r5 7·3I 2.8o 2.02 3·5I o.q r6. November 000 8.45 7-42 7·56 7·96 o.r5 I.+9 oro 8.+8 7·4° 7·48 8.03 0.13 r.so 030 8-48 7-40 7.62 8.o6 0.24 r.so oso +·56 9·77 5·29 7·50 0.54 r.6o 070 7·63 !3.92 3·42 7-43 o.86 !.75 087 9.28 16-47 I.62 7·29 r.88 I.83 Gotland Deep 57°2o'N 2o0 o3'E II. May 000 2.62 7·56 9·59 8.!2 r.s8 0.25 o.os 7-12 070 4-49 !0.24 2.0) !.70 2.85 0.04 5.26 roo s.o8 !!.21 !.20 !.70 3.IO 0.04 4-IO ISO s.6o 12.46 0-40 7.01 2.24 !.77 3.10 o.o8 5.I I 200 ...... 5·75 !2.77 0.2! 7·05 2.60 r.8o 2.65 0.07 6.27 2+0* ...... s.8r !2.93 0.07 7.I8 2.34 r.86 2.70 O.IO 6.70 25. J\.. ugust 000 14.50 7·27 6.68 8.30 O.II r.56* 0 0 II.40 070 3·53 9·05 3·77 7.24 0.91 !.64 o.so 0 I.I5 roo s.oo rr.o6 r.q 7·0+ I.5I !.76 2.60 0 3.20 ISO 5·55 !2.27 0.32 7.02 2.30 I.78 2.82 0 4·65 200 5·78 !2.74 0.06 7.0! 3.20 I.87 !.45 o.r5 3·25 240 5.82 12.86 0 7.19 4.50 r.88 0 0 Io.8o 21. November H.S vg-at.fl 000 7-47 7.19 7·7° 8.or o.rs LSI 070 3.66 9-44 2.45 7·30 !.32 I.63 roo 5·0+ II.I6 I.OI 7.02 r.6s r.68 ISO 5·59 I2.37 0.13 7·05 2-43 !.72 200 5·78 I2.74 o.o9 7-12 3·52 I.76 240 5·84 r2.9I 0 7·24 6.37 I.84 23·5 (table continued on p. 78) 78 - Table 23 (continued). Landsort Deep 58°35'N r8°r4'E Depth Temp. s 02 pH POcP Alkal. NO;-N NO;-N NH!-N m oc •j 00 mlfl [.Lg-at.jl mvaljl [.Lg-at./1 [.Lg-at.fl [.Lg-at.jl ro. May 000 ...... 3-27 6.74 9·89 8.36 0.16 I-47 0 O.IO 6.38 070 ...... 3·87 9-76 !.79 7-13 2.23 r.68 r.65 O.IO 4-30 roo ...... 4.28 10-40 o.6o 7-39 2-44 1.69 2-55 0.05 4·40 I 50 ...... 4-59 10.91 0-47 7.12 2-44 !.30 0.06 4-03 200 ...... 4·65 11.07 0.37 7.10 2-44 I.JI 3·45 o.o8 3-95 440 ...... 4·74 II.I9 0.41 7-04 2.20 1.74 2.20 0.05 2.76 30. August 000 ...... 12.12 6.59 7-56 8.12 0.06 1.45 0 0.05 6.r5 070 ...... 3·46 9-24 2-55 7-19 I. 52 r.65 o.83 0.08 4-05 roo ...... 4·50 10.74 0.17 7.00 2.69 1.73 2.90 0.05 5.20 I 50 ...... 4.68 10.99 0.95 7·05 2.55 1.74 2.70 0.05 4-30 zoo ...... 4·76 II.09 0.31 7.06 2.68 1.75 3-57 0.05 6.8o 440 ...... 4.88 11.24 o.r5 7-07 z.35 1.75 4·23 0.07 5-05 17. November 000 ...... 6-46 6.74 7-91 7-96 0.13 1.44 070 ...... 3·53 9-39 1.99 7· 24 1.82 !.63 roo ...... 4·35 ro.5r 0.16 7.10 2.60 r.66 I 50 ...... 4.61 ro.88 o.os 7.1 I 2.67 200 ...... 4-74 II.06 0.08 7.11 2.89 I.67 440 ...... 4·85 II.2I 0.07 7-13 2.6r I.69 In Table 23 values for nitrate, nitrite and ammonia temperature was -0.3°C and negative temperature are given. The results of these analyses are published was observed down to 40 m depth. elsewhere (SEN GuPTA, in press). In the first half of rg66 the inflow of North Sea S. H. FoNsEuus water into the Baltic Sea was slight and slight Kungliga Fiskeristyrelsen, Hydrografiska Avd., Box 1038, changes only were observed in the salinity of the G6teborg 4, Sweden. off-bottom layer. References FoNSELIUS, S. H., 1967. "Observations at Swedish light ships and in the central Baltic". Annis. bioi., Copenh., 22: 54-6. KoczY, F. F., 1954. "Monthly average values of hydro graphical observations at Swedish lightships 1923-1952." (In Swedish). Fishery Board of Sweden, Ser. Hydrogr. Rep. (5). SEN GUPTA, R., 1967. "Inorganic nitrogen compounds in the Baltic." Meddelanden fran Oceanografiska Institutet i G6teborg. (in press). Some Peculiarities in the Oceanographical Regime of the Baltic in 1966 (Figure 92; Table 24) The winter of rg6sfrg66 in the Baltic was severe. In the second half of February the whole northern Baltic was covered by stationary ice, and the middle Baltic by drifting ice. Only the open part of the southern Baltic was free of ice and here the water temperature in the upper layer (up to 20m.) was below o.5°C between 20. and 30. February. At the same time drifting ice was observed in the Figure 92. Distribution of hydrogen sulphide (ml/1) in the area of 56°45'N (the Gotland Deep), the surface off-bottom layers of the Baltic Sea in August 1966. -79- Hydrography Baltic-Belt Seas Table z4. Hydrological data for the deeps of the Baltic Bornholm Deep (55°IO'N, I5°57'E) Depth Temp. s o. pH m oc o; oo [.Lg-at./1 2z. February 0 ...... o.os 7-43 9·19 S21 10.9 0.35 7·S7 20 ...... 0.10 7·50 g.rs S17 10.6 0.34 7·96 40 ...... 0.22 7·52 S.97 Sor 10.9 0.35 7·95 6o g.o2 7.06 630 r6.5 0.54 7·69 So 15.S2 1.29 II6 7.26 17. May 0 ...... •.. 4·58 7·34 9·07 S1o 3·9 0.13 S.26 20 ...... Z.I4 7·43 S.87 792 3·9 0.13 S.I3 40 ...... I. 59 7.6S S.6S 775 3·9 0.13 S.1I 6o !.21 11.65 7·7 1 6S9 6.7 0.22 7·93 So 7·94 15.99 I.06 95 44·6 1.44 7·19 go ...... S.ZI r6.4o 0.32 29 57·6 r.S6 7·19 13. August 0 ...... 17·34 7.21 6.Sr 6oS 2.1 0.07 S.34 20 ...... 15.99 7.Z1 6.77 6os I.2 0.04 8.36 40 ...... z.64 7·57 8.ss 766 !.2 0.04 7·95 6o 3·54 II. 55 6.o6 541 6.o 0.19 7.66 So 7·Z9 15.59 0-45 40 27-4 o.88 7·17 0.00 o.po 90 ...... S.03 16.15 0.07 6 103.6 3·35 7-30 0.16 7.20 30. October 0 ...... 9·70 7-43 7·31 653 2.0 0.06 S.ro zo ...... g.6I 7·43 7.26 64S I -4 o.os S.oS 40 ...... 4·59 S.22 6.3S 570 11.7 0.38 7.62 6o s.6z 12.16 4-46 39S 17.0 0.55 7.22 So 7.00 IS.I2 1.37 122 47·0 1.52 6.94 90 ...... S.oo 16.15 0-42 37 105·3 3·40 6.92 0.00 0.00 24. November 0 ...... 7.01 7·50 7·75 692 zo ...... 6.gg 7·50 7·73 6go 40 ...... 6.gS 7·50 7·69 6S7 6o S.74 13.03 4.66 416 So 9-4S r6.o4 I.S4 164 90 ...... 9·44 r6.64 !.22 109 Landsort Deep (5S 0 35'N, 20. May 0 ...... 4·74 6.26 9·14 Sr6 3·1 0.10 S.34 zo ...... 0.59 6.g6 S.98 794 2.S 0.09 S.I3 40 0-44 7·47 S.1 I 7Z4 S.z 0.26 7·95 6o 3·3S S.gS 3·45 30S 44·6 1.44 7·32 So 4.ZI 10-44 0.67 6o 7I.I 2.29 7·23 IOO 4·37 ro.66 0.54 4S 7S.2 2.53 7·13 200 4·67 II.06 0.37 33 66.7 2.15 7·05 430 4-74 11.37 0.39 35 I38.s 4-48 ?.II S. August 0 ...... rz.6o 6.s6 7·34 655 o.oS S.rS zo ...... 4.0S 6.gS S.31 742 2.2 0.07 7·9S 40 ...... z.z6 7·52 S.27 739 4·0 0.13 7.Sg 6o 2.27 8.37 5·15 460 31.1 I.OO 7·27 So 4·14 !0.21 o.So 71 70·9 2.29 6.9S IOO 4-41 ro.66 0.37 33 75·2 2.43 6.S6 zoo 4·67 II.I7 0-41 37 66.1 2.13 6.85 430 4.S2 11.2S 0.31 28 6r.S 2.00 6.s5 0.00 0.00 20. October 0 ...... S.3S 6.29 7·77 694 2.0 0.06 7.S2 20 ...... S.gz 6.64 7·56 675 S.S 0.28 7·93 40 ...... z.s3 7·56 8.II 72 4 9.2 0.30 7·76 6o 2.31 7·92 6.94 62o 15.1 0.48 7·33 So 3·S4 g.Sr 1.19 106 63.2 2.04 6.gS IOO 4·43 !0.73 0.33 29 6S.o 2.20 7.00 zoo 4·7Z 11.09 0.24 21 81.2 2.63 6.91 430 4-79 11.33 o.zo rS 75·S 2.45 6.91 o.oo 0.00 (table continued on p. So). So - Table 24 (continued). Gotland Deep (57°22'N, I9o57'E) Depth Temp. s 03 02 P04-P POeI' pH H 2S H 2S oc O/ 3 i] m '00 ml/1 [_lg-at.jl 1ng/1n [J¥g-at mljl p.g-at.jl 3· April 0 ...... r. ro 7.6S g.I6 SrS 20 ...... r.og 7-77 S.g6 8oo 40 ...... r.oS 7-77 g.II 8q 6o ...... 3-S5 8.87 5-00 446 So ...... 4·87 10.52 r.8s r6s roo ...... 5-32 I I.5 I 2-75 246 I 50 ...... S-S9 I2-4S 0-40 36 200 ...... 5-76 12.79 0.20 rS 230 ...... 5.s2 12.90 0.26 23 12. May 0 ...... 3.06 7-S7 8.79 785 3-0 O.IO 8.12 20 ...... 2.58 7-59 8.86 791 3-0 O.IO 8.24 40 ...... 2.52 7-59 8.98 So2 3·0 O.IO 8.24 6o ...... 3-58 8.87 -t-85 -\33 2I.-t o.69 7-51 So ...... 4.6o IO.S-\ I. I 7 10-t 39-2 1.27 7.2 I roo ...... 5.1 I I 1.24 I.26 113 43-5 I.4I 7· I I ISO ...... 5.6o 12.50 0.22 20 66.2 z.q 7.10 200 ...... 5-73 12.79 0.19 I7 77-I 2-49 7-0S 2 33 ...... 5.8o 12.86 0.22 20 79-6 2.57 7-2-t IO. August 0 ...... IJ.20 J.20 6.47 57S 3· I 0. IO 8.39 20 ...... 5-27 7-S6 8-4S 755 I.7 O.Oj s.os 40 ...... 3-63 7-59 S.r6 729 3--t 0. I I 7-90 6o ...... 2.26 8.22 6.r6 S50 13.2 0-43 7-27 So ...... -1·36 10.21 r.68 ISO 22.7 0.73 6.95 roo ...... S-04 r r.oS I.43 r2S 37-7 I.2 I 6.g6 ISO ...... 5-S-t 12.34 0.26 23 s8.o I.8j 6.93 0.00 0.00 200 ...... 5-73 12.65 O.II IO go.; 2.93 7· I I 0.08 3.61 233 ...... 5-78 12.79 0.04 4 125-9 -\-07 7.18 0.32 14-44 2-t- October 0 ...... 10.74 7-29 7-26 648 2.9 o.o9 S.rS 20 ...... 10.74 7-29 7-26 64S I.2 0.04 S.I2 40 ...... ro.5r 7-30 7-I9 642 7·2 0.23 ;.87 6o ...... r.86 7-77 7·65 683 I 3· I 0-42 7·27 So ...... 3-48 9-13 3-13 z8o 45· 2 I.46 6.g6 roo ...... 4.82 II.OO o.8o 7I -\3·4 I.-tO 6.93 IjO ...... 5-55 12-43 0.21 Ig I 12. I 3-62 6.94 0.00 0.00 200 ...... S-74 r2.Ss 0.!2 II II3.2 3-66 6.95 0.00 0.00 235 . . "." ...... 5-78 I2.S8 0.00 0 I79-3 5·79 6.97 0.20 g.oo In the second half of rg66 an increased inflow salinity was observed in the intermediate (So- of North Sea waters was observed in the south 120 m) layer only in the Gotland Deep (see Table 24). western part of the Sea. In mid-May the average The lack of an appreciable inflow of North Sea salinity in the off-bottom (40-45 m) layer, in the waters in the second half of rg65 and the first half Arcona Deep was 12.6°(00 in mid-August r6.50foo of rg66 resulted in reduction in the content of and in late October 17.2°(00. In October fresh oxygen in the Bornholm-, Gotland- and Faro North Sea waters reached the Bornholm Deep Deeps and in the formation of hydrogen sulphide where higher salinity was observed in the inter in the off-bottom layer in the middle of rg66. mediate (50-70 m) layer, and the Slupsk Gut Water layers (beginning at 75 m depth) polluted where the increased salinity was observed in the by hydrogen sulphide were also observed between off-bottom layer. In November the salinity con Gotland and Oland in August (Figure 92). tinued to rise in the deep layer of the southern In the autumn of rg66, as a result of the inflow Baltic. of fresh North Sea waters, the content of oxygen In the middle and northern parts of the sea increased in the off-bottom layer of the Bornholm salinity in the deep layer remained almost the Deep, but hydrogen sulphide remained in the same throughout rg66, a gradual decrease in off-bottom layers of the Gotland- and Faro Deeps - 8r- Hydrography Baltic-Belt Seas and in the off-bottom layer between Gotland and Gotland Deep the lowest amount of phosphates Oland. in the o-20 m layer was observed in October. A great amount of phosphates (47 mgjm3 was This may be explained by a high content of found in the central part of the Gotland Deep in phosphates in this area in winter; the phosphates 3 February, and it was somewhat higher (r2 mgjm3) minimum (about I.J mgjm on an average) in the in the layer from ro to 20 m. In the southern part surface (0-20 m) layer was observed in August of the Gotland Deep the winter maximum of to the south of the Gotland Deep. phosphates in the surface (o-20 m) layer was on In the off-bottom layer of the Gotland and average 6.8-6.3 mgjm3. In the southern Baltic, Bornholm Deeps an accumulation of phosphates however, the content of phosphates in the surface was observed, characteristic of stagnation pheno layer increased till ro.o to 13.5 mgjm3 . mena in the Baltic. In the northern Baltic, to the North of 58°N, M. V. KALEIS, N. B. ALEXANDROVSKAYA, the summer minimum of phosphates in the o-20 m E. A. YULA layer was observed in August and it was low (on 3 Institute for Scientific Research of Fishing Industry, an average r.o mgjm ). In the southern part of the Bezdeligu r, H.iga, Latvian SSR. PART II. PLANKTON AND BENTHOS - 8-t- Distant Northern Seas The Continuous Plankton Recorder Survey: Plank 40 30 20 ton in the Irminger Sea Region during rg66 65 (Figure 93) The plankton Recorder survey in 1966 was continued as in previous years. Samples were collected at a depth of 10 metres at monthly intervals on a number of standard routes (see GLOVER and RoBINSON, Annis. biol. Copenh. 22: 60 p. 59-60). The Survey is supported by the British Treasury C8 C7 C6 C5 and by contract N62558-3612 between the Office of Naval Research, Department of the United States Navy and the Scottish Marine Biological 87 86 Association. The methods of presentation of the results and an account of the survey in the waters JFMAMJJASOND JFMAMJJASOND around the British Isles are given by GLOVER and RoBINSON in this volume (p. 86ff). This account is [~ -£ ~ ~ restricted to two statistical areas in the Irminger LA~OPLA:::_jl ~ Sea which have been traversed regularly since 1957 by Plankton Recorder routes. 60 The positions of the two areas are shown in 30 Figure 93· The histograms show the fluctuations 10 in abundance of a few selected species or groups of organisms in the two areas in 1966. The line 400 graphs give the average monthly abundance of 100 these organisms in each area during the nine 50 years 1957-1965. The results are presented in 150 this way so that the fluctuations in abundance in ALAN US 1966 may be compared with the average seasonal MARCHICUS cycle. Gaps in the baseline in July and September I-IV indicate that there was no sampling in these months in 1966. CALANUS The estimate of phytoplankton is obtained from a visual assessment of the green colouration of the filtering silk. The spring outbreak in B6 started at the normal time, in May, but was short-lived 8 and had disappeared in June, whereas in the 4 western area B7, it started late (in June). The 2 most striking feature of the phytoplankton cycle during the year, however, was in B6 where, after the normal decline in late summer, there was a YOUNG STAGES most unusual and abundant crop in October, OF increasing even further in November, consisting SEBASTES of Thalassiothrix longissima, Thalassionema nitz ~- J FMAMJ JASON D JFMAMJJASOND schioides, Thalassiosira spp. and Hyalochaete spp. Such an event is quite without parallel since 87 86 sampling was started in this area in 1957, although Figure 93· Histograms showing numbers, per Recorder T. longissima and T. nitzschioides were abundant sample, of selected organisms in areas B 6 and B 7 in 1966. in the late autumn of some years before 1956 in The line graphs show the mean values for the period 1957 to 1965. The estimates of phytoplankton are based on the neighbouring area B5. visual assessments of the green colour of Recorder silks; Numbers of copepods were generally close to the numbers of Thalassiothrix longissima are given in the average in both areas, but were lmv in B6 in thousands per sample. For further details sec text. - ss Plankton Dist. N. Seas May and June and high in October and November The distributions of the young stages of Sebastes when the phytoplankton, also, was abundant. The in rg66 do not contribute any significant additions young stages of Calamts finmarchicus were some to the geographical patterns already presented in what below average in spring, but appeared at earlier volumes of the "Annales Biologiques", with the normal time. They were unusually abundant the exception of the occurrence in April of a small in both areas in August. The over-wintering patch of young without sub-caudal melanophores stages V and VI of Calanus appeared early and between Flemish Cap and the north-eastern margin were close to or above average in both areas except of the Grand Bank. Similar patches in this region in May and October in B6 when they were below were noted in the years rg6o, rg6z, 1964 and rg65. average. YANULOV (rg6z, Sov. Fish Invst. norwest. Atlan.) Euchaeta norvegica was abundant in both areas has commented on morphometric differences in from June onwards; there were very high numbers the adults from this area; these may be related in B7 in June and in B6 in August. The gaps in to the occurrence of the apparently isolated patches sampling in July and August make it difficult to of young with characteristics closer to those of assess the seasonal cycle of this copepod. the oceanic young than those generally occurring The young stages of Sebastes appeared later over the shelf and slope. than usual in area B7 where they were most The non-pigmented (oceanic) young stages abundant in June. They were again scarce in B6. A more detailed account of Sebastes in rg66 is Small numbers were taken in April to the west given by HENDERSON below. of the Reykjanes Ridge in the region where they have usually occurred, but the distribution was R. S. GLOVER, G. A. RoBINsox fairly uniform without any indication of a centre Scottish :Vlarinc Biological Association, Oceanographic of abundance. The small patch near Flemish Cap, Laboratory, 78 Craighall Road, Edinburgh 6, Scotland. noted above, contained only small numbers of young. There was a rather wider distribution in Plankton Investigations from Aberdeen 1966 in the May, with numbers slightly greater over the Distant Northern Seas Area Reykjanes Ridge, and with some indication that the young were rather more numerous further to Plankton sampling from the Aberdeen laboratory the southwest. The numbers taken in both these in the Distant Northern Seas area in rg66 was months, however, were appreciably lower than very limited. Details are given under the Near in most of the earlier years (see GLOVER and Northern Seas (p. gr). RoBINSON, above, and Figure 93). In June the J. H. FRASER numbers taken were slightly higher than the Marine Laboratory, Victoria Road, Torry, Aberdeen, Scotland. average for previous years, but in July were again below the average. In August and in September, respectively, nine and three larger specimens were Sebastes in Continuous Plankton Records in 1966 taken. Regular sampling with the Hardy Continuous Plankton Recorder in the North Sea and North The pigmented (shelf and slope) young stages Atlantic was continued at the standard depth of The population north of the Grand Bank ro metres throughout rg66. The work was supported of Newfoundland, in an area where Recorder by a grant from H. M. Treasury through the sampling has been available only from rg63, was Natural Environment Research Council and by repesented in rg66 by small numbers on a record Contract N62558-36rz between the Office of in late May and again in June and July. In these Naval Research, Department of the United States months the numbers were rather larger than had Navy, and the Scottish Marine Biological Associa been found in rg65, but were still well below the tion. The routes currently traversed by the Recor mean for the earlier years. This population was der survey were shown by GLOVER and ROBINSON not represented in samples taken in August or Annls. bwl., Copenh., 22: Figure 8z). September. Very few young Sebastes were found The general level of sampling was well maintained over the main part of the Grand Bank. Over the during the months April to September, the period Nova Scotian Shelf and in the Gulf of Maine they of occurrence of young Sebastes, but the seamen's were few in number and limited to July and August strike in the United Kingdom in May and June G. T. D. HENDERSON resulted in the loss of some sampling in the central Scottish Marine Biological Association, Oceanographic part of the area in these months. Laboratory, 78 Craighall Road, Edinburgh 6, Scotland. -86- Near Northern Seas The Continuous Plankton Recorder Survey. Plankton around the British Isles during rg66 (Figures 94-104) The survey by the Continuous Plankton Recorder was continued in 1966 on the same basis as in other years. It was financed by the British Treasury through a grant from the Natural Environment Research Council and by Contract N6z558-36rz between the Office of Naval Research, Department of the United States Navy, and the Scottish Marine Biological Association. This report is restricted to the results from the area around the British Isles, shown stippled in Figure 94· Other reports on Recorder collections are given elsewhere in this volume by HEKDERSOK (p. 85) and by GLOVER and RoBINSON (p. 84£.). The methods of presentation of the results are the same as those used by GLOVER, COLEBROOK and RoBINSOX (Annls. biol., Copenh., r8: 69-74). Recorders are towed at a depth of ten metres, at monthly intervals whenever possible, along standard routes. A chart of the survey routes is given by GLOVER and RoBINSON (r967) in Annls. biol. Copenh. 22: 67. For each month, in each sub area shown in Figure 94, the mean number per Figure 94. A chart showing the area sampled by Continuous Recorder sample (of 3 m3) has been calculated for Plankton Recorders during 1966. The area has been divided the common species of plankton. The results of a into sub-areas (see text). The stippled sub-areas have been selected few of these are shown in Figures 95-104 sampled regularly since 1948 and are the basis of the results presented in Figures 95-104. in which the data for 1966 are presented as histo grams (gaps in the baseline indicate that there area C5, the coastal Atlantic (C4) and the eastern was no sampling). A measure of the "normal" and southern North Sea (Cr, Dr and Dz) and seasonal cycle is provided by line graphs of the particularly scarce in the Norwegian Sea (Ar) and average numbers per sample obtained by combining Norwegian coastal waters (Br). The spring out results from Plankton Recorder collections during break was slightly late in oceanic waters (D5, C5 the eighteen years 1948-1965. Both the annual and B5) but numbers were higher than usual in and long-term means were calculated from loga C5 and B4 in May when Thalassiosira spp., Thalas rithmic transformations of the original counts. sionema nitzschioides and Chaetoceros spp. were Information from other areas and for species not abundant. The spring outbreak was early in the illustrated here will be supplied on application to east-central and southern North Sea (Cr, Dr and the Director, Oceanographic Laboratory, 78 Craig Dz) with Chaetoceros spp. and Thalassiosira spp. hall Road, Edinburgh 6, Scotland. again abundant. The results are arranged in two groups in each The dense green colour in the oceanic areas C5 Figure; above the heavy line are the graphs and and B5 in July consisted mostly of Radiolaria histograms representing sampling over deep oceanic which were present in unusually large numbers. waters from the most southerly (Ds) to the most Thalassiothrix longissima was abundant in these northerly (Ar); below the line are the results from and neighbouring areas (D5, C5, B5 and B4) in the Atlantic shelf and the North Sea arranged in October and November. In the North Sea, Rhizo a sequence clockwise around the British Isles from solenia alata var. alata in the north-west (Bz) C4 to Dr. in September and Ceratium species in Cr from Phytoplankton (Figure 95) was estimated from September onwards were more abundant than a visual assessment of the green coloration of the usual; otherwise fluctuations from the long-term filtering silks. It was very abundant in the oceanic mean were not large. -87- Plankton Near N. Seas Copepods (Figure 96) were above average in JFMAMJJASOND JFMAMJJASOND Atlantic oceanic areas C5, B4 and Ar but less abundant than usual in the southernmost area D5 and, from August onwards, in Bs. In the central and northern North Sea (Br, Bz, Cr and Cz) they were close to normal but somewhat below 4 average in the southern North Sea (Dr and Dz). 3 In previous reports the results for C alamts 2 finmarchic%s and Calamts helgolandic%s have been combined. However, stages V and VI of these species have been separately identified since r958, and the long-term means can now be calculated from monthly sampling over a period of eight years (compared with eighteen years for other species). Therefore, for the first time in this series, results are presented for C. finmarchicus and C. hel golandicus independently (Figures 97 and 98). Stages V and VI of Calanus finmarchic-us, a "cold-water temperate" form, were above average almost everywhere but particularly in the oceanic areas C5 and B5, the Norwegian Sea (Ar) and the east A1 central North Sea (Cr); see Figure 97· In a number of areas, however, the spring increase was below ~ average or later than usual. The situation in the central North Sea was interesting: in the west (Cz), they were abundant until June, declining thereafter to near average levels but in the east (Cr) they were much below average until June when they increased to relatively high numbers and remained abundant until the end of the year. The distribution of Calamts helgolandicus may be classified as "warm-water temperate" and regarded as complementary to that of C. fin marchicus. To some extent, this was reflected in the fluctuations in abundance; in r966 stages V and VI of C. helgolandicus (Figure 98) were less numerous than usual or were present for a short season; for example, they were abundant in the oceanic areas D5 and C5 in June only, and in the north-western North Sea (Bz) in July and Septem ber only. C. helgolandicus is normally most abundant in the coastal waters north of Ireland (C4) where numbers were higher than average for most of the year. In the central and northern North Sea it is normally most abundant in the autumn, and in r966 at this time it was close to or above average but it was below average in May, June and July. This was particularly noticeable, also, in the south-east (Dr) where it was abundant in January, March, October and November so that the seasonal distribution in this area was the reverse of that normally found. Figure 99 shows the numbers of the combined JFMAMJJASOND JFMAMJJASOND genera Pseudocalanus and Paracalanus, most of Figure 95· (left) -Phytoplankton. which are Pseudocalanus eLongat~ts. As in every Figure 96. (right) -Total copepods. year since 1962, they were below average in most For further details, see text and Figure 9+ -88- JFMAMJJASOND JFMAMJJASOND areas for the greater part of the year. In the oceanic Atlantic they were present in average numbers 05 in spring and early summer and were abundant .... only in areas D5 and C5 in June; thereafter num C5 bers fell away rapidly. They were exceptionally scarce in the Norwegian Sea. Numbers were above average in May, June and July in coastal Atlantic waters north of Ireland (C4). In the North Sea the 85 seasonal trend was, in some respects, the reverse of that found in the oceanic Atlantic; numbers being higher everywhere (areas Br, Bz, Cr, Cz, Dr and Dz) in the second part of the year than 84 during the first five or six months. Numbers of Acartia clausi (Figure roo), which had been falling in oceanic waters since 1963, became more abundant again in rg66, particularly in areas C5 and B4- In area D5 they were low in July and August and there was a recovery in A1 September. In B4 the seasonal peak was in Septem ber and in B5, where numbers were low until August, the seasonal maximum was in October. A similar seasonal cycle was recorded in the north western and central North Sea (Bz, Cr and Cz) and the coastal Atlantic waters (C4) where there was a tendency for peak numbers to occur later than usual. In the southern North Sea (Dr and Dz) numbers were generally below average. As usual, there were many features of similarity between CliOJ'Le limacina (Figure ror) and Spiratella retroversa (Figure roz). Both species have been scarce in the oceanic Atlantic since r953 (although 150150 there was a temporary recovery of Spiratella in rg63). In rg66 both species reappeared in relatively 81~ high numbers in these oceanic areas, although the season length of Clione was very short. Both remained below average in the Norwegian Sea (Ar) where there were very late peaks of abundance, in October and November (as there were, also, in other oceanic areas such as D5, C5 and B4). In the north-western North Sea (Bz), also, both species were above the average abundance. In the central North Sea, rather unusually, the peak abundance of both species occurred in the west (Cz) before the east (Cr); this is the reverse of the usual sequence. After the extraordinary abundance of Salpa jusijormis in rg64 and rg65, it declined in rg66 to quite low numbers (Figure ro3) but it was still present over a wide area. Like several other species, the greatest numbers occurred in October J FMAMJ J ASOND JFMAMJJASOND and November (C5, Ar, Bz and Br). Dolioletta Figure 97· (left) - Calanus finmarchicus, stages V and VI. gegenbauri (Figure ro4) was rare, as it has been Figure 98. (right) - Calanus helgolandicus, stages V and VI. for many years, occurring in D5 in June and C5 For further details, see text p. 87 and Figure 94- from June to August. - 8g- Plankton Near N. Seas JFMAMJJASOND JFMAMJJASOND JFMAMJJASOND JFMAMJJASOND 05 500 :·:·: ::::· Ct:::.. :J~- ~ C5 85 ~ 85 84 84 ~ ~A1 _&_A1 ~81 ~R ~ ~C2~ ~02~~ ~mc1~ JFMAMJJASOND JFMAMJJASOND + _+.:,_:_+_..:...+ __o 2 ..... ~:!:::8~"""~ -'+"------+~+_,_+_,+_ __...._+ D 1-===~~c::::····=:;::::::·:,=:z::.:!::LJ:S.·=·;:s.:::::::..._ JFMAMJJASOND JFMAMJJASOND Figure 99. (left) - Pseudocalanus elongatus and Pa1'acalanus Figure ror. (left) - Clione limacina. Crosses indicate the spp. (combined). occurrence of Clione in small numbers during the period 1948-r965. Figure roo. (right) - Acartia clausi. Figure 102. (right) - Spiratella retrovnsa. For further details, see text p. 88 and Figure 94- For further details, see text p. 88 and Figure 94- -go- j FMAMJJASOND JFMAMJJASOND phenomenon was noticed in the Atlantic south west of Iceland (area B6, see GLOVER and RoBIN 05 SON, p. 84 of this volume). Thirdly, the normal sequence of seasonal timing of some species in the ~ ~ central North Sea was reversed so that they appeared in the west (Cz) before the east (Cr). C5 The increased numbers of the two pelagic ~ gastropods, Clione and Spiratella, in the oceanic ll Atlantic and their abundance in the North Sea 85 may indicate the beginning of a reversal of the ~ ~ trend of declining abundance which has affected ~ 84 ~ these and other organisms for several years. This may be related to the occurrence of many warm A1 water species in oceanic waters where they had been exceptionally rare or absent since about rg6o. ~~ hi ·~ They included C alocalanus pavo, Lucicutia flavi C4 cornis, "'o/I ecynocera clausi, Calamis tenuicornis, ~ ~ Calantts gracilis, Clattsocalanus arctticornis, Ett 82 - calan.tts crasS14S, Encalanus elongatus, Rhincalan'Uts /Jtk_...• nasutus, Xanthocalanus minor, E~tchaeta acuta, 81 /1l_:::: Euchaeta marina, Ettchaeta hebes, Undeuchaeta C2 plumosa, Pleuromamma gracilis and Pleuromamma borealis. Salps, together with Plettromamma robusta C1 and Candacia armata, penetrated into the Nor wegian Sea in October and November and, with 02 Euchaeta hebes and Rhincalanus nasutus, into the 01 extreme north-western North Sea in September and October. Candacia armata and Metridia lucens j FMAMJJASOND J FMAMJJ ASOND were particularly abundant in the northern and Figure ro3. (left) - Salpa fusiformis. east-central North Sea at this time. Figure ro4. (right) - Dolioletta gegcnbauri. R. S. GLOVER, G. A. RoBINSOK For further details, see text p. 88 and Figure 94· Scottish Marine Biological Association, Oceanographic Laboratory, 78 Craighall Road, Edinburgh 6, Scotland. The sampling coverage was less satisfactory in rg66 than previously; this was partly the result of a strike bv British merchant seamen in Mav and Investigations from Aberdeen in rg66 June. It is" obvious from the figures that "there are more erratic month-to-month fluctuations than Phytoplankton usual, especially in the southern North Sea; to In March the coastal waters west of Scotland some extent these are the product of inadequate showed little evidence of any marked spring sampling in some areas. diatom growth. Rhizosolenia species were moderately However, there is a pattern of consistencies in abundant but most neritic forms were still very the results which serves to characterize rg66. The sparse. To the west of the Hebrides, at about the first of these concerns the general impression of same time but in an area of mixed oceanic and overall abundance which was higher than usual for shelf water, the diatom population was very many species. This is in contrast to the last five varied and included the curvirostris form of Rhizo or six years when many organisms, including some solenia alata and Rhizosolenia acuminata. In May, of the most characteristic components of the although the collections from this same area did plankton, have been below average and, in some not contain such high numbers of diatoms the variety cases, very scarce. of species present was just as marked. At 57°45'N The second feature was the late peak of abundance ogo3o'W the Rhizosolenia alata forma gracillima of many organisms in September, October or were forming auxospores- a phenomenon normally November; for example, Clione, Spiratella, Calanus, observed, in northern seas, within the period Acartia, Salpa and the phytoplankton. A similar August to October. Dinoflagellate numbers were - gr- Plankton Near N. Seas high and included such species as Cerati'Nm buce and N ematobrachion boopis. Of these some are of phalum var. heterocampta, Ceratium azoricum, Cera special interest. Unde'Vtchaeta magna was described tium compress~tm and Oxytox~t1n scolopax. by TANAKA from Japanese waters and has not Sampling in the North Sea proper did not begin previously been reported from the European area. 0 1 1 until April by which time the spring outburst was It was taken 6o Z3 / 2'N 7°49 / 2'\V on 24. May rg65 well established and characterized by high num and its identity was confirmed by the British bers of Chaetoceros species with occasional very Museum, but the information was too late to dense patches of Thalassiosira gravida. In May include in the Annls. l:iol., Copr:.nh., for rg65. A re on the southern part of the Butt of Lewis to examination by the British Museum of FARRAN's Faroe Bank line large areas were dominated by specimens labelled U. major showed two of these to Thalassiosira gravida - which severely affected be U. magna so that although the record of U. magna filtration of even the zooplankton nets. On Faroe in European waters is new it has in fact been Bank Chaetoceros decipiens was abundant and at previously taken. The identity of Kollikerina was 59°44'N 07°15'W and at 6I 0 0I'N 02°00'\V a few confirmed by P. L. KRAMP; this medusa known cells of H emialus hauckii were taken. from the Mediterranean area has not previously The transition from spring to summer conditions, been found north of the Azores. Peraclis moluccensis in all areas surveyed, was normal although perhaps was previously recorded in this area from an a little more extended in eastern areas of the "Explorer" collection in 1956. North Sea. Autumn conditions in the waters off Aglantha was abundant only in collections taken the east coast of Scotland were marked by a by the deeper nets. By May oceanic fauna had slightly more pronounced secondary diatom peak also extended to Faroe Bank and a reduced and quite extensive areas were dominated by community reached Shetland, including Euchaeta Rhizosolenia alata forma gracillima, many of which hebes and Stylocheiron longicorne. M uggiaea atlan were m auxospore. tica had reached Orkney by August and was still present there in September. Only very little of this D. D. SEATO:\' oceanic fauna had by then penetrated into the J\Iarine Laboratory, Victoria Road, Torry, Aberdeen, Scotland. northern North Sea and was represented there by Cosmetira, Sagitta serratodentata and some Rosacea Zooplankton plicata. Lepas was attached to floating weeds. Sagitta setosa was present in the Clyde and in vVest Coast of Scotland and Faroe Shetland Channel shelf waters south of Barra (southern Outer Calan~ts was generally abundant in rg66 in all Hebrides), in the Minch and also on the shelf to shelf waters in this area and usually accompanied the north of the Butt of Lewis. by Spiratella retroversa, especially so in June to No samples were taken in the area west of the north-west of Ireland and in the southern Scotland later than August or in the Orkney-Fair Minch. Isle area later than September. Oceanic water, with a considerable proportion of Lusitanian species was evident as far as the Northern North Sea north of the Outer Hebrides in March, especially noteworthy being Phronima at 56°27'N 7°50'W During spring and summer C alamts reached and the copepods Unde'Uchaeta major and U. magna very high figures in the northern North Sea, being at 58o3r'N 8°or'W. The euphausids N ematoscelis specially abundant over the Norwegian Deeps in megalops, Stylocheiron longicorne, Euphausia krohni, April and May, and in the central part of the area and the copepods M etridia venusta, Luicicutia in July when adding to the crustaceous content atlantica, Phyllop'Vts helgae and Aegisthus mucronatus were Themisto and Thysanoessa inermis. Spiratella were also found in this area. retroversa was also widespread from May to July This community continued to be widespread in north and east of Shetland and in the Fair Isle, May and June and then included the siphonophores Fladen and Fisher Bank areas continuing until Rosacea plicata, R. cymbiformis, Vogtia spinosa November. Plankton in the region of the Moray and Muggiaea atlantica; the medusae Kollikerina Firth was distinctly less. jasic'Nlata, Cobolonema, Bythotiara; the polychaetes There was only a very slight penetration of Travisiopsis lanceolata, Lepidasthenia grimaldii and oceanic fauna into the northern North Sea during Lagisca h~tbrechti; the pteropods Euclio cuspidata, the first eight months of rg66, and associated with Peraclis moluccensis and Pneumodermopsis pa~tci this was a northerly flow of southern North Sea dens; and the euphausids Thysanopoda acutijrons species. The medusa Tima bairdi was found with -92- Sagitta setosa off the entrance to the Skagerak 3" and off Esbjerg whilst on the west side E~ttonina indicans was found off Aberdeen and in the Moray Firth. The copepods Labidocera wollastoni and Isias clavipes were found as far north as Esbjerg 60' and Labidocera as far as the Little Fisher Bank in areas with abundant Sagitta setosa. This northerly trend of southern North Sea water can be further associated with the reported extension of Channel water taking Pelagia as far as the Texel coast. By September the penetration of oceanic species from the north was more marked. 1\!htggiaea atlantica, for example, was found in the Moray Firth, and penetrating as far south as 57°N near the Scottish coast, and a few Salpa fusiformis CHLOROPHYLL and Sagitta serratodentata reached 58°N 4°E. Larvae of Branchiostoma (Amphioxus) lanceolat~Im were found over a wide area in August from the Danish coast to I 0 \V with numbers reaching about 500 in a single haul of the Gulf III at 54°Io'N 2°5o'E. Numbers of Pleurobrachia, reported in I965 to 6d" be unusually high, were normal in Ig66. Numbers taken in a I5 minute tow by the I metre net only once reached IOOO (off the north coast of Scotland) before September and October when similar figures were more widespread in the Fair Isle and Moray Firth areas. J. H. FRASER l\Iarinc Laboratory, ·victoria Road, Torry, Aberdeen, Scotland. DRY WEIGHT 5-20 APRIL 1966 3" o' 2' 3" •. s" Chlorophyll a and Zooplankton Standing Crop Figure 105. Chlorophyll a (mgjm3) and standing crop of (Figures 105-roS) zooplankton (g dry weight(IOo m 3), 5.-20. April, 1966. The assessment of the phytoplankton and zoo plankton standing crops in the northern North survey for which data are available in this series Sea was continued in Ig66. The areas surveyed (April I96I - see: Annls. biol., Copenh., 19: 64), and the results available for April, July and they are not unusually high for that period of the November are shown in Figures I05, I06 and I07 re year (c.f. STEELE (Ig6I) Mar. Res. Scot., I96I (6) ). spectively. The methods used have been described The zooplankton dry weight chart shows less by ADAMS (Annls. biol., Copcnh., r8: 69) and extensive areas of greater than I g dry weight/ ADAMS and BAIRD ( Annls. biol., Copenh., 19: IOO m 3 than the April I96I survey (Annls. biol., 63-5; 2r: 63-5; 22: 65-6.). The April chlorophyll Copenh., r8: 68). a concentrations were measured with a spectro There have been no previous comparable surveys photometer; the July and November chlorophyll a in this series in July. For the chlorophyll a chart concentrations with a Turner model III fluoro attention is drawn to the areas of greater than meter which gives greater precision for lower 0.5 mgjm3 off the west coast of Norway and off values, i. e. below I t-tg/l. The fluorometer was the east coast of Scotland. The zooplankton dry calibrated by making parallel measurements of weight chart is very similar to that for June I965. the chlorophyll rich samples with the spectro The July survey is therefore one of a group surveys photometer. (May-June I963, June 1965 and perhaps October Although the chlorophyll a values for 5-20 April I965) in which an extensive area of greater than are higher than those for the only comparable 3 gjioo m 3 has been recorded. -93- Plankton NearN. Seas 20 10 20 Cf' 3" 2" o• ,. 3" 4' 61' 0·1.. ._o-s o-s/ o-6 I '"o·s 0·5 .o\ 0·6 0·1 .6.0·3 .. 05 I \:V0·5 2 4 t:" ~8~~: .. 0·2 """4 4·0 0·2 .. 0 2 .. 4 .. f·6 ~I 0·3 .. 09 o'"> 0~3 0~3 CHLOROPHYLL CHLOROPHYLL OA3 10 10·5 ,:;,; 61" 3·6.. ' ~ ."!£) ' .. '\ 3q~ 6·3 .. 1~ 2-5 .. 3-8 ¥lJ. .. .. 12·4 f~~ ..... 5·7 .. ~P.· 6·7 .. 1·6 6tj s'!-a • 4·1.. .. 6·2 5·9 2·8. :~ 5·2...... f., 2·4 ·~ 8·8.. f.o 3 ,.., 4·1.. 5·1.. 6·1.. DRY WEIGHT 4-20 NOVEMBER !966 3" ,. o· 3" 5" Figure ro6. Chlorophyll a (mgjm3) and standing crop of Figure ro7. Chlorophyll a (mgjm3) and standing crop of zoo zooplankton (g dry weight/roo m 3), g.-25. July, rg66. plankton (g dry weight/roo m 3), 4.-20. November, rg66 The chlorophyll a values in November were very oo 10 30 40 similar to those recorded west of 3°E in November 5·8.. rg64. No comparable data has been collected east of 3°E in any previous November of this series, but the general pattern is the same as that observed in October rg65. The zooplankton dry weight is also very similar to that observed in November 3~ rg64 although again no strictly comparable data .. : 2·7 J are available for the eastern area surveyed. 55° .. 2 4 Part of the central North Sea was surveyed in • \_ 2..... ·55 . 3·4 -~ August rg66; the standing crop of zooplankton .. 7·0 s·a 3·0 is shown in Figure ro8. 3·5 .. DRY WEIGHT .. 25-31 AUGUST 1966 J. A. ADAMS, I. E. BAIRD J\'larine Laboratory, Victoria Road, Torry, Aberdeen, Figure 108. Standing crop of zooplankton Scotland. (g dry weight/roo m 3), zs.-3I. August, rg66. -94- Baltic-Belt Seas Investigations on Zooplankton in the Western Part of the Gdansk Bay (Figure rog; Tables 25-27) This paper presents the result of seven years' (rg58-rg64) investigations on the quantitative and qualitative composition of zooplankton in the coastal zone of the Gdansk Bay, as well as its distribution and ecology against the background of seasonal biological changes. It is based upon 476 quantitative plankton samples taken mostly by means of an Apstein net nr. 25 xxx. Five minutes horizontal surface hauls and hauls within particular water layers as well as vertical hauls from bottom to sea-surface are included. The respective groups, species and their develop ment stages have been calculated as numbers of individuals per m 3 of water. Investigations were carried out in an area of 8oo km2 , including 3 regions designed as follows: Region I- Puck Firth (average depth 3m) Region II- Gdansk Bay (coastal zone down to isobath 20 m) Region III - Gdansk Bay (from isobath 20 m • down to 70 m depth) ...... Such a division made possible the designing of curves representing the quantitative occurrence of either species or whole groups in particular regions, as well as the connection between hydro graphical conditions and the quantitative occurrence Figure rog. of certain species. Table 25. Occurrence of plankton organisms in the area of investigation :VIonths Species, groups Jan. Feb. :VI arch April :\Iay June July Aug. Sept. Oct. Nov. Dec. Rotatoria ...... X X X XX XXX XXX XX X XX XX X X Bosmina coregoni maritima X X XX XXX XXX XX X X Evadne normanni ..... X X XX XXX XX X X X X Podon polyphemoides .. X X X XX XXX XX X X Podon intermedius .... X X X XX XXX XX X Podon leuckarti ...... X X XX X Freshwater Cladocera sporadic A cartia bijilosa ...... X X X X XX XXX XXX XXX XXX XXX XXX XX A cartia tons a ...... X X XX XXX XX X A cartia longiremis .... XX XX XX X X X X X XX XX XX XX Eurytemora sp...... X X X X X X XX XX XXX XX XX X Temora longicornis .... X X X X XX XXX XX X X XX XXX XX Centropages hamatus .. X X X X X X X XX XXX XX X X Pseudocalanus elongatus XX XX XX X X X X X XX XX XX XX Limnocalanus grimaldi sporadic Freshwater Copepoda sporadic Pleurobrachia pileus ... X X X X X X X X X X X X Fritillaria borealis .... X X X XX XX X X X X X X X x- sporadic or not numerous xx- numerous xxx- very numerous or massed - YS- Plankton Baltic-Belt Seas Table 26. Occurrence of more important groups of microplankton in the area Region I Region II Region III Puck Firth 0-20 m o-70 m River open region River open region o-20 m at bottom estuaries estuaries Species surface s-7" 1oo 5°/00 6-7"1 00 5°/oo bottom 7-7.5"/ oo Cladocera Bosmina coregoni maritima X XX X XXX XX X Evadne nordmanni ...... X XXX X XX XX X Podon poZyphemoides ...... X XX X XX XX Podon inte~'medius ...... XX X XX XX X P0don Zeuckm'ti ...... X X X X A Zona affinis ...... X X X X A lona rectangula ...... X X X X Diaphanosoma brachytwum .. . X X X X Chydorus sphaericus ...... X X X X Copepoda A cartia bifilosa ...... X XXX X XXX XX X A cartia tons a ...... X XXX X XX XX A ca1'tia longiremis ...... X X X XX Etwytemora sp ...... XX XXX X XX XX T emora Zongicornis ...... X X X XX XX X Centropages hamatus ...... X XX XX PseudocaZanus elongatus .... . X X XX LimnocaZanus grimaldi ...... Eucyclops serrutatus ...... X X X JVI egacycZops viridis ...... X X X H aZicyclops magniceps ...... X X X NI esocyclops leuckarti ...... X X X Eudiaptomus graciZoides .... . X X X PZeurobrachia pileus ...... X Fritillaria borealis ...... X Table 27. Ecologic groups of zooplankton in the area of Taking into consideration the years rgs8 and investigations rg6z for the quantitative determination, maps were prepared of the seasonal species composition. I - Freshwater species (5-6° I 00 salinity): As a result of this, a table has been set up showing I. A Zona affinis the occurrence of the species in the respective " A Zona rectangula 3· Diaphanosoma brachyurum regions as well as the biological plankton seasons 4- Chydorus sphaericus of the area of investigation (Table 25). 5· Eucyclops serrutatus By analysing the hydrological diversity of the 6. 1\d egacyclops viridis 7. H aZicycZops magniceps area and differences in the plankton composition 8. lvfesocycZops leuckarti (Table z6) and taking into account the Venetian g. Eudiaptomus graciloides classification and the diagram of Remane, the IO. LimnocaZanus grimaldi indicative species of the particular salinity groups II -Brackishwater species (most numerous in about 7° I 00 have been determined (Table 27). salinity): Generally, the main components of the zooplankton I. B osmina coregoni maril'ima of the Gdansk Bay are: Protozoa, Cladocera and, 2. Evadne nordmanni particularly, Copepoda. 3· Podon sp. 4· A cartia bifilosa Other less numerous animal groups or groups 5. A cartia tons a occurring periodically in microplankton only, are 6. Acarl'ia longi1'emis Ctenophora, Nemertini, Annelida, Cirripedia, Bryo 7· Eurytemora sp. 8. Temora longicornis zoa, Lamellibranchia, Gastropoda and Appendicu g. Centropages hamatus laria. III- Marine species (most numerous above 7"1 00 salinity): K. SIUDZINSKI I. PseudocaZanus elongatus Sea Fisheries Institute, AI. Zjednoczenia I, Gdynia, 2. Pleurobrachia pileus Poland. - g6- Atlantic Area Scottish Plankton Investigations in the Atlantic Area in 1966 The Continuous Plankton Recorder was towed on the established lines in the Atlantic. Details are given under the Near Northern Seas. No plankton samples were taken from Aberdeen in the Atlantic area in rg66. J. H. FRASER ::\1arine Laboratory, Victoria Road, Torry, Aberdeen, Scotland. PART III. THE FISH - g8- Gadoid Fish COD Danish Investigations on Cod in West Greenland Waters 1966 (Figures I TO-I I 3) Cod larvae 100·50·25mw The fisheries 200·150-100- - 700-650 - - The output of the cod fishen· was 30,000 tons 800·750 which is 5,ooo tons more than in rg65 but 7,000 tons below the output in the best year rg62. The reason for the increase may to some extent be an increase in the number of the Greenland fishing boats and extension of the fishing factories. As usual the fishery was mainly carried out in inshore waters. Four fishing vessels, two of roo tons and two of 200 tons have fished with long-lines in the Davis Strait. The two year-classes rg6o and rg6r predominated Figure r 1 o. Cod. \Ycst Greenland. Larval distribution, rg6(,_ strongly in all catches, the latter especially in catches from ICNAF Divisions rE and rF. explained by a long spawning period off East Most of the catches consisted of small and Greenland and possibly also by mixing of cod medium-sized cod between 54-58 em (weight eggs and larvae transported by the current from r.s-r.8 kg) and 65.5-68 em (weight 2.5-3 kg). South-west Iceland spawning grounds. Age and size of cod in commercial stocks Biological data Length measurements and otolith collections Larvae were made from catches taken with different "Dana" fished Jor cod larvae with a 2 m stramin commercial gear:' from the Faroese trawler "Skala net in July between 63°40'1\ and 66°50'N, and berg", "Dana", "Adolf Jensen" and "Tornaq". from the coast to 57coo'\\". The catches were In addition samples were collected from the rather poor. It looks like the year-class rg66 will Greenlanders' catches on different places along be rather poor. the \\'est Greenland coast. One sample was taken in Angmagssalik Fjord in East Greenland. Occurrence of small cod (age-groups I, II, and III) Figures III, 112, and II3 show the age composi Cod belonging to the age-groups I and II seemed tions in catches, with trawl (Figure III), long-line, to be very rare, while cod belonging to age-group hand-line and pravvn trawl (Figure rr2), and Green III (year-class rg63) were found in rather large land fishermen's catches (hand-line and long-line) numbers especially in ICNAF Divisions rE and rF. (Figure II3). In rg65 this year-class seemed to be rather poor. In all catche" except one the hi'O rich year The apparently rich occurrence of this year-class classes rg6o and rg6r (age-groups VI and V) in the two divisions seems to shovv that it has predominated. b 13 of the 29 samples these two recently been transported by the current from year-classes together amounted to more than East Greenland to southern \\'est Greenland. 8o%. Out of II offshore samples from trawl catches It is worth mentioning that the studies in rg63 the 1961 year-class predominates in g. In two of (N OI 40 20 10 20 10 L,(} 20 10 10 40 20 20 20 10 40 20 20 10 30 60 20 40 10 20 10 80 60 60 3.0 F 40 20 590 20 10 0 58 ~---~---- 55 50 Figure rrr. Age and length composition of cod taken on the banks by the Faroese trawler "SkaJaberg" in :\fay-June. Divisions 1E and 1F. It is reason to believe that cod or older, which were rather common in the the year-class 1960 is of \Vest Greenland origin catches until about ten years ago, are now very while the year-class 1961 originated from East rare. The intensive trawl fishery takes the cod out Greenland waters and has been transported as in an earlier age than before. A rich year-class has fry to the West Greenland coast by the current. its maximum in the catches when it is about 5-years old. \Vhen 7 and 8-years old they decrease In the sample from commercial catches in very rapidly, and when g-years old they occur Angmagssalik Fjord in East Greenland the year in so small numbers that they are without any class 1961 predominates with 59%, and the other importance to the fishery. year-classes were represented as follows: 1960 24.9%, rg6z 10.7%, 1959 z%, 1958 z.g%, and The length of the cod is in the majority of the 1957 o.s%. samples between 50 and 70 em with maximum about 6o em and weights between 1.5 and 3 kg. The two rich year-classes 1956 and 1957 which were very important to the fisheries in the period Tagging from rg6r to 1964 were without importance. The rg56 year-class had practically disappeared from Tagging experiments have been carried out the catches while the 1957 year-class made up with cod of different sizes in all divisions in the about ro% in 5 samples and 20% in r sample. In area except in rA in both inshore and offshore all other samples it was nearly absent. In the last waters. 2,905 cod were tagged. years the rich year-classes disappear from the 431 recaptures of cod tagged in the period catches in a younger age than before. 10-year-old 1959-66 have been reported in 1966. 382 have -100- 55° 50° 42 48 ~ 60 .66 72 78 84 90 44 50 56 62 68 74 80 a; 93 ~rn • 1 • 1 1 1 1 1 1 1 1 1 1 1 o 1 1 1 o/o 20 :1 10 ~ww~._------~~------~~--~0 20 u II 10 c::;-, ~~~------~~----~~~~0 ) I 20 v ~ II 10 I ~~~~~------~------~~0 I 20 650 I 15 hl I 0 10 63° 10 I 620 I . F gure rrz. Age/length composition of cod taken with prawn trawl (pt), long-lines (II), and hand-lines (hl) on the banks been recaptured in West Greenland waters, 7 off East Greenland and 39 in Iceland waters. 3 recaptures were without exact information about the place of recapture, they were caught either off East Greenland or in Icelandic waters. P.M. HA:\"SEN Gmnlands Fiskeriunders0gelser, J regersborgalle I B, Charlottenlund, Denmark. -IOI- Gadoid Fish Cod ~ 60 61 % 18 % 61 comm. 25 20 so comm. 1B 0 40 40 19 20 comm. 20 0 40 \ 20 0 20 pound n. 20 0 40 n comm. 20 24' comm. Figure II3. Age and length composition of cod from inshore waters. Material obtained from the Greenlanders' catches. -IOZ- The Spawning Stock of Icelandic Cod in 1966 Soviet Investigations of Young Cod of the 0, I, (Table z8) II and III Age-Groups in the Barents Sea in 1966 Table z8 shows the age distribution of the spawn (Tables 29-3I) ing stock of cod in 1966. The table is based upon From September 1965 to April 1966 the Polar material collected from the main gears used in the Institute (PINRO) conducted, as in earlier years, fishery: long-lines, trawls, gill-nets and purse a quantitative analysis of small cod on board the seines in the ratio: o.IIJ : o.o65 : 0.750 : o.o68. R. V. "Tunets" and the scouting ship "Priz". The total mortality in this stock is now about For this purpose a common bottom trawl with a 70% annually, from which the four-fifths are roo mm mesh cod-end was used. A ro mm mesh caused by the fishery. As seen in the table the (from knot-to-knot) nylon net was inserted into first-time spawners now constitute about 85% of the cod-end. Trawlings were made on fixed stations the entire spawning population. The percentage of standard routes and covered Sub-area I and of first time spawners has been increasing rapidly Division IIb1). Waters adjacent to the north with increased fishing mortality. In the period western coast of Norway, from the Nordkyn Cape 1945-49 first-time spawners made up 30% of the to the Malangen Bank, were also investigated. spawning populations. The figure was 56% for the period 1950-54, 63% for the years 1955-59 The southern Barents Sea (Sub-area I) and 79% during the years 1960-64. First of all it should be noted that young cod of The fishery in 1966 was mainly based upon the the 1965 year-class were not registered at all over year-classes from 1956, 1958 and 1960. the whole Sub-area I. At present we have no safe joN JoNSSON data to explain this phenomenon, and we can Hafranns6knastofnunin, Skulagata 4, Iceland. only assume that changes had taken place in Table 28. Icelandic spawning stock of cod I966 Age of first spawning Age-groups 3 4 5 6 7 8 9 IO II I2 I3 I4 Total 3 ...... 9 9 4 ...... 254 254 5 ...... go8 908 6 ...... 29 I,767 I,796 7 ...... 6 83 I,340 I,429 8 ...... 54 252 2,323 2,629 9 ...... 6 so I40 559 755 1:0 ...... 8 5I 357 34I I,258 2,0I5 II ...... I6 9 30 z8 27 IIO I2 ...... 6 I6 6 22 6 56 I3 ...... 6 8 I4 I4 ...... IO 6 I6 IS ...... 2 6 8 I6 ...... Total ...... 9 254 943 I,924 I,709 2,845 942 I,3I8 43 6 6 9,999 Spawning classes I 2 3 4 5 6 7 Total Number ...... 8,45I 873 533 78 s8 6 9,999 Table 29. Average number of young cod of different year-classes taken per I hour-trawling in Sub-area I in the autumn and winter of I96S/66 Number Age and year-class Areas ;\1onths of o +(I) I+ (2) 2 + (3) 3 + (4) Total Total of trawlings I965 I964 1963 I962 the young Central ...... Nov.-Jan. 93 go 35 4 I30 I2,077 Western ...... Jan.-Feb. 63 IO I2 8 3I 2,030 Coastal ...... Dec.-Jan. 23 s6 2I 6 83 I,896 Eastern ...... Nov.-Dec. 29 ·*) Acconling to the ICES statistical divisions. -I03- Gadoid Fish Cod environmental conditions, which caused such an Spitsbergen and Bear Island (Division II b) unusual distribution, previously not observed, of the I965 year-class; or that mass mortality may According to data on the abundance of the have occurred at early stages of their development. young cod in the Bear Island-Spitsbergen area, As regards the young cod of older year-classes, the the rg63 and I964 year-classes were quite strong average catch taken per one hour trawling in ones. The mean catch of the rg63 year-class in the Sub-area I, was largest in the central areas along \¥est-Spitsbergen area was 362 specimens, and in the main branch of the Murmansk Current (I30 the South Cape region 129 specimens (Table 3I). specimens per I hour trawling). A comparatively In the Bear Island area the average catch of the great number of young ones (83 specimens per I963 year-class was 64 specimens and that of the I hour trawling) was also taken in the eastern part I964 year-class was 8g. In the remaining parts of the sea. In areas under the influence of the of the area the catches of the young of the rg63 coastal branch of the Murmansk Current the and rg64 year-classes ranged from single fishes catch of young ones amounted to 83 specimens to 27 specimens per I hour trawling. The great (Table 29). In the remaining parts of Sub-area I abundance of the rg63 and I964 year-classes is average catches ranged from 3 to 63 specimens probably due to the lack of a considerable number per I hour trawling. The relatively great catches of enemies (mainly immature Spitsbergen cod). were mainly caused by the I964 year-class. The As in Sub-area I, the I965 year-class was not met average catch over the whole Sub-area I of this with in the catches. year-class amounted to 56 specimens against 47 in Summing up, one should note the following: rg64jrg65 (Table 30). The I963 year-class was very abundant (74 specimens per I hour trawling) in I. Young cod of the rg65 year-class at an age rg63. But in rg64, the average catch of this year of o + (I) are assumed b be extremely scarce class was only rr specimens and in rg6S/Ig66 in the southern Barents Sea as well as in the 20 specimens. Bear Island-Spitsbergen area. Table 30. Average number of young cod of different year-classes during their I-4 years of life per I hour-trawling in the Barents Sea Years of life 2 3 4 Mean for the second and third years of life Fishing areas: lib I IIb I lib I IIb I IIb the whole Year-class Sea I958 ...... II 2I 8 r8 I4 24 I5 7 ro 20 I4 1959 ...... II r6 4 II r8 II I9 I4 I2 I3 I2 1960 ...... 29 12 I9 8 6 I3 IO 7 4 .,9 3 r96r ...... 3 ·?'> 3 Table 31. Average number of young cod of different year-classes taken per I hour-trawling in Division lib in the autumn and winter of I965j66 Number Age and year-class Areas Months of o -1- (r) I -1- (2) 2 + (3) 3 + (4) Total Total of trawlings r965 r964 1963 1962 the young The Bear Island Bank: Southern Slope ...... Sept.-Dec. 28 liZ 76 I r89 5,304 Eastern Slope ...... Sept.-Dec. IO 69 3I Table 34· Average number of cod of each year-class landed per 10 hours fishing by trawlers at Aberdeen and seine-net vessels in Scotland during 1964 Trawl Seine North East and North North East and :VIorav Year-class Central Northern Orkney Coast Central Northern Orkney Firth 1963 ...... 5·2 3·7 10.6 3·5 I.] 13·7 2.I 1962 ...... 7].8 6r.g qs.o 5+6 37·3 r6.7 43-4 6o.8 rg6r ...... ]2.6 ros.r qr.o 1]6.] 31.2 16-4 38·3 104.2 rg6o ...... 20.] II.] 13·2 r6.r 7-4 3-4 IO.c} 12.9 1959 ...... 25·9 3·7 3·8 3·9 5-4 4-4 I.6 2.8 1958 ...... 10-4 4·0 1.3 2.2 2.2 r.s O..f o.g 1957 ...... r.s 0.6 0.9 0.] 0.3 O.I O.l 1956 ...... O..f 0.2 O.I o.s 0. I O.OI 1955 and over .. O..f 0.2 O.I 0.2 0.1 0.04 Total ...... 2!2.5 192.2 315·9 258·4 86.5 43·0 roS.o !83·9 -ro6- Table 35· Number of cod of each year-class landed per 10 hours fishing by trawlers at Aberdeen and seine-net vessels in Scotland during 1965 Trawl Seine North East and North North East and Moray Year-class Central Northern Orkney Coast Central Northern Orkney Firth 1964 ...... 56.8 28.1 10].2 49·3 8.5 r.8 86.9 63.0 1963 ...... 34·3 21.8 102.6 44·6 29.8 3·0 68.6 36·5 1962 ...... 8].6 46·5 ]2.1 67·3 33·8 I2.6 43·4 42·3 1961 ...... 21.3 38.0 35-3 ]9.2 17.2 ].8 21.3 52-5 1960 ...... 4·1 ].0 8.1 6.2 5·8 3·0 3·0 3·7 1959 ...... 7-7 4-4 3·4 1.2 3-3 0.3 1.3 3·0 1958 ...... o.6 2. I o.S 0.] 1.7 0-4 0.2 0.1 1957 and over .. 1.2 I.5 1.1 0.2 1.4 0.6 0.6 Total ...... 213.6 149·4 330.6 248·7 101.5 29-5 225-3 20I.I Table 36. Numbers of cod of each year-class landed per 10 hours fishing by trawlers at Aberdeen and seine-net vessels in Scotland during 1966 Trawl Seine North East and North North East and Moray Year-class Central Northern Orkney Coast Central Northern Orkney Firth 1965 ...... 5.8 1.3 159-6 26.9 2.3 3·8 I 13-3 71.6 1964 ...... II6-4 ]8.6 237·8 218.o 44·0 48.8 180.5 273-4 1963 ...... 180.5 38.2 74·8 22.8 33-I 11.2 33·4 31.0 1962 ...... 84·4 36.6 27·9 24.0 17·7 I3-7 9-0 14-5 I961 ...... 26.2 I7·4 12.5 20.6 8.5 6.4 r.S 20.4 1960 ...... 4·4 4·0 3·2 2.9 3-4 1.0 0.3 2.0 1959 .... " ..... 1.5 1.9 I. I 1.3 z.s 0.5 0.1 0.4 1958 and over .. 0.] 0.9 o.8 0.5 2.6 0.4 0.05 I.] Total •••• 00 ••• 419.9 1]8.9 517·7 317.0 I I4.I 85.8 338·5 415.0 Table 37· Length and age distribution of cod taken with the the rg63 and rg64 year-classes. The new rg66 standard trawl in the Kiel Bay in 1966 year-class seems to be abundant as one-year-olds, Length Number per r hour's fishing but experience in previous years has shown that in em Jan. March May July Sept. Nov. we cannot conclude the strength of a year-class <6 .... 0.1 0.6 with certainty from the figures obtained for the 6-Io 3·7 3-1 0.] r.6 55.8 28-4 II-I5 37·6 23·3 33-2 23.1 9-6 I3].0 o-group in the last months of the year. The catches 16-20 25-9 16.8 41.1 84·4 63.0 22.! often decrease in winter time and reach represen 21-25 2].6 8.4 11.5 17-5 33·5 29-7 tative values only m July, as may be seen m 26-30 47·9 13.8 18.7 7-4 ].I ].I Table 37 for the rg65 year-class from which no less 18.6 17.1 6.0 31-35 14·3 9-0 4·2 than zz6 specimens per hour were caught m 36-40 12.0 10.9 6.8 7·5 4·8 3·9 41-45 10.0 9-9 6.2 5.6 2.9 2.4 December rg65 (d. Annls. biol., Copenh., 22: 88f.) 46-5o 4·8 4·5 4·1 3-4 2.4 1.5 The older age-groups decrease heavily from the 51-55 I.] r.8 1.1 2.3 o.6 0.7 beginning to the end of the year due to the high 56-6o 0.6 1.1 o.8 1.0 o.6 0.3 natural and fishing mortality. 61-65 0-4 0.3 0.3 0.5 O.I 0.1 66-]0 0.2 O.I R. KANDLER >70 o.6 0.2 0.2 0.2 Institut fur lVIeereskunde der Universitat Kiel, Year-class Hohenbergstrassc 2, Kiel, Germanv. 1966 1.7 63.1 175·9 1965 66.2 44·9 82.3 126.3 104.8 48·9 1964 93·5 36-9 43·6 23.0 12. I 8.o Stock Condition and Distribution of Cod in the 1963 24.1 14·7 II.8 8.9 6.0 3-2 Eastern Baltic in 1966 1962 6.2 10.2 3·3 3·3 o.8 1.3 1961 o.8 I.] 0.3 0.3 0.1 0-4 (Tables 38-40) 1960 An analysis of changes in the condition of the and older o.6 0.5 O.I 0.1 cod stock in late years showed the increased Total number 191.2 109.0 141.8 187.0 237·7 abundance of cod since rg65 following its reduction Number in rg58-rg64. This is also showed by the catch examined 3,584 1,702 3,685 m rg66 being ZJ4,JOO centners (in Latvia), t.e. -107- Gadoid Fish Cod Table 38. Age composition (%) of spawning cod in the Gotland Deep Age Year fished 2 3 4 5 6 7 8 9 Total 1960 ...... o.S 2.8 39.1 34-2 17.8 4·6 0.6 O.I 100.0 -:r96r ...... 3·1 r.6 21.4 41.4 r6.s s.r o.S 0.1 100.0 -:r962 ...... 0.3 II.O 31.3 25.0 25.6 5·0 1.4 0.2 0.2 100.0 1963 ...... 0.3 8.8 34·7 29.1 19-3 6.2 1.3 0.3 100.0 1964 ...... o.s 4·5 24·3 33·7 24.1 S.o 3·1 1.2 0.3 100.0 "1965 ...... 13.1 20.3 20.0 23.1 14-5 5-9 2.3 o.s 0.3 100.0 1966 ...... 5-7 21.4 28.6 25-3 13.3 4·1 1.4 0.2 100.0 Average 1946-1966 .. 1.4 6-4 26.3 35-2 20.2 7-3 2.3 0.7 0.2 100.0 Table 39· Monthly size composition (%) of cod in the Gotland Deep, 1966-1967 Month em 10 IS 20 25 30 35 40 45 so 55 6o 65 70 75 So Total April ...... 3-4 2.3 5·4 s.s 13.8 22.4 19.5 11.9 6.3 4·0 r.6 0.4 0.5 100.0 337 June ...... I.O 4·7 10.7 18.1 13.2 r8.7 14-4 S.o 4·2 4-7 1.3 I.O 100.0 166 July ...... I.O 3·5 9-7 20.2 r8.8 25.1 13.2 3·3 4-0 0.6 0.6 100.0 245 September 0.2 3·6 5-9 10.0 15.8 13.8 19-4 r6.1 10.1 4·0 0-4 o.s 0.2 100.0 265 November 1.5 0.3 4·0 6.8 19-9 19-9 13.6 16-4 9-0 s.6 1.2 0.6 0.3 0.6 0.3 100.0 323 December I.O I.O 4-9 16.5 21.4 29.8 11.7 6.8 3-9 I.O 2.0 100.0 103 January ... 2.6 0.7 3·2 8.4 17.8 25-9 15.6 15-9 6.6 1.2 r.S 0.3 100.0 401 February .. 0.1 1.9 4·3 8.1 22.9 22.6 16.1 !2.2 6.3 3·6 o.S 0.9 O.I 0.1 100.0 752 approximately 2.8 times higher than in 1964 (the in 1966 as compared with 1964-1965. In 1966 the year of the poorest catch between 1950 and 1966) catch per haul was 615 kg against 400 kg in 1964- and r.6 times higher than the average for a number 1965. of years. It exceeded the catches of the best years 1956 and 1957. In the eastern Baltic as a whole, Concentrations of cod were high in coastal areas, the catch of cod in 1966 was twice as high as particularly during the feeding period - the Latvian catch during the second half of 1966 made in 1965. up 192-400 centners, 2-4 times more than th.e Such an appreciable increase in the catches of average annual catch for the period 1950-1966. cod in 1966 can be explained by introduction into the fishery of two rich year-classes, which meant Throughout 1966 surveys were made of the a good recruitment for the commercial stock. spawning grounds of the cod in the Gotland Deep. It was ascertained that in 1966 the cod remained As is seen from the age composition of spawning in 100-130 m depth in the Gotland Deep through cod caught in experimental trawlings in the out the whole year. The catch per trawling hour Gotland Deep (Table 38) the bulk of the catches in the autumn-winter season was higher than' in consisted of two-year-olds and three-year-olds the spawning period. In September-December the belonging to the 1963 and 1964 year-classes. The average catch per trawling hour was n6% of the 1963 year-class was estimated as abundant and catch in April-June. the 1964 year-class as highly abundant. The distribution of cod in the eastern Baltic The size composition of the cod caught in the in the winter of 1966 is as in years with cold Gotland Deep (Table 39) changed slightly through winters; in January-February relatively low the year, and monthly fiuctations in the mean catches were made in the area of Ventspils-Liepaya, size were relatively small, viz. from 35.6 em to central Baltic, and much higher ones in the Klai 39·3 em. peda-Pionerska area, south-eastern Baltic. Investigation of the maturity stages showed that The distribution of cod in the spawning period individual specimens of spawning cod were observed of 1966 corresponded to the medium oceano in the Gotland Deep as early as in November graphical regime; the greatest concentrations of (Table 40). This is a new evidence that autumn spawning cod were found in the southern part of spawning of cod took place also in that area. the Gotland Deep. The decrease in the size of An analysis of the feeding of the cod showed spawning grounds lead to more dense concentra it to be intensive both in coastal areas and at tions of the spawning cod in the Gotland Deep 100-130 m depth in the Gotland Deep. The -IoS- Table 40. Maturity stages of cod from trawl catches in the Compared with the autumn of I964 and I965 Gotland Deep, 1966-1967 (% as estimated by the six ball the cod fed less intensively in the autumn of Ig66. scale) The index of stomach content was 78°/00 in Ig66 Month Jan. Feb. 1\IIarch April May June against I3ZOfo0 in I964-I965. In Ig66 there was April .... 4·7 22.3 2-4 50·3 20.3 a decrease in the share of the main food objects, June .... 2-4 19.2 4·8 17-4 42·5 13·7 mysids in the food of young fish, and Baltic July .... 0.4 8.9 0.4 17·3 19.0 54·0 herring and M esidothea entomon in the food of September 2.8 54·5 o.S 3·6 S.r 30.2 November 6.s 64·3 8.6 0.3 20.3 the adults. December 3·9 78·7 15·5 1.9 January s.6 ss.s 25·5 12.6 o.s One of the factors influencing the abundance of February 3.2 30. I 27.1 30·3 9·3 11fysis mixta is the amount to which they are eaten by fish. During the last two years a great number average number of feeding fish from September of young cod (the rich I964 and I965 year-classes) to December was 65% in the coastal areas and 70% was observed in the eastern Baltic, and this led in the area of the Gotland Deep. The cod mainly to a decrease in the abundance of mysids. fed on Harmathoe· sarsi in the Gotland Deep I. A. LABLAIKA, D. UZARS (making up go% (by weight) of the food) and on v. the crustaceans M esidothea entomon and M ysis BALTNIRO, Bezdiligu r, Riga, USSR. mixta in coastal areas (making up 40% and 30% (by weight) respectively). HADDOCK Soviet Investigations on Young Haddock of the The southern Barents Sea (Sub-area I) * 0, I, II and III Age-Groups in the Barents Sea The main aggregation of young haddock in the (Tables 41-44) autumn and winter of Ig65j66 was observed in Assessment of the abundance of young haddock coastal (79 specimens per r hour trawling) and in the autumn and winter of I965j66 was carried western (38 specimens) areas. In catches taken in out during three cruises of the R. V. "Tunets" the central areas the young haddock was very and during a trip with the scouting trawler seldom met with, in all 2 specimens per I hour "Priz". In all cruises a 25 m bottom trawl was trawling. used. A ro mm mesh (knot-to-knot measurement) The total catch of young haddock in I965j66 net was inserted into the cod-end. During the was lower than in previous years (Table 4r). The crnises of the R. V. "Tunets" a nylon cover was average catch of young haddock of the rg62 year used and on the trip with the scouting vessel class up to 36 em in length was very small this "Priz" a cotton one. year, amounting to I fish per I hour trawling. Table 41. Average number of young haddock up to 36 em in length taken per I hour-trawling in Sub-area I in the autumns and winters 196o/r966 1960-1961 1961-1962 1962-1963 1963-1964 I964-I965 1965-1966 Num- Num- Num- Num- Num- Num- :::-ium- :::-ium- Num- Num- Num- Num- ber of ber of ber of ber of ber of ber of ber of ber of ber of ber of ber of ber of Areas trawl- fishes trawl- fishes trawl- fishes trawl- fishes trawl- fishes trawl- fishes ings ings ings ings ings ings Central ...... roS 26 III 102 153 IIO 109 I9 ro6 II 93 2 Western ...... 84 44 I32 79 70 73 84 95 87 36 63 38 Coastal ...... 27 I73 26 273 26 569 28 249 29 So 23 79 Total ...... 2I9 51 269 I07 249 qS 22I 77 222 30 I79 25 Eastern ...... 4I I 42 IS 62 38 33 34 36 IS 29 North-eastern ... 38 Table 42. Average number of young haddock of different year-classes taken per I hour-trawling in Sub-area I in autumn and winter 1965/1966 Number Age year-class Area Months of o +(I) I+ (z) 2 + (3) 3 + (+) Total Total of tra\vlings I96S I964 I963 I962 the young Central ...... Nov.-Jan. 93 I I Table 43· Average number of young haddock of different coastal regions from 23 to 35 specimens per I hour year-classes at 1-4 years of life taken in western, central trawling, and coastal areas of the sea in autumn and winter By comparing the data on the abundance of the Mean during Years of life the second young ones in the autumn and winter of Ig6s/66 Year-class and third years with those obtained in previous years, one can 2 3 4 of age estimate the I963 and I964 year-classes to be 2 I957 38,, 9 14 I2 medium ones, but the I963 year-class is somewhat I958 4 5 2 4 more abundant than the Ig64 one. It was also I959 7 14 33 2I 25 I96o 30 40 72 24 s6 confirmed that the I962 year-class is a poor one. I96I 32 so 34 6 42 I962 5 3 4 3 The Spitsbergen and Bear Island Areas (Divisionllb) I963 I6 9 I2 IO I964 II I2 As usual young haddock were very scarce in I965 Table 44· Average number of young haddock of different year-classes taken per I hour-trawling in Division lib in the autumn and winter of 1965/1966 Number Age and year-class Areas Months of o+ (I) I+ (z) 2 + (3) 3+ (+) Total Total of trawlings I965 I964 1963 I962 the young Bear Island Southern slope Sept.-Dec. 28 Scottish Investigations on the Faroe Stock of Table 45· Landings (nominal catches) and landings per unit Haddock 1966 effort of three market size categories of haddock by Aber deen motor trawlers from Faroe- r966 (Tables -t5--t7) Hours C\\'t per roo hours fishing Commercial statistics :\Ionth fishing Large :\icdium Small Total Landings of haddock by motor trawlers landing January .. _ -t.3H 19.8 zs.o 86.0 I30.8 February .. at Aberdeen are shown in Table 45· The mean 3-759 2-t-9 5+5 6-t.2 I-+3·6 :VIarch .... . 6.996 }0.} 83.0 98.o 2I I.} annual landing per roo hours fishing was 159 cwt. April ...... 7 ,)22 r8.9 62.8 I32-3 2I4.0 This is II% greater than the corresponding value :Vlay 2,92S 19.0 52 A T 23.6 I95.o of 143 cwt attained in rg65. Also, the mean landings June ...... 3,T')3 24.2 53·0 67·9 l-+5·1 per roo hours fishing of each of the categories large, July ...... -t,66r 22.:) 50.I 78·4 rsr.o August ... . 6,-tr; 39-0 53·0 -+3·7 I35· 7 medium and small were, individually, greater than September . 6,J35 23·-t 37-5 57-I I r8.o those of the corresponding categories in rg65. October ... -t, I J 3 1-t-3 r8.9 6;.r IOO.} ;\fovembcr . 2,625 35.0 39·8 66.4 I4I.2 December . 1,542 50.6 I9r.8 Age composition 55-3 85.9 Total :Vlcans 2 5-7 50.9 82.I I 58.7 The age composition of the haddock landed on Annual land- Aberdeen market is shown in Table 46, both by ings (cwt) 86,022 numbers and by weight. Tagging Length composition The mean lengths of the haddock sampled are During rg66 a total of 724 haddock were tagged shown in Table 47. The usual tendency for the from Faroese line boats. Bv the end of the vear mean lengths to decrease slightly in the spring was 17 of these had been return~d. " apparent, and on this occasion was from February R. jONES, D. G. CROSS to March. :\larine Laboratory, .·\berdeen, Scotland. Table 46. Aberdeen trawlers, market samples-- Faroe haddock- 1966 a) :-\umbers landed per 10 hrs. fishing Year-class Jan. Feb. :via.rch April :\Iay June July .-\ug. Sept. Oct. );'ov. Dec. 1965 I.Z 2I.2 2-t-4 g6.9 196-t 2.9 -tl.7 6.6 I 5-7 257·6 ss.o 12-t--t I77.6 376.8 153·3 1963 I9r.8 59-3 -t2-9 21 1.2 3IO.) -ti6.5 332.2 I68.6 223.8 q2.5 204.1 190.6 1962 262.0 330.8 637.0 892.6 -t67·7 375·5 301.6 '33-3 122.7 I03.0 104-9 zso.s 196I 203-3 272-4 sr6.o 333-9 346--t I-+9-0 I66.6 271. I I37-3 70.8 58.2 204.6 1960 70.8 57-2 34-1 39-9 67.2 -+3-6 -t0.2 -+9-0 -+9·5 21.-t 30--t IO-t-5 1959 28.3 32. I H·9 20.-t 2-t.S 35-5 II.7 2-t.O 17.8 I7-7 I9.9 17. I 1958 I-+·7 I6.7 g.6 9--t -t· I -t· I -+·3 3-9 -+·7 +9 ;.6 5·5 1957 ...... 3·0 2.-t 3·7 2.7 0.5 3-7 r.6 3·0 1.2 3-5 o.8 1956 and older . 0.3 o.S 0.2 1.0 0.5 O.I Total ...... 773·9 770·9 I,29I-4 I,5)2.6 r, zzS.o I,O-t4.6 r,rr6.3 682.6 562.6 b) Estimated*) weights landed per 10 hrs. fishing (cwt) Year-class Jan. Feb. :\larch April :\Iay June July Aug. Sept. Oct. ~ov. Dec. I965 ~ 0.13 o.q 0-40 1964 0.02 0.25 0.05 0.08 T.69 0.62 o.86 r.68 3.66 1.39 1963 r.s r 0 ·55 0.}2 1.70 3.26 -t-21 3.60 r.SI 2.59 2.03 3-43 3.10 I962 3-42 -t-9I 8.q I r. r6 6.76 j.OO +54 2.29 2.00 r.SI 2.10 5.16 I96I .:j..22 5-42 9-42 6.24 6.60 z.Sz 3.02 ).66 2.90 1.72 1.67 5-23 I96o 1.83 LH 0.83 1.02 1.77 0 ·75 o.9I 1.30 I. I 7 o.59 0.9-t 3-09 1959 0.87 r.o6 1.28 o.67 0.78 0.90 0.34 0.76 0.59 0.)9 0.75 0.56 1958 o.ss 0-44 0.35 0-34 o.r6 o.r6 O.I6 o. I6 0. I7 0.24 0.39 o. r6 1957 ...... 0. IS 0. I2 0.13 O.I I 0.02 O.I 2 0.06 0. IZ 0.07 o.rs 0.06 I956 and older . O.OI O.O-t 0.02 0.05 0.02 ::-< Total ...... 12.58 I}-9-t zo.so 21.53 q.o9 14-3-t 12.72 I0.35 I3-I4 19.09 \Vt. landed per ro hrs. fishing 1}.08 2I. I} I9-50 q.)I I5.IO I3.57 Ir.So 10.03 q.rz I9.I8 *) Using data from I~usscll, E. S., r9q. Fish, Im·est. Lond., Ser. 2, I (I). =" = :\egligible -III- Gadoid Fish Haddock <::: Table 47· Mean lengths (ern) of each haddock age-group sampled from Aberdeen trawlers Year-class Jan. Feb. :\I arch April :vra;' June July .Aug. Sept. Oct. :Xo\·. Dec. rg65 ...... 3 [.0 33-9 32-9 30.0 1964 ...... 34-4 34-0 35-6 32.6 34-8 36.1 35-4 39-2 39-6 38-7 1963 ...... 36-9 38.g 36·4 37-2 40.6 40.1 41.0 40-9 41.9 44-9 47-4 46.<; rg62 ...... 43-6 45-5 43-3 43-0 45-I 43-9 45-7 47·7 46-9 48. I 50.2 50·7 rg6r ...... 50.8 50.1 48·7 48.8 49-4 49-3 48.6 50-9 51.1 53 5 s6.5 54-4 rg6o ... 54-6 54-2 53-5 54-4 54-9 47-7 52.2 55· I 53- 0 55-7 58.o 57· 1 1959 ...... 57-8 59-I 56.4 59-2 sS. r 54-2 s6.; 58.4 59·3 59-3 6r.S 59-2 1958 ...... 62.6 55- I 61.2 60.7 62.6 62.3 61.7 64.2 6r.6 67-3 68.8 57·0 1957 ...... 6;.3 66.8 6o.4 64-3 68.7 59-3 62.1 62.5 J0.8 6;.7 74-9 rg56 and older .... 64-6 65-3 So.s 67.0 6s.o J4.0 Scottish Investigations on the West Coast Stock of F. R S. "Explorer" off the Scottish north and Haddock, rg66 west coasts is shown in Table 49- As well as the data (Tables 48-sr) obtained during the Ig66 cruise, data from a Commercial statistics cruise made in January I967 are included. Data from this cruise were required for the comparison The landings of haddock by Scottish vessels of mean lengths made in Table 51. :fishing to the west of Orkney are shown in Table 48. Just as in the Korth Sea, the Ig6z year-class was Age composition still extremely well represented in the catches in The age composition of the haddock caught by all areas. Table 48. Haddock landings (nominal catches) and fishing effort by Scottish vessels in rg66 from the north and west coast of Scotland )forth North Outer South South o[ Firth of Coast :\linch Hebrides :\Tinch Lat. 560:\ Clyde Landings ('oo tons) 2 ::\Totor Tra\d ...... 86.71) 23. 1 ) 3·9 o.S 9-4 Steam Tra\\'l I.O 0. l Light Tra,,·] 2. I 3·1 0.02: O.I 0.1 2 Seine ...... 44·4 7°·7 ) 0.5 6.g 0.2 Fishing Effort ('oo 11I's) ::\'lotor Traw I ...... 6orl) 1582) 33 3 48 Steam Trawl 9 I Light Tra\\'1 So 294 3 '20 15 Seine - ...... 394 7622) 4 183 9 Landings per unit effort :Vlotor trawl (tons per roo hrs) .. 14-4 q.6 12:.0 22. I 19·4 Steam trawl (tons per roo hrs) II.S 17.0 Light trawl (tons per roo hrs) 2.6 I.O 0.5 0.6 0.7 0.6 Seine (tons per roo hrs) ...... rl.3 9-3 13.0 3·8 ? ' 1.3 1) includes sq. rSZZ; 2) Includes sg. r8YY Table 49· Numbers of haddock caught per ro hrs fishing by F.R.S. ''Explorer'' off the north and west coasts of Scotland Area ::-\orth Coast l' rg66 4:20 ..f20 lj 17 rg65 675 1,082 Srr 8 130 38 IS 7 12 IOI 2 1964 64 88 72 I95 3I 154 79 ., ,, 1963 87 rrS 97 426 14 323 530 412 3 rg6z 2,799 772 2,123 7,487 1,314 5,9+4 6,912 2,197 5,864 92 67 84 1961 15 20 17 r69 41 137 338 76 280 14 3 IO 1960 & older 7 5 I I 13 II -II2- Table 50. Mean lengths (em) of haddock of each age-group from the north and west coast of Scotland North Coast North :VI inch Outer Hebrides South Minch Cruise Mean No. of :VIeau No. of :VIeau No. of Mean No. of Year-class length fish length fish length fish length fish 1966 January r 967 18.7 42 r8.5 5 0 0 r965 Feb./March 1966 r8.1 135 16.4 7 0 r8.2 9 January 1967 30·5 roS 27-7 39 0 29.0 2 1964 Feb./March 1966 28.3 13 30.0 r66 3I.3 7I 3I.O I January 1967 34·2 9 32.0 9 0 0 1963 Feb./March 1966 30-4 I7 3I.2 362 3+4 371 35·0 January 1967 35·2 12 38.0 4 0 36.0 1962 Feb./March 1966 36.2 560 33·8 6,367 35·3 4.837 36·3 55 January 1967 39·8 77 36.2 393 40.2 330 42-4 20 1961 Feb./March 1966 50.0 3 43·6 144 44-4 237 44·7 8 January 1967 58.o 2 47·6 12 so.6 II 58.0 1960 Feb./March 1966 0 sz.o 0 0 January 1967 0 0 0 0 Table 51. Mean lengths of four recent year-classes in the autumn or winter of each sampling year, compared with the mean lengths of other year-classes sampled in the autumn or winter from 1959-1962 Area North Coast North Minch Year-class 1962 1963 1964 1965 Earlier Year- 1962 1963 1964 1965 Earlier Age*) years class years r+ ...... 25·9 26.2 30.5 3I.6 26.r 24.1 23·5 27·7 30.8 2-j- ...... 3I.6 34·2 36.8 30.8 30.0 32.0 35.2 3+ ...... 32-4 35-2 37·3 33.1 38.0 38.0 4+ ...... 39.8 4I.8 36.2 40-4 Area Outer Hebrides South Minch Year-class 1962 1963 1964 1965 Earlier Year- 1962 T963 1964 I965 Earlier Age*) years class years 1-j- ...... 26.8 22.0 24.0 28.o 26.6 29-3 29.0 32.2 z+ ...... 30.1 z8.6 34.1 3I.I 36·4 3+ ...... 34·0 36·9 36·3 36.0 39-3 4+ ...... 40.2 39·9 42-4 44·7 --·~'' ------*) For the purpose of this table, April rst has been retained as the birthday of a haddock Length composition Scottish Investigations on the North Sea Stock of Haddock, 1966 The mean lengths of the haddock captured in the (Tables 52-55) two "Explorer" cruises are shown in Table 50. For comparative purposes, the mean lengths of the 1962 Commercial statistics and more recent year-classes have been compared with those of earlier year classes in Table 51. On Landings of haddock by Scottish motor trawlers average, it appears that the growth of the 1962 in 1965 and 1966 are shown in Table 52. These show and later year-classes has been slower than that that north of latitude 57°30'N, landings were of earlier year-classes. greater in 1966 than in 1965. South of this latitude, on the other hand, landings tended to be poorer. Tagging Age composition During 1966, a total of 2,776 haddock were tagged off the Scottish north and west coasts. By The age composition of the haddock caught by the end of the year, 233 of these had been returned. F. R. S. "Scotia" in three North Sea trawling surveys is shown in Table 53· "0"-group haddock R. JONES, D. G. CROSS (1966 year-class) were well represented in the Marine Laboratory, Victoria Street, Torry. Aberdeen, November cruise. Comparison with the numbers Scotland. of "0" group haddock caught in earlier years -II3- Gadoid Fish Haddock Table 52. Landings (nominal catches) of haddock by Scottish earlier year-classes. These data show that not motor trawlers from the North Sea in 1965 and 1966 only the rg6z year-class, but also the 1963 and a) North of Lat. 57°3o'N (Division IVa) 1964 year-classes appear to have been growing at Wt.landed Quarterly Vi't. landed Effort tons per less than the average rate in all parts of the North Period Year ('oo tons) ('oo hrs) roo hours Sea. The 1965 year-class, on the other hand, J an.-:VIarch 1965 24.8 154 r6.r appears to be growing at slightly more than the rg66 44·3 228 19-4 average rate in all areas sampled. April-June rg65 15.6 141 11.1 rg66 22.1 155 14·3 Tagging July-Sept. 1965 28.o 229 !2.2 1966 34·6 222 15.6 During rg66, a total of 2,145 haddock were Oct.-Dec. 1965 55.8 345 16.2 tagged. By the end of the year, zrz of these had rg66 II3.6 481 23.6 been returned. b) Lat. 55°X to Lat. 57°30'N (Division IVb) R. JoNES, D. G. CRoss Jan.-March 1965 12.3 q6 8-4 :VIarine Laboratory, Victoria Street, Torry, Aberdeen, 1966 5·6 140 4·0 Scotland. April-June 1965 rz.8 226 5·7 1966 9-4 233 4·0 German Investigations on the Haddock July-Sept. rg65 17·3 232 7·5 of the North Sea in rg66 1966 21.6 259 8.3 Oct.-Dec. 1965 22.6 260 8.7 During two voyages with R.V. "Anton Dohrn" rg66 17.6 22! 8.o in rg66 the distribution, density and age com c) All Areas position of the haddock stock in the North Sea Jan.-March 1965 37·1 300 12-4 and Skagerak was investigated by experimental rg66 49·8 368 13·5 herring trawls. April-June rg65 28-4 367 7·7 rg66 31.5 388 8.r The trip in August/September took place in most July-Sept. rg65 45·4 461 g.8 areas of the North Sea and a second survey in rg66 56.2 481 11.7 November/December was undertaken in the north Oct.-Dec. rg65 78·3 6os 12.9 eastern parts (Utsira(Egersund) of the North Sea rg66 131.2 702 r8.7 and the western area of the Skagerak. suggests that this is going to be an average, or The mean catches of haddock per ro hours' better than average year-class. Of the older trawling broken down by age-groups, and the mean haddock, the rg6z brood, although in its fifth year, length will be published in Statistical News Letters, was still very well represented in the catches. No. 37- The strong year-class rg6z was most numerous Length composition in August/September rg66 - as had also been The mean lengths of the haddock caught by the case the year before - in the northern and "Scotia" are shown in Table 54· By the end of the central North Sea. In contrary to this, the age year, the mean length of the rg6z year-class in all groups II and III were of less importance in the parts of the North Sea was still below average for experimental hauls from all areas. The year-class its age. This is shown in Table 55, where the mean 1965 was found in greater quantities near the lengths of the rg6z and later year-classes are Scottish coast and on the fishing grounds of the shown and compared with the mean lengths of Gut-Doggerbank. Table 53· Numbers of haddock caught per 10 hrs fishing by F.R.S. "Scotia" in the North Sea in 1966 Area Northern North Central Central Moray Firth and Orkney All All All Cruise April July Nov. cruises April July Nov. cruises April July Nov. cruises No. of hauls 9 5 7 21 r6 12 II 39 3 7 10 Weighted Weighted Weighted Year-class rnean mean mean rg66 334 195 144 3-497 1,748 103 2,183 1,559 1965 45 58 54 51 191 65 13 !02 2,342 369 r8o 237 1964 58 34 33 44 24 rg 8 18 38 207 39 8g 1963 162 8g 99 7 12 2 7 20 38 54 49 1962 2,997 686 6,o6o 3,468 359 409 205 331 rso 1,379 975 r,og6 1961 go 14 15 47 13 13 13 13 28 13 r8 rg6o & older 8 4 5 5 4 Table 54· Mean length (em) of haddock of each age-group from the North Sea in 1966 :\loray Firth ~orthern X orth Central Central and Orkney Cruise 1\Iean No. of :Ylean No. of :Ylean No. o[ 'VIe an No. of Year-class length fish length fish length fish length fish 1966 July ...... () S.o I73 0 9-9 3I Xovember ..... 14-5 23+ I+-9 3.847 0 I7·+ I,528 I965 April ...... I9.2 40 20.2 306 2!.3 234 () July ...... 24.0 29 25. I 78 26_(, II6 November ..... 26J) 38 26.8 q 29-4 I26 I96+ . . . . . April ...... 28.I 52 30.2 38 28.2 + 0 July ..... 3!.2 I7 33-2 23 0 35-9 62 November 31-2 23 30-5 9 () 3!.2 27 I963 ..... April --- 32-3 q6 30-5 II 31-5 2 () July ...... 0 40-3 14 0 38.o II November ..... 35-0 62 33-0 2 0 3-t-.2 38 1962 April ...... 35·3 2,69/ 38.6 57+ 42.0 I5 0 July ...... 37-0 343 39-5 491 0 37-3 +I+ November ..... 37-9 4,:242 39-2 225 () 36.8 682 1961 ..... April ...... 44-7 81 +8-9 21 0 0 July ...... 42. I 7 4I.I I6 0 42-5 8 November 45-8 IO 4!.3 14 0 +I.6 9 Table 55· Mean lengths of four recent year-classes in the autumn of each sampling year, compared with the mean lengths of other year-classes, also sampled in the autumn during 1950-62 ~!\rea Xorthern ~orth Central Year-class 196:2 I963 I96+ 1965 Years Year- 1962 1963 1964 I965 Years Age1') 1950-62 class 195o-6z I -i- 2(l.9 2!.2 2).0 z6.g 25-9 26.5 21.5 25-3 26.8 26.2 2 _[_ -- ...... 30-4 32-4 31.2 3I.8 30.6 31-5 30-5 31.6 3+ ...... -- . 34-9 35-0 35-4 35-8 33-0 36.8 4-~ --- ...... 37-9 38.2 39-2 38.s Area Central :\Ioray Firth ancl Orkney Year-class I962 I963 1964 1965 Years Year- 1962 I963 1964 1965 Years Age*) 1950-62 class 1950-62 I-f· ..... --- 25-4 23.2 28.3 27-7 cq.6 28.+ 29-4 28. I 2 -'--- 3I.O 3I.I 33-9 28.8 31.0 3I.2 34-7 3T 35-6 38.6 35-5 34-2 39-5 4+ 42-7 36.8 44--1 *) For the purpose of this table. April Ist has been retained as the birthday of a haddock During both trips haddock of the 0-group (rg66 found in small numbers at the Ling Bank, and year-class) was found in great numbers in the north and south-west of the Doggerbank. northern Korth Sea and the Skagerak. But the G. "WAG::JEI< time of the year was too early to allow for con clusions as to the size of the new recruitment. Bunclesforschungsanstalt flir Fischcrei, 1 nstitut hir See Haddock of the age-group \. and beyond were ilschcrei, 2 I-1amburg _so, Paln1aille 9, Gen11any. WHITING Scottish Investigations on the West Coast Stock of The continued presence of large numbers of Whiting, rg66 fish of the rg6z year-class resulted in increases in (Tables 56-59) catch per unit effort by motor trawlers and seine Commercial statistics net vessels in all the commercially important In Table 56 are shown the landings (nominal areas (except for seine-netters working the North catches), fishing effort and landings per unit effort Minch grounds -vvhere increased fishing effort gave by trawlers and seine-netters working off the north a slightly reduced catch per unit effort compared and west coasts of Scotland during rg66. with the high level of rg65) _ -II5- Gadoid Fish Whiting Table 56. \Vhiting landings (nominal catches) and fishing effort by Scottish vessels in 1966 from the north and west coasts of Scotland North North Outer South South of Firth of Coast :VIinch Hebrides :'.Tinch Lat. 56°1\f Clyde Landings ('oo tons) :VIotor trawl ...... r8.2o1 3-302 O. .f6 0.08 0.30 Steam trawl 0.09 0.01 Light trawl r.66 r8.o3 0.06 0.12 0.12 1.13 Seine ...... 7·73 32·772 0.17 I 1.2-f 0.16 15-5-t Fishing effort ('oo hours) 1 Motor trawl ...... 6or rs82 33 3 -t8 Steam trawl 9 Light trawl So 294 3 20 IS Seine ...... 394 7622 4 183 9 Landing per unit effort :VIotor trawl (tons per roo hrs.) 3·0 2.1 1.4 2.3 0.6 Steam trawl (tons per roo hrs.) I.O I. I Light trawl (tons per roo Ius.) 2.! 6.r 1.9 0.6 o.S 1.7 Seine (tons per roo hrs.) ...... 2.0 4-3 4·2 6.r r.8 3·6 1) Includes sq. r8ZZ; 2) Includes sq r8YY Table 57· Numbers of whiting caught per ro hrs. fishing by F.R.S. "Explorer" off the north and west coasts of Scotland Area North coast North Minch Outer Hebrides South :VIinch Fcb./31ar. Jan. All Feb./Mar. Jan. All Feb./:VIar. Jan. All Feb./Mar. Jan. All Cruise 1966 1967 cruises 1966 !967 cruises !966 !967 cruises 1966 1967 cruises ., No. of Hauls 2 3 9 3 12 7 9 6 3 9 Weighted Weighted Weighted Weighted Year-class n1ean 1nean tnean 1nean. 1966 roo roo 163 163 8; 8; 1965 335 90 253 I.f5 .f?I 226 IO 53 20 682 373 579 1964 25 so 33 644 5-fO 6r8 302 67 250 rsr 397 233 1963 qo 41 115 6o 20 5I 89 46 75 1962 15 so 27 2,831 1,291 2,446 1,448 233 1,178 838 1,157 944 1961 5 3 48 66 52 63 67 6-t 45 28 39 1960 & older 25 3 20 6 20 9 2 Table 58. Mean lengths (em) of whiting of each age-group from the north and west coasts of Scotland North Coast North :VIinch Outer Hebrides South :.viinch Cruise :VIe an No. of :VIeau No. of :VIeau No. of Mean No. of Year-class length fish length fish length fish length fish 1966 Feb./March 1966 J anu'ary 1967 20.2 10 16.2 49 0 17-9 26 1965 Feb./:VIarch 1966 17-9 67 20.0 123 2!.3 7 18.5 409 January 1967 26.9 9 28.6 I.f1 30.6 8 29.8 II2 1964 Feb./March 1966 26.2 5 27.2 547 28.o 212 29.2 91 January 1967 31.8 5 32.2 162 3-f.O IO 33·2 119 1963 Feb./March 1966 0 32.8 II9 31.9 42 34·6 53 January 1967 0 35-2 12 37-0 3 39-6 I4 1962 Feb./March 1966 31.0 3 33-3 2,-fOS 33·5 1,013 35·4 503 January 1967 37-4 5 35·8 387 .f2.7 35 37·6 347 1961 Feb./March 1966 41.0 42.6 .f1 .fl.2 H 42.! 27 January 1967 0 42.6 20 47·6 10 -t6-4 8 1960 Feb./March 1966 0 40·7 20 -t2.2 2 42.0 January 1967 0 SI.O -t6·7 3 0 Age composition The striking feature of these age compositions Routine surveys of the Scottish north and west is the dominance in the catches of the rg6z year coasts were made by F. R. S. ''Explorer'' in class. This is even more apparent on the west coast February/March rg66 and in January rg67 and the grounds than in the North Sea, all the other age compositions of the catches are shown in year-classes being relatively poorly represented. Table 57· It seems likely, though, that the rg65 year-class -II6- Table 59· Mean lengths of four recent whiting year-classes, caught in winter, compared with the average mean lengths of fish caught at the same age during the period 1959-62 Area North Coast North Minch Earlier Earlier Year-class 1962 1963 1964 1965 Years Year- 1962 1963 1964 1965 Years -J:Age (1959-62) class (1959-62) ...... 2j.O r+· 30.0 27·+ 26.9 31.4 27·3 26.0 z8.5 28.6 30·7 2+· ...... 29.1 29-5 3I.8 33.6 29.7 34-9 }2.2 35·3 3-+ ...... 32. I 37-4 33.2 35·2 ...... 38·7 ++ 37·+ 36.2 35.8 41.7 *Age, ,\rea Outer Hebrides Year- South :VIinch 1-j- ...... 26.9 28.6 30.6 3I.2 class 2 7·7 28.1 3I.5 29.8 30.1 z-t- ...... 33.0 35·5 34·0 34·8 32.1 32-5 33-CZ 35.8 3+ ...... 34-4 37·0 37·+ 34·8 39·6 4I.l ...... 2 4+ 4 ·7 42-4 37.6 39·5 * For the purpose of this table, April rst has been retained as the birthday of a whiting is stronger than those of 1963 and 1964. The Table 6o. Landings (nominal catches) of whiting by Scottish strength of the rg66 year-class can not be evaluated motor trawlers from the North Sea in 1965 and 1966 accurately on the basis of the January 1967 survey a) North of Lat. 57°3o'N (Division IVa) alone. vVt. landed Quarterly Length composition Period The mean lengths of the whiting of age-groups J an.-i\1arch I.4 154 0-6 caught during the two surveys by F. R. S. 4·7 228 "Explorer" are shown in Table 58. April-June 2-4 141 5-4 I 55 Table 59 compares the mean lengths of four July-Sept. s.z 229 recent year-classes with the mean figures for the 7·2 222 period I959-r962. Only in the North and South Oct.-Dec. 8.2 345 Minch areas does the rg6z year-class appear to be of 10-4 . 481 below average size as 4+ fish. Tagging 318 whiting were tagged on the Scottish west coast during rg66. By the end of the year r6 had been returned to the Laboratory. J. HISLOP, D. G. CROSS :Vlarine Laboratory, Victoria Street, Torry. Aberdeen, c) All areas Scotland. Jan.-:;viarch 1965 4-4 300 r.s 1966 9-4 368 2.6 Scottish Investigations on the North Sea Stock of April-June 1965 3·6 367 I.O 1966 8.o 388 2.1 Whiting, 1966 July-Sept. 1965 rz.s 461 2.7 (Tables 60-63) 1966 15.2 481 3·2 Oct.-Dcc. 1965 15.6 6os 2.6 Commercial statistics 1966 16.o 702 2.3 The landings (nominal catches), fishing effort and landings per unit effort of whiting landed by Scottish motor trawlers in 1965 and rg66 are Throughout the year the rg6z year-class persisted shown in Table 6o. There was a marked increase in all areas in much larger numbers than are both in landings and in landings per unit effort in usually obtained for 4+ whiting. The 1963 year rg66. class was found to occur at a very low level of abundance everywhere. The 1964 year-class was Age composition also found to be below average strength. In the During rg66, F. R. S. "Scotia" made three Moray Firth and Orkney area the 1965 year-class routine surveys of the North Sea and the age was quite well represented and the rg66 year-class compositions of the catches taken during these was strong in the North Central and Moray Firth surveys are shown in Table 6r. and Orkney areas. -IIJ- Gadoid Fish Whiting Table 6r. Numbers of whiting caught per IO hrs. fishing by F.R.S. "Scotia" in the North Sea in 1966 Area Northern North Central Central :Nloray Firth and Orkney All All All Cruise April July Nov. cruises April July Nov. cruises April July Nov. cruises No. of hauls 9 5 7 21 16 12 II 39 3 7 10 Weighted Weighted Weighted Year-class mean mean mean 1966 3 3 1,510 1,510 7,305 7.305 1965 6 0 42 17 46 2 307 106 690 2,075 1,156 1,432 1964 373 0 134 205 120 9 314 143 !64 285 171 205 1963 77 0 45 48 16 6 79 31 0 9 8 8 1962 1,{01 2! 491 769 130 73 364 178 136 360 305 322 1961 246 9 71 131 26 19 83 40 0 I4 5 8 1960 & older 19 0 4 12 4 3 2 0 0 Table 62. Mean lengths (em) of whiting of each age-group from the North Sea in 1966 Nloray Firth Northern North Central Central and Orkney Cruise :\lean No. of Nlean No. of :VIean No. of :VIean No. of Year-class length fish length fish length fish length fish 1966 July ...... November ..... 13·5 ·> 16.3 1,661 r6.s s,rq 1965 April ...... 21.8 5 19.7 74 r8.8 69 July ...... 26.5 2 22.4 6zz November ..... 28.3 30 zs.z 338 24·3 8o9 1964 . . . . . April ...... 27·7 335 26-4 202 July ...... 22.6 II 28.6 86 November ..... 31.0 94 28.1 346 29·4 !20 1963 ..... April ...... 32.6 69 31.0 26 July ...... 31.3 8 33·9 3 November ..... 34·0 31 29-4 87 36.2 6 1962 . . . . . April ...... 31.1 1,261 31.2 208 30.0 14 July ...... 33-4 IO 33·6 88 33·5 108 November ..... 34·3 343 32·7 400 33·1 zq 1961 ..... April ...... 34·2 221 34·5 42 July ...... 35·8 5 36·4 23 36·5 4 November ..... 38.2 so 35·5 92 36·5 4 Table 63. Mean lengths of four recent whiting year-classes in the autumn of each sampling year, compared with the mean lengths of other year-classes, also sampled in the autumn during 1958-I962 Area Northern North Central Year-class 1962 1964 1965 Years Year- 1962 1963 1964 1965 Years A.. ge* 1958-62 class 1958-62 I-'- ..... 2 22.6 (26.o) ' 24·9 28.3 7·7 25.8 25·4 2+ .. 29·7 (32.0) 31.0 30·9 28.6 31·7 28.1 29·3 3+ .. . .. 34·0 34-0 32.8 32.7 29·4 31.2 4+ ... 34·3 34.1 32-7 32.8 Area Central :VIoray Firth and Orkney Year-class 1962 1963 1964 1965 Years Year- 1962 1963 1964 1965 Years A.ge* 1958-62 class 1958-62 1+ ...... 22.4 27.0 2j.2 25·7 22.8 25·9 2-1·3 25.9 2+ ... 27-4 28.1 29·7 28.1 28.3 31.0 3+ ... . . 29.1 30.8 30.2 36.2 33·5 4+ .. 33·3 33.1 35·6 * For the purpose of this table, April 1st has been retained as the birthday of a whiting Length composition average length at these ages during the period Table 62 shows the mean lengths of whiting of rg58-6r. The rg6z year-class, which showed be age-groups 0-5 sampled by F. R. S. "Scotia" in low average mean lengths, for its first two years the North Sea during rg66. of life is now of average size in all areas except In Table 63 the mean lengths of some recent year in the Moray Firth and Orkney area. The weak rg63 classes at various ages are contrasted with the year-class is above average size in two areas, but -II8- numbers of fish of this brood caught during rg66 this was shown at journeys in August/September were small, so little significance may be attached to and December at the Utsira and Ling Bank /Eger this. Average growth is shown by the rg65 and rg64 sund areas. But the time of the year was too early year-classes. to allow for definite conclusions about the quantity of this year-class. Tagging G. "WAGNER During rg66, a total of 951 tagged whiting were Bunclesforschungsanstalt flir Fischcrci, lnstitut flir Sec liberated in the North Sea. By the end of the year fischerei, 2 Hamburg 50, Palmaillc 9, Germany. rog of these fish had been recaptured. J. HISLOP, D. G. CROSS German Investigations on Whiting in the Western :\Iarinc Laboratory, ,Victroia Street, Torry, Aberdeen, Scotland. Baltic in rg66 (Table 64) German Investigations on the Whiting Tbe following report deals with the experimental of the North Sea in rg66 trawling in the Kiel Bay in rg66. Details concerning time, place and number of hauls are given in the In rg66 the density, age composition and reports on the stocks of cod (p. 105) and flatfish distribution of the whiting stock of the North Sea, (p.zogf.).Theresultsforwhitingareshownin Table64. Skagerak and English Channel was investigated by routine trawl surveys from R.V. "Anton Dohrn". The mean catches per month vary to a much greater extent than for cod (cf. p. ro6). As already In January only a few experimental hauls were observed in previous years, the smallest catches performed at the Outer Silver Pit, the Sandettie were obtained in May, and after a remarkable grounds and in the eastern English Channel. On increase in July, a new decline occurred in Septem the trips in March the research vessel visited the ber in spite of the appearance of the new rg66 eastern and central North Sea. During a third vear-class which caused maximum catches in voyage in August/September experimental hauls November, up to 1,330 specimens per hour's were made nearly over the whole North Sea while fishing. The average of 86 hauls amounted to a fourth journey in November/December took place roo whiting, much less than in rg65 when an in the UtsirajEgersund area and the western average catch of 271 specimens per hour was section of the Skagerak until the slope of the recorded. Obviously, smaller quantities of the Norwegian furrow. 0-group invaded the Kiel Bay in the autumn of The mean catch per 30 minutes will be given in rg66 than in rg65. The trawl catches of small Statistical News Letters, No. 37, as well as the catch whiting in the Kiel Bay are characterized by per ro hours' trawling, broken down by the age enormous fluctuations from year to year as well composition. In January and December the whiting as in the course of the year and from one place to of the year-classes rg64 and rg65 predominated in the southern North Sea, the hauls made at the alti Table 64. Length and age distribution of whiting taken with tude of Texel gave specimens of age-group I (year the standard trawl in the Kiel Bay in I966 class rg64). In January in the English Channel Kumber per I hour's fishing the whiting of the year-class 1964 was the chief Length component, whereas on the Skagerak grounds in in em Jan. :\!larch May July Sept. Nov. December the year-class rg66 (age-group 0) was 6-Io 0.9 0.4 0.2 0.3 31.2 44·3 most numerous. II-I) 47-4 35-9 14·3 Il.3 3·6 I76·4 In March the 0-group (year-class rg65) dominated I6-2o 58.o 37-4 I0.2 54·3 4·4 12.2 21-25 ).0 4·7 1.4 8.9 3-7 3·4 in all areas of the eastern and central North Sea, 26-30 2.3 4·0 1.5 1.5 o.8 r.6 except at the SW-Dogger, where the year-class rg64 3I-35 0.7 1.0 0.4 0.5 O.I made up the largest part of the catches. These 36-40 O.I 0.2 O.I O.I results are reflected in the catches in August/ Year-class September at the same fishing grounds. At this I966 0.3 34·8 232.6 I965 .... I IO.I 78.I 24-9 74·5 8.4 5·3 time the strong year-class rg6z (age-group IV) I964 .... 4·2 4·8 2.7 1.9 0.7 O.I was found in experimental hauls from the northern I963 North Sea (see the tables in Statistical News Letters, and older O.I 0.7 0.4 O.l No. 37). Whiting of the year-class rg6r and older Total were scarce during all four research voyages. number I14-4 83.6 zS.o 76.8 43·9 238.0 Number The 0-group was clearly a relatively good one, examined 2,145 I,359 337 I, I)2 720 3,690 -rrg- Gadoid Fish Whiting/Blue Whiting another. They are caused by differences in the second year of life when they return to the Kattegat. hydrographical conditions at the time of immigra Within these twelve months the frequency of each tion, the situation of the fishing places to the main year-class is reduced to s-ro% and less; in the currents, and probably by changes in the behaviour following year the decrease continues to a similar of the small whiting taking up for certain times a extent, and older specimens are therefore rare. pelagicallife. R. K";,;_XDLER The majority spends one year only in the Kiel fnstitut fur :VIecrcskundc dcr Universitat Kicl, Bay, from August/September until July in their Hohenbergstraf3e 2, Kiel. Germanv. BLUE WHITING Results of Soviet Investigations on l\!I icromesistius 2. Young fishes of r2-r6 em of length were po~ttassou in the North-East Atlantic in rg66 mainly met with west of Spitsbergen and near (Tables 65-68) the Hebrides; fishes of 35 em in size were found Investigations on the biology of Blue Whiting south-west of Iceland and west of Great Britain. were carried out on board the R. V. "Volgodonsk" In catches taken in the Barents Sea and the during two special cruises in rg66. During the Norwegian Sea fishes of 26-30 em in size first cruise (December rg65 to March rg66) spawn prevailed (mean length 29,40 and 28,28 em). ing places were investigated. During the second South of the Faroe Islands the length was one (May-August) observations were made on 23-30 em (mean length 28.39 and 26-48); and the distribution of fattening shoals. west of Ireland 22-26 em (mean length 23.82; Table 65). Data were collected on the biology of blue whiting on board the research vessels "Perseus II", 3· Great shoals of pre-spawning and spawning "Tunets", "Neptun" and others, at the same time blue whiting were found on the Porcupine Bank. when cod, haddock, redfish and herring were According to data from the echometrical survey, the shoals were distributed on slopes of the bank studied. above the depths of r8o-3oo m and they were Detection of blue whiting shoals, as well as found over an area about 8oo miles2 • Spawning observations on distribution of vertical migrations in the area took place from 23. February, with were carried out with the help of the fish locator the peak in the middle of March. The water "Paltus". Experimental trawlings were made with temperature during this period of spawning was bottom and mid-water trawls. Biological analyses g.8-ro.5°C. were performed according to the usual methods 4· In the day-time shoals of pre-spawning blue for Gadidae. The determination of the stages of whiting were found by the fish locator near the sexual maturity was conducted according to bottom. During the time when the sea surface V. P. SoROKIN's scale (r957). During the experimen was sunlit, the blue whiting was found close to tal trawlings made by the research vessels 273 tons the bottom. During the spawning period we of blue whiting were taken. 88,5r4 fishes were might observe shoals ro-30 m from the bottom measured and 6,rr2 were analysed biologically. (sea depth r80-250 m) and only separate shoals As a result of extensive investigations of the near the bottom; when the weather was sunny, areas of distribution of the blue whiting, and the fish migrated into the mid-water layers. In summarizing the studies on spawning, feeding and the evening both pre-spawning and spawning size-composition in different areas, one may con shoals of blue whiting scattered and at night they clude as follows: were observed in a depth of up to 8o m from the r. In spite of the wide distribution of blue surface, sometimes also in the water column at whiting in the North-east Atlantic, areas of a depth of 20-40 m from the ground (sea depth dense concentrations were found only in the r8o-25om). southern part of the Norwegian Sea and to the 5· In the area to the west of Ireland the blue west of Great Britain. During experimental whiting reaches maturity at a length of I7- trawlings in these areas 7 tons of blue whiting 20 em. Males mature at a smaller length than were taken per 2 hours. females; the main number of males mature at -120- Table 65. Size composition of blue whiting in different areas of the North-east Atlantic in 1966 Fishing area and date West The The South- West The The The The The Spits- Barents Norwegian west of Green- Eastern Outer Rockall Hebrides' Porcupine bergen Sea Sea Iceland land Slope of Bayleys Bank Shallow Bank the Faroe Bank Length March-June Shallow Jan., June, Feb.-March em Sept. Sept., Oct. Jan.-Dec. July Sept. May Jan.-Aug. Aug. Aug. July-Aug. II I2 7·3 O.I 13 9.2 0.5 I4 32.0 0.9 I5 33·0 + I.2 + I6 I.9 + 3·7 + I7 O.I O.I O.I 2.7 O.I IS + 0.3 0.9 0.9 I.6 0.2 19 0.2 I.5 4·6 3·0 0.4 20 0.5 2.8 8.9 3·0 I.3 21 + 0.7 2.2 0.3 9.0 5·9 4·3 22 O.I I.6 3·9 2.8 I. I 5·6 19.0 I8.3 23 0.3 0.5 2.9 2.6 4·0 1.4 ro.5 13.8 26.4 24 0.5 I.O I. I 4-2 6.1 3·3 r6.2 13·7 19·5 25 0.5 2.1 5·4 5·s 2.6 12.5 10.7 IS.r 7·9 I4.2 26 6.9 II.8 6.7 6.5 17.3 II.5 12.6 5·4 7·5 27 I.O II.4 19.2 I I. I 7·8 14.8 20.7 7·3 2.7 3·8 28 2-4 15.2 22.8 8-4 6.5 12.8 I3·7 3·2 I.9 I.9 29 0.5 I0.7 13.2 6.9 rS.r 7·8 6.6 I.6 3·9 0.8 30 7·3 2!.7 I2.9 12.6 7·8 6.2 8.8 0.7 I.5 0.5 3I 0.5 !2.8 6.1 7·2 9·1 3·7 5·5 0.3 2-4 0.3 32 2.9 I0.7 4·2 10.2 7·8 2.0 6.3 0.2 I.5 0.2 33 I.O 6.2 I.5 5·5 3·9 1.2 2.7 O.I o.S O.I 34 I.O 0.6 4-4 6.5 0.5 I.6 O.I I. I O.I 35 0.5 3·0 7·8 0.3 2.5 + 0.5 O.I 36 0.1 I.6 2.6 0.3 I. I + o.8 + 37 + I.9 3·9 O.I I. I 0.5 + 38 + L4 I.3 O.I 0.3 + 39 0.7 + 0.3 + 40 o.6 0.3 + 4I 0.4 + 42 0.5 I.3 0.3 + 43 O.I 44 0.3 45 O.I 46 47 O.I 48 Mean length I5.8o 29.40 28.28 29.58 30·35 26-49 28.39 26.48 23·55 23.82 n ..... 206 290 5.469 2,337 77 7,719 365 8,025 744 63,282 -I2I- Gadoid Fish Blue Whiting Table 66. The ratio of mature (maturity stages 11-111 and Table 67. The ratio of males and females (in %) on the later) and immature (stage II) blue whiting according to Porcupine Bank in February-March, 1966 size-classes on the spawning grounds to the west of Ireland Males and (February-March, 1966) females Males Males Females Females Time Males Females investigated Im- Investi- Im- investi- in all Length mature "Mature gated mature Mature gated I decade of February 41.4 8.6 I,28I em (%) (%) (in all) (%) (%) (in all) 5 II decade of February 41.8 58.2 532 r6 roo roo III decade of February 49·6 50-4 6I7 17 so so 4 roo I decade of March 46·5 53-5 542 r8 roo 4 II decade of March 57·5 42·5 804 19 so so 2 For the whole period 45-2 54·8 3.776 20 so so 2 2! 33-2 66.8 9 22 23.1 II 76·9 s6 36·3 63·7 on spawning grounds was nearly I: I, but in 23 9-0 91.0 77 33-2 66.8 96 24 r6.7 83·3 6o 22.4 77·6 125 general, females predominated m the bottom 25 2.1 97-9 94 !3.2 86.8 !20 trawl catches (Table 67) 26 2.3 97·7 85 4·8 95-2 8s 27 roo 53 1.7 98·3 6o 6. During the pre-spawning period the blue 28 roo 25 r.6 98·4 62 whiting fed on the spawning grounds; while 29 roo l4 roo so spawning the stomachs of nearly all the fishes 30 roo 6 roo 44 31 roo 2 roo 24 were empty. After spawning they began to feed 32 roo roo 24 intensively. A comparison of food components 33 roo roo !2 shows, that to the west of Ireland, in the Barents 34 roo II Sea, on the Rockall Bank and off West Green 35 IOO !2 36-40 IOO 35 land, fry constitute a great portion, while m other areas Euphausiacea are more common. 25-26 em. (Table 66). Females are larger than males and among the latter fishes of 30 em in V. K. ZILANOV length are scarce. The ratio of males to females PINRO, 6, Knipovich Street, Murmansk, USSR. Table 68. Food composition of blue whiting (in %) in different areas Areas and date of investigation The The South- West The The The Porcupine Bank The Barents Norwegian West Green- Faroe Rockall Ireland Sea, Sea, Iceland, land, Shallow, Bank, February, June, Shallow" Food Sept. July, April, July, Sept., May, June, :Niarch, July, July, components I963 196I I966 I966 1966 I966 1966 1966 1966 Euphausiacea. 38.6 78.s 73·3 59·6 59·0 38.0 70.0 28.5 57·5 Copepoda .... 21.4 48.2 12.0 4·3 2.7 Temisto ...... 8.7 6.8 6.4 Sagitta ...... o.8 0.2 Pandalus ..... 3-I r.6 Pisces ...... s6.7 3·6 28.3 64-5 4·8 52 30.00 69-4 4l.I Others ...... 10.2 r.6 O.I Number of fish 100 examined .... 175 709 200 77 200 IOO 2,I06 400 -IZZ -- Herring INTRODUCTION The contributions on herring give a rather herring coming from an area south-west of Bear detailed picture of the distribution, abundance and Island where a considerable part of the Norwegian age composition of the major stocks of herring herring stock did overwinter in rg65. The total and their exploitation in the north-eastern Atlantic. herring catch by Icelandic vessels reached a new As an appendix, a report has been published on record peak of 770,000 tons. Fishing on over the results of the Icelandic-Norwegian-Soviet wintering herring by purse-seine, drift-nets and survey of the Norwegian Sea in early summer rg66. pelagic trawls had been carried out by an increasing This report links the findings on hydrography and number of vessels of various nations. Some vessels plankton with the data on herring distribution later on followed the shoals when migrating to in the area north and east of Iceland. Norway via northern Faroese waters. From Ice Norwegian and Icelandic contributions on distribu landic, Norwegian and German figures only, the tion, migratory routes and composition of the total catch of adult Norwegian herring amounted Norwegian spring spawners might be summarized to about r,z mill. tons. as follows. Other groups of Atlanta-Scandian herring as Towards the end of January rg66, the first spring spawners off Iceland and western Scotland shoals of pre-spawning herring coming from the are of relatively low importance. The Icelandic wintering grounds south-east of Iceland reached spawning stocks are of small size at present. the coast of M0re, moving then north-eastwards. In the Norwegian herring caught off Norway As in previous years a second group of mainly and Iceland, year-class 1959 makes up more than younger specimens came from the wintering area half of the stock, its relative importance was still in the eastern Norwegian Sea arriving for spawning increasing in rg66. Second in abundance is the at Lofoten rather late. In contrast to rg65 a rg6o year-class followed by the rg6r year-class. considerable admixture of second-time and third The r6 year-old herring of year-class rgso still time spawners has been determined in this group amount to about ro% of the total catch (in num which previously consisted mainly of recruits. bers). Year-class rg63 seems to be more abundant This change is due to the fact that the strong than previously predicted. Information and analysis year-classes 1959 and rg6o are still the only ones of Soviet catches is not yet available. represented in the northern samples. Norwegian According to the reports on the results of the catch of adult herring along the coast was higher International Survey of the 0-group herring in the in rg66 than in rg65, particularly in the south Barents Sea and adjacent waters in August where the "winter herring fishery" was quite September rg66, the juveniles were confined to successful, while the total catch in the Lofoten the coastal area, suggesting that abundance of area was very small, largely because of adverse the rg66 year-class is at least as low as that of weather conditions and little effort. the rg65 year-class. The total Norwegian catch of In August, in the area south of Jan Mayen, large about zoo,ooo tons of juvenile herring consisted herring concentrations were found and successfully only to one-third of 0-group herring. exploited in relatively warm water close to the Tagging of Atlanta-Scandian hening by Nor eastern border of the cold East Icelandic Current. wegian and Icelandic teams have been successfully These non-feeding herring migrated in southerly continued. Transport of herring over land to and south-easterly direction. They assembled at distant factories and some shift towards the use the wintering grounds very early. Of particular of herring for human consumption rather than biological interest is the late immigration to the for reduction to oil and meal hampered the ex same overwintering area of a second group of periments to a certain extent. -123- Herring Exploratory fishing and some commercial fishing 1963 year-class resulted in rich catches in eastern activity close to the slope off Ireland and Scotland English waters (Longstone, North Shields, Whitby, has been reported by Ireland, Germany and Scot Haisborough). In contrast to these good results, land. The fishery west of the British Isles gained the East Anglian season was again a complete in importance during recent years. At the south failure Special effort has been made by lLEs to coast of Ireland the fishery in autumn and winter describe year-to-year changes in growth of Downs (landings by Irish boats) increased considerably herring during the past 6 years due to improvements in effort and in good recruit Effort of Dutch and German herring fisheries, ment by 3 year-old fish. both bottom trawling and drifting, in the North The rapid development of the herring fisheries Sea is still decreasing The German fishery on by purse-seine in the northern North Sea and 0-group herring was extremely poor. Skagerak seems to have passed its maximum. The total Norwegian catch decreased by a quarter to Some member countries were not able to provide about 450,000 tons and the total Swedish catch reports on the exploitation and investigation of went down by r8% to r86,ooo tons; Polish and North Sea herring in time for inclusion in this Soviet landings also decreased considerably. While review, thus leaving the picture somewhat in fishing in the Shetland and Fair Isle area proved complete. very productive, the results in the eastern sections According to brief German and Dutch notes, and in the Fladen-Gut area were poor. The fishery herring fisheries off south-eastern Ireland and is mainly based on North Sea autumn spawners northern Ireland were more productive in rg66 of year-class rg6o and particularly 1963. There than in rg65. Year-class rg6z was dominant in the was little invasion of those herring into the Skagerak south. Polish and Finnish contributors on Baltic and prospects for a new period of rich fishing on herring review the development over the past autumn spawners in that area seem rather· dim. few years and relate them to hydrographical and It looks as if there is again a shift of autumn feeding conditions. In the southern Baltic, the 1964 spawning herring towards the north-westernmost year-class of the autumn spawning group was part of the North Sea. No major spawning was very abundant, leading to considerable rise in the found off the Scottish east coast in rg66. catches. Herring fishery in the Dogger area was less G. HEMPEL, productive than in rg65, according to Dutch and lnstitut fur :Meereskundc der l: niversitat Kiel, German reports. Very good recruitment of the Kiel, Hohenbergstrasse 2, Germany. -124 The Icelandic Herring Fishery in 1966 surface layers where these shoals assembled was (Tables 6g-8r) about 4.5° to 5.5°C but a few miles further west the temperature was about two degrees lower. During the south-easterly and southern migration Surveys the herring seemed to follow the eastern border of Winter surveys the cold East Icelandic current and only approached the coast when it had reached the southern limit During the first four months of the year the of the very cold water masse3. Thus the large non "Haft6r", (a 250 brt. vessel) was engaged in feeding shoals were formed 3-4 weeks earlier in herring survey work. During January the ship rg66 than in rg65 and consequently the over surveyed the overwintering area of the Norwegian wintering concentrations were located considerably herring 6o-go n.m. off the east coast of Iceland. After the beginning of the eastward migrations of earlier (first half of September) in rg66 than in these herring concentrations the "Haft6r" surveyed previous years, some so-go n.m. off the east the first part of the migration route in order to coast where the herring remained more or less direct the Icelandic purse-seiners to profitable stationary until the end of the year. fishing grounds. During late January and early During the October survey another invasion of February the fishing grounds off the south coast large non-feeding shoals was located in the area were investigated. As in previous years some south of Jan Mayen. This migration followed a herring concentrations were located south-west similar southerly route as the August migration and south of Ing6lfsh6fdi i.e. off the eastern south and by the end of October it had reached the coast. Elsewhere only very scattered concentrations overwintering grounds off the east coast. These were found. During the period g. March-6. April late arrivals came almost certainly from the area two surveys were carried out in order to locate south-west of Bear Island where a considerable the spawning areas of the Icelandic spring spawners part of the Norwegian herring stock did overwinter (ISPR). The surveys were badly hampered by in rg65. foul weather and no definite egg patches were located. Autumn surveys off the south-west and south coast During the period September to 5. December, Summer surveys one ship was engaged in herring survey work off the south and south-west coast. In spite of repeated During the period g. May-r6. December the surveys very few herrings were located in this ".LEgir" was engaged in environmental and acoustic area and consequently the fishing was very poor surveys on the herring grounds. In addition two indeed as will be discussed in the following section other boats, the "Haft6r" and a chartered boat of this report. of 85' assisted in this work. The first herring concentrations were located some 170 n.m. east of the southern east coast on the 8. Mav. These The fishery concentrations moved very fast west ar{d north The winter and spring fishery during the following days. During the second half of May the herring invasion had a very definite During the first two weeks of the year the herring northerly direction towards Jan Mayen. Through fishery was continued on the overwintering grounds out June and July considerable concentrations of the Norwegian herring stock some go-rzo n.m. were located in the area south-east, south and off the east coast. During this period the landings south-west of Jan Mayen. In addition considerable amounted to 6,ooo tons. This fishery was terminated concentrations were located in late June some due to bad weather which lasted until the spawning roo-rso n.m. off the east coast. These concentra migration of the Norwegian herring had moved tions dispersed, however, during July but at the further east and south-east. Before the end of beginning of August the herring began to assemble January it became clear that a considerable and form suitable shoals for purse-seining. During section of this migration headed for the banks on the second half of August the herring in the the eastern side of the Faroe Islands where both Jan Mayen area assembled in very good shoals Icelandic and especially Faroese purse-seiners in a limited area some roo n.m. south-west of carried out a profitable fishing throughout February JanMayen andduringthelastfewdays of the month and March. these shoals migrated very fast in south-easterly As in the previous two years some herring and southern directions. The temperature in the fishing took place during the second half of January -125- Herring Table 69. Monthly Yield of the north and east coast fishery above this was entirely due to the presence of Approximate No. large non-feeding migrating shoals much earlier Month Thousand tons of purse-seiners than in 1965. During the period October-Decem May 28 I-40 ber the fishery was very badly hampered by bad June 92 40-I6o weather. The total catch of 70o,ooo tons is by far July 62 I6o the highest ever recorded for this fishery. The A.. ugust ...... q6 I6o September ...... I32 I6o-I86 record catches of 1965 and 1964 were 577,000 and October ...... 94 I86-Iso 425,000 tons respectively. This increase in the November ...... I04 ISO-I25 catch was due to more favourable shoal behaviour December ...... 42 I25 especially in August and more experience m Total ...... 700 locating and' fishing in the Jan Mayen area. in a limited area off the eastern south coast. The The summer south coast fishery total landings from this fishery were about 1o,ooo As in previous years the smaller purse-seiners tons. The herring landings in February, March and that have become uncompetitive in far offshore April were negligible or approximately 3,200 tons. areas off the north and east coast were especially In May some herring fishery took place in inshore engaged in this fishery. In 1965 the fishing took waters near Vestmannaeyjar and on either side place in two separate areas i.e. around the Vest of Reykjanes. The May catch amounted to just mannaeyjar and off the eastern south coast. In above 5,000 tons. Thus the total landings of the 1966 the herring concentrations off the south Icelandic winter and spring herring fisheries coast were much smaller than in the previous amounted to 24,500 tons as compared with 6g,ooo year, especially on the eastern fishing grounds tons (corrected number) in 1965. This sharp where the fishery was negligible in 1966. The decrease in the fishery was mainly due to the total landings of tllis fishery amounted to about scarcity of herring on the south coast grounds and 43,000 tons as compared with 6g,ooo tons in rg65. an increasing number of boats taking part in a flourishing capelin fishery that amounted to no The autumn south and south-west coast fishery less than 124,600 tons. During the previous five years the autumn south-west coast fishery has decreased rapidly. The summer and autumn north and east coast fishery In 1966 this fishery proved to be a complete f~ilure The summer north and east coast fishery started yielding only 2,8oo tons compared with 45,000 tons earlier than previously experienced, or on 12. May. in 1965 and about 65-70,000 tons in the period This was doubtless due to the positive results of rg6r-rg62. the "Haft6r" herring survey and the subsequent In 1966 the total Icelandic herring catch reached location of dense herring concentrations a few a new record peak of 770,000 tons. days before the fishery began. During late May and the first half of June the fishery followed the Table 70. South coast winter and spring herring 1966 age herring migration towards Jan May en as described distribution in the previous section of this report. During the Year-classes Age ISPR ISUM Total middle part of the summer the fishery took place either in the Jan Mayen area or some 150-200 n.m. I964 2 2 454 I8o I963 3 I63 96 485 26I off the east coast. By the middle of August large I96Z 4 27I 353 54 222 non-feeding migrating shoals began to assemble I96I 5 259 209 8 I37 and these gave rise to a very rich fishery in late I96o 6 I39 89 6z August or at least 2-3 weeks earlier than in 1965. I959 7 42 57 32 I958 8 30 30 I8 Table 6g shows the monthly catch and the I957 9 30 37 2I approximate number of boats participating in the I956 IO 36 87 44 I955 II I2 2I II fishery. As compared with last year the table I954 I2 6 2 2 shows that during May-July the fishery developed I953 I3 9 4 much along the same lines as in rg65. In August I952 l4 6 there is on the other hand a striking difference I95I IS 2 I95o I6 6 because in 1965 the August yield was the lowest 5 3 Total ..... I,OOO I,OOO I,OOO I,OOO whereas in 1966 August proved to be the best No...... I66 436 392 998 fishing month of the whole season. As explained :.viean ..... 5·3 s.6 2.6 4·4 -r26- Table 71. South coast winter and spring herring, 1966, length Table 72. North and east coast summer and autumn herring distribution 1966, age distribution Length em 1SPR Total Year- )J='J I7 3 classes ~\gc ::-.JS ISPR ISU:\I Total IS r 5 6 1965 r6 19 40 15 1964 2 639 7 20 9I 35 1963 3 6 47 6g 279 22 2I 164 63 rg6z 4 2 6 9 138 r6 4 22 147 58 rg6r 5 23 IJ6 400 55 2 71 23 6 2 I26 50 rg6o 6 232 qz 127 34 r6 rg6 24 6 5 Io8 45 1959 7 587 409 9 6g r6 5°7 25 24 5 93 42 1958 8 5 I6 36 34 I6 IO 26 IS 28 83 48 I957 9 I 7 IS 3 27 go :12 76 63 I956 IO 2 7 I73 6g 7 28 102 87 23 62 I955 II 3 II 64 7 29 114 154 20 92 I954 I2 4 2I 18 IO 30 139 135 5 85 I953 13 ro 26 55 34 I7 31 176 rz8 3 84 I952 14 8 3I 55 I7 32 133 133 3 8s I95I IS I7 4I 27 25 33 (,6 87 49 I950 I6 go 8g 9 87 34 66 99 59 I949 I7 5 4 4 35 54 7I 43 I948 IS 4 3 3 36 6 32 IS I947 I9 2 2 2 37 2 2 1946 20 2 Total .... . 1,000 1,000 1,000 1,000 I945 2I ::-.To .... - .. . r66 -+36 397 999 I944 22 Average .. . 30-3 31.0 23.2 27·9 Total ... 1,000 I,OOO I,OOO I,OOO I,OOO I,OOO No...... 3,9I3 2,I90 IIO 29 6I 6,303 Biological data Mean . '. 7-9 8.2 S.o 5-6 2.5 8.o The winter and spring fishery The north and east coast summer and autumn fishery The age and length distribution of the south The age distribution of the samples taken during coast winter and spring season (January-May) the rg66 north and east coast season is shown in is shown in Tables 70 and 71. The age is arranged by Table 72. As in rg64 and rg65 the dominant year number of winter rings and the length is measured class of the Norwegian herring is that from 1959 to the centimetre below. The dominant year contributing S870foo and 4090foo to the northern classes in this fishery are especially those from and southern types respectively. The corresponding r96r and 1962, i.e. 4 and 5 year-old herring. As figures for r 965 were 480° I00 and 366° I00 respective! y. regards the summer spawners, the 1962 year-class The r6 year old rgso year-class contributed go0fo0 predominates. It should be noted that a consider and 8g0loo to the two Norwegian types as compared able proportion (39%) of the herring were immature with rgg0fo0 and r850foo in rg65. Its place as the (in maturity stage II). These were entered under? second important year-class has been taken by in Table 70. The vast majority of these herring the rg6o year-class which contributed 232% and were 2 and 3 year-old fish. The overall age distribu 0 142°l00 to the two Norwegian types as compared tion of the herring in this fishery is shown in the with r6o0fo0 and 930foo in 1965. The ratio between last column of Table 70 where the 1963 year-class the northern and southern types of the 1961 is the most abundant. The average age of the two vear-class should be noted. As usual the southern Icelandic stocks was 5-3 and 5.6 years which is types predominated in 1966 but this will almost very similar to that of the previous years. The certainly change in the coming years with the average age of the immature herring was 2.6 years increasing presence of the slowly growing northern which is a little lower than in 1965. types. An interesting feature of the age distribution The dominance of the relatively young year of the southern type (NS) is the presence of 470foo classes is clearly reflected in the length distribution. of the 1963 year-class. This is very unusual for Thus the overall average length was only 27.9 em. such a young herring and might indicate that The average length of the two Icelandic stocks this year-class is more abundant than has been was on the other hand 30.3 and 31.0 which is previously predicted. The average age for the very similar to that of 1964 and rg65. It should Norwegian types was 7·9 and 8.2 years. This was be noted that prior to rg64 the average length of 0.7 and 0.9 years lower than in 1965. The average the herring in this fishery was considerably higher, age of the Icelandic spring spawners of 8.0 years or 32 to 34 em. was 2.8 years lower than in 1965. The overall -127- Herring Table 73· North and east coast summer and autumn herring Table 74· The mean weight by length of the north and east 1966, length distribution coast herring in 1965 and 1966 Length em ="N NS ISPR ISlJi\I Total :.VIean- :\Iean- 19 66 Length em \\·eight 0' weight ()" 20 82 1965 "' 1966 "' 21 262 3 19 67 6o 0' 164 2 20 77 70 23 33 21 87 79 ,, •>? 24 2 66 101 93 25 5 131 4 23 105 108 26 6 49 3 24 120 128 27 13 16 5 25 131 138 28 16 33 6 26 151 157 29 2 5 34 33 3 27 1J6 181 00 1~ 30 -co 6 9 69 I 28 195 197 31 89 29 18 103 67 29 216 235 32 213 95 155 241 16 172 30 238 254 33 268 224 200 244 245 31 265 281 34 164 227 136 172 r6 184 32 290 313 35 so 115 64 103 33 72 33 313 349 36 44 71 173 34 55 3+ 340 386 37 7+ 89 191 79 35 371 422 38 53 65 45 56 36 404 457 39 17 27 9 20 37 432 +89 40 5 38 460 524 Total ... 1,000 I,OOO I,OOO 1,000 I,OOO 1,000 39 soo 562 No...... 4,282 2,192 110 29 61 6,67+ 40 566 623 A.. Ycragc 2 33·5 34-1 3+6 3 ·7 23·+ 33·6 the mean weight of each em group above 30 em is 30-80 g higher in 1966 than in 1965. Thus the average age during the summer and autumn herring in 1966 was much heavier in relation to season was 8.0 years as compared with 8.6 in length than in any previous year on record. This 1965. unique weight of the herring was doubtless due Table 73 shows the length distribution of the to the intensive feeding on exceptionally large north and east coast herring in 1966. In previous quantities of C. finmarchicus which were distributed vears the distribution has been bimodal due to the over vast areas south and south-east of Jan Mayen. predominance of the two year-classes from 1950 These conditions were especially prominen< at the and 1959. In 1966 the strength of the 1950 year eastern and north-eastern edge of the East Icelandic class has, however, decreased so that one can no Current. The strength of tribes is shown in Table longer talk of a bimodal length distribution. The 75· There was a further development of the trend mean length of the three spring spawning stocks that has taken place in the tree previous years. shows that as in previous years the Icelandic Thus the Norwegian tribes contributed 97% in stock has the highest mean length of 34.6 em 1966 as compared with 94% in 1965 an.d 87% in whereas the mean length of the Norwegian types 1964. The Icelandic spring spawners, wh1ch only a was 33·5 and 34· I em. As compared with 1965 few years ago contributed over so% of the north this shows an increase of the northern Norwegian and east coast herring, contributed in 1966 only herring of 0.5 em and a decrease of only o.I em of 3%. It should be noted that the proportion of the southern Norwegian herring. This shows that strength of tribes resembles that of the period the herring in 1966 has been much longer compared prior to 1956. with age than in 1965 because the average age of the Norwegian herring decreased by 0.7 an 0.9 The south coast summer fishery years although the mean length increase~ as The age distribution of the samples taken during reaards the northern type and was practically the south coast summer fishery is shovvn in Table 76. u;changed for the southern type in spite of this The dominant year-class in both the spring and considerable drop in age. Table74showsthe mean weight of each em group Table 75· Strength of tribes for 1966 and 1965. As regards the smaller em Herring tribes Number Percentage XN ...... 62.o% groups from 19-28 the weight i~ si~ilar but the 3,913 NS ...... 2,190 35.o% 29-40 em herring is much heav1er m 1966 than lSPR ...... 110 2.6% in 1965. Thus the mean weight of 33 em herring ISCM ...... OA% is 349 g in 1966 but only 313 g in 1965. Similarly Total roo ~/~ -128- Table 76. South coast summer herring 1966 Table 79· South coast autumn herring 1966 Year-classes Age ISPR ISUM Total Length em TSPR ISUM Total 1965 9 17 3 2 1964 2 14 12 2 43 r8 3 2 1963 3 380 456 389 19 6 + 1962 4 2II 319 199 20 1961 5 296 126 102 ZI 3 2 1960 6 56 28 22 22 ...... +4 zS 1959 7 l4 7 6 23 85 5+ 24 ...... r6o 1958 8 I4 10 7 104 25 ...... 213 136 1957 9 7 6 4 1956 10 7 27 IS 26 204 136 26 r8z 1955 II 4 2 27 91 142 1954 12 28 ...... 103 83 63 72 1953 29 ...... IS+ 144 25 66 1952 30 256 205 9 82 31 rz8 250 So Total .... . 1,000 1,000 J,OOO 1,000 32 179 98 40 No ...... 142 675 43 2 1,249 33 103 76 32 Mean .... . -j.2 4·0 2.3 3·4 34 51 45 r6 35 8 2 Table 77· South coast summer herring 1966, length Total .... . I ,000 r,ooo r,ooo 1,000 distribution No ...... 39 132 329 500 Average .. . 30.6 27.1 Length em ISPR ISUM Total 30·3 25·3 17 ...... 5 2 summer spawning is that from 1963 i.e. 3 year-old r8 ...... I4 5 herring. 19 ...... II 5 20 ...... 21 8 It should be noted that approximately I/3 of 21 ...... 46 17 the herring is not allocated to either of the stocks. 22 ...... 62 23 These 432 herring were practically all immature 23 ...... 7 ro8 39 24 ...... 6 160 63 2 and 3 ringers in maturity stages I and II. The 25 ...... 7 24 189 77 average age of 3-4 years is slightly higher than 26 28 39 178 8+ in 1965. The length distribution is shown in Table77. 27 ...... 49 89 167 107 z8 127 121 r8 83 The overall mean length of 28.r em is considerably 29 ...... 127 r82 I4 116 higher than in 1965. 30 183 203 2 129 The south coast autumn herring 31 ...... q8 144 5 98 32 169 89 67 As mentioned in a previous section this season 33 ro6 40 33 was a complete failure. The age distribution of 34 42 22 17 the five samples taken are shown in Table 78. The 35 7 19 I4 36 r6 II table shows that the majority of the herring were 37 4 4 immature 2 and 3 ringers. The overall average 38 ages of only 2.9 years is not only by far the lowest Total .... . 1,000 1,000 I,OOO ever recorded for this fishery but also much lower No ...... 142 675 1,321 than the average age of the summer fishery Average .. . 30·3 29.8 28.r e.g. which is to a large extent based on immature Table 78. South coast autumn herring 1966, herring. age distribution It should be noted that in all the three fisheries Year-classes Age ISPR ISUM Total based on the Icelandic herring stocks the summer spawners appear much more abundant than the 1965 22 14 1964 2 26 691 450 spring spawners. 1963 3 513 379 265 315 The length distribution of the south coast 1962 4 128 439 22 143 autumn herring is shown in Table 79· The table 1961 5 231 1J4 49 shows that the length distribution of the mature 1960 6 51 45 r6 1959 7 8 4 herring is very similar to the winter and spring 1958 8 26 8 4 herring. The overwhelming majority of immature 1957 9 8 2 herring is the main cause for the low overall mean 1956 IO 26 2 length of 27.1 em. Only one Norwegian herring Total .... . I,OOO 1,000 I,OOO I,OOO No...... 39 132 317 489 were recorded in the south coast samples comprising Mean .... . 4·0 3·9 2.3 2.9 r,89o herring. -129- Herring Table So. Tags returned at the north and east coast plants Table 81. Tags returned at the south and south-west coast in 1965 plants in 1965 Year of tagging Norway NE-coast S-coast Total Year of tagging Norway NE-coast S-coast Total I954 ...... I949 ...... 2 I955 ...... I950 ...... I956 ...... 2 I95I ...... 3 3 I957 I952 ...... 3 7 IO I958 ...... 5 6 6 IO I953 ...... 4 I959 4 II IS I954 ...... 3 4 7 I96o ...... l4 I IS I955 ...... I6 9 25 I96I ...... 5 26 3I I956 ...... 5 3 8 I962 ...... 23 I9 43 I957 ...... 9 I3 2 24 I963 ...... 2 IS !02 II9 I958 ...... 9 20 29 I964 ...... 36 400 436 62 I959 ...... l4 43 5 I965 3 4 6I9 626 I96o ...... I9 42 I 62 Total ...... 9 IO] I,I]9 I,295 I96I ...... I3 I23 6 142 I962 ...... I8 I 54 6 I]8 I963 ...... I3 56 12 8I It should be noted that two tags from 1949 I964 ...... 9 I83 48 240 were returned i.e. these two herring have been I965 ...... 8 29 322 359 16 years at liberty . Total ...... I48 692 402 !,242 Table 81 shows the return of tags from the south coast reduction plants. As regards the 9 Norwegian tags one must bear in mind that considerable Tagging returns quantity of herring was transported from the east coast fishing grounds to the south coast reduction Table So shows the return of tags during the plants. Considering the fact that the 1,295 tags summer and autumn season 1965. During this were returned from only 143,000 tons of herring, season 1,242 tags were returned as compared with the high rate of returns from the Icelandic herring 1961 in 1964. Considering that the quantity reduced stocks indicate their small size at present. in the reduction plants was 5I3,ooo tons as compared J. JAKOBSSON with 369,000 tons in 1964, it appears that the Hafranns6knastofnunin, Skulagata 4, Reykjavik, Iceland. 1965 returns are somewhat lower per reduced unit in 1965 indicating a slightly increased quantity of herring on the fishing grounds. The high pro Soviet Investigations on the Age Composition of the portion of south coast tags returned from the White Sea Herring in the North-Western White Sea north and east coast reduction plants in 1965 in rg65-rg66 was due to landings of south coast herring trans (Table 82) ported to these plants. Therefore Table 79 does The White Sea herring (Chtpea harengus pallasi not give a representative illustration of the ratio natio maris-albi) in the north-western White Sea of Norwegian and Icelandic herring on the north (the Kandalaksha Bay and the Tersky Shore) are and east coast fishing grounds. present in two forms: small and large. Table 82. Age-composition of small Kandalaksha herring in 1955 and 1966 (in "/ 00) Season Season ..c\ge Year-class I965 Year-class I966 Spring Summer Autumn Total Spring Summer Total I-'- ...... IO] ' I964 24 37 I965 2 2+ ...... I963 27 286 609 280 I964 3 3+ I962 54 ]I I42 84 1963 956 980 957 4 4+ ...... I96r 486 430 ]I 356 I962 I8 20 IS 5 s+ ...... 1960 244 47 ]I 122 I96I 15 I6 6 6+ ...... I959 8r 47 47 I96o 5 4 7 7+ ...... I958 Io8 ]I 65 1959 5 4 8 8+ ...... 1957 24 9 I958 Total ...... !,000 !,000 I,OOO I,OOO I,OOO !,000 I,OOO Number of fish investigated .... 37 42 28 I07 673 I03 776 A.verage ...... 4.62 4-46 2.84 3·97 3·09 3·47 3.28 -130- Small herring form the local Kandalaksha stock Table 83. The landings of immature herring (mill. hi) in the and are the main object of the fishery. Large herring different districts, I966*) are not numerous and they are not of any importance Small herring Fat herring Area Mill. hi 0/ to the fishery. /0 Mill. hi % In 1965 the commercial stock of these herring Finn mark ...... 0.235 28-4 I,..J.20 89.I Troms ...... 0.122 0.2 consisted of old age-groups and was not abundant. I4·7 0.003 NordlandjN. Trondelag O.I96 23.6 0.055 3·5 In 1g66 it was replenished with the successful 1963 S. Trondelag year-class and its number increased. More and Romsdal .. O.I I I 13.-J. 0.105 6.6 Sogn and Fjordanc The spawning population of small Kandalaksha Hordaland. Rogaland o.r65 19.9 0.010 0.6 herring mainly included fishes at an age of 4 and Total ...... o.829 IOO.O 1,593 IOO.O 5 years in 1965 and mostly 3-year-old fishes in 1966 (Table 82). The 1962 year-class was very poor and *) Preliminary figures was of no fishery importance. The 1963 year-class of herring (3 year-olds) mainly reached maturity Table 84. The landings per month (mill. hl) of immature in 1966 and being abundant, they gave great herring r966 recruitment to the total stock. In the autumn of Month Small herring Fat herring Total 1966 they occurred in great concentrations in the January o.oo8 o.oo8 February ...... Kandalaksha Bay. March ...... The recruitment of this year-class to the total April ...... 0.019 0.019 stock of small Kandalaksha herring gives favourable :vray ...... O.OJ7 0.048 0.125 June ...... 0.075 0.232 0.307 prospects for the fishery in the next 2-3 years. July ...... 0.101 0.497 o.598 ...... B. M. TAMBOVTSEV August 0.026 0.431 0-457 September ..... 0.067 0.319 0.386 PINEO, 6, Knipovich Street, :VIurmansk, USSR October ...... 0.303 o.oi8 0.32I November ..... O.I..J.7 o.o28 O.I75 December ..... 0.025 O.OOI 0.026 Total ...... 2,422 Norwegian Small and Fat Herring Investigations in o.829 1,593 1966 1965 year-class. On this basis the survey concluded (Figure I q; Tables 83-86) that also the 1966 year-class was exceptionally Surveys low. In the western part of the investigated area From 27. August to 10. September a joint (between 73ooo'N to 74ooo'N and 5°0o'E to 8°oo'E) International 0-group fish survey in the Barents heavy records of mature herring were located. Sea and adjacent waters was carried out (ANON., 1966). The routes and herring records of the Off the Finnmark and Murman Coast rather Norwegian research vessels "G. 0. Sars" and good concentrations of fat herring of the 1963 and "Johan Hjort" are shown in Figure II4. 1964 year-classes were found almost in the same area in tile as in the previous year, although the distri The 0-group herring were restricted to the bution was slightly more westerly in rg66. Norwegian coastal belt with a slight extension north-eastwards from North Cape. None were recorded north of 72°0o'N or east of 34ooo'E. It The fishery appears that the 0-group herring had not penetrated The total catch of immature herring landed in into the fjords at the time when the survey was Norway in 1966 amounted to 2,422 mill. hl, carried out, although they were present in the 0,829 mill. hl being taken as small herring and coastal waters. A very few scattered individuals 1,593 as fat herring and "forfangstsild" compared were recorded along the West Spitsbergen Current, with 2,270 mill. hl in 1965 (1,257 mill. hl small but they did not form any identifiable recordary herring and 1,013 mill. hl fat herring and "for patch. fangstsild"). When comparing the records of 0-group herring The yields landed in the different districts are in the autumn 1966 with those obtained at the same shown in Table 83. It will be seen that the most time in 1965, it was suggested that the abundances important fishing areas for small herring were were almost equal, although the distribution Finnmark and Nordland-North Tr0ndelag. How pattern was different. The 0-group in 1966 had a ever, the distribution according to district was more coastal distribution than the 0-group of the not as pronounced as in 1965, when 77.8% of the -131- Herring Table 85. Length distribution of fat herring in the different Table 86. Age composition of fat herring in the different 0 0 districts ( / 00) 1966 districts ( / 00) 1966 S-Trondelag Sogn and S. Trondelag Sogn and More and Fjordane "Vlore and Fjordane Length Finnmark Troms Romsdal Hordaland Year- Finnmark Troms Romsdal Hordaland (em) and Rogaland class and Rogaland 9·5 I965 I79 10.0 5 I964 525 -.s 3 I963 296 75 1I.O 12 1962 24 -.s I96I 264 12.0 1960 75 -.s I959 43 13.0 1958 9 -.s 1957 5 14.0 I956 -.5 1955 15.0 4 I954 -.s 1953 16.o 4 I952 -.s I3 I95I 17.0 12 27 I950 5 22 -.s 27 Total . . . 1,ooo 1,000 1,000 1,000 18.o 34 -.s 36 Number . 509 II9 188 2!2 19.0 61 -.s 46 20.0 38 17 landings were derived from these two districts. It -.s 20 100 should be noted that 89.r% of the fat herring were 2 I.O 35 133 -.5 35 142 5 caught in Finnmark. 22.0 38 125 5 The fishery on small herring was mainly carried -.s 38 208 23.0 29 I25 5 out in October and November, whereas the most -.s z6 9I IS important fat herring fishery took place during 24.0 18 I7 IO 9 the summer (Table 84). -.5 5 10 25.0 3 9 5 -.s 3 9 z6.o I3 Biological data -.s 8 I8 27.0 9 The small herring catches consisted entirely of -.s 8 IO the 1966 and 1965 year-classes. 28.0 IO 4 The length and age compositions of the fat -.s 8 40 4 29.0 95 5 herring and "forfangstsild" are presented in Tables -.s I35 27 85 and 86. No samples were secured from Nordland 30.0 I8o 27 North Tnzmdelag. -.s I8o 22 3I.O I 55 Judging from the length distribution and age -.s 6o composition of the herring caught in Finnmark it 32.0 55 will be seen that the fat herring catches were -.s IO 33·0 mixed with small herring, mainly of the 1965 -.s 10 year-class. It should be noted that the fat herring 34-0 22 are mainly listed in the fishery statistics according ·5 5 to weight (length). These herring comprise fish 35·0 9 -.s 4 ranging in weight from about 55 to rso g or in 36.0 length from r8.o to z8.o em. Notwithstanding the -.s 5 difficulties of getting representative samples of Total . . . 1,ooo I,OOO 1,000 I,OOO the fat herring catches, it is concluded that most Number . 734 120 200 225 of the landings consisted of the 1964 and 1963 Mean . . . 17.18 22.20 29.92 z6.oz year-classes. -132- .0 Q'F ;... lA :a V E RY SCATTER E 0 0 0 SCATTERED p /_o--o- -o~6 9 ,."'i o - i~I!HHIHn· 0 ENS E Q ' \• 4 76' /*" 0 ¢ -x-1 ? ;.;. 0 A ... I /A ... 0 ·&' o- __ '!--X-·--~--!<----~ 66~I I i 55° Figure rq. Further south in South Tr0ndelag-M0re and Norwegian Adult Herring Fisheries 1966 Romsdal some older herring appeared in the (Figure II5; Tables 87-95) catches. It should be emphasized that the samples in this district consisted mainly of "forfangstsild". The fishery 0. DRAGESUND The winter herring season Fiskeridirektoratets Havforskningsinstitutt The season lasted from 31. January to 27. March. Nordnesparken 2, Bergen, Norway. Catch and effort data for rg63j66 are given in Table 87. Reference The first catch on the southern fishing grounds A::-wN., rg66. "Preliminary report of the joint International was taken about roo n.m. off M0re. As in the year 0-group fish survey in the Barents Sea and adjacent waters August-September rg66. ICES Doc CM rg66 j before the herring shoals migrated further north H: 23, pp. r-rg (mimeo.). eastward when they approached the coast and, -133- Herring Figure rr5. Spawning migration route of the Norwegian winter herring 1966 (southern invasion). the main fishing took place between Grip and listed in Table 88 concerning the industrial herring Halten. The spawning migration route of the fishery derive from the north-eastern part of the Norwegian winter herring rg66 (southern invasion) Norwegian Sea (about 250 nautical miles north is shown in Figure rr5. west of Andenes). However, most of the herring Also in rg66 mature herring from the northern caught for salting came from the area off Iceland overwintering area migrated into Lofoten for and north of the Faroes. spawning, but somewhat later than in rg65. The The total catch and number of boats over the fishery started 26. February off Vesteralen and years rg63j66 are given in Table 88. It should be continued in the Lofoten area until the end of emphasized that both the landing figures and March. number of boats participating in the summer The total catch of winter herring amounted to herring fishery are preliminary. 4,955 mill. hl of which about 36o,ooo hl was taken in the Lofoten. The majority of the herring was Biological data caught by purse-seine (g6.6%) and the average \Vinter herring catch per purse-seine was 12,534 hl as compared During the season 48 samples containing 5,015 with 6,754 hl in rg65. fish were examined for age, length, maturity and racial characters. The length (em below) and age The summer herring season off Iceland and in the distribution of the samples from the various Norwegian Sea fishing districts are shown in Tables 8g and go. Still Almost no herring were caught for oil and meal the samples off M0re and Helgeland show a bimodal processing off Iceland in rg66, and the figures length distribution with a corresponding dominance Table 87. Catch and effort statistics for the Norwegian winter herring fisheries, I963/I966 Purse-seine Gill-net Trawl Total r,ooo hl No. of r,ooo hl No. of r,ooo hl No. of r,ooo hl Year vessels vessels vessels 1963 ...... 350 214 260 465 40 40 65o 1964 ...... 2,506 268 442 479 130 79 3,078 1965 ...... 2,q8 318 180 266 103 127 2,43I 1966 ...... 4,788 382 109 58 58 43 4,955 -134- Table 88. Catch and effort data from the summer herring season, north and east of Iceland and the Norwegian Sea, 1963/66 Indust1'ial herring Salted herring Total No. of vessels Catch No. of vessels Catch Ko. of vessels I,ooo hl purse-seine I,ooo hl drift-net + barrels during Year purse-seine the season Tons I963 938 9I 83,130 I,044 97,092 I964 933 59 44,520 990 92,003 I965 34I*) 33 29,500 379 35,209 I966 440*) I5 14>458 458 42,549 *) Including the BjornoyafAndenes area Table 8g. Length distribution of Norwegian winter herring Table gr. Distribution of spawning groups of Norwegian 0 (Ofo0) 1966 maturity stages IV-VIII winter herring ( / 00) 1966 Off More Helgelanf Lofoten Off More Helgeland Lofoten Gear Purse- Purse- Purse Spawning Purse- Purse- Purse- em seine Gill-net seine Gill-net seine groups seine Gill-net seine Gill-net seine I ...... 226 I5I I70 26 II ...... 3II 3I8 I83 27 III .... . 324 374 372 28 9 2 14 IV ...... 79 73 98 29 47 2I 22 78 5 v ...... 2 2 30 I63 2I 40 258 VI ...... 3I 292 I56 I 50 330 VII .... . 3 13 32 248 27! 285 209 VIII ... . 20 II7 260 225 88 3 33 IX ...... II 28 59 2 27 I25 I5 I+ 34 75 X ...... 8 29 22 I3 35 I7 42 25 XI ...... 7 3 26 3 36 4I 3I IS 4 XII .... . I2 29 20 20 2 IIO 37 29 IO XIII ... . 8 26 6o I3 29 38 8 42 XIV ... . 2I 39 5 XV .... . 40 XVI ... . 1,000 I,OOO I,OOO I,OOO I,OOO XVII .. . Total XVIII number 3,229 96 499 200 78I 1,000 1,000 I,OOO I,OOO I,OOO True mean Total length . . . 31.78 32.95 3!.95 33·25 3I.OI number 2,236 70 357 I 53 589 0 Table go. Age composition of Norwegian winter herring ( / 00) rg66, maturity stages IV-VIII Off More Off Helgeland Lofoten Purse-seine Gill-net Purse-seine Gill-net Purse-seine Year-class Age Type N S N S N S N S N S I963 3 1962 4 3 I5 I96I 5 I3 306 207 I29 20 348 Ig6o 6 3I7 I94 I03 223 III 239 1959 7 6os 372 5I8 576 537 377 I958 8 3 I9 7 I957 9 3 1956 IO 2 IO 1955 II 8 I954 I2 8 7 I9 I953 I3 3 17 3 I9 2I 37 1952 I4 5 I2 69 3 I9 7 37 7 195I IS 4 4 3 7 2 7 I950 I6 45 66 I03 79 I05 !52 III 3 1949 I7 I948 I8 3 1947 19 4 IO 7 I946 20 1945 2I 1944 22 I943 23 I,OOO I,OOO I,OOO I,OOO I,OOO I,OOO 1,000 I,OOO 1,000 I,OOO Total number 2,056 907 59 29 366 I05 I39 54 6II I38 Mean age 7.23 7.08 7·44 7·90 7-53 7·84 8.so 8.22 6.58 6.I4 -135- Herring Table 92. Maturity characters of Norwegian winter herring. Percentage maturity (all age-groups) 1966 Maturity stage I II III IV v VI VII VIII ¥ I.] 3·4 22.0 ]2.9 59 January 3 19·4 8o.6 36 Off More <;' 0.1 0.] !.4 15·5 64.8 16.6 o.g 1,406 February 3 0.1 0.] 0.4 1!.6 62.6 2J.2 1.3 1,356 'i' 6.5 gz.g 0.6 154 ::\1arch 3 100.0 90 '7 2!.7 48.g 30·4 92 Helgeland February 3 16.8 53·5 29·7 101 'i' 0.{ 2.3 95.8 I.5 259 March 3 !.4 98.1 0.5 213 ¥ 0.2 2.3 7·5 6g.o 15.9 1.5 429 Lofoten J\'Iarch 0 !.3 2.0 I.5 58.5 24.6 12.1 395 of the 1950, 1959, 1960 and 1961 year-classes, The maturity stages of the herring caught from whereas in Lofoten the former year-classes were the end of January to the end of March are shown almost entirely absent. The winter herring catches in Table 92. As in the last years most of the herring off M0re and in Lofoten were predominated by the were already in maturity stage V when the winter 1959 year-class, followed by the 1960 and 1961 herring season started. Off M0re spawning (So% year-classes, whereas off Helgeland the 1950 year of the herring in the samples in maturity stage VI class showed up more frequently than the 1961 or above) occurred during the last week of February year-class. about one month after the fishing season started. The distribution of spawning groups (Table 91) Further north in Lofoten, the spawning started shows that the recruit spawners constituted zz6°/00 some days later than off M0re and Helgeland (the of the herring in the samples (purse-seine) off first week of March). As a whole the spawning was M0re compared with 464%0 in 1965. In Lofoten somewhat delayed compared with the year before, the first time spawners made up 3450foo of the especially in Lofoten. samples in 1966, whereas in 1965 the corresponding figure was 742%0 (purse-seine). Second and third Table 94, Age composition of samples from the Norwegian 0 time spawners predominated the catches off M0re Sea / 00 1966 and Helgeland, whereas first and second time Gear Purse-seine Drift-net Drift-net Trawl spawners were dominating in Lofoten. Month June June July December Sample No. 304 301-303 305-307 308-310 Year- Table 93· Length distribution of samples from the Norwegian 0 class Age Sea ( / 00) 1966) 1963 3 Gear Purse-seine Drift-net Drift-net Trawl 1962 4 3 Month June June July December 1961 5 82 106 66 Sample No. 304 301-303 305-307 308-310 1960 6 357 314 233 em. 1959 7 561 543 616 25 1958 8 z6 ...... 1957 9 27 1956 10 28 3 1955 II 3 29 ...... 7 1954 12 3 3 14 30 ...... 10 107 1953 13 7 IO 31 140 113 57 200 1952 14 14 32 z8o 290 220 320 1951 15 3 33 340 303 360 174 1950 16 21 52 34 200 187 190 53 1949 17 35 30 70 13 1948 18 36 7 27 13 1947 19 3 13 67 37 43 1,000 1,000 I,OOO r,ooo 38 20 23 Total number 98 288 39 7 293 74 I,OOO 1,000 1,000 1,000 Mean age . . . 6.5 6.8 7·3 7·0 Total number 100 300 300 75 Norwegian tribe % % % % True mean (N + S type) 92.9 95·9 g8.9 98.6 length . . . . . 32.67 33·39 Uncertain tribe 7.1 4·1 I.1 !.4 Table 95· Norwegian herring samples (research vessel Norwegian Herring Tagging Experiments and samples) from the Norwegian Sea 1966 Tagging Returns No. of (Tables g6-1oo) sample Date Locality Gear The tagging localities and number of fish tagged 0 Drift-net 301 20. June 72°2o'N ro 3o'E are listed in Table 96. All the herring tagged were 302 21. June 72°2o'N 10°30'E Drift-net 303 22. June 72°21'N 11°42'E Drift-net caught by purse-seine and tagged with internal 304 27. June 72°36'N II 0 28'E Purse-seine steel tags. 305 3· July 71o56'N 11°12'E Drift-net The amount of winter herring reduced to oil 72°57'N 09°48'E Drift-net 306 7· July and meal in 1966 were 3,98r mill. hf compared 307 g. July 71oo7'N o2°07'W Drift-net 308 12. Dec. 65°07'N 10044'W Trawl with r,939 mill. hl in 1965 (Table 97). 309 13. Dec. 65°oo'N 10o35'W Trawl In 1966 only 0-437 mill. hl were caught by the 3!0 13. Dec. 65°o2'N 10°5o'vV Tra·wl Norwegian fleet off Iceland and in the Norwegian Sea for oil and meal processing and consequently, Norwegian Sea relatively few tags were recovered at Norwegian Length and age composition of herring sampled plants from this fishery (Table 98). It should also during 1966 in the Norwegian Sea and Icelandic be noted that most of the summer herring were waters are given in Tables 93 and 94· The sampling caught in the north-eastern part of the Norwegian localities are given in Table 95· Sea. The purse-seine sample from the north-eastern A comparison of the recaptures from the summer part of the Norwegian Sea caught at the end of herring fishery with those from the winter herring June comprised herring of the 1959, 1960 and r96r fishery during the last four years is shown in year-classes, whereas the drift-net catches from Table 98. In 1966 a total of 242 internal tags were the same area were slightly mixed up with older received from the different factories, 230 during fish. The age-composition of the herring caught the winter herring season and 12 during the summer with drift-net in July showed almost the same season off Iceland and in the Norwegian Sea. Out picture as in June, the influx of older fish being of a total number of 230 recovered tags during somewhat higher. It should be noted that the the winter herring season, roo were tagged as distribution of the samples in July were collected spring and large herring, ''forfangstsild" and fat further west than in June. herring; 130 were tagged as north and east The age composition of the herring caught in coast herring. Out of 12 tags returned off Iceland the overwintering area in late autumn 1966 was and in the Norwegian Sea only 6 had been released similar to that obtained during the summer, off North and East Iceland. although some admixture of recruits, mainly of The per mille returns per mill. hl of I-tags the 1963 year-class, was found in the samples. (herring tagged off Iceland) and N-tags (herring 0. DRAGESUND tagged off the Norwegian coast) during the two Fiskeridirektoratets Havforskningsinstitutt, different seasons in question are shown in Table 99· Nordnesparken 2, Bergen, Norway. It should be noted that the figures both for I- and Table 96. Tagging experiments, 1966 Number of liberations Category Date Area by type of tag Large herring ...... 15. February Griptaren 1,000 Internal Large herring ...... 16. February Griptaren 175 Internal Large herring ...... 18. February Grip 325 Internal Spring herring ...... 21. February Grip 385 Internal Spring herring ...... 23. February Griptaren 33 Internal Spring herring ...... 24. February Buagrunnen 582 Internal Spring herring ...... ro. March Rostbanken 300 Internal Spring herring ...... 12. March Sklinnabanken soo Internal North Sea herring ...... 25. June Sirahola 2,000 Internal North Sea herring ...... 27. June Egersundbank 2,000 Internal Open Ocean herring ...... 27. June N 72°36' E 11°28' 6g Internal Open Ocean herring ...... 4- July N 72°o2' E I1°os' 1,431 Internal North Sea herring ...... 25. July 14m E off Sumburgh Head 700 Internal North Sea herring ...... 27. July 13 m E off Out Skerries 950 Internal North Sea herring ...... 31. July 14m E of Bressay so Internal North Sea herring ...... 31. July 14m E off Bressay 1,200 Internal North Sea herring ...... I. August 14 m E off Bressay I,IOO Internal Fat herring ...... 23. August V arangerfj ord 1,989 Internal Herring Table 97· Landings (mill. hl) for oil and meal processing in N- tags recaptured during the Norwegian winter Norway, 1962-1966 herring season in rg66 were somewhat higher than Season Year 1962 1963 1964 1965 1966 in the previous seasons. No I-tag tagged in rg65 Norwegian winter was recovered during the summer season off herring season . . 0,054 0,079 2.497 I,939 3,98I Iceland and in the Norwegian Sea m rg66. The Summer herring reason for the lack of I-tags during the summer season north and herring season is most likely due to the fact that east of Iceland and in the Nor- almost no herring were caught off Iceland for oil wegian Sea . . . . 1,537 1,046 o,877 0,341 0,437 and meal processing. Table 98. Number of returns of internal tags in 1963, 1964, 1965 and 1966 from the different experiments. The within season recoveries and tags received from factories without magnets are excluded The summer herring season, Year of tagging Category Number The Norwegian winter herring north and east of Iceland, tagged season and in the Norwegian Sea 1965 I966 1963 1964 1965 1966 195I NH 3,064 I952 NH I7,308 2 I953 NH IO, I8I I954 NH 8,783 3 2 4 2 1955 NH 9,24I I956 NH 8.443 2 4 2 1957 NH 7.550 2 2 I 1958 NH 9.594 2 I 4 9 6 I959 NH 9.946 12 6 7 I5 7 5 1960 NH 6,847 5 3 5 I8 9 I961 NH 9.450 28 I7 I8 26 25 14 1962 NH Io,668 30 2I 32 42 40 II 1963 NH 2,900 I3 7 9 27 I 1964 NH 4.987 I9 40 6 2 1965 NH 999 I3 Total ...... 97 82 I30 I23 121 43 6 1951 SH 9,986 2 I952 LH I0,295 I952 SH I0,863 2 2 3 1952 FH 7.971 1953 LH 1o,o8o I953 SH I0,046 1953 FH 8,496 I954 LH 10,042 2 2 I954 SH 10,291 4 2 I954 FH 14.970 2 2 I955 LH I0,045 I 2 1955 SH 9,087 I955 FH I3,586 3 I956 LH 4.998 2 I956 FH I2, 799 2 I957 LH 9,500 2 I957 SH 8.450 I I957 FH 3,900 2 I958 SH 9,998 3 2 2 I958 FH 6,200 2 1959 SH I3,950 9 2 3 2 3 1959 FH 8,IOO I2 4 5 3 3 I96o LH 2.449 II 7 3 4 2 I96o SH 1,500 4 4 2 2 I96I LH 400 I96I FH I A 50 7 2 7 2 I962 LH 1,550 II II 5 4 3 I962 FH 2,700 15 II II 4 4 1963 SH 3,000 9 9 5 7 I963 FH z,soo II 7 2I I964 FH 3,300 9 I4 4 I965 SH 700 I7 Total ...... I08 IOO 2 6 N H = North and east coast herring. S H = Spring herring L H = Large herring. F H = Fat herring and "Forfangstsild". Table 99· Returns of Icelandic tags (I-tags) and Norwegian tags (N-tags) off Iceland and in the Norwegian Sea and during the Norwegian winter herring fishery I-tags N-tags Year of Year of Returns Returns per Returns Returns per tagging return mill. hl in °/ 00 mill. hl in °/ 00 Iceland ~orway Iceland Norway Iceland Norway Iceland Norway I958 I959 40 22 I9-95 1.52 2 62 0.96 4.I6 I959 I96o 63 34 I5-37 3·37 5 I6 o.87 I.I5 I963 I964 27 I3 I7.2I 3-39 7 9 4-3I 2.27 I964 I965 6 I9 I3·37 3-I4 0 IO 0 2.49 I965 I966 0 I3 0.00 5.02 I I7 I I.8I 9-37 Table 100. Number of returns of internal tags (North Sea) in 1965 and 1966 Recaptures from North Sea NE Year of Area of Number Shetland NE North Sea Skagerak (not specified) Iceland tagging tagging tagged 1965 I966 I965 I966 I965 I966 1965 I966 I966 1965 Skagerak 4,000 68 2 I72 25 I4 8 25 I966 NE North Sea 4,000 22 3I6 I6 3 2 I966 Shetland 4,000 287 77 II 45 Total 377 2 565 25 4I 8 73 2 During rg66 a total of 4,000 herring were tagged and Svinoy. But there was a slight increase in the with internal steel tags in the north-eastern North landings from the other area as well. The effort Sea, while other 4,000 herring were tagged in the in all areas increased from 1,383 fishing days to Shetland area. The details of tagging localities and 2,601 (88.r%). The activity of the pelagic-fishing liberations are listed in Table g6. All the herring factory trawlers increased from 17 trips to 65. tagged were caught by purse-seine and were in In the North Sea the total catch showed an good condition when liberated. The number of increase from 12,973 tons to 14,636 tons (r2.8%). returns from different areas for these experiments At the same time the effort decreased from goo to together with those from the tagging experiments 6oo fishing days (26.7%), whereby the catch per in rg65 are shown in Table roo. The within season day increased from 14-4 tons to 22.2 tons (54.2%). recoveries are included in this table. In winter and spring there was no fishery on the 0. DRAGESUND, S. HARALDSVIK "Ostkante" (NE North Sea). Only one trip was Fiskeridirektoratets Havforskningsinstitutt, made to this area in January, which yielded Nordnesparkenz, Bergen, Norway. So tons of herring. The catch per day was ro tons. This fishery had no importance in autumn either. Only in two days some trips with the pelagic Survey of the German Commercial Herring Fisheries trawl were made which yielded 28 tons herring. in 1966 The summer fishery started in the beginning (Table IOI) of July in the Foula, Hebrides, Cape Wrath and Fair Isle area. The fishing in the Fair Isle area The total landings of the German herring lasted until the end of the second decade of August fishery increased about g.2% from ro8,8oo tons and was very successful. No fishing took place on to rr8,goo tons. 8o.7% of the catch (95,900 tons) the Bressay Grounds. Only one trip came in were herring for human consumption and rg.3% August and September from the Fladen Ground. (23,000 tons) industrial herring (Table ror). The The catch per day amounted to 14 tons in August herring landings comprise at present 20.9% of the and only 4 tons in September. The total catch total landings of the German fishing fleet. The was r67 tons in both months. The catch per day increase was due to larger trawler catches. g.2 tons. In the northern area, especially in the Fair Isle Herring trawlers area, the main fishing was in July and August. The trawlers were fishing in the North Sea, N of 5 trips, respectively 17, were made in these months the Hebrides, N of Ireland, E of Iceland and in and yielded 1,158 tons and 3,262 tons. The catch the Svinoy area. The total catch increased from per day was 28.3 tons respectively 17-4 tons. In 22,8oo tons to 52,goo tons (132%). This was September and October two further trips were mainly due to increasing landings from E Iceland made in this area. The total catch during the whole -139- Herring Table 101. Total herring landings (in 1,000 tons) of the German fishing fleet in 1966 (Yield of 1965 in brackets) N of N of S of E of Svinoy North Channel Ska- He- Ire- Ire- Ice- Nor\v. Baltic Total Sea gerak brides land land land Coast Trawler ...... q.6(13.0) -(-) 9-5(4.1) 2.4(0.1) -(-) zz.s(5.6) 3-6(-) -(-) 52.9 (22.8) Lugger ...... 27.0(37-2) o(-) 0.3(3-9) 0.2(0.2) 0.1(-) r.o(o.3) 0.7(0.3) r.o(-) -(-) 30-3 (41.9) Drift-net ..... 9-5(13.6) o(-) o(o.1) -(-) -(-) o(-) -(-) -(-) -(-) 9-5 (10.4) Trawl ...... g.8(13-3) o(-) o(r.3) o(o.r) -(-) o.6(o.r) -(-) -(-) -(-) 10.4 (q.S) pel. Trawl .... 7-7(13.6) o(-) 0.3(2.5) 0.2(0.1) 0.1(-) 0.4(0.2) 0.7(0.3) r.o(-) -(-) 10.4 (16.7) Deep-sea cutter 17.5(28.1) -(-) 0.1(0.3) -(-) -(-) -(-) -(-) -(-) 18.1(14.9) 35-7 (43-3) for consumption r.g(r.z) -(-) o.1(o.3) -(-) -(-) -(-) -(-) -(-) 10.7(10-4) 12.7 (11.9) for factories ... 15.6(26.9) -(-) o(-) -(-) -(-) -(-) -(-) -(-) 7·4 (4-5) 23.0 (31.4) Total ...... 59.1 (78.3) o(-) 0-4(4.2) 9-7(43) 2.5(0.1) r.o(o.3) 23-5(5-9) 4-6(-) 18.1(14.9) rr8.9(1o8.8) season was 4,864 tons, the effort 255 fishing days 48 fishing days. The catch per day was 28.0 tons and the catch per day 19.1 tons. and 27.2 tons. The season 1966(67 started at the From the Gut area came only 3 trips in August end of September. The total catch increased from (2) and September (I). The total catch in this 5,638 tons to 17,7II tons. This was due to a higher area amounted to 663 tons. The catch per day effort in these month. The effort increased from 18-4 tons. 165 fishing days to 692 fishing days, whereby the catch per day decreased from 34.2 tons to Very strange was the change of the trawler fleet 25.6 tons. from the north to the south, in which case no There was some fishing on the same stock in fishing took place in the Gut area. This change February and March in the Svinoy-area (Norway). took place in the second decade of August. The The catch yielded 3AII tons, the effort was trawlers then started a fishery on the spawning 99 fishing days and the catch per day amounted places on the Whitby Bank, Flamborough Head to 34-5 tons. and on the NE Bank until the end of the first decade of September. Only little fishing took place Luggers on the south-western edge of Dogger Bank from the second decade of September to the second decade The luggers were fishing in the North Sea, of October. The total catch in the Dogger area Skagerak, Hebrides, North and South Ireland and showed a small increase from 7,733 tons to 8,835 in the E Channel area with drift-net, bottom and tons while the effort decreased from 539 fishing· pelagic trawl. The total catch decreased from days to 339· However, the catch per day increased 41,862 tons tD 30,361 tons. The effort was with from 14.3 tons to 26.1 tons. 9.422 fishing days, nearly the same as in 1965. The cause of this decline was smaller catches in In the Hebrides area the trawlers were fishing the North Sea, where the total catch decreased from July to December. On 47 trips they caught from 37,200 tons to 27,000 tons. The drift-net 9,508 tons. The effort increased from 3II to catches decreased from 10,400 tons to 9,500 tons 832 fishing days and the catch per day from whereas the trawl fishery dropped from 14,800 tons 13.1 tons to 14.0 tons. The main fishing took to 10,400 tons, the pelagic fishery also declined place in September and October. from 16,700 tons to 10,400 tons. North of Ireland a little fishing occurred from The drift-net fishery was performed from April October to December. The total catch increased to December, however, the best fishing time was from 126 tons to 2,403 tons, the fishing effort from from June to October. The catch per day decreased 7 days to 138 fishing days and the catch per day from 3-7 tons to 3.1 tons. from II.7 tons to 18.9 tons. The main catch came from the Dogger area, where In the overwintering area of the Atlanta 4,373 tons were caught in 1,237 fishing days from Scandian herring off E Iceland and on the route June to November. The catch per day was 3-5 tons, to the Norwegian spawning places the German somewhat smaller than in the year before. The trawlers were fishing with pelagic net in January best fishing was in August with 5-3 tons per day. and February. In January the total catch yielded The "Ostkante" in July, and also the Gut in June, 3,699 tons and in February 1,307 tons herring. had with 2,314 tons respectively 1,902 tons some The effort amounted to 132 fishing days respectively importance in this fishery. All other areas of the North Sea, Skagerak and in the Channel area herring from 24.5 em to 35.0 em were caught, the were poor. In the eastern Channel in November/ average length was 31.34 em (Table 1). December the catch amounted to 24 tons in 47 In March the bulk of the catch was formed of a fishing days. mixture from recovering (4300fo0), juveniles, stages The bottom trawl fishery of the luggers amounted I and II (294%0) and full herring (167%0). In to 10,432 tons in 4,077 fishing days. The catch per April spent herring (790%0), some recovering day decreased from 3.2 tons to 2.6 tons. It was (1zo0fo0) and juveniles were also present (Table 40). iished from January to December with bottom August showed a mixture from stage II to trawl. The best catches were made in April, August VIII. Predominant were the stages III (2270fo0), and September. The main catches came from the VII (227%0), VIII (zzo0fo0) and IV/V (248%0). Dogger area (3,186 tons), "Ostkante" (2,950 tons) In all these months some spawning herring were and the Gut (2,076 tons). The poorest fishing was in the area (10 to 230fo0). from September to November in the "Binnensee" According to the meristic characters the catches area. In 52 fishing days only 8o tons herring were were a mixture of late winter and autumn spawn caught. The fishing in November/December in the ers. In March the autumn spawners were more eastern Channel was a failure. dominant, whereas in April and August late win The pelagic fishery of the luggers in the North ter spawners formed the bulk of the catches. Sea, Channel, Skagerak, Hebrides, North and South The age distribution (Table 2) showed the of Ireland amounted to 8,686 tons herring in predominance of the year-class 1960 in all three z,nz fishing days. The main catch was made on months (314-464%0) and was a mixture of a the "Ostkante" with 6,957 tons in 1,604 fishing strong autumn and late winter spawning year-class. days, where the fleet was fishing from January In March the 1963 and 1961 year-class had some to May and from September to November. The importance (z640fo0/1390fool· Both year-classes were luggers participated also in the pelagic herring autumn spawners. In April the year-classes 1958 fishery off E Iceland and in the Svinoy area. In (175%0) and 1959 (123%0) had also some significance, January and from October to December they but they were without any doubt late winter were working off E Iceland. The total catch spawners. In August the year-classes 1961 (146%0 ), amounted to 669 tons in 47 fishing days. From 1963 (124%0) and 1957 (II70fo0) were again a February to April they fished in the Svinoy area. mixture of both types. The total catch was 1,040 tons in 94 fishing days. Bressay area From this area 8 samples with 2,389 herrings Cutters were examined in March, July and August. The The total yield decreased from 43,300 tons to material came from bottom trawls and pelagic 35,700 tons. 17,500 tons came from the North trawls. Sea. 15,6oo tons of this catch were herring for The average length in March was 24.10 em, in factories. The main catch, 12,182 tons, originated July/August 26.69 em to 28.87 em (Table 1). from the "oil" herring fishery in July to October. In March maturity stages II (6so0fo ), I (1700fo ) The landings from the Baltic for human consump 0 0 and VIII (170% ) were predominant, whereas in tion and industrial purposes increased from 14,900 0 July stages V (553% ), IV (18o0fo ) and II (1410fo ) tons to 18,100 tons. 0 0 0 formed the bulk of the catches. In August stages VII (386%0), VIII (275%0) and II (191%0) popu Biological data lated the area (Table 40). The catches in March consisted of autumn The relevant detailed tables are found in Statistical spawners, whereas in July and August some late News Letters, No. 35· The biological data are in these tables given in a monthly split by areas. winter spawners were admixed in the younger maturity stages and in the stage VIII (Tables z8, "Ostkante" (Viking Bank/Utsira) 29 and 36 to 39). In March, April and August 1966 5 samples of The year-classes 1963 (725%0) and 1962 (z6SOfo0) herring were collected from pelagic trawl (III/IV) were the abundant age-groups in March. In July and bottom trawl (VIII). and August year-classes 1963 (549%o/5300fo0), 1960 In March and April the length varied between (I420fo0/1360fo0), 1961 (1370fo0/1240fo0) and 1962 17.0 em and 35.5 em, the average length was (1220fo0/II30fo0) were the most abundant age 28.30 em, respectively 31.0 em. In August only groups (Table z). -141- Herring Fladen Ground (138%0), whereas in September stages VI (235%0), In June and August 12 samples with 2,68r I (219%0), VII (178%0), V (150%0) and II (rrJOfoo) herrings were investigated. The average length were prevailing (Table 40). amounted to 23.52 em in June and 26-43 em in The herring were autumn spawners, presumably August (Table r). some herring in maturity stages I and II belonged Maturity stages I to III (rooo0fo0) populated to the southern North Sea group. the area in June, whereas stages VII (28r0fo0), In January the year-class 1963 was the most V (199%0), II (144%0) and VII (r280fo0) were the abundant, followed by year-classes 1962 and 1964 most abundant groups in August (Table 40). (121%0). In March only the year-classes 1963 The bulk of the catches was formed of autumn (5400fo0). and 1964 (448%0) were dominating. spawners. Only in the juvenile stages in June and August showed prevailing of the year-classes 1963 August was a small admixture of late winter (7oiOfo0) and 1962 (134%0), while in September spawners (Tables 28, 29 and 36 to 39). the sequence of the year-classes was 1963 (497%0), In June the year-classes 1963 (870%0) and 1962 1964 (326%0) and 1962 (roJOfo0) (Table 2). (I2o0fo0) formed the bulk of the herring. In August more than eight year-classes were in the catches. The most abundant were the year-classes 1963 ''Binnensee'' (658%0), 1964 (rr30fo0) and 1962 (ro30fo0) (Table 2). In March and November 2 samples were examined. The average length was 17.20 em and 23. 39 em Gut (Tabler). 12 samples with 6,072 herrings from the bottom The sample from March were juvenile herring from maturity stage I (990% ), while in September trawl were examined in March, August and Sep 0 maturity stages V (65o0fo ), VII (r250fo ) and tember. 0 0 I (roo0fo ) were abundant (Table 40). The average length in March was 19.36 em and 0 25-72, respectively 26.03 em, in the other two The herring were autumn spawners (Tables 28, months (Table r). 29 and 36 to 39). In March the year-class 1964 (939%0) was Maturity stage I (958%0) was the most abundant group. Some stages II and V w,ere also present. dominating and in November the year-classes 1963 and 1964. They mainly belonged to the northern In August the stages V (329% ), VII (317% ), 0 0 autumn stock (Table 2). VI (rJoOfo0) and I (130%0) were predominating, while in September the stages VIII (351%0), VII (294%0) and V (148%0) were prevailing Egersund (Table 40). The bulk of the herring were autumn spawners 6 samples in March, August and December with 1933 herrings from bottom and pelagic trawl came (Tables 28, 29 and 36 to 39). from this area. The predominating age-group was the year-class The average length in March amounted to 1963 in all months (541 to 7270fo ). In March the 0 23.20 em, in August and December 27.22 to year-class 1964 (429% ) had some importance, 0 29.09 em (Table r). whereas in August year-classes 1964 (156%0) and In March stages I (5500fo ), II (2oo0fo ) and 1962 (1o90fo0) were also significant. 0 0 VIII (rJoOfo0) were dominating, in August maturity stages IV to VI, whereas in December recovering Dogger Bank herring (VIII = 554%0) and juvenile (II) were From this area 22 samples with 7 A 55 herrings prevailing (Table 40). from bottom and pelagic trawl in March, August The catches were in all months a mixture from and September were investigated. autumn and late winter spawners. The average length in March amounted to r8.82 The age composition showed in March the em. In August and September they varied from predominance of the year-class 1963 (695%0). In 24.36 em to 25.39 em (Table r). August the year-classes 1963 (Joo0fo0) and 1962 Maturity stage I (955%0) was predominating (2o80fo0) were prevailing, while in December the in March. In August the most abundant maturity year-classes 1963, 1960, 1957 and older and 1961 stage was VI (8o90fo0), followed by stage V were found (Table 2). -142- Skagerak Ling Bank Only r sample with ro6 herrings were investigated 258 herrings Ill 2 samples were investigated lll in December. August. The average length of this sample was 20.89 em The average length was 23.95 em (Table r). (Tabler). Maturity stage V (87r0fo0) was dominating The sample was a mixture of late winter and (Tablqo). autumn spawners. Only autumn spawners were met with in the Maturity stages I (65 r0fo0), II (I320fo 0) and area. VIII (r7o0fo0) were prevailing (Table 40). The year-class 1963 (674% ) was prevailing, The bulk of the catch was formed from the 0 followed by 1960 (rz30fo0) and 1962 (I070foo) year-class 1965 (5900fo0). The year-classes 1964 (Table 2). (r9o0fo0) and 1960 (r230fo0) had some importance (Table 2). Hebrides Great Fisher Bank Only I sample with 224 herrings from pelagic 5 samples with 1,879 herring came from this trawl was examined in September. area in March and August. The average length was 29.77 em (Table r). The average length was 17.05 em respectively Predominating was the maturity stage V (9090fo0) 27-40 em (Table r). (Table 40). In March juvenile herring of maturity stage I The catch was a mixture of autumn and late (9290foo) populated the area, whereas in August winter spawners. adult herring stages IV to VI were dominating The dominating age-groups were the year-classes (Table 40). 1963 (6rr0fo0) and r96r (I4IOfo0) (Table 2). The herring were autumn spawners with a small admixture of late winter spawners. East of Iceland The year-classes 1964 (6640foo) and 1963 (297%0) were prevailing in March (297%0), while in August rr samples with 4,698 herrings from pelagic the year-class 1963 (794%0) dominated (Table 2). trawl were investigated in January, October, November and December. East of Dogger The average length was 31.93 em to 33.65 em (Tabler). From this area 9 samples with 6,912 herrings were investigated in March and August. In January maturity stage V (9200fo0) was dominating (Table 40). Only Atlanta-Scandian late The average length was r6.24 em respectively winter spawners populated the area. 19.72 em (Table r). In all months the year-classes 1959 (373-484% ) In both months maturity stage I was dominating 0 and 1960 (246-351% ) were dominating. In (Table 40). Only autumn spawners were met with in 0 November and December the year-class r96r had the area. also some importance (II70fo0) (Table 2). In March the year-class 1964 (96r0fo0) was prevailing, whereas in August the year-classes 1964 (8r70fo0) and 1965 (r360fo0) were found (Table 2). "Rosengarten'' In January 2 samples with 512 herrings from German Bight bottom and pelagic trawl were examined. 3 samples with 4,030 herrings were examined Maturity stage V (8350foo) was dominating (Table in March and August. 40). The average length was 15.72 em in March The average length was 31.43 em, respectively (Tabler). 31.12 em (Table r). The herring were autumn spawners (Tables 28, The herring were Atlanto-Scandian late winter 29 and 36 to 39· spawners. In both months the year-class 1964 (9480fo0 , The year-classes 1959 to 1961 were prevailing respectively 9440foo) were dominating (Table 2). (Table 2). -143- Herring Svinoy area Table 102. Catch and effort statistics for the Norwegian North Sea and Skagerak herring fisheries 1964-66 3 samples with 701 herrings from bottom and pelagic trawl were examined in January and March. Gear Purse-seine Tra\d Total 1,000 No. of r,ooo No. of 1,000 The average length was 31.79 em to 32-46 em Year hi vessels hi vessels hi Tons (Tabler). 1964 1,596 195 435 519 2,031 188,883 1965 6,277 284 198 439 6-475 602,175 In January maturity stages V (85o0fo0) and 0 1966 4,820 334 69 347 4,889 454,667 IV (roo / 00) were prevailing, whereas in March stages V (6oo0fo0), VI (270%0) and IV (I300fo0) were dominant (Table 40). in rg65. During the two cruises in the area, one The herring belonged to the Atlanta-Scandian with R. V. "G. 0. Sars" from zo. June to r5. July, late winter spawners. and one with R. V. "Johan Hjort" from r8. October to 5· November, only small concentrations of The year-classes 1959 (459%0), rg6o (347%0) and mature herring were recorded. rg6r (I940foo) were present, whereas in March On the first cruise small shoals of herring were the year-classes 1959 (535%0) and rg6o (258%0) were dominant. However, in this month the year located in the Egersund Bank-Coral Bank area. classes older than 1957 (rz60fo0) had some import On the second cruise the best registrations of ance (Table z). herring were observed north of the Skaw, north of K. SCHGBERT Hanstholmen and south-west of Lista. The herring Bundesforschungsanstalt fur Fischerei, Institut fur See in eastern Skagerak were dominated by Kattegat fischerei, 2 Hamburg 50, Palmaille 9, Germany. autumn spawners, while the two other areas were populated mainly by Bank herring. The herring north of Hanstholmen consisted exclusively of The Norwegian Herring Fisheries in the North Sea juveniles (rg65 year-class) and were forming large and Skagerak 1966 shoals in shallow water, between 40-80 m. In the (Figure 116; Tables 102-112) eastern Skagerak and south-west of Lista the herring were a mixture of spents and immatures. Survey The herring in these two areas were found around A cruise for herring investigations, with R. V. the zoo m depth contour line, forming a scattering "Peder R0nnestad", was carried out in the north layer, which had a vertical migration between western North Sea from r8. July to 5. August. bottom and surface, descending during the day The route of the ship is shown in Figure rr6, where and ascending during the night. also the surface temperature and the records of herring obtained by asdic and echo-sounder are The fishery entered. The total Norwegian landings of herring from Good concentrations of herring were located the North Sea and Skagerak amounted to 4,889 east of Bressay-Sumburgh Head, east of Fair Isle mill. hl in rg66, against 6,476 mill. hl in rg65; and east of the Orkney. Except for the latter i.e. a decrease of 24.5%. The decrease in catch area, only a few shoals were located further than was caused by many factors such as lower abundance I5 nautical miles off land. In the area east of of herring in the north-eastern North Sea and Orkney also large shoals of sprat were observed. Skagerak, the purse-seine fleet changing over to In the north-eastern North Sea and Skagerak fish mackerel in the autumn and a fishing stop in the abundance of mature herring was lower than the last two months of the year. Table 103. The landings of herring (r,ooo hl) from the North Sea and Skagerak, 1966 Area Month Total % Jan. Feb. :March April 2\Iay June July Aug. Sept. Oct. Nov. Dec. NW North Sea o.s I .2 0.2 532-4 780.2 853.1 35-4 I.3 2,204-3 45·1 North of 59°N NE North Sea 0.8 1.2 28.8 48·7 4·8 1I.9 2.7 o.s 99·4 2.0 North of 59°N NE North Sea 77·2 2.7 2.7 42·7 546.6 634-4 416-4 198.2 qr.3 194-5 0.9 0.6 2,258.2 46.2 South of 59°N Skagerak 25.1 16-4 155-4 90.9 17·9 16.7 4·8 327.2 6.7 Total 102.3 4-0 5.1 71·7 595·3 I,I7I.6 1,224·9 1,209·4 268.1 213·7 17.6 5-4 4,88g.1 100.0 -144- ~-¥! q ~~[?<:- !_ 60o 'Rs" .., .. ~ 1 -o- r:::-r-150 CJ// /~#Z(. \ _... : ,(J_~ . ~\ -· - -,r.-- g fJ • ...... ~ ....)rs / -~ ~ ··11 J 0 0/ /' ··~------o : .... 12 13 ~~-<· , P E DE R R 0 N N E S T A D " 59 o ~71~-·.:_ ...... 151 ~··· 18.VII- 5.VJII 1966 0'-'" ..• SURFACE TEMPERATURE ' •. : ----c ·- HYDR. ST. t ----11- TAGGING LOCALITIES II VERY SCATTERED I SCATTERED !1111Htt1- DENSE · ~~- VERY DENSE 58°~------.------.------,------,------,------,------r------r------~- 30 2° 1' oo 1° 2° 3° 4° 5° 6° Figure rr6. Table 104. Length and age composition, north-western North Sea, north of 59°N, purse-seine, 1966 A. Per mille length composition Length in em r8 rg 20 21 22 23 24 25 26 27 28 June ...... 20.0 IO.O IO.O 40.0 July ...... 1.3 1.3 r6.3 67·5 101.3 71.3 30.0 August ...... 84-5 123.2 g8.6 88.0 29 30 3r 32 33 34 35 36 True mean Number June ...... 140.0 220.0 3rO.O rgo.o 70.0 20.0 31.02 roo July ...... 68.3 r8r.3 233-8 r55-0 57·5 r2.5 1.3 1.3 30.03 8oo August ...... 126.8 158-5 rrg.7 123.2 38-7 24.6 q.r 29.64 284 B. Percentage age composition - Number of winter rings Year 2 3 4 5 6 7 8 9 9+ class rg63-64 rg62-63 rg6r-62 rg6o-6r rg5g-6o rgsS-59 r957-58 rgs6-57 1955-56 Number and older June 2.0 4·0 8.o 3-0 q.o roo July 0.7 27-4 5-4 2.5 3·9 2.8 12.! 0.3 7II August . 37-5 4-2 1.4 2.8 2.8 8.3 72 Table 105. Maturity and vertebral count, north-western North Sea, north of 59° N, purse-seine, rg66 A. Percentage maturity (All age-groups) - Maturity stage I II III IV V VI VII VIII Number June ...... 59-8 r2.4 97 July ...... r6.5 29.2 O.r o.r 799 August ...... rr.o 20.5 4-l 23-3 roo B. Vertebral count (Actual numbers- all age-groups) Number of vertebrae 54 55 56 57 58 59 :'dean Number June 7 38 42 r2 s6.6go roo July rg r77 177 r6 56-482 390 -qs- Herring Table ro6. Age composition of spring- and autumn-spawned herring in the north-western North Sea, north of 59°N, purse-seine, rg66 Spring group Autumn group Total sample Year \Vinter- Number Year \Vinter- )(umber :;--;-umber class rings June July August class rings June July August Spring Autumn 1965 -l I964 -l 196-t 2 76 19 I963 2 2 102 7 95 III 1963 3 -l 1962 3 3 31 2 5 36 1962 4 4 4 I96r 4 II 6s 6 8 82 1961 5 21 54 2 1960 5 23 192 23 77 238 1960 6 6 I2 1959 6 2 6 19 8 1959 7 Ij I 95s 7 13 2 IS IS 1958 8 1957 8 2 20 2 2~. 1957 9 1956 9 86 G 106 Table 107. Length and age composition, north-eastern North Sea, north of 57oN - rg66 A. Per mille length composition Length January :\larch April :\Iay June Aug. Sept. Oct. November in cn1 Purse-s. Trawl Tra,\"1 Purse-s. Purse-s. Purse-s. Purse-s. Purse-s. Purse-s. Drift Trawl rG j.O 17 r8 I.9 19 IS-3 9-5 20 sr.6 28.6 70-4 I. I 6S.o j.O 21 99--! 95-2 95-5 10.3 I.1 48·5 25.0 22 I07.1 142-9 1}0.7 41.2 2.3 19.0 48·5 Ij.O 23 112.8 238.r 85·4 sr.s S.o r6.3 -f5·3 90.0 II0.9 142-9 95-5 sr.s 43·5 -f8.S ss.o 6.4 190.0 61.2 104.8 35-2 I 13-4 50·3 65. I 80.9 83.6 10.0 100.0 320.0 49-7 47·6 2j.I 41.2 73-2 122.1 I IO.O 96.5 -fO.O 130.0 rSo.o 47·8 38.1 35-2 Ij.f.6 100.7 ss.s 100.3 102.9 so.o JIO.O ros.o 78--t 47·6 j0.3 103. I 141.9 127-5 100.3 119.0 70.0 rSo.o 35-0 I09.0 66.7 I Ij.6 237-I 167.0 164.2 74·4 125-4 210.0 140.0 zs.o 89-9 19.0 qo.7 123-7 223.1 r68.2 87-4 128.6 310.0 110.0 s.o 26.8 19.0 75·-l 30-9 97·3 120.8 6r.5 209.0 2+0.0 30.0 5-0 19.1 2j.I 20.6 59-5 47·5 48·5 77- 2 20.0 33 1].2 j.O 10.3 28.6 I-f-9 -f"2.I 35-4 50.0 3-l I.9 IO.I 10.3 2.3 22.7 r6.r 35 6.5 True n1can zs.So 26.22 2]-9I 27-34 29-52 J0.22 zS.oS 2j.6I c-Jumber .. 523 199 97 737 309 3II roo roo 200 B. Percentage age con1position c-Jumber of winter rings Year I 2 3 4 5 6 7 8 9 9+ class I964-65 1963-64 1962-63 1961-62 196o-6r 1959-60 1958-59 1957-sS 1956-57 1955-56 Number and older Jan. (Purse-seine) 65-7 13.1 3-0 15.2 I.O I.O I.O 99 :\larch (Trawl) . . . 0.5 49-2 8.2 j.Z 23.1 3· I r.s 7-2 195 April (Purse-seine) r.r 23.2 '2-f.2 r8.9 23.2 I. I 2.1 6.3 95 :\1ay (Purse-seine) r6-4 21.5 19.6 34.1 1.9 L4 o.s -f-2 0.5 214 June (Purse-seine) 23-5 22.1 17.2 30-9 I.O r.s 3--f 0.5 204 Sept. (Purse-seine) 34·-f ro.S 9-7 25.8 I. I 3-2 rr.S 93 Oct. (Purse-seine) ro.S 8.6 II.S +5-2 3·2 6.5 q.o 93 )Jov. (Drift-net) . 65-7 S.r S.r I I, I I.O I.O I.O -f.O 99 Xov. (Trawl) r8.5 71.5 7-0 I.5 I.O o.s 200 Catch and effort data (maximum number of seiner was 14.431 hl compared with zz,roz hl in vessels participating) for r964j66 are given in 1965. The corresponding figures for the trawlers Table roz. About 99% of the total catch was taken were o,r99 hl in rg66 and 0.45r hl in r965. Part by purse-seiners, and the average catch per purse- of the year the trawlers were working as helping Table 108. Maturity and vertebral count, north-eastern North Sea, north of 57oN 1966 A. Percentage maturity (All age-groups) Maturity stage I II III IY y VI YII VIII Number Jan. (Purse-seine) 58.o 15.0 I.O 6.0 2.0 I8.o IOO March (Trawl) 32·5 19.0 6.5 5·0 0.5 36-5 zoo April (Purse-seine) q.o 12.9 73·1 93 :VIay (Purse-seine) 0.9 11.4 69. I 0.5 II.8 220 June (Purse-seine) 4·8 56.2 II.4 2!0 Sept. (Purse-seine) 4·0 40·4 l.O 1.0 51.5 99 Oct. (Purse-seine) ..... 2.0 6.I 88.9 99 Nov. (Drift-net) 9.0 24.0 54·0 roo Nov. (Trawl) ...... 0.5 34·7 55-3 6.5 199 B. Vertebral count (Actual numbers, all age-groups) Number of vertebral 53 54 55 56 57 58 59 Mean Number Jan. (Purse-seine) 3 51 42 2 56-414 99 March (Trawl) IO 95 86 5 2 56-465 I98 ::\Iay (Purse-seine) II I24 75 9 56·374 2I9 June (Purse-seine) ... . IS 95 84 6 56·376 202 Sept. (Purse-seine) ... . 3 48 35 56·39I 87 Oct. (Purse-seine) .... . 41 ., 43 7 56·559 93 Xov. (Drift-net) 45 45 5 56·546 97 NoY. (Trawl) .. IO 83 91 I3 56·543 I97 Table 109. Age composition of spring and autumn spawned herring in the north-eastern North Sea, north of 57°N, 1966 Spring group Number vVinter Jan. :VIarch April May June Sept. Oct. Nov. Nov. Year-class rings Purse Trawl Purse Purse Purse Purse Purse Drift Trawl I965 6 1964 2 7 5 7 5 4 26 29 1963 3 3 2 2 3 2 1962 4 2 3 5 3 1961 5 3 4 3 2 3 4 1960 6 1959 7 4 2 1958 8 I957 9 <1957 9* Total ...... I6 I7 7 I7 8 5 28 37 Autumn group Total sample Number Number vYinter- Jan. March April May June Sept. Oct. Nov. Nov. Spring Autumn Year-class rings Purse Trawl Purse Purse Purse Purse Purse Drift Trawl I964 I 30 6 3I 1963 2 55 86 20 27 4I 23 10 33 Io8 84 403 I962 3 IO I3 21 46 4I 9 8 8 12 I2 r68 1961 4 2 I2 IS 36 31 9 II 8 3 14 I27 1960 5 I2 4I 22 70 s8 I8 36 IO 2 20 269 1959 6 4 I I 2 7 I958 7 2 2 I 2 II 8 I957 8 3 2 3 6 I I7 I956 9 14 6 9 6 II I3 4 64 Table IIO. Length and age composition, Skagerak 1966 A. Per mille length composition August October November Length in em Purse-seine Drift Trawl Trawl Purse-seine IO ...... IO.I II ...... 90.9 12 ...... 232-3 19.2 I3 ...... 32-3 222.2 76·9 14 ...... ro.8 171.7 576·9 IS ...... 43·0 141-4 307·7 r6 ro.8 IOI.O 19.2 17 ...... ro.8 30-3 r8 19 20 ...... 8z.r ro.8 21 ...... III.I 64·5 22 ...... 144·9 86.0 30.0 23 ...... 159·4 53·8 70.0 24 9I.8 75·3 IIO.O 25 ...... 144-9 86.0 190.0 26 144·9 96.8 110.0 27 ...... 58.o g6.8 130.0 z8 24.2 75·3 8o.o 29 ...... 14·5 86.0 70.0 30 14·5 75·3 170.0 31 4·8 43·0 40.0 32 ...... 4·8 zr.s 33 2!.2 True mean ...... 24-33 25-45 13-93 14·73 27.14 Number ...... 207 93 99 52 roo B. Percentage age composition Number of winter rings 0 2 3 5 Year-class 1965-66 1964-65 1963-64 1962-63 ro6o-6r August (Purse-seine ...... 2I.O 62.0 IO.O October (Drift-net) ...... IO.I 21.3 38.2 5.6 October (Trawl) ...... 98.o 2.0 November (Trawl) ...... IOO.O November (Purse-seine) ...... 13·5 49·0 6.3 7·3 14·6 6 7 8 9 9+ Year-class 1959-60 1958-59 1957-58 1956-57 1955-56 Number and older August (Purse-seine) ...... roo October (Drift-net) ...... I. I I. I 2.3 89 October (Trawl) ...... 99 November (Trawl) ...... 52 November (Purse-seine) ...... 3· I 5-2 I.O 96 vessels for the purse-seine fleet. This fact may to derived mainly from the Egersund Bank area. The some degree explain the low figure for this category low figures for February-March was caused by in 1966. a diminished effort due to the Norwegian winter The landings from different areas, by months, herring fishery. By mid-June to the end of August are given in Table 103. the majority of the fleet was fishing in the Shetland The Shetland fishery was more productive than area, while some fishery still continued in the in rg65, whereas the landings from the other Egersund Bank area. In the autumn the main fishing grounds in the north-eastern North Sea centre of activity was in the Egersund Bank area. and Skagerak showed a marked reduction compared The herring fishery in Skagerak gave this year with the previous year. only 327,200 hl, of which the dominant part was In the first five months of the year, the landings landed in August and September. -qS- Table III. Maturity and vertebral count, Skagerak rg66 A. Percentage maturity (All age-groups) :\Iaturity stage I n III TY v YI \-II YlTI X umber August (Purse-seine) .... . 19.6 29-9 Lf·-1 18.6 Ij . .f 2. I 2. I 97 October (Drift-net) ...... !0.2 23.9 .f2.0 11.-f 3--\ 1.1 S.o 88 October (Trawl) .... . 94·9 j.I 99 Xovember (Trawl) .... . 88.5 II.j 52 :No,·ember (Purse-seine) ...... 40·-\ I 2. I I.O I.O 45 5 99 B. ·vertebral count (Actual number, all age-groups) Number of vertebral 5-\ 55 56 57 ss :\lean ::\umber August (Purse-seine) j6.362 .,3 5 H 39 3 94 October (Drift-net) 7 -\3 34 3 j6.326 89 October (Trawl) ... 5 43 26 3 56·351 77 November (Trawl) zS 20 j6 . .f51 SI :!'\ ovem bcr (Purse-seine) 41 54 2 j6.j82 98 Table II2. Age composition of spring and autumn spawned herring, Skagerak 1966 Spring group \\'inter August October ::\o\·cmbcr Year-class rings Purse Drift Trawl Trawl Purse 1966 0 5 1965 3 1964 7 9 1963 3 1962 + 1961 5 1960 6 1959 7 1958 8 1957 9 1965 0 9 86 so 6 1+5 196+ 1 19 IS 13 5 +7 1963 2 59 20 34 rS 113 1962 3 9 2 6 Ij 1961 4 2 7 7 16 196o 5 3 I I 14 zS 1959 6 1958 7 1957 8 3 4 1956 9 5 6 Biological data the spring and autumn spawned components (separated on otolith characters). During the year, 29 samples, totalling 2,912 herring were examined. The biological details for North-western North Sea (grounds west of 2°E and north the herring sampled from the various areas in of 59oN) 1966 are summarized in Tables 104-rrz. They The spring spawned component constituted 26% contain length, age, maturity and vertebral count of the samples from this area. The 1964 and 1961 distributions, together with age compositions of year-classes provided 42% and 34% respectively -149- Herring of this group. Among the autumn spawned herring There was no sustained fishery by Scottish the rg6o and the 1963 year-classes were dominating vessels on other North Sea grounds until the last and made up 38% and r8% respectively. However, week of July when good catches were landed from it should be noted that the 1956 year-class was the traditional Buchan grounds within 70 miles of still prominent in this area and contributed 17% Fraserburgh. The fishery continued there through of the autumn spawned fish. out August. North-eastern North Sea (grounds east of 2°E and north There was no major spawning fishery in rg66. of 57°30'N) The catches at Clythness, on the north coast of the The admixture of spring spawned fish in the Moray Firth, were very poor ( Annls. biol. samples was rz%, and among these the 1964 year Copenh., 22). class contributed 55%· Among the autumn spawned Trawl herring, the 1963 year-class was dominating, but Herring trawlers, mainly Swedish and Danish, the rg6o year-class was also abundant in this area. landed catches at Aberdeen from the north-eastern These two year-classes provided 37% and 25% North Sea, from Shetland waters and from the respectively of the total autumn spawned fish. Fladen ground. The catch and effort statistics by Recruitment of two year-olds (1964 year-class) of months and the total for the year are given in autumn spawners was almost lacking this year in Table II4 together with the totals for the previous the north-eastern North Sea. three years. Skagerak (east of 8°E) Purse-seine The spring spawners made up only 8% of the One English boat and two Scottish boats (work samples, and 56% of these belonged to the 1964 ing as a pair) fished with purse-seines in the North year-class. Sea during rg66. All the landings were from The autumn spawners were dominated by r year Shetland waters except one catch of 30 crans from old herring (rg65 year-class), which made up 38% the north-eastern North Sea in June. The combined of the catch. The rg63 and rg6o year-classes of the catches were 629 crans for 4 arrivals, 2,719 crans autumn spawners were represented with 30% and for r6 arrivals and 2,438 crans for 14 arrivals in 7% in the samples from this area. June, July and August respectively. S. HARALDSVIK Fiskeridirektorates Havforskningsinstitutt, Biological data Nordnesparken 2, Bergen, Norway. Drift-net North-eastern North Sea (grounds east of 2°E) Scottish Herring Fisheries rg66 The length, age and maturity compositions of (Tables I I3-I34) the samples from this area are given in Table rr5 North Sea and the age compositions of the spring and autumn The fisheries spawned herring (separated on otolith characters) Drift-net are given in Table rr6. The sample in May came The drift-net fishery in rg66 began in late April from surplus bait landed by a line-boat. and continued until the first week of September. Spring spawned herring made an even smaller The catch and effort statistics by months and the contribution to the samples than in rg65. The total for the year are given in Table II3 along with rg6o and rg6z year-classes were equally represented the totals for the previous three years. in the autumn spawned herring, each contributing A small fleet fished various grounds in the 32%. northern North Sea without success until the second North-western North Sea (gro~tnds west of 2°E and week in May when a productive fishery started north of 55°]0'N) on the west and north coasts of Shetland. An The samples taken from this area have been increased fleet fished successfully on these grounds divided into those taken north and south of 59°N. during May and June. The centre of fishing moved in July to the north and east coasts of Shetland Samples from north of 59 °N and in August to the east Shetland and Fair Isle The length, age and maturity compositions of grounds. The average catch per haul was high these samples are given in Table II7. The age com during May and early June, lower during late June positions of the spring and autumn spawned herring and July, and rose again sharply in the first week (separated on otolith characters) are given in of August. Table rr8. -150- Table II3. Drift-net fishing - Scotland, east coast 1963-1966 r963 r964 r96s r966 Total April May June July Aug. Sept. North-eastern ~orth Sea (cast of Z 0 E) Catch in crans ...... 3,868 6,q6 2,292 so6 0 6r -H5 No. of hauls ...... 190 212 202 z6 5 5 r6 Average catch per haul (crans) ...... 20.4 29.0 II.3 19.5 0.0 12.2 27.8 North-western North Sea (north) (west of Z0 E and north of 59°N) Catch in crans ...... 61,407 6z,z58 65,211 7Z,8Z4 0 10,630 26,753 17,040 r8,z48 153 No. of hauls ...... 2,528 z,581 2,960 2,719 8 335 1,066 873 428 9 Average catch per haul (crans) ...... 24-3 Z4-1 22.0 26.8 0.0 3I.7 25.1 19-5 42.6 17.0 0 North-\wstern North Sea (south) (west of Z E, south of 59°N and north of S5°3o'N) Catch in crans ...... II r,6o3 38,607 42,86o I2,S71 9 o 746 2,823 8,991 2 No. of hauls ...... 4,769 2,234 2,178 580 6 3 41 II3 415 z Average catch per haul (crans) ...... 23-4 17-3 19-7 I.5 0.0 18.2 ZI.7 I.O Table 114. Trawled herring - Scotland, east coast, 1963-66 1963 1964 1965 1966 Total Feb. March April May June July 1\ug. Sept. Oct. North-eastern North Sea (east of Z0 E, north of 57°3o'N) Catch in crans .. 7.S79 5.331 5,616 3,073 192 284 726 1,398 362 III Hours fishing .. r,683 1,022 1,205 830 33 72 JOO 302 88 35 Catch(1oo hours (crans) ...... 450·3 52I.6 466.1 370·3 s8r.8 394·4 242.0 462.1 413-7 318.3 Shetland waters (Stat. squares 19 D, r8 C) Catch in crans .. 6rr z,rr6 431 132 94 38 Hours fishing .. 205 554 r6o 53 37 r6 Catch(1oo hours (crans) ...... z98.o 38I.9 269·4 248·5 Z54.I 235·6 Fladen (57°Jo'N-6o 0 N, 0°-2°E) Catch in crans .. 2,143 3.780 1,287 1,505 25 8-I 190 38 968 84 112 Hours fishing .. 875 1,389 481 770 38 8s 1!{ ·n 361 45 10S Catch(IOo hours (crans) ...... Z44-9 272.1 267.6 19S-4 66.9 roz.8 165.9 172-7 z68.z 187·3 106.7 Gut and southwards (55°N-57°3o'N, west of 2°E) Catch in crans .. z,ro8 7,250 Z,268 76 76 Hours fishing .. 438 898 477 5 5 Catch(1oo hours (crans) 481.3 807·3 475-5 1,514.0 1,5q.o Table us. Length, age and maturity composition- north-eastern North Sea- drift 1966 A. Per mille length composition (All age-groups) Length in em. zs z6 27 z8 Z9 30 31 32 33 Mean No. May 20.0 20.0 8o.o 26o.o 140.0 320.0 140.0 20.0 29.11 so June 20.0 6o.o 16o.o z6o.o z6o.o 16o.o 60.0 20.0 29-41 so B. Percentage age composition Number of "·inter rings z 3 4 s 6 7 8 9 ro ro+ Year-class 1963-64 196Z-63 1961-6z 1960-61 1959-60 1958-s9 1957-58 1956-57 195S-56 1954-55 No. and older May 10.0 32.0 22.0 32.0 2.0 2.0 so June 8.o 30.0 22.0 30.0 4·0 2.0 4·0 so C. Percentage maturity (All age-groups) maturity stage I II III IV v VI YII VIII No. :Yiay ...... 8.o ss.o 34·0 so June ...... 4·0 72.0 20.0 4·0 so -I5I- Herring Table n6. Age composition of spring- and autumn-spawned herring in north-eastern North Sea- drift 1966 Spring group Autumn group Total sample \¥inter Number ViTinter Number Number Year-class rings May June Year-class rings ::VIay June Spring Autumn 1964 2 1963 2 5 3 I 8 1963 3 rg62 3 r6 IS 31 1962 4 2 Ig6I 4 9 II 2 20 rg6r 5 Ig6o 5 I6 I5 3I rg6o 6 I959 6 2 3 1959 7 1958 7 rgsS 8 I957 8 1957 9 rgs6 9 2 2 Total ..... 2 Total ..... 49 3 97 Table n7. Length, age and maturity composition- north-western North Sea: north of 59°N- drift 1966 A. Per mille length composition (all age-groups) Length in em 20 2! 22 23 24 25 26 27 28 29 30 3I 32 33 34 35 :\{ean No. May 3-8 22.8 49-3 63.6 50-3 46-5 I24-3 279-9 2I5-4 93-9 38.8 I0.4 o.g 29.53 1,054 June 6.I 62.0 220.9 275-3 105-9 34-8 46.9 92.3 go.S 48.4 12.I 4·5 27.I8 66I July 3.I 3-I LO 8.3 47-8 183.8 263.8 147-5 39-5 45-7 g8. 7 95-5 43-6 I6.6 2. I 27.29 963 August ... 2.7 4-5 4-5 3-6 rS.g 72.9 I95-3 r8r.8 93.6 71.1 121.5 q6.7 66.6 13-5 2.7 28.q I,II1 September 22.2 51.9 I40.7 288.9 ISS-6 59-3 96.3 I03.7 51.9 29.6 27.10 135 B. Percentage age composition Number of winter rings '7 3 4 5 6 7 8 9 IO 10 + Year-class I964-65 1963-64 1962-63 1961-62 1960-61 1959-60 1958-59 1957-58 1956-57 1955-56 1954-55 No. and older May 1L9 ILO r6.I 38-4 3-6 6.g 2.7 o.s 0.2 I,057 June 55·4 15-9 s.S 17-3 0.6 o.S L7 0.2 665 July 0.6 59·3 ro.S 4-1 15-7 L1 LO I.2 0.2 0.5 g6s August ... L1 50-9 ro.S 9-5 17.5 o.6 LO 0.6 1,!20 September 60.9 rr.6 8.7 12.3 2.2 0.7 135 C. Percentage maturity (all age-groups) Maturity stage I II III IV V VI VII VIII No. May ...... 0.4 6.2 38-9 I.O 0.2 5-5 47-8 r,o6r June ...... LI 30.2 52-7 5-9 0.3 9-9 666 July ...... 5-5 23-7 3I.I 20.6 10.3 0.3 8.6 972 August ...... 2.0 23.6 6.r 7-I I2.I 5-2 rs.z z8.6 I,I29 September .... . S.o 8.7 S.o rr.6 z.g 13.8 47-I 138 Table n8. Age composition of spring and autumn spawned herring in north-western North Sea: north of 59°N- drift 1966 Spring group Autumn group Total sample Year \¥inter Number Year- vVinter Number Number class rings May June July Aug. Sept. class rings May June July Aug. Sept. Spring Autumn 1965 5 IO 1964 2 I5 3 I964 2 42 122 264 253 15 1963 2 84 244 3IO 316 6g 6g6 I,023 I963 3 4 2 4 2 rg62 3 I I I I04 10I II9 I6 12 451 I962 4 5 3 I 5 rg6r 4 r66 35 39 103 I2 14 355 I961 5 43 I2 23 25 1960 5 362 IOI I29 I7I I7 103 780 Ig6o 6 30 2 6 I I959 6 8 2 5 6 39 2I I959 7 62 2 6 7 1958 7 12 3 4 4 77 23 I958 8 I957 8 29 II 12 I9 2 73 I957 9 1956 9 Sg r6 6I 3 215 I956 IO I955 IO 5 2 7 I955 I954 & older ro+ & older Io+ 5 7 r6 Total .. IS Total .. 868 5I7 654 8oS r2o 2,967 -152- Table II9. Length, age and maturity composition- north-western North Sea: 'south of 59°N and north of 55°3o'N -drift 1966 A. Per mille length composition (all age-groups) Length in em. 20 2I 22 23 24 2S 26 27 z8 29 30 3I 32 Mean No. April ...... 40.0 120.0 300.0 400.0 IOO.O 20.0 20.0 24·S4 so June ...... 8_o 4S-5 243·3 286.1 251.3 II7.6 29·4 2.7 I0-7 2.7 2.7 24.29 374 July ...... I.9 I.9 32·3 I6S.I 214-4 284.6 I44.2 66-4 20.9 30-4 24·7 9·5 3·8 25.00 527 August .... 1.2 7- I SI.I 120.I I73.6 204·5 173.6 88.o 70.2 64.2 42.8 3·6 26-47 841 September 54·1 162.2 162.2 378·4 189.2 54. I 25.6I 37 B. Percentage age composition Number of '"'inter rings 0 I 2 3 4 5 6 7 8 9 10 Io+ Year-class I964-65 I963-64 I962-63 I96I-62 I96o-6I I959-6o I9S8-59 I9S7-58 I9S6-s7 I955-56 I954-S5 No. and older April .. 72.0 28.o so June .. o.s 91.3 6.6 I. I o.s 376 July .. o.6 8I.8 12.4 2.3 2.4 0.2 0.2 0.2 531 August 0.4 68.6 I8.1 5·9 5·3 0.2 0-4 0.2 O.I 0.1 0. I 852 Sept. . - 76·3 23-7 38 c. Percentage maturity (All age-groups) :vraturity stage I II III IV V VI VII VIII No. April ...... 22.0 40.0 26.o 12.0 so June ...... 3·7 33·8 60.4 2. I 376 July ...... 1.3 I3.0 63·5 I9.0 2-4 o.8 53 I August ...... O.I 6.0 20.9 34·3 22.3 7·7 3·3 5·4 852 September ..... 47·4 10.5 13.2 I5.8 13.2 38 Table 120. Age composition of spring and autumn spawned herring in north-western North Sea: south of 59°N and north of 55°30'N - drift 1966 Spring group Autumn group Total sample Year- Winter Number Year- ·winter Number Number class rings ApL May June July A.ug. Sept. class rings ApL May June July Aug. Sept. Spring Autumn I965 I964 I 3 3 6 I964 2 3 63 52 23 I963 2 33 280 378 ss6 27 142 I ,274 I963 3 I962 3 I4 25 66 I 53 9 267 I962 4 I96I 4 4 I2 so 66 I96I 5 I96o 5 2 I3 45 6o I96o 6 I959 6 2 3 I959 7 I958 7 3 4 1958 8 I957 8 2 2 I9S7 9 I956 9 2 I9S6 IO I955 10 I955 & I954 & older 10+ older ro+ Total 3 63 52 24 Total 47 3II 475 8I7 36 143 I,686 Spring spawned herring made up nearly zs% of with the increased catch per haul, indicates the the stocks sampled, owing to the appearance of arrival on the drift-net grounds of a body of a strong recruit year-class (rg64) which contributed herring which had spawned elsewhere. The fish at 73% of the spring fish. Among the autumn spawned maturity stage II in August were almost all spring herring the rg6o year-class supplied 42% of the spawned herring. autumn fish during May and zo% in the period June to September. The 1963 recruit year-class, Samples from south of 59oN which was poorly represented in May (ro%), The length, age and maturity compositions of contributed s6% of the autumn fish sampled these samples are given in Table II9 and the age during the remainder of the fishery. compositions of the spring and autumn spawned The sudden appearance of autumn spawned herring (separated on otolith characters) are shown herring at maturity stage VIII in August, together in Table 120. -153- Herring The strong rg64 recruit year-class was responsible than had been the case for several years. The rg63 for spring spawned herring making a larger con year-class dominated the autumn spawned herring, tribution (8%) to the stocks sampled in this area making up 76% of the samples. Table rzr gives the mean lengths of the two to Table 121. Mean lengths (em) of 2-5 ringed herring in North- five-ringed herring in the samples from Fraserburgh western North Sea: south of 59 oN and north of 55°3o'N and Peterhead between rgso and rg6r, and in 2 3 4 5 the samples from the north-western North Sea I9SO ...... 24-SI 24.92 26.05 27·73 south of 59°N and north of 55o3o'N between rg6z 1951 ...... 24-73 2S·76 25·93 26-49 I9S2 ...... 24.86 26.25 26.82 27.26 and rg65 . I9S3 ...... 24·S4 26.37 27.00 28.09 I9S4 ...... 24.69 26.92 28.12 28.71 Herring trawl ...... 24.18 26.8r 28.68 I9SS 29·34 The length, age and maturity compositions of r9s6 ...... 24·76 26.97 28.36 29·43 I9S7 ...... 24.28 26.r6 28.30 29.31 the samples of trawled herring taken in the north 19s8 ...... 24·S1 26.76 28.09 28.97 eastern North Sea in April and May are given in I9S9 ...... 24-88 26.28 28.2s 29.25 Table rzz and the age compositions of the spring ...... 26.14 2 28.86 1960 24·S7 7·75 and autumn spawned herring (separated by otolith 1961 ...... 24·96 26.84 28.22 28.96 1962 ...... 2S.67 27.10 28.35 29.0S characters) are given in Table 123. 1963 ...... 2s.8r 27-46 28.47 29.29 The stocks sampled by herring trawl were very 28.28 28.28 1694 ...... 2s.86 29-49 similar to those taken by drift-net in the same 1965 ...... 24·78 27·94 29-4S 29.so 1966 ...... 24.90 26.73 29-43 30.03 area. Table 122. Length, age and maturity composition of trawled herring- north-eastern North Sea - 1966 A. Per mille length composition (All age-groups) 24 25 26 27 28 29 30 31 32 33 34 Mean Total April ...... 20-4 8r.6 61.2 !02.0 !02.0 183·7 204.1 163·3 40.8 20.4 20.4 28.9s 49 May ...... 8o.o 240.0 360.0 220.0 8o.o 20.0 30.II so B. Percentage age composition ~umber of winter rings I 2 3 4 s 6 7 8 9 ro ro+ Year-class 1964-65 1963-64 1962-63 1961-62 196o-6r 1959-60 r9s8-59 1957-s8 r9s6-s7 1955-s6 1954-5s No and older April .... . 18-4 22.4 34·7 4·1 4·1 May .... . !2.0 28.o 36.0 2.0 8.o 8.o 2.0 C. Percentage maturity (All age-groups) Maturity stage I II III IV v VI VII VIII No. April ...... r6.3 12.2 2.0 69·4 49 :Way ...... 2.0 22.0 4·0 IO.O 62.0 so Table 123. Age composition of spring and autumn spawned herring in north-eastern North Sea - trawl 1966 Spring group Autumn group Total sample Winter Number Winter Number Number Year-class rings April May Year-class rings April May Spring Autumn 1964 2 1963 2 8 8 1963 3 1962 3 9 6 1S 1962 4 1961 4 IO 14 24 1961 5 1960 s 16 rS 34 1960 6 1959 6 2 2 I9S9 7 1958 7 2 2 1958 8 1957 8 4 4 1957 9 19S6 9 2 4 6 1956 10 1955 10 1955 and older ro-t- I9S4 and older 10-1- Total ...... •7 Total ...... 47 49 3 96 -154- Table 124. Length, age and maturity composition- north-western North Sea, north of 59°N- purse-seine 1966 A. Per mille length composition (All age-groups) Length in em. 20 21 22 23 24 25 26 27 28 29 30 3I 32 33 34 ::VIean No• June ...... 20.0 40.0 z6o.o 140.0 90.0 50.0 60.0 roo.o r6o.o 40.0 40.0 27-70 roo July ...... 10.4 62.5 197-9 114.6 20.8 52.1 145-8 156.2 r35-4 72-9 3!.2 29.16 192 August ..... 6.8 13.6 20.4 20.4 !22.4 292.5 210.9 8r.6 54·4 88-+ 54·4 20.4 r3.6 27.08 147 B. Percentage age composition Number of winter rings 2 3 4 5 6 7 8 9 IO ro+ No. June ..... 45·0 22.0 5-0 r6.o 2.0 2.0 7-0 r.o roo July ..... 34·9 ro.8 7-7 3°·3 I.O I.5 3-6 f.Z I.O L5 192 August ... 2.8 72-3 8.8 4-I 8.7 0.7 2.0 147 c. Percentage maturity (All age-groups) Maturity stage I II III IV v VI VII VIII No. June ...... 23.0 55-0 r8.o I.O 3-0 roo July ...... ro.8 2.! 32.8 26.1 r6.9 II.3 195 August ...... 3·4 31.1 2.7 1.4 4-I 32·4 6.r r8.9 148 Table 125. Age composition of spring and autumn spawned herring in north-western North Sea north of 59°N- purse-seine 1966 Spring group Autumn group _ Total sample 'Winter Number \Vinter Number Number Year-class rings June July Aug. Year-class rings June July ~\.ug. Spring Autumn 1965 2 1964 2 2 2 1964 2 r8 20 32 1963 2 27 45 75 70 147 1963 3 1962 3 22 20 13 55 1962 4 I I 196r 4 4 14 6 2 24 196r 5 4 r6 1960 5 12 43 12 2r 67 1960 6 2 1959 6 2 1959 7 2 r958 7 2 2 3 1958 8 1957 8 2 7 3 12 1957 9 1956 9 7 I4 21 1956 10 r955 IO 2 2 1955 & older ro+ r954 & older ro+ 3 4 Total ...... 00<> 42 35 Total ...... 77 149 IIZ roo 338 Table 126. North Minch herring catches 1966 Catches (crans) No. of arrivals Catch per arrival Drift-net Ring-net Trawl Drift-net Ring-net Trawl Drift-net Ring-net Trawl January ...... II,782 5,214 186 372 62 r3 31.67 84.10 r4-31 February ...... 16,349 9.749 5r3 558 95 r2 29-30 ro2.62 42-75 March ...... 12.+06 5,966 28 458 66 27.09 90-39 28.oo April ...... 1,632 433 58 225 r3 4 7- 25 33-3r 14-50 May ...... 102 15 6.80 June ...... 36 -+24 r4 6o 2-57 7-07 July ...... 2,786 970 129 51 21.60 19.02 August ...... 6,901 I,r43 232 6o 29-75 19.05 September ..... 2,851 1,865 128 84 22.27 22.20 October ...... 14,256 2,968 2,415 335 88 6o 42-56 33-73 40.25 November z8,76o 6,747 2,227 827 151 So 34·78 44.68 27.84 December ..... 11,033 ro-440 1,717 z85 20! 29 38,71 51.94 59.2r Total ...... 108,]92 46,ozr 7,14-f 3,563 946 r99 30-53 48.65 35-90 - I 55 - Herring Table 127. South Minch herring catches 1966 Catches (crans) No. of arrivals Catch per arrival Drift-net Ring-net Trawl Drift-net Ring-net Trawl Drift-net Ring-net Trawl January ...... 7.937 2 I ,533 6,66o r68 246 103 47·2+ 87·53 64.66 February ...... s8o 7.982 8,3I2 I3 I35 I67 44-62 59-I3 49-77 March ...... 2,021 5,049 40 roo 50· 53 50·49 April ...... 72 64 I 4 72.00 r6.oo May ...... 76 6 12.67 June ...... 676 56 I2.07 July ...... 6I 4·398 6 I84 IO.I7 23-90 August ...... 723 5.75I I34 2I 266 8 34-43 2!.62 r6.75 September ..... 6,379 3,006 578 232 I29 35 27-50 23-30 I6.5I October ...... 448 6,473 I76 22 I93 r6 20.36 33·54 II.OO November I 58 I9,868 I2,237 3 328 I90 52.67 60.57 64-4I December ..... 3I3 20,523 I9,744 5 254 327 6z.6o 80.79 6o.38 Total ...... I6,599 92,379 52,954 47° I,838 950 35-32 50.26 55-74 Table 128. North Minch, drift-net 1966 A. Per mille length composition (All age-groups) Length in em. :Month 2I 22 23 24 25 26 27 28 29 30 3I 32 33 34 Mean No. January 76.0 2I6.o I84.0 8o.o IO+O 92.0 68.o I04.0 6o.o I6.o 26-46 2j0 February .. 2.7 29-3 87.8 98·4 58.5 79·8 I67-5 I78.2 I67·5 II 1.7 I8.6 27-92 376 March ..... z.s IO.I 30-4 63·3 40·5 6o.8 f4I.8 2I2.7 235·4 I57·0 43·0 2.5 28.82 395 April ...... 20.9 41.8 75-3 62.8 I04.6 I88.3 I92.5 I96.7 II3.0 4 ·-., zS.zr 239 July ...... August .... 8.5 42·4 67.8 262.7 296.6 110.2 IOI.7 50.8 59·3 27.I7 rr8 September 35-I 87·7 149-I 236.8 254·4 114.0 43·9 52.6 8.7 I7-5 25-55 If4 October ... 6.8 54-4 I29-3 Io8.8 231.3 238.I I83·7 27.2 6.8 6.8 6.8 2j.22 I47 November 7·7 7·7 46.2 I8+6 246.2 207·7 I53·8 92-3 30.8 I5·4 7·7 27-73 130 December 7-2 36.2 I95·7 253.6 231.9 Io8.7 65.2 72-5 j.2 21.7 27.8I 138 B. Percentage age composition Number of winter rings I 2 3 4 5 6 7 8 9 IO ro+ 1964-65 1963-64 1962-63 1961-62 1960-61 1959-60 1958-59 I957-58 1956-57 1955-56 1954-55 No. January ... 44-0 19.6 15.6 8.o 2.8 2.4 3·6 2.8 I.2 250 February .. 2!.2 12.3 23-3 24·7 4·0 2.4 5· I 5-I o.8 I. I 373 March ..... 11.9 8.4 28.r 25.8 7·8 r.8 7·8 6.6 o.8 I.O 395 April ...... r8.o 13.0 31.0 I6.3 5·0 1.3 9-2 3·8 0.4 2.1 239 July ...... 25-7 65.1 I.O 3-1 2.4 0.3 0.3 I.O 295 August .... I3.0 78.1 I.O 3·7 3-I o.s 0.5 192 September I.+ 66.2 2.8 12.0 !2.0 3-5 0.7 O.j 142 October, ... 2.0 79-0 2.0 10.2 3·0 1.5 I.O o.s 0.5 196 November 1.4 64.6 r.6 10.2 10. I 3· I 5·1 I. I I. I I. I 548 December 0.3 61.3 1.7 13-3 8.o 5·3 0.7 2.7 3-3 0.7 2.7 300 Purse-seine Spring spawned herring made up 23% of the purse seine samples and the 1964 year-class contributed The length, age and maturity compositions of 70% of the spring fish. Among the autumn spawned the samples of purse-seine herring taken in the herring the 1963 year-class supplied 43% and the north-western North Sea, north of 59°N from rg6o year-class 20% of the samples. June to August are shown in Table 124. The age compositions of the spring and autumn spawned The most noticeable difference between the herring (determined by otolith characters) are samples taken by the different methods is the large given in Table 125. proportion of ripe herring among the purse-seine samples in August. This is accounted for by one There is a great similarity between the purse sample of so fish taken south of Fair Isle which seine and the drift-net samples from this area. was composed almost entirely of herring in stage VI. Table 129. Length and age composition - South Minch - ring-net 1966 A. Per mille length composition (All age-groups) Length in em. Month 19 20 21 22 23 24 25 26 27 28 29 30 31 33 Mean January 4.1 12.2 32-5 24·4 48.8 r6.3 28.5 I5S.s 178.9 227.6 219-5 36.6 !2.2 27-93 February 14.2 28.4 103.4 162.3 135-9 73·0 22.3 r8.3 62.9 107-S 137·9 105-5 24-3 2.0 2.0 zs.zs March . . 49.6 95.0 99.2 rrg.S 37·2 24.8 r6.s 20.7 53·7 144·6 rSs.g r24.o 24.8 ZS-48 April zo.o So.o 200.0 300.0 200.0 6o.o 20.0 6o.o 40.0 20.0 24-S+ June . . 33.6 I47·7 167.8 r8r.2 140.9 140.9 73·8 67.1 13-4 13·4 13-4 6.7 23.64 July . . 70.3 70.3 19.5 31.3 132.8 242.2 246.1 74-2 27-3 19-5 46.9 rs.6 3·9 24.05 August 5.2 31-4 52.4 26.2 78.5 r78.o 288.o 230-4 36.6 47· I 26.2 24.81 September - 7. 2 7-2 21.6 208.6 251.8 187.0 57·6 36.0 122.3 79.1 14-4 7·2 26.14 October 5.2 s.z 51.5 149.5 340.2 226.8 6r.g 56.7 46.4 36.r rs.5 s.z 25.69 November 3 7 r.S 20.3 35.1 162.3 193-7 IS3-I 79-3 72.0 86.7 92-3 ]2.0 22.1 5·5 26.65 December 6.7 3·3 6.7 140.5 244·1 177-3 73·6 80.3 97·0 103·7 53-5 6.7 6.7 26.71 B. Percentage age composition Number of winter rings I 2 3 4 5 6 7 8 9 IO ro+ No. 1964-65 1963-64 1962-63 rg6r-6z rg6o-6r 1959-60 rgs8-59 1957-58 1956-57 1955-56 1954-55 January ... !2.2 3·7 26.8 19.5 9-3 2.8 9-3 S.r 3·7 4-5 February .. 52.0 2.7 14.8 8.2 5.1 r.S 5-3 4-3 r.8 3-9 March ..... 43-4 I ·7 20.7 12.0 7.0 2.9 5·8 2.9 1.2 2.5 April 8o.o 6.0 12.0 2.0 June ...... 91.9 3-4 2.0 0. 7 1.3 0.7 July August .... o.8 67.8 8.3 s.o o.S o.S o.8 September . +9 8I.3 o.S 4·9 October ... 13.4 82.6 0.7 2.0 0.7 November 0.7 6g.g 58 II.7 S-9 0.7 2.2 0.7 December . 68.6 9-3 7-9 5·7 2.1 3·6 0.7 o.; Table 130. Percentage of spring and autumn spawned herring- North Minch 1966 January-March April-June July-September October-December No. Spr. Aut. No. Spr. Aut. No. Spr. Aut. No. Spr. Aut. Year-class Rings 196+-65 7 71 29 21 91 9 1963-64 2 243 20 So 43 44 56 179 22 78 32 68 1962-63 3 128 2 gS 31 3 97 8 87 22 s 95 rg6r-62 4 237 99 73 100 21 86 30 30 70 rg6o-6r 5 214 IS s5 39 3 97 12 roo 17 24 76 1959-60 6 53 8 92 12 8 92 roo 4 roo 1958-59 7 22 5 9S 3 roo 2 roo 1957-58 8 59 2 g8 21 roo 2 roo 3 100 1956-57 8 and older 69 roo IS roo IO 100 Percentage of spring and autumn spawned herring - South Minch 1966 Year-class Rings January-March April-June July-September October-December 1964-65 IOI z8 72 12 ss 42 1963-64 2 387 7 93 176 II 89 434 IO 90 6go 7 93 1962-63 3 26 roo 8 roo 9 II Sg r8 roo rg6r-62 4 r88 2 g8 9 roo 33 42 ss 114 13 87 rg6o-6r 5 I 17 3 97 roo 30 13 87 85 zz 78 1959-60 6 6s 3 97 6 roo 36 3 97 1958-59 7 23 roo z roo 3 roo 4 roo 1957-58 8 63 roo roo 3 roo 37 14 86 1956-57 8 and older IOS 99 roo roo 39 IO 90 -157- Herring Table 131. Maturity and meristic characters- North Minch Maturity and meristic characters - South Minch - drift-net rg66 ring-net rg66 A. Percentage maturity (All age-groups) :\Ionth 11 III IV V VI Vll VIII No. :\Ionth I II III IV \- VI VII VIII J:\o. Jan... 22.8 38·-t !.2 2.0 1.2 0.-f 34·0 250 Jan... 8. I 4·5 o.S r.6 0.8 84.I 246 Feb. +5 21.0 I. I 3.2 I.I 0.3 68.g 376 Feb. I6.6 3-t-3 0.2 0.2 48·7 -t93 March 3.0 8.9 2.8 2.s r.S 0.3 So.8 395 :\larch . 2 r.g rg.8 o.S s7.o 242 .'\ pril . 5-9 7-9 -f.2 o.S 0.4 I.] 79-I 239 April .. 38.0 36.0 26.0 so August 0.8 2-f.O 20.7 26-4 IO.] s.8 5.o 6.6 !21 June .. 32 ·2 3-t-9 2-f.2 0.7 8.r 149 Sept ... 12.2 30. I g.8 S.r I].I S.g 4.1 g.S I23 July .. 30.8 2S-4 22.7 j.I 0.] IS-3 29S October 3-f.O 2] . .) 12.0 1.3 0.] 0.] 2-f.O ISO :\ugust I3·5 I].2 I6.r 22.9 r8.2 8.3 3.6 192 Nov. s. I q.o 30.1 rr.8 4·4 34-6 136 Sept ... 0.] 4·2 12.0 21.8 2.8 29.6 19.0 9-9 142 Dec. 0.] -t-3 22.1 9-3 0.] 62.9 qo October 6.6 8.] ... 6 1.5 o.s 13.8 6-t-3 rg6 ::\ 0\". ].8 6.o +7 4·4 r.6 75·-t S48 Dec ... 3·3 2.0 +3 3·0 8].3 300 B. V.S. (Actual numbers all age-groups) 5-t 55 56 57 ss 59 Mean Xo. 55 57 ss 59 ~Iean ::\o. January .. I6 IOJ Io8 rS s6.5I 246 January . . 2 6g 3 s6.sr I-t3 February . I6 q2 IOI 9 s6.38 269 February . Io roo 7 s6.s2 I99 :\Iarch ... . 12 Ig6 I6] I3 S6·-t7 390 :\larch . . . . 4 65 8 s6.ss qo ,\pril .... . II 92 123 IO s6.s7 237 April .... . 19 56. 38 so ,\ugust .. . 2 59 53 6 s6.ss IZI June .... . 25 4 56.65 49 September 3 30 46 6 sG.6s 85 July . . . . . 3 37 6 s6.s3 93 October .. 2 45 42 7 s6.s6 98 August . . . ., 20 22 + s6.s8 48 November 2 37 j8 IS s6.8o 132 September -t 30 -tS 7 s6.6s 8g December + 45 62 25 56.79 I 36 October . . 8 2I IS 2 s6.24 46 November 5 ISS s6.66 297 December 6 IlO 56.69 192 C. I\: 2 (Actual numbers all age-groups) 12 q I5 I6 17 Mean Xo. I2 I3 q IS r6 17 :\lean No. January .. 2 I39 57 q q.I8 2-t8 January .. 2 2-f 66 4I 6 I.f.20 I.fO February . I34 ]I !2 .., q.I] 272 February . 26 122 44 6 q.I6 200 :\larch ... . 5 202 77 12 IJ.99 392 '\larch ... . I6 83 37 5 I-f-20 I.p April .... . 130 56 6 I4.I I 23S April .... . II 26 9 I.f.OO 47 August .. . 6I 3I q.o9 IIS June .... . 5 24 15 14·33 46 September .fi 21 2 I4.IO 8I July .... . 32 43 I6 I3.87 93 October .. 45 I6 3 I.f-02 82 August .. . s 21 I8 2 I-t-37 40 November 8] 35 2 L-t-.22 I 33 September 8 so 31 I q.28 go December 27 75 36 q.o8 139 October .. IO 26 7 I 13-93 45 No,·cmber 42 I 57 83 6 q. IS 288 December 99 6; 6 J-t-29 I9-t West Coast (Minch) Catches were low in June but from July until the end of September a productive fishery took place The fisheries with a total catch for the pericd June to September In 1966 drift-net, ring-net, pair-trawl and purse over three times greater than in 1965. During the seine vessels fished in the Minch from the ports of rest of the year the fishery was slightly less pro Stornoway and Ullapool in the North Minch and ductive than in 1965 in terms of total catch but from Mallaig and Oban in the South Minch. Landing in both areas and for both methods of fishing the statistics from ports in both areas in 1966 are catch per landing showed a slight increase. Pair given in Tables 126 and 127, by months. As in trawling started in the Minch on a small scale in previous years, fishing went on throughout the 1965 but increased markedly in rg66 when a total entire year with the best catches being made in of over 6o,ooo crans were landed by this method of the late autumn and winter period. The summer fishing. In addition, 7,6oo crans were landed from fishery in 1966 was, however, highly successful. 97 purse-seine arrivals at the Minch ports. - rs8- Table 132. Statistics of Clyde Spawning fishery rg6r-66 rg6r 1962 1963 1964 1965 rg66 Ring-net fishery Number of arrivals ...... 1,094 532 378 goo 1,314 1,793 Total catch (crans) ...... r8,750 s.g6o 4.637 14.732 z8,399 zz,86g Catc:ifarrival (crans) ...... 17. I II.2 12.3 16-4 21.6 12.8 Trammel-net fishery Number of arrivals ...... s6 217 331 149 163 229 Total catch (crans) ...... 494 1,642 854 2,029 2,913 3,252 Catch/arrival (crans) ...... 8.8 7·6 2.6 13.6 17.9 14·2 Table 133. Mean length and meristic data of 1961-1964 although the rg6r-6z and rg6o-6r year-classes year-classes in 1966 Clyde spawning fishery also made appreciable contributions to the catches. Mean length V. S. K2 The rg64-65 year-class was poorly represented 3 Ringers Ba!lantrae 27-48 (27) 56.8o (15) 14.50 (r6) in the samples compared with the rg63-64 year 4 Ringers Ba!lantrae 28.98 (579) 57.18 (380) 14.02 (377) class in rg65. The percentages of spring and autumn 5 Ringers Ba!lantrae 29.62 (202) 56·95 (129) 13.95 (129) spawned herring in the samples are given in Table 6 Ringers Ba!lantrae 31.25 (4) 57.00 (2) 13.50 (2) 130. As in previous years, the catches from both 3 Ringers S. Arran 26.69 (r6) 56.78 (9) 13-44 (9) areas throughout the year were predominantly of 4 Ringers S. Arran 29.21 (135) 57-14 (76) 13-99 (76) 5 Ringers S. Arran 29.69 (7o) 56.98 (so) 13.96 (so) autumn spawned fish. Spring spawned fish provided 6 Ringers S. Arran 31.00 (z) 57-00(2) 14.00(2) about ro% of the samples in the N. Minch in the first half of the year and about zs% after June. In the S. Minch the proportion of spring spawned Biological data fish was lower being about 7% in the period up Length and age composition data from the North to June and about rs% in the second half of the and South Minch samples are given in Tables rz8 year. The rg64 year-class was the dominant one and rzg. The North Minch data are derived from amongst the spring-spawners in both areas in all drift-net samples and the South Minch data from months. Maturity and meristic data by months ring-net samples. The rg63-64 year-class dominated are given for the North and South Minch separately the catches in both areas in most months in Table 131. Table I34· Scottish herring tagging rg66 Liberations Recaptures Area Period Number Area Number (Days of liberty) A. Scottish combination tags r) Upper Moray Firth April 580 Upper Moray Firth 30 (2- 15) 2) Utsira area ...... April 3,323 Utsira area ...... 5 (2- Sr) Egersund area .... . 53 (31-270) Skagerak ...... 2 (195-238) Kattegat ...... 2 (r77-r8r) Shetland ...... 6 (r14-u8) Dogger ...... 2 (145-147) E. of Fladen ...... 5 (4-138) Western North Sea . (125) Unknown ...... 20 g6 B. Internal tags Utsira area ...... April Coral Bank 3 (55-101) Viking Bank ...... (134) Egersund area .... . 94 {30-275) Skagerak ...... 2 (181-199) Shetland ...... 41 (69-138) Unknown ...... 31 172 C. Spaghetti tags U tsira area ...... April 194 Utsira area (10) -I59- Herring Clyde Scottish Fisheries on Adolescent Herring, rg66 The catch and effort statistics of the ring-net (Tables I35-r38) and trammel-net fisheries for spawning herring for North Sea the years Ig6I-66 are given in Table I32. In the ring-net fishery the total catch fell sharply compared The catch and effort statistics for the halflin fisheries with that of I965 although still well above the in the Moray Firth and Firth of Forth during the level of other recent years, and the catch per unit I965-66 season are given in Table I35- In the Moray effort was very much lower than in I965. In the Firth the drift-net catch was about 25 times trammel-net fishery the total catch was slightly greater and the catch per arrival was about 5 times higher than in I965 and although the catch per higher than in the preceding year. The data in unit effort showed a decrease this was much less Table I35 for this area refer only to drift-net. In marked than in the case of ring-net. The catches addition, ring-netters landed I6,I33 crans for from both sections of the fishery were dominated 358 arrivals and pelagic pair-trawlers 27,06I crans by the I96I and Ig62 year-classes with the I962 for 737 arrivals. In fact both the catch and the year-class providing about 6o% of the ring-net catch per arrival do not reflect accurately the catch and about 73% of the trammel-net catch. potential productiveness of the fishery. Because Recruit spawners of the I963 year-class were very of limited markets the catch was restricted by scarce in the catches by both methods of fishing. the imposition of a quota system for a major part of the season. By contrast no herring were caught during the I965-66 season in the Firth of Forth. Biological data In the Moray Firth g6-4% of the catch were Length and meristic character data for the Ig6o I ringed fish, the remainder being 2 ringed fish to I963 year-classes are given in Table I33· Both of autumn spawned origin. Of the I ringed fish the I962 and I963 year-classes were considerably 8g% were autumn spawned and rr% spring bigger than other recent year-classes at equivalent spawned. This is a higher proportion of spring ages in previous years. The high V. S. count which spawned fish than has appeared in the catches from characterized the I962 year-class as recruit spawners this area for many years. in I965 was again evident in the data on this The mean length, length range and mean V.S. year-class in Ig66. of these fish are given in Table I36. The mean size of the I963 year-class was significantly higher than Tagging that of other year-classes as I ringed fish in this fishery in recent years. During Ig66, tagging experiments were carried out in April in the Upper Moray Firth and in the Clyde Utsira area. The details of liberation and recapture The catch and effort statistics for the Clyde are given in Table I34· ring-net fishery for adolescent herring in the Ig66 G. McPHERSON, A. SAVILLE season are given in Table I37. The catch and catch per Marine Laboratory, Victoria Street, Torry, Aberdeen, arrival fell considerably for the second successive Scotland. year. A feature of the catches in this fishery in Table 135. Statistics of halflin herring fisheries 1961-66 r96r-6z r962-63 I965-66 Upper Moray Firth Duration of season ...... 30[9-I0[2[62 6[ro[62-rz[r[63 23/II/63-2rjr2[63 r2[roj64-27 /3/65 25[9/65-9/4/66 Number of arrivals ...... 458 524 6o 286 I,388 Total catch (crans) ...... 3,233 9,934 588 2,768 68,460 Catch/arrival (crans) ...... 7-I r9.0 9.8 9-7 49-3 Upper Firth of Forth Duration of season ...... I9[r[63-23[2[63 25[r[64-I I/4/64 6/3/65-27/3/65 Greatest number of boats engaged IO 27 4 Estimated catch of halftins (crans) 2,014 7,r6z 5I Estimated catch of halfiins per arrival (crans) ...... 23-4 28.6 -r6o- Table 136. Length and mean V. S. of herring year-classes in inshore waters off the Scottish east coast in 1965-66 Locality Date Length range (em) :\Iean (em) :\lean\'. S. Autumn 1963 year-class :Vlora.y Firth (drift-net) September 1965-April 1966 17-26 Autumn 1962 year-class :VIoray Firth (drift-net) September 1965-April 1966 19-28 25.07 (++) Table 137· Statistics of Clyde adolescent herring fishery Herring Trawling off the West Coast of Scotland rg66 1961-66 (Tables 139-142) Season During the first half of June 1966 a further 1961 1962 1966 1963 1964 1965 herring trawling survey was made by F.R.S. ::--iumbcr of "Explorer" off the west coast of Scotland (see arrivals ... I,274 3,001 4,172 4,51 I 4·319 4,925 Vols. 19-22). The grounds investigated on this Total catch occasion extended from west of Shetland to the (crans) ... 49,015 IO,I43 38,782 67,413 54,o8r 32,743 Stanton Banks. Most of the catches were small but Catch/ ani val herring were widely distributed in the region from 8.o r6.2 (crans) 11.3 12.9 II.O 7·3 Stanton Banks to west of Orkney. Further north, west of Fair Isle and Shetland, there were generally no herring in the trawl hauls. The largest concentra Table 138. Mean length and meristic characters of I, II and tions of herring were located off the Butt of Lewis III ringed herring in Clyde adolescent fishery in 1966 and in the vicinity of the Stanton Banks where Hings Length V. S. 1{2 catches of up to 42 baskets per hour haul were I J Spring spawned 22.16 (87o) 57.08 (187) 13-95 (172) taken. Echo-sounding records suggested that the l Autumn spawned 21.34 (223) 56.68 (47) q.I7(4I) herring stocks were much larger than indicated II {Spring spawned 26-47 (388) 56.79 (181) q.22 (175) by the results of the trawl survey. The majority Autumn spawned 25-90 (444) 56-45 (201) 14.15 (184) of the echo-traces were clear of the sea-bed and III f Spring spa wncd 28.10 (107) 56.85 (33) 14-41 (32) above the range of the trawl. · 1 Autumn spawned 26.91 (93) 56.41 (29) 1-1·41 (27) Biological data Length, age, maturity and meristic data of 1966 was the unusually high representation of catch samples are given by statistical squares in autumn spawned herring. These accounted for Tables 139-142. There was a marked difference about 28% of the catch over the season as a in the size composition of the catch compared whole and in some months provided of the so% with previous years (Vols. 19-22), when the mean samples examined. Of the autumn spawned fish, lengths ranged between 28 em and 31 em. In June 28% were 1964 year-class, 56% 1963 year-class 1966 most of the hauls contained a large proportion and 12% 1962 year-class. The 1965 year-class was of the 1963-64 year-class, with mean lengths of the dominant one amongst the spring spawned 24 em to 26 em. Almost all the catches comprised fish (39-7%). It was noteworthy that the 1962 a mixture of spring and autumn spawners with year-class again made an appreciable contribution the autumn spawning component forming 70%- to the catch (26%) subsequent to the spawning 90% of the total. Age composition data for spring season. spawners show that while two year-old herring The mean lengths and meristic characters of the of the 1964 year-class generally predominated principal age-groups are given in Table 138. The four, five, and eight year-old fish were prominent 1964 year-class as I year-olds in 1965 was markedly in some samples. The 1963 year-class was dominant bigger than earlier year-classes at this age. This among the autumn. spawning component in all was again evident in this year-class as 2 year-olds localities except that south of St. Kilda (r3 VV) in 1966 and the 1965 year-class as r year-olds was where older age-groups, especially nine year-olds even bigger than the 1964 one at this age. (1957 year-class) predominated. A. SAVILLE I. G. BAXTER :\larinc Laboratory, Victoria Street, Torry, :\Iarine Laboratory, Victoria Street, Torry, Aberdeen, Scotland. Aberdeen, Scotland. - r6r- Herring Table 139· Length distribution ("/ 00) Statistical square r7A r6\V'\A;' r6XX r6YY r5VV 15\V\V qVV r3VV r2V\' IIVV rr\Vv\' IoVV Length em I6.5 I.6 I7.0 17·5 r.6 r8.o r8.5 4-7 I9.0 4·7 19·5 I5·7 20.0 I5·7 20.5 32.9 5·5 0.9 21.0 50.I 2 7·3 1.3 0.9 21.5 90·9 0.5 10.9 I.O 3·4 22.0 Il7·5 9·1 1.2 16-4 5-4 I6.o 23.2 19·7 zz.s 9·2 I44.2 II.O 10.3 43·7 8.2 I.7 zr.6 22.3 37·4 27.6 23.0 36·7 I3I.6 20.! 2!.2 109·3 I3.I 6.7 sz.z 59·9 71.5 35-4 2 3·5 55·0 II2.8 zg.z 31.8 163.9 ,to.8 20.1 31.9 r6.8 84·5 63·9 99·7 55.I 24.0 45·9 76.8 64.0 45·3 120.2 40.8 I3-4 63.6 33.6 125·9 I03·5 I38A 63.0 2+5 rs6.o 70·5 6 5.8 88.0 1 14·7 183·7 60-4 8o.5 r8.5 I I3·3 I22A 96.1 63.0 25.0 91.7 53·3 124·3 105.6 87·4 102.0 67.I 83.I 35.2 II3·3 94·8 I2I.9 90.6 25·5 I IO.I 20.4 93·2 89.2 6o.r 8r.6 8o.5 78.8 36.9 55.8 58·5 82.5 43·3 26.0 128-4 25.I 84.1 I09.o 32.8 40.8 I00.7 41·5 I6.8 41.4 25.6 69.2 31·5 26.5 73-4 6.3 67.6 4I.9 38.2 61.2 So.5 z6.5 I5.I 12.0 35·1 rr.8 ZJ.O 18.3 3·I 38-4 39·6 32.8 40.8 20.1 14·3 I0.1 2.7 24-4 7·9 27-5 27·5 r.6 q.6 32·3 ro.9 20.4 33·6 8.2 10. I 3·6 3·7 17·9 I5·7 28.o r8.3 21.9 40.I I0.9 53·7 43-4 r8.5 9·0 II.3 r8.3 1 5·7 28.5 9.2 20.1 34·6 16-4 53·7 53·7 57.0 r8.o II.6 13·3 1 5·7 29.0 45·9 r.6 54·8 52·9 r6.4 6I.2 73·8 65.9 I I5.8 27.0 23.6 35·5 5!.2 29.5 27·5 31.1 65·7 ro.9 6r.z 73·8 89-4 I q. I 50 A 38·3 29.8 31·5 30.0 45·9 r.6 49-4 68.0 ro.9 8r.6 73·8 94·3 144·3 45·0 49·9 33·1 114.2 30·5 27·5 r.6 54·8 41.3 21.9 I63.3 I 14-I 82.8 I05·7 62.9 57·2 20.7 98.4 31.0 36·7 3· I s8.5 33·0 21.9 20-4 47·0 52.6 94.0 6I.I 46·9 10.2 98·4 31.5 27·5 6.3 36.6 25.9 5·5 20.1 25·3 63·7 45·0 46.9 8.3 55.r 32.0 4·7 21.9 12.5 5·5 13-4 25.8 33.6 25.2 34·6 7·9 27.6 32·5 II.O 1.9 9.6 I5. I I8.o 37·6 0.3 1 5·7 33·0 9.I 4·4 5·5 6.I I8.5 9.0 30·9 3·9 33·5 5·5 2.4 !.2 I6.8 12.6 I3.0 34·0 3·7 !.2 I.7 I0.6 3·9 34·5 3·9 No. of fish in catch .... 109 547 49 596 555 3,004 8,788 254 Mean length . 26.35 23.00 27.13 27.02 27.06 27·79 29.18 26.74 27.06 27.68 0 Table 140. Age composition ( / 00) Year- \"linter- Statistical square class rings I 7 XX 17A r6WW r6XX r6YY r5VV r5W\V qVV r3VV 12VV rrVV II\VW roVV 1964-65 28.2 1963-64 2 700.9 935·7 493·6 513·3 798.9 530.6 356·7 434-4 r8r .8 610.0 574· 1 78r.o 456·7 1962-63 3 74.8 18.8 131.6 90.9 67.0 6r.2 89.2 18.8 18.5 10.7 26.9 53·6 27.6 1961-62 4 112.1 3·1 120.7 147·8 50.3 40.8 184·7 163-4 156.6 137·8 Io6.I 78·7 149.6 196o-6I 5 37-4 r.6 80-4 83.0 27.9 40.8 172.0 97·9 203.7 57·2 46.2 44·0 161.4 1959-60 6 3· I 3·7 31.1 II.2 61.2 82.8 77·8 97.6 32.2 I9.9 3·9 ss.r 1958-59 7 9·3 5·5 13.2 61.2 19.1 13.9 28.6 4·3 I. I 1957-58 8 37·4 3· 1 73·1 43·9 II.2 J42.9 51.0 97·9 r8r.8 66.2 105·7 18.8 43·3 1956-57 9 r8.7 3.I 54·8 24.6 20-4 31.8 37·3 so.s 46·5 48.2 3·9 19·7 1955-56 and earlier >9 9·3 3·1 36.6 33·5 8o.8 39-4 68.5 q.S 86.6 No. of fish in catch 109 49 596 555 3,004 8,;88 254 -162- Table 141. Percentage age composition of spring and autumn spawning components A. Spring spawners Year- 'Winter Statistical square class rings I 7 XX 17A r6vVV1 r6XX r6YY rsVV 15WVv qVV r3VV r2VV nVV rrWW roVV 1965 29.63 1964 2 66.66 65·97 62.66 IOO.O 33-I5 17.12 32.17 21.28 33-59 17-57 1963 3 3-96 r.So 1.52 1962 4 25.0 14·58 I7-90 7·14 33-69 19.82 42.6I 27.82 42.69 47-30 1961 5 r.8s I r.8I Io.SI 7·14 r6.zz 19.82 7-09 I5-37 27.03 1960 6 r.8s 1.39 0.90 4·50 0.97 1959 7 0.45 o.I8 0.97 1958 8 2.17 7·14 12.25 20.00 20-45 1957 9 I.2I r.So 2.6r 7-93 1956 and earlier >9 r.So 9-91 2.6r 13-49 1.35 %of spring spawners in catch 8.33 ro.6r 13.01 r8.44 21.25 23.91 14.71 28.9I B. Autumn spawners Year- vVintcr Statistical square class rings I 7 XX I7A r6WW r6XX r6YY I5VV I5WW 14VV r3VV 12VV nVV IIWW IoVV I964 0.5I I963 2 69.70 95.89 42·39 76-71 48-71 47·73 28.8r 44·92 I7 .. 92 66.75 68.88 79-00 57·14 1962 3 8.o8 2.05 I8.7o 8.22 IO.I2 6.82 8-47 2.18 1.43 0.73 3-37 6.j2 3·85 I961 4 IO.IO O.I7 10.22 +·79 15-41 +·55 I9-49 13.66 q.o5 5·3+ 5·38 6.67 2.20 1960 5 O.I7 2.74 7-57 4·55 2I.I9 8.60 I6.so 6.80 3·85 3·96 q.84 1959 6 O.I7 1.37 3·67 6.82 7·63 8.65 rr.81 s.s8 2.27 0.35 4·40 1958 7 I.OI 1.12 6.82 2.54 1.64 3-87 0.22 O.II 1957 8 0.34 2.05 4.68 I 5.91 5.08 8.95 I9.76 3·+0 7.2I 1.57 4·95 1956 9 2.02 O.I7 2.8o 2.27 4·24 4.18 s.so 6.07 3-90 0.30 0.55 I955 and earlier >9 I.OI 5-9I 4·55 7.22 9.16 5·34 4·94 I2.09 ~~S of autu1nn spawners in catch gz.sz 78.07 91.67 89·39 86.99 8r.56 78·75 76.09 85.29 71.09 Table 142. Maturity and meristic characters A. Percentage maturity (All age-groups) Statistical square r 7XX I7A r6\VW r6XX I6YY I5VV rsWW 14VV I3VV r2VV IIVV 11\V\V 1oVV Maturity stage I ...... 3-64 39-12 13.00 7-41 5-46 1.35 3-3I 1.34 5-9I 7.62 r r.s6 5-SI II ...... 53·63 50·55 4l.2I 41.33 65.03 37·84 39·63 17.62 54·66 51. IS 68.59 42-91 III ...... 24-54 n6 6.59 10.34 7-65 8.II 1.95 1.01 O.J2 1.03 o.81 0.79 IV ...... o.r6 1.28 2.19 2.04 o.o9 v ...... VI ...... 0.90 0.33 2.36 VII ...... VIII ...... I8. I8 2.35 37-9I I9.67 40.82 52-70 ss.oz 80.03 37-8I 40.2I r8.7r B. K 2 . Numbers at each maturity stage (all age-groups) Number of keeled scales Maturity stage I2 I3 I4 IS r6 17 ?dean I ...... II 6I 34 3 14·27 II ...... 55 16I 82 II 3 14-19 III ...... 8 27 12 3 14.20 IV ...... 2 3 I3.60 v ...... VI ...... q.oo VII ...... VIII ...... 3 62 203 131 r6 2 All stages ...... 3 139 456 260 33 5 -163- Herring The English Herring Fisheries in rg66 and Haisborough fisheries. Good recruitment to (Tables 143-I49) these fisheries was expected, and indeed predicted, The fisheries because of the exceptionally high numbers of herring of the 1963/64 year-class present in them The catch and effort statistics are summarized as two year-olds in 1965. On the other hand, in in Table 143 to show the catch, effort and catch per view of the very low level of larval production in effort in each of the fisheries for each type of the Southern Bight in recent years, the yield in fishing gear used. Although the bulk of the herring 1966 from fisheries based on the Downs stock i.e. landed in 1966 were still caught by drift-nets, this at East Anglia, Hinder and Sandetti<'~ was expected year single and pair boat trawlers and ring-net to be low. vessels operated in some numbers off the north The total catch in the North Shields fishery, east coast, and in the Longstone spawning fishery which is based very largely on three year-old these boats landed by far the major part of the recruits, was over 4,000 crans higher than in 1965 total catch. even though there was a considerable reduction As in the previous year the 1966 fisheries were in effort (about 215 shots less with II boats fewer mainly affected by the same two factors:- participating) consequently .the catch per effort (1) the extremely low abundance of recruiting figure was more than double that of 1965. Through three year-old (1963/64 year-class) Downs herring; out the North Shields fishery three year-old (z) the very good recruitment of the 1963/64 recruits of the 1963/64 year-class made up between year-class to those fisheries which were based 78 and 94 per cent of the catches. entirely or to a considerable extent on the Bank A little further north in the Longstone spawning stock i.e. the North Shields, Longstone, Whitby fishery the catch was approximately 4,000 crans Table 143· Catch and effort of the English herring fisheries in 1966 I. Drift-net 2. Trawl Crans Crans Month Crans Shots per '\'Ionth Crans Landings per shot landing North Shields fishny North Shields pair trawlers :VIay ...... 88 2.4 June ...... I,484 12.1 June ...... 290 8 36·3 July ...... 8,846 24.2 July ...... 93 8 II.6 August ...... I,246 2!.1 Season ...... 383 I6 23·9 September ...... 2.8 I7 North Shields single boat trawlers Season I I ,68I 19.8 July ...... 2I 4 5·2 Whitby fishery Whitby pair 11•awlers August ...... I I,023 27.6 A.. ugust 220 6 September ...... 4,220 I3·7 Season I5,243 21.6 Whitby single boat trawlers Longstone fishery August I09 54·5 August 665 I6.6 Longstone pair trawlers Haisborough fishery August ...... 3,56o I38 25.8 September ...... 4,884 I37 35.6 Longstone single boat trawlers October ...... 9,274 320 29.0 August 944 22 November ...... 33 I2 2.8 Season ...... q,I9I 30·3 East Anglian fishery 3· Ring-net October ...... 298 29 10.3 Crans November ...... 56 I 8I 6.9 Month Crans Landings per Season ...... 859 IIO 7·8 landing Hinder fishery Whitby 1•ing-net November 8o9 q6 5·5 August ...... 849 32 26.5 September ...... Sandettie fishery 232 26 8.9 Season I,o8I 58 I8.6 November I8 I I I.6 December I I 5 2.2 Longstone ring-net Season ...... 29 I6 r.S August 5,28r zzz 23.8 Table 144. Age distribution (as mean number per net per shot) for the drift-net fisheries North Shields Hais- East Age Year-class :VIay June July .\ugust Sept. Whitby Longstone borough c\nglia T-Ender 2 I964/65 0.4 I6. I 13·7 4·7 I.4 o.8 0 z8.3 7·7 2I.4 3 I963/64 IZO..J. JI6.6 4I5.0 293.8 .J-9.2 524.I 2JI.9 380.5 I 1).] g8.8 4 I962j63 II.S 20.1 39·5 I2.j r.g .J-9.6 2-f.2 I 5 I..J. 2!.0 7·7 5 rg6Ij62 J.I 3-5 3·9 0 I.] .J.. I s.c, I5.2 23.8 5-9 Over 5 o.g o.8 2.6 0 2.3 8.2 s.6 I3·3 7·0 3.6 ? I.7 3-.J. 8.g 0 I.] 0 0 0 6.6 0 Total I42.0 360.5 .J-83.6 3 IT. 2 sS.z 586.8 307·3 s88.7 I8r.8 J 37-4 The age distributions for the v\'hitby, Longstonc, Haisborough and Hinder fisheries arc for the spawning components only. i.e. fish in maturity stages Y, V-VI, VI and VII-I at \Vhitby, Longstone and Haisborough, stages V-Vl, VI and VII-I at Hinder. (:\laturity stage VII has been split into VII-I (early VII) and VII-II (late VII) ) . Table 145· Maturity distributions (drift caught herring) North Shields Whitby Longstonc Hais- East borough Anglian Hinder .I.Jaturity stage :Vlay June July August Sept. fishery fishery fishery fishery fishery 0/ Ol 0/ 0/ 0/ ~'~ /o /o % ~~ % /0 /0 % /0 I ...... 3-9 ).2 4-9 0 3-I 0.1 2.2 I..J. I.3 0 ll ...... 25.8 2I.9 12.9 6.0 3·(' I.O 1.3 Io.8 ·z.s I.O III ...... 6.8 37·3 22.9 7·7 z.s 0.2 I.( 0.3 0.2 0.3 III-1\" .. 1.2 S.o 12.7 9·8 r.s 0.2 0.~ O.I r.6 0 IV ...... 0 4-2 I4.0 I3.2 0 I.3 I.3 0 0 I.O O.I IV-Y ...... 0 0 I 5-4 10.3 I.5 3·3 I9.0 7-2 o.S 0.6 v ...... 0 0.0 q.S 33·3 19-9 IJ.3 3+9 37·7 76.2 26.7 V-VI ...... 0 0 0 15.0 36.2 I7..J. 2.2 9.0 I.O 20.6 VI ...... 0 0 0.3 0 8.2 .J..J..l 2.6 15.8 .J..T .J.T.7 VII-I ...... 3-.J. 0 0.3 0 I 7·-J. q.2 31.0 j.O 2.-J. r.S Vll-1I ...... 38. I Io.S O.I +7 6.1 o.g 0 8.2 9-0 7· I VITI 20.9 J 2.5 I.] 0 0 0 3·-t 0.3 () O.I Number of fish 977 3.756 3,22J -t6S 392 I8,689 696 20,3-J.O 3,594 z,S;z Table I45A. Maturity distribution (trawl caught herring) North Shields lvlaturity stage July Longstone % % I ...... 40·3 0 II ...... Io.S 0 III ...... I2.3 0 III-I\" 4·0 0 IV 5·9 0 I\"-\" ...... 5-s 1.3 v ...... I2.3 4· I V-'d ...... I. I 10.8 n ...... +4 72-5 VII-I ...... 0 8.8 VII-II ...... 0.4 2.5 VIII ...... 2.8 0 Number of fish .... . I,213 1,-tS(, Stage Vl [ has been split into stage Vl I-1 (Early Vll) and stage VII-II (Late \'li). more than in the previous year. Practically the The total catch in the \Vhitby fishery was same number of boats took part in this fishery considerably less than in rg65 (some 3,500 crans but the season lasted longer. The weekly proportion down) due entirely to a very drastic reduction in of three year-olds in the catches varied between effort, and in fact, the drifters, which still landed So and 86 per cent. As already mentioned trawlers most of the catch in this fishery, made 456 fewer and ring-netters landed most of the herring caught shots. This reduction in effort was largely due to in this fishery. Because of good catches, landings the much earlier start to the fishery (about 3 weeks were restricted from rz.-27. August to between early compared with rg65) and the consequential rz and 15 crans per crev:-member. late arrival of some of the Scottish vessels, and to -r6s- Herring Table 146. Mean length for age. (Drift caught herring) _Age ...... 4 5 6 7 Year-class ...... 1962/63 1961[62 196o[61 I959/6o "Whitby spawners. (Fish in maturity stages V, V-VI, VI and VII-I) :Mean length ...... 23.25 24.92 26.83 30.12 30-41 Number of fish ...... 61 1s,3o2 1,647 134 237 cr 2 ...... 1.9466 2.3476 o.s599 0.8287 Longstone spawners. (Fish in maturity stages V, V-VI, VI and VII-I) :Mean length ...... 24-7S 27.67 Number of fish ...... 146 13 cr2 ...... I.9759 Haisborough spawners. (Fish in maturity stages V, V-VI, VI and VII-I) JYiean length ...... 23.2S 24-78 26.s8 29.13 30.29 31.11 :" Table 146A. Mean length for age (trawl caught herring) .-'\ge 2 3 4 5 6 7 Year-class 1964[6s 1963[64 1962[63 1961[62 196oj6r 1959[6o Longstone spawners. (Fish in Maturity Stages V, V-VI, VI and VII-I) Mean length ...... 24-70 27-44 30.02 30-71 Number of fish ...... 681 8s 54 28 cr2 •.....•...... I.5923 2.4165 0.7331 0.5913 In Tables q6 and q6A the mean lengths are based on raised length distributions i. e. sample age/length key x market measurements. 0.25 em has been added to each mean length. Table 147. Mean V. S. by age in the spawning fisheries A.. ge 3 4 5 6 Year-class 1963/64 1962[63 1961[62 196oj61 Whitby spawners (Mat. V, V-VI, VI and VII-I) ...... s6-4492 56·34SS 56·37SO 56.0833 Number of fish ...... 463 55 8 12 cr2 ...... 0-4601 0-4896 Longstone spawners (Mat. V, V-VI, VI and VII-I) ...... 56-S042 56.3867 56·3333 56·3333 Number of fish ...... 3S5 75 33 33 a2 ...... 0.3863 0.3214 0-4792 0.2917 Haisborough spawners (Mat. V-VI, VI and VII-I) ...... 56. 3889 56.3640 56.2947 56.3ooo s6.2667 Number of fish ...... 18 456 302 10 IS cr2 ...... •...... o.so89 0.4477 Hinder spawners (Mat. V-VI, VI and VII-I) ...... 56-4828 56·3S75 56·7917 56·5385 56-sooo Number of fish ...... s8 221 24 13 10 cr2 ·································· 0-4646 0-4216 0.3460 Mean V. S. is based entirely on laboratory samples of commercially caught herring. (Drift and trawl caught herring combined). the much earlier end to the fishery (about z weeks per effort was well up on 1965 by over 4 crans compared with 1965). Here the weekly proportion per shot. In this fishery, on two occasions, landings of recruits of the 1963/64 year-class in the catches were restricted to zo crans per boat due to lack varied between 8o and 93 per cent, and the catch of outlets at the ports. - r66- Table 148. Mean K 2 by age in the spawning fisheries Age 2 3 4 5 6 Year-class 1963(64 1962(63 1961(62 r96o(6r 'Whitby spawners (Mat. V, V-VI, VI and VII-I) ...... 14·7134 14.8241 q.Sooo q.857I Number of fish ...... 157 I9 5 7 a2 ...... 0.3981 0.5848 Longstone spawners (Mat. V, V-VI, VI and VII-I) ...... 14·5683 14.6000 I4·739I 14·3333 Number of fish ...... 139 45 23 IS a2 ...... 0.4645 o.sr8z o.565z Haisborough spawners (Mat. V-VI, VI and VII-I) ...... 14·7286 I4.788r Ij.I667 14·8750 Number of fish ...... 140 uS 6 8 cr2 ...... 0.4294 0·5445 Hinder spawners (Mat. V-VI, VI and VII-I) ...... 14·944+ 14·9028 14.7500 q.6667 q.8750 Number of fish ...... r8 I44 I2 I2 8 cr2 ...... 0.2908 0.3122 Table 149· Percentage distribution of otolith types in the 3 As a result many of the Scottish drifters, which and 4 year old spawning fish stayed on at Yarmouth after the good Haisborough Age 3· 1963(64 Year-class fishery ended, soon gave up and went home. Longstone Whitby Haisborough Hinder Otolith type fishery fishery fishery fishery The total East Anglian catch was only 859 crans w ...... 4·9 4·2 23.0 at 7.8 crans per shot. Approximately a dozen N ...... 91.8 94-3 70·9 drifters later fished the Hinder grounds for a total ? ...... 1.7 3·3 !.5 6.1 of 809 crans at 5-5 crans per shot. Number of fish ... 367 403 Age 4· 1962/63 Year-class Biological data w ...... 24.0 38.1 17.5 13.0 N ...... 66.7 50.0 75·7 82.6 The biological details for the herring sampled ? ...... 9·3 I 1.9 6.8 4·4 from all the English North Sea herring fisheries in Number 1966 are summarized in Tables 144-149. They con of fish ... 75 42 251 23 tain distributions of age, maturity and otolith type Maturity V, V-VI, V, V-VI, V-VI, VI V-VI, VI stages ... VI and VI and and VII-I and VII-I together with the mean length, mean V.S. and VII-I VII-I mean K 2 of the spawners, by age-groups, in the various fisheries. The Haisborough fishery in the autumn was The recruitment of the 1963/64 year-class (the again good with, as further north, a high proportion three year-olds) has already been discussed in the of recruit spawners in the catches. However, in preceding section. Older fish were scarce in all the this fishery older fish were more in evidence, fisheries in 1966, other than at the Haisborough, particularly in catches from the Outer Silver Pit and because of this all those over five years of and Botney Gut, and the weekly proportion of age have been added together in Table 144. the 1963/64 year-class varied between 49 and The mean lengths of the recruiting three year 79 per cent. The total catch was approximately olds tended on the whole to be somewhat lower in 3,000 crans higher than in the previous year and 1966 than those of the recruits in the previous the catch per effort was up by 6.9 crans per shot. year. However the proportion of wide type otoliths was also lower in 1966 particularly amongst the The East Anglian fishery at the end of the year Longstone, Whitby and Haisborough spawners. was even worse than in 1965 and virtually a complete failure. Only very small catches of R. J. WooD, W. G. PARNELL herring were made on the traditional grounds. Fisheries Laboratory, Lowestoft, Suffolk, England. -167- Herring 0-group herring on the English East Coast in the Thames Estuary. Because of the similarity (Tables ISO-ISI) of these herring with those sampled inshore in the Investigations on the o-group herring, which same regions during 1966, the details have been are distributed during summer along the English included in this contribution and are listed sepa east coast, were carried out in 1966, mainly during rately in Table 151. the months of July and August. A number of One of the outstanding features of the 1966 samples were obtained inshore with a beach seine, investigations was the high mean V.S. of the and others with a mid-water sprat trawl offshore, majority of all the samples obtained over the up to a distance of 7 miles from the coast. The whole region. Along the East Anglian coast and area covered extended from the Firth of Forth southwards a high mean V.S. is quite normal, in the north to Dungeness in the south, and the and together with a high mean K 2 it is thought catches of o-group herring were examined in a that this indicates that the herring are of Channel similar manner to that described by WooD (1959), origin. Further north, however, the high mean with K 2 counts additionally made on several of V.S. of many of the samples was surprising, the samples in which the herring were considered particularly in view of the low mean K 2 's. 0-group to be of sufficient size. Relevant details of all the herring which are caught in this more northerly samples are given in Table 150. area are known to be mainly of "Bank" origin Four samples of 1-group herring were examined (WooD, 1959), and the spawning herring which during January and February 1967 from the sprat were sampled in 1965 on the adjacent spawning fisheries which took place off the River Tyne and grounds off Whitby, the Longstone and Hais- Table rso. Samples of o-group herring from the English east coast in I966 Dominant Number of Length \'2 em Length o-group Locality Date range A. length range B :.VIean V.S. herring (em) group (em) caught Firth of Forth (Kincardine) j. 7· 66 C.I.S. +I- 7-4 5·5 4· I- 7·4 s6.68 (44) Amble ...... I. 7· 66 B.S. +·o- 6.s s.o 4·0- 6.j s6.78 (4o) 25 Blyth ...... 2. 7· 66 B.S. +·0- 6.8 j.O 4.I- 6.8 s6.63 (40) 20 South Shields ...... 3· 7· 66 B.S. 4.6- s.8 j.O 4.6- 5.8 s6.36 (rr) rr2) Hartlepool ...... 4· 7.66 B.S. 3-9- 8.o j.O 4.I- 7.0 s6.68 (4o) zs,ooo 2-3 miles off Hartlepool .. 3· 7· 66 T S-2- 7·6 5·5 j.2- 7.6 s6.6o (so) I,soo 4 miles off Whitby ...... 4· 7· 66 T 6.I- 8.9 7·5 6.I- 8.8 s6.7I (38) 14·37 (35) 38 I-2 miles off Scarborough . +· 7· 66 T S-4- 9· I 7·S 6.I- 9.1 s6.s6 (so) q.28 (so) s,ooo Scarborough ...... s. 7· 66 B.S. 4-S- 7-4 5·5 s.I- 6.7 s6.58 (so) soo3) 1 6,000 r / 2 miles off Scarborough . 4· 8. 66 T 7-3-Io.s 7·S 7·3- 9.2 56.62 (so) (8.o) 2 miles off Filey ...... 7 8. 66 T 7-3-IO.O (and) 7-3- 9-5 56.64 (so) q.Io (5o) 6,ooo (8.s) s miles off Bridlington .. . s. 7· 66 T 5-4- 8.4 6.0 5-4- 7·6 56.62 (so) Bridlington ...... +· 8. 66 B.S. 5·4- 8.5 6.j 5-5- 8.o s6.s8 (so) I mile south of Flamborough Head .... 4- 8. 66 T 7·3-IO.O 8.o 7·3- 9.6 s6.s6 (so) j,OOO 1 I-r / 2 miles off Sutton-on-Sea 6. 8. 66 T 6.s- 9-7 7·0 6.s- 9-7 s6.7o (so) q.I8 (so) 3,000 Inner Dowsing Lightvessel 6. 8. 66 T 6.j-II.j 7·S 6.6-Io.9 s6-48 (so) I+· I4 (so) S33 1 I / 2 miles off Skegness ... . 6. 8. 66 T 6.j-I0.7 7·0 6.6-I0.7 s6-4o (so) I+-3° (so) 2I7 5-6 miles off Skegness ... . 6. 8. 66 T 6.3-II.j 7·0 6.3-I0.2 56.68 (so) q.26 (so) 1,200 Lowestoft ...... 7· 6. 66 B.S. 3-9- 6.s j.O 4-r- 6.s 56.74 (so) Lowestoft ...... I. 7· 66 B.S. s.o- 8.8 6.s s.o- 8.8 s6.70 (6o) q.88 (so) Lowestoft ...... 4· IO. 66 B.S. s.o-Io.s 6.0 s.o- 6.9 5S·49 (3S) I-2 miles off Benacre ... . 8. 7· 66 T 6.3- 9-S 7-S 6.3- 9.2 s6.72 (so) q.67 (48) 1 I / 2 miles off Aldeburgh .. 8. 7· 66 T 6.6-Io.o 7·S 6.6- 9-S s6.64 (so) I+·S4 (so) 1 2 / 2 miles off Bawdsey ... . 8. 7· 66 T 6-4-I r.s 9-S 7·3-1I.2 s6.7o (so) J4.61 (49) Felixstowe ...... 9· 7· 66 B.S. 6.o- 8.s 6.s 6.o- 8.s 56.72 (29) 14.89 (28) 10 1 2 j 2 miles off Clacton .... . 9· 7· 66 T 6.j-I2.S 8.o 6.s- 9.6 56·73 (37) q.67 (36) 39 Margate Roads ...... IO. 7· 66 T IO.I-12.0 II.O IO.I-12.0 57.00 (I3) 14.69 (13) 14 1 I6o I / 2 miles off Hythe ...... IS. 7· 66 T 9.6-I3.0 Io.s 9.6-II.7 S7·16 (so) 14.96 (so) (3r. IO. 66) 1 I-5 / 2 miles off Lowestoft ( to ) T 8.I-IS.s 9-S 8.I-IS.s j6.84 (79) q.96 (77) 7 ( 7· II. 66) Numbers of o-group herring caught are given for the beach-seine as mean number per haul, for the mid-water trawl as mean number per hour's fishing -168- Table IS I. Samples of r-group herring caught off the English east coast in January/February 1967 Length Dominant Length 1 1 Locality Date Gear ) range A / 2 em length range B Mean V.S. Mean K 2 (em) group (em) ro'NE-r2'ESE of the Tync g. I. 67 T ro.g-rs.o 13.0 1o.g-q.g 56.67 (33) 14·36 (33) 12'NE-12'SE of the Tyne . 6. 2. 67 T ro.8-17.s q.o 10.8-16.3 s6.62 (so) 14.26 (so) Baymans Hole ...... 24- I. 67 T 12-4-18.0 14·5 12.4-17.9 s6.82 (so) q.2o (so) Thames Estuary ...... 17. I. 67 T 8.3-15.6 13·5 8.3-10.5 ss.86 ( 7) (Swire Hole) ...... 11.8-15.6 56.89 (s6) 14·56 (55) Length range A is range of complete sample Length range B is range of group of fish on which vertebral and K 2 counts were made The numbers of herring on which counts were made are given in parentheses 1) C.I.S. Sample from power station cooling water inlet screen B.S. Beach-seine T Mid-water trawl 2) torn net 3) very short warps borough had the characteristically low mean V. S. References and medium K 2 's of "Bank" spawners (V/ooD Vloov, R. J., 1959. "Investigations on a-group herring". and PARNELL, 1967). The high mean V.S. of many J. Cons. perm. int. Explor. Mer, 24: 264-76. of the o-group herring samples obtained between \VooD, R. J. and vV. G. PAR::-:IELL, 1967. "The English Skegness and the Firth of Forth during rg66 must Herring Fisheries in 1965" ..-\nnls. bioi. Copenh., 22: qo-4. therefore be considered exceptional. The r-group herring sampled during the first two months of 1967 were most interesting, not Growth Data for Herring of the Southern Bight, only because of their similar mean V.S. and mean derived by Back-Calculation on Scales (Tables 152-153) K 2 to inshore samples examined from the same areas during rg66, but also because they indicated Tables 152 and 153 summarize back-calculated that the lengths reached by both "Bank" and growth data for herring of the Southern Bight "Downs" fish of the rg65 year-class after one sampled at the Lowestoft Laboratory in the years year were very similar in these two areas. Clearly rg65 and rg66. the herring in the south, although probably 2 Table 152 (East Anglia) refers to samples from months or so younger than those in the north, fish caught after September, containing no signifi reached similar lengths because of better growth cant mixture of maturity stage VI and VII fish, conditions. It was apparent in July that growth from the Haisborough and Dowsing grounds. in the south was good, and the lengths of the They are taken to represent pre-spawning con herring caught off Hythe and in Margate Roads centrations of the Downs stock. were extraordinary for winter spawned 0-group fish. (For example, winter spawned herring caught Table 153 (Hinder) refers to fish sampled later at Hythe with a beach seine on rs. July rg65 had in the season in the Hinder area, and containing a length range from 5.2 to g.o em, with 7.0 em large proportions of stage VI fish and of later the dominant length-group.) On the other hand, maturation stages. They are taken to represent many of the herring caught in July from Bridling spawning components of the Downs stock. ton northwards looked thin and undernourished. The data deal with each age of growth (column In the north in rg66 o-group "Bank" herring were r) and each calendar year of growth (column 2) particularly abundant in the inshore waters between separately, the relevant year-classes being listed Hartlepool and Skegness, but further south o-group in column 3. The year-class convention is as "Downs" herring were present in relatively very follows: the rg6oj6r year-class is the one spawned small numbers. The abundance of sprats was in late rg6o (or possibly early rg6r), which spent found to be at a low level over the whole region its first year of growth (as o-group fish) in rg6r. in which these investigations were carried out in This year-class will be represented by the three rg66. year-old fish of the East Anglian fishery in late 1963 (or possibly early 1964). Column 4 gives the sample size and column 5 the year in which the R. J. WooD year-class was sampled, and the age at which it Fisheries Laboratory, Lowestoft, Suffolk, England. was sampled. -r6g- Herring Table 152. Back-calculated growth data for East Anglian herring 3 4 5 6 7 8 9 10 II Mean Mean Comparative Average Age of Year of Year No. in Year Age initial length Correlation growth growth growth growth class sample of of length increment Slope coefficient mean per year sample fish (em) (em) (R) (em) (em) 0 . . . . 1960 1959(6o I965 6 0 I2.94 12.94 1961 1960(61 I965 5 0 I3-38 13-39 I966 6 0 13-4I 1962 1961(62 1965 4 0 I2.87 I966 5 0 I3.00 1962(63 121 I965 3 0 11.55 Ir.6o 37 1966 4 0 11.66 1964 1963(64 72 I966 3 0 I3-48 I . . . . 1961 I959/6o I965 6 I2.94 7-48 -0.3453 -o.968o 7·54 1962 1960(61 I965 5 I3-38 7-48 -0.2783 -0-4028 7·72 I966 6 I3-4I 7·44 -0.3863 -0.5949 7-69 1961j62 1965 4 I2.87 8.88 -0-4582 -0.6713 8.9I 8.85 I966 5 13.00 8.70 -0-4686 -0.7848 8.78 1962(63 I965 3 II. 55 8.99 -0-4831 -0.6733 8-49 37 I966 4 II.66 8.73 -0.3667 -0.5989 8.28 1965 1963(64 72 I966 3 13-48 7-48 -0-4349 -o.6I97 7·76 C'/Iean 12.79 Mean -0.4027 II ... 1962 1959(6o I965 6 20.42 4·36 -0.6273 -o.8627 4-13 1963 196o(61 I965 5 20.86 4-59 -0.3940 -0.5369 4·56 I966 6 20.84 4·4I -0.6532 -0.7224 4-37 1961(62 I965 4 21.75 4.26 -0.3608 -0.5464 4·63 1966 5 21.70 4·33 -0.3I39 -0.4922 4·67 1965 1962/63 121 I965 3 20.53 3-78 -0.3655 -0.640I 3.60 3-70 37 1966 4 20.39 4·04 -0.5263 -0.6569 3-79 1966 72 I966 3 20.96 3-59 -0.3635 -0.5979 3.60 3.60 Mean 20.93 Mean -0-4506 III .. I959(6o I965 6 24-78 2.28 -0.2289 -0.3545 2.f4 2.f4 196o(6I I965 5 25-44 2.61 -0.2338 -0.4363 2.65 2.51 1966 6 25.25 2-40 -0.4665 -o.6674 2.38 196I(6z 1965 4 26.oo 1.74 -0.1670 -0.3555 1.92 I.98 I966 5 26.03 r.85 -o.23I2 -0.4359 2.03 1966 I962(63 I966 4 24-43 2.39 -0.273I -0-4937 2.1) 2.15 Mean 25.32 Mean -o.z668 IV ... 1959/60 I965 6 27.06 r.68 -0.3785 -0.8023 1.59 I. 59 I96o(61 1965 5 28.06 1.05 -0.I099 -0.3514 I.I2 1.14 I966 6 27.65 I.I7 -O.I344 -0.3804 I.I7 1966 196I (62 I966 5 27.87 r.q -0.0062 -O.OI62 I. I7 1.17 Mean 27.66 C'llean -O.I573 y .... 1965 I959(6o 5 I965 6 28.74 I.OO -0.2594 -0.37I6 0.99 0.99 1966 I96oj61 14 1966 6 28.82 0.90 -o.I748 -0.3272 o.9I 0.91 Mean 28.78 Mean -o.2I7I The first year's growth (o-group growth) 1s Column g. Correlation coefficient for the within given by the mean 11 for the sample. Growth data year-class relationship. for subsequent ages of growth are summarized The comparison of growth data of this kind is as follows: possible because there is a negative and significant Column 6. Back-calculated mean length at the relationship between increment and initial length. beginning of the year of growth. For the This means that length increments for two year second year of growth (I-group) this classes which differ in their mean initial lengths will be the mean 11 ; can be corrected to a standard initial length, Column 7· Mean increment of length for the year which in this case is the grand mean initial length for of growth; the relevant age of growth (also given in the Table). Column 8. Slope of the linear regression equation The correction factor is the product of the difference for the within year-class relationship between an individual mean initial length and the between increment and initial length; grand mean initial length, and the grand mean slope. -IJO- Table 153. Back-calculated growth data for Hinder herring 2 3 4 5 6 7 8 9 IO II Mean Mean Comparative Average Age of Year of Year No. in Year ..t\ge initial length Correlation growth growth growth growth class sample of of length increment Slope coefficient mean per year sample fish (em) (em) (R) (em) (em) o . . . . 1960 1959(6o 5 I965 6 0 I2.98 I2.98 1961 196o(6I 146 1965 5 0 I3.3I 13·39 I9 1966 6 0 I3-47 I962 196I (62 347 1965 4 0 12.84 I3.07 59 1966 5 0 13.29 1962(63 303 1965 3 0 I 1.72 I LSI 76 1966 4 0 II.30 1964 1963/64 341 1966 3 0 13.31 I3·3I I .... 1961 1959(6o 5 1965 6 12.98 8.ro -0.5385 -0.999I 8.r8 8.I8 1962 I96o(6I q6 1965 5 13·3I 7·54 -o.255I -0.3476 7·76 I9 1966 6 13·47 7·40 -0.22I6 -0.4077 7.68 7·72 I96rj62 347 I965 4 12.84 8.85 -0.4I94 -o.6626 8.88 59 1966 5 I3.29 8.84 -o.5Ioo -0.7636 9.os 8.96 303 1965 3 I 1.72 8.84 -0-4543 -0.5976 8.41 76 1966 4 11.30 8.64 -0.3584 -0.5372 8.04 8.23 341 1966 3 I3.3I 7·74 -0.467I -o.6oos 7·95 7·95 Mean I2.78 II ... 1962 I959[6o 1965 6 21.08 3·72 -o.26oo -0.3882 3·78 1963 196o[6r 1965 5 20.86 4·57 -0.4431 -o.6647 4·52 1966 6 20.87 4.22 -0.3523 -0.6424 4.16 4·34 I96I{62 1965 4 21.69 4·40 -0.3836 -0.5905 4·63 1966 5 22.13 4.00 -0.3520 -0.5468 4·39 4·51 I962{63 1965 3 20.56 3·97 -0.3322 -0.5904 3.81 1966 4 I9.94 4·25 -0.3577 -o.6I76 3.88 1966 1963/64 1966 3 27.05 3·67 -0.3026 -0.4233 3.68 Mean 21.02 ::VIe an -0.3479 III .. 1959[6o 5 I965 6 24.80 2.24 -0.1557 -0.3308 z.q 2.14 I96o{6I 146 I965 5 25-43 2.46 -0.275I -0.5048 2.49 19 1966 6 25.08 2.27 -O.I539 -0.32I7 2.23 1965 196I(62 347 1965 4 26.09 r.82 -0.1795 -0-4167 1.98 59 1966 5 26.13 I.83 -0.1329 -0.3029 2.00 1.99 1966 I962(63 76 I966 4 24.19 2.53 -0.3141 -0-4772 2.30 2.30 Mean 25.29 Mean -0.20I9 IV ... 1959[6o I965 6 27.04 1.70 -0.2648 -0.3825 1.62 r.62 196o(61 I965 5 27.89 1.14 -0.0914 -0.3027 I.I9 I.I5 I966 6 27·35 1.15 -O.OI29 -o.064I I. 12 1966 I961 (62 1966 5 27.96 1.25 -0.2662 -0-4965 !.32 !.32 Mean 27.56 Mean -o.I588 v . . . . 1965 I959/6o 5 I965 6 28.74 0.92 -0.07I3 -0.3I63 0.93 0.93 1966 1960(61 I9 I966 6 28.5I o.88 -0.0545 -0.2635 o.88 0.88 Mean 28.62 Mean -o.o629 Comparative growth estimates for the period 0-group growth. High levels of growth in the covered by the rg65 and rg66 samples are given years rg6o to rg6z were followed in column ro. by a large decline in rg63 and a return to high levels in rg64. Comparison between estimates for East Anglia I-group growth. A sharp increase in growth in and Hinder show that the two sets of data give 1963 was followed by a decline very similar results. The only large differences in rg64 and a further fall in rg65. refer to samples comprising very few fish, so that II-group growth. A rise in rg63 was followed by a it is possible to describe the growth changes that small rise in rg64 and a large have occurred in recent years in the following fall in rg65 to a level which was terms: maintained in rg66. -171- Herring 0 III-group growth. A rise in 1964 was followed by Table 154. Length distribution ( / 00) of herring a fall in 1965. em q.o 14·5 15.0 rs.s 16.o 16.5 17.0 0 2 2 I 2 IV-group growth. Growth fell in 1965. /00 8 20 em 17·5 r8.o 18.5 19.0 I9·5 20.0 20.j 0 The significance of these growth changes is not / oo 32 42 61 86 !04 IIZ rr6 discussed here. They can be best evaluated by em 2I.O 2!.5 22.0 22.5 23.0 23.5 24.0 rr6 82 comparison with changes in other years and for oI oo 105 53 28 !2 3 em 24·5 zs.o zs.s z6.o z6.s 0 other stocks. It is to be hoped that growth data /00 3 3 3 2 of this kind will be made available by other n = !,253 laboratories so that these comparisons can be made. 13 random samples of German oil-herring catches comprising 3,950 fish ( = 132 kg) were analysed at T. D. ILEs the Cuxhaven Laboratory of the "Institut fUr Fisheries Laboratory, Lowestoft, Suffolk, England. Kusten- und Binnenfischerei" as to their species and length composition. They were composed on an average of 6o.6% herring, 23.1% sprat, 13.5% The German Oil-Herring Fishery in rg66 whiting, 2.2% dab, 0.3% horse mackerel, 0.2% (Table 154) gurnard and 0.1% mackerel. 0.3% of the catches consisted of undersized protected fish: 0.2% In 1966, because of scarcity of fish, landings of whiting and 0.1% dab. the German oil-herring fishery amounting to P. F. MEYER-WAARDEN 12,465 tons (value: 1,678,ooo German Marks) were Institut fur Klisten- und Binnenfischerei, 2 Hamburg 50, the lowest since 1964. Since 1952, landings were Palmaille 9, Germany. lower only in 1963 (= rr,912 tons). If compared with 1965, catches per boat and fishing day The Herring Fisheries of the Netherlands in rg66 decreased from 8.8 tons (1965) to 5·9 tons so that (Tables 155-159) many fishermen decided to quit oil-herring fishing and turn to other fisheries. Consequently, during The fisheries the months of July-October the number of oil Herring trawl (Table 155) herring fishing trips decreased from 617 (1965) to The landings of trawl-caught herring do show 409 (1966). Fishing grounds were as usual: Weisse a steady decline, and also during 1966 the catch Bank, Clay Deep, Amrum Bank, Dogger Bank, (52,303.3 tons) was lower than in the previous Lower Scruff, Upper Scruff. year (r965 -55.471.0 tons). The length composition of 13 herring samples The decrease of the total catch by the trawlers taken in July (1), August (7) and September (5) was mainly caused by a drop in the effort of about was as follows: 18%, as compared with 1965. For the first time Table 155. Catch aiJ.d effort data of the herring-trawl fisheries in 1966 Top figures: total catch in tons. Middle figures : effort in roo fishing-hours of a motor-trawler sao B.H.P. Bottom figures: catch per roo hours fishing. Area Jan. Feb. March April May June July August Sept. Oct. Nov. Dec. Total NE 42.2 291.8 998·3 256.! !38.0 82.7 67.2 13·4 26!.5 269.2 262.6 937·0 3,619.9 53·8 106.1 !70.2 211.6 100-4 53.1 5!.1 49·5 45·2 8s.9 62.7 47·5 1,037·2 0.8 2.8 5·9 1.2 !.4 1.6 !.3 0.3 s.8 3.1 4·2 19.8 3·5 NW ...... 0-4 17·7 486.8 69·4 595·2 2,909.9 495·6 247·2 151.3 266.3 79·8 5,319·7 r.6 8.1 68.7 32.0 134·4 164·4 27.0 17·9 12.3 19.6 7·0 493.1 0.2 2.2 7·1 2.2 4·4 17·7 18.3 13.8 12.3 13.6 1!.5 10.8 Central ...... 72.0 4-7 22.7 19·3 1.314·3 5,095·2 14,387.2 6,420-4 1,265.1 129.0 - 28,729.9 0.4 2.9 4·9 60-4 70.2 264.6 286.3 211.4 73.6 19.1 993·9 184.6 r.6 4·6 0.3 18.7 19·3 50.3 30·3 17.2 6.8 28.9 South 2.2 2.2 SE Ireland ... 2,964·5 1,926.6 4·1 72-4 320.3 1,81o.o 2,557.5 3,762.8 1,215.6 14,633·8 20.5 39·0 2.6 4·2 13.8 46·5 119.0 132·3 62.9 440.8 144·7 49·4 r.6 17.2 23.2 38.9 21.5 28-4 19.3 33·2 -IJZ- Table 156. Catch data of pair trawl fisheries in 1966 (Total catch in tons) Area Jan. Feb. ~1arch April :May June July Aug. Sept. Oct. :0Jov. Dec. Total NW ...... 11I.1 32.3 143·4 Central ...... 0.1 39.1 186.2 76r.1 658.z 340.7 1,985.3 South ...... 30.0 0.7 0.2 19.2 33·4 2,186.5 732.4 3,302.1 5.430.8 Table I57· Age composition in numbers per unit effort and percentage age composition Area Years z 3 4 5 6 7 8 9 >9 Total North -east Bank ... !2.1 3·3 I.6 2.9 0.2 0.2 0.2 X 1000 20.5 0.3 58·9 15.9 ;.8 q.o O.I I. I o.8 I.1 % F!amborough-Whitby 29.8 4·2 0.5 r.s 0.1 X 1000 36·3 O.I 8z.r 1I.j L4 4·2 O.l 0.4 % Dogger ...... 0.3 8.6 4·9 o.8 o.8 0.1 O.I X IOOO 15.6 r.8 55.r 31.3 4-9 5-2 0.2 0.6 0.7 0.2 % Sandettie ...... 17-3 62.9 5.8 7·0 s.8 0.6 o.6 % SE Ireland ...... 0/ 4-0 rr.8 44·1 8.o 12.3 +-8 3·4 7·7 3·9 /0 Table 158. Mean length (em) for age, for different areas (age in years) Area Years 2 3 4 5 6 7 8 9 IO >ro Maturity North-east Bank 24·3 25.6 27·7 30·4 30-9 29.8 3I.8 30.8 3I.8 Stage VI Flamborough-Whitby 24.8 24.8 26.6 30·3 30·5 3I.9 30-9 3I.8 Stage VI Dogger ...... 23.6 25.1 26.3 29.8 30·3 3I.I 30.6 3I.O 31.3 3I.7 Stage VI Sandettie ...... 22.9 24-3 26.8 28.9 30.0 29-3 30·3 Stage VI SE Ireland ...... 23.6 26.5 27.8 z8.8 29-5 29.8 30.0 30.0 30.6 30-3 All stages the trawling grounds in the south were not exploited. In the south the catch reduction was due to The reduction of the effort in the various areas was the poor results of the rg65-rg66 season m 88.7% south, 24-5% NE, 46.6% NW and rz.o% January and February. central. The effort exerted in the Irish Sea, how Drift-net eves, increased by so%. Concerning the areas fished no detailed data In the central North Sea the catch per effort are available from the drift-net fisheries. increased, as compared with rg65, especially on the Flamborough- Whitby grounds in August and The number of shots again decreased from September. Poor catches on the Dogger in Septem r,679 shots in rg65 to some 864 shots in rg66. The ber induced the trawlers to leave the central total catch in rg66 by the drift-net fishery amounted North Sea rather early for the more profitable to 2,401.6 tons. grounds in the Irish Sea. As in the previous years the East Anglian season The catch per effort in the areas NW and NE was a complete failure. showed no improvement. Biological data Pair trawl (Table 156) The total catch landed by the pair trawlers Data for length and age and catch composition dropped from 13,458.5 tons in rg65 to 5.430.8 tons are compiled in the Tables 157-159 for the following in rg66. This decrease in the catch was caused by fisheries. the reduction of the landings from the central and North-east Bank: the southern North Sea. Period: August-September 0 In the central North Sea the catch reduction Area: 55-30°-56.oooN and I -0°vV was mainly effected by a reduction in the number Gear: Herring trawl of landings. Maturity stage: VI. The extremely good results of the sole fishery Flamborough-Whitby: by the cutter-fleet withheld many skippers from Period: August-September turning over to herring-fishery, notwithstanding Area: 53-30°- 54-30°N west of 0.3o'E the improved catches on the Flamborough-Whitby Gear: Herring trawl grounds in July and August. Maturity stage: VI. -173- Herring Table 159. Length composition (%2 on various fishing grounds (Length in em below) ,, Area Length I] I8 I9 20 2I 23 24 25 26 27 28 29 30 31 32 33 3+ Korth-east Bank O,I 0, I L] 9.0 q,3 I-},3 14·9 ILI 6.6 6.-t I0.9 8--t r,S 0.-J, Flam borough-vVhitby 0.2 3·2 16.2 30.0 2j.6 I3·3 3·3 Lj ? ? 2.6 r,6 0.2 Dogger ...... O.j 3·3 12.2 Ij.J 22.4 I9-+ 9-0 4·6 3·8 4·5 2. I 0.3 Sandettie ...... 0.9 I0.9 29.2 26.] IL6 +3 2-4 +·3 6.+ 2.+ 0.9 SE Ireland ...... 0.2 1.0 I -3 2-4 5-7 9-+ 22.2 zs.s I ].8 12.5 2.0 Dogger: 23% of the total yield were brought to Swedish 0 Period: September-medio October ports while 76% were landed in Denmark and r /, Area: 53-45°-55°N and I 0 -3°E in other foreign countries. Gear: Herring trawl The incompleteness of the Swedish fishery Maturity stage: VI. statistics unfortunately still prevails and inform~ Sandettie: tion about the quantitative distribution of the Period: November catches on the different fishing grounds cannot Area: Sandettie Bank, Galloper and Korth be given in details. Broadly speaking the greater Hinder part of the landings for human consumption Gear: Pair-trawl consisted of adult bank herring caught the year Maturity stage: VI. round in the North Sea proper. A much smaller part was composed of maturing, spawning and SE Ireland: spent Kattegat autumn spawners and a still Period: November-December smaller part consisted of Skagerak spring spawners Area: North of 5I 0 N and between 0°-4o·w taken within the skerries along the BohusHin Gear: Herring trawl coast. The oil and meal factories took over those Maturity stage: all maturities. quantities which occasionally were landed in excess . Recruitment of the rg63 year-class turned out of the quota. In addition, no small amounts of to be good on the Flamborough-VVhitby grounds, immature herring (one and two year olds) were but on the Dogger grounds the year-class rg63 landed for industrial purpose partly as by-catch did not meet the expectations. in the sprat fishery, partly by the smaller trawlers On the southern grounds recruitment was again which have to operate inside the mouth of Skagerak poor, but better than in 1965. and restrict themselves to fishing on the young On the Irish grounds year-class 1962 is dominant bank herring and Kattegat autumn spawners. 39% and stronger than the new recruitment year-class of the 58,ooo tons of industrial herring were delivered to the two existing West Swedish reduc 1963. tion plants, while 6r% were landed in Denmark. Growth was poor in all year-classes, but the ler.gth for age of the three-year-old fish was 0.5 em In the preceding autumn, 1965, the adult bank longer than in 1965. herring did not penetrate into the central and eastern Skagerak as they did in the autumn of 1964 ]. ]. ZrJLSTRA, K. H. PosTUMA (and to a lesser degree in the autumn 1963). So Eijksinstituut voor Visserijonclerzoek, in the first part of 1966, and in fact during the Haringkaclc I, IJmuiclen, Holland. whole year, the adult bank herring was almost completely absent from the Skagerak. The invasion of the strong 1960 bank herring The Swedish Herring Fisheries herring year-class in the winter season 1963/64 in the North Sea, Skagerak and Kattegat in rg66 and even more in 1964/65 had given rise to expecta (Figures II]-I2I) tions of a new period of many years' winter herring (Note: The references to the tables arc to the "'Statistical fishery of the same kind as had occurred at two :1\'ews Letters" (SNL) No. 35). earlier occasions in the Skagerak in this century. The landings of herring for human consumption But the expectations were baffled only after two amounted to rz8,ooo tons (a decrease of about 9% winter seasons. compared with 1965) and the landings for industrial After New Year the pelagic pair trawling was purposes were 58,ooo (a decrease of about 33-7%). resumed in the mouth of Skagerak and by degrees Thus the total yield was r86,ooo tons which is the main fishery moved north-west and northwards about r8% below the total of rg65. in the Egersund area towards Viking Bank. The -I74- North Sea The poor bottom-trawl results contrasted with % 18 20 22 21. 26 28 30 32 31. em 0 1 2 3 I. 5 6 7 8 9 10>10 wr % the powerblock ring-netting, especially the Nor 20 40 wegian one, which up to the first of July was just 10 20 about as successfull as in I965. Still more remark 0 0 20 1.0 able than the quantitative differences between 10 20 bottom trawl and ring-net catches was the complete 0 0 disagreement with regard to the size and age 1.0 80 Egers B. K 15 composition of the two kinds of catches. This 30 n· 1.95 28·1.· 56 60 fact was established already in I965 through P10 wr the Ig6o year-class was scarcely represented (Sample g, Figure II7 and SNL Table 4I). In the Figure II7. autumn the adult herring concentrations were found off the entrance of the Skagerak and they stayed in this area to the end of the following winter. biological samples showed about the same composi In February some twenty pelagic pair-trawlers tion as at the end of the preceding year: with an made one or two successful trips each for the increasing predominance of the I963 year-class of Norwegian winter herring off the M¢re-Romsdal the bank herring and with the year-class Ig6o coast (Figure I2I and SNL Table 4I). playing a diminishing role (Samples I -3, Figure II7 One sample from the Skagerak was examined and SNL Table 4I). and showed a predominance of the I964 year-class Fishing was continued in spring and summer on by 87.5% and only 6-4% of the I year olds (Figure every conceivable ground in the northern North rr8 and SNL Table 42). These latter may, how Sea by a reduced number of boats which for the ever, have been better represented according to main part were using bottom trawls, but progress reports from the fishermen and the landing places was extremely poor. Many fishing boats had often about the size categories of the catches. The small to return with landings as small as 50 boxes number of 3 year olds (4-4 %) were all immature (about 25 hl) of herring. Had it not been for the fish. by-catches of mackerel and white-fish (mainly In a sample of the Kattegat autumn spawners haddock), fishing would have yielded no profit. from the middle of September, the Ig6o year-class -175- Herring still dominated by 56% (Figure rrg and SNL Table Skagerak 43). The fishery in Kattegat during the autumn was much below average. The :fishery on the Skagerak spring spawning herring was carried on as usual: in winter, from December to May, mainly with set-nets and from August to December with small purse-seines. A Figure II8. very slight displacement of the set-net fishery southwards along the Bohuslan coast has been Kattegat noticed in the last few years. The whole year's %r--~~-- .. -- ... ------· --lo;, total output amounts to some 300 tons only. 30: NE. An holt n ~ 206 19 9· 66 (Figure 120 and SNL Table 44.) 20· A _m[ottom""" ecow ~~ H. HoGLuND 22 zz-., 26 28 30 32 em C l 2 3! 5 6 7 89iO>iQ wr Q Ha,·sfiskelaboratoriet, Lysekil, Sweden. Figure 119. The Polish Herring Fishery in the Southern Baltic from 1957 to rg66 1 2 3 !_, 5 6 7 8 9 10>10 w % (Figures 122-126; Tables 160-161) 60 0 16 The catches f.· f.· 66 20 During the years 1957-1966 the Polish herring -~~~~~~~~--+D catches in the Baltic showed in general an increasing trend (Figure 122), butlargefiuctuationswereobserv ed in some years. Those fluctuations were caused 1~:~isetr.e 6P~"i:20 by alterations in the abundance of the stock of -~--.--.-.-~;..-.--____,______r~:::--'----~~- s~ Baltic herring, by changes in the amount of Q 16 60 fishing and by different patterns of distribution 2' 10·66 Small purse rlLO of the stock. setne 20 The catches in 1966 were very good. Especially . ·- 0 0 "1 2 3 I. 5 6 7 8 9 10>10 wr the summerjautumn season (Table 16o) gave high catches. As to the young herring, the spring season Figure 120. was productive too, due to the good year-class 1964/65. Off More, Norway In 1966, as in other years, mainly the feeding % ,------,---···---···------,% 30 60 NNW. Grrp M 25 concentrations on offshore grounds were exploited. 20 n-207 21·2·66 40 Pelagtc tr<01wl In the spring/summer season autumn spawners 10 20 predominated in the catches, whereas in the 20 22 24 summerfautumn season spring spawners prevailed. As usually, a large part of the spring spawners, Figure rzr. feeding on the grounds of the southern Baltic were coming from the central Baltic. The springfsbtmmer season is regulary sampled The coastal catches on spawning grounds in the Bornholm Basin only. In this season herring amounted to 300 tons only. Nevertheless, in 1966, catches are not important in the Gulf of Gdansk. and particularly in the spring, these catches were The good and poor year-classes in the autumn/ better than in the previous years, owing to a spawning stock can be easily followed in Figure 123. slight improvement in the coastal spring spawning The year-classes 1954, 1960, and 1961 were stock. numerous, whereas the year-classes 1955 and 1962 were poor. These two year-classes were hatched Biological data just before the very cold winters of 1956 and 1963. The figures 123, 124 and 125 show the length No distinct long-term trend has been observed in and age composition of the herring caught on the age composition in the last ten years. It can feeding grounds, separately for the Gulf of Gdansk therefore be supposed that the total mortality and the Bornholm Basin. in this stock of herring has been rather stable. -176- 1000)1 Table r6o. Polish herring catches in tons in the Baltic, 1966 tons30 :\fonth Adult herring1) Young hcrring2) Total January ..... I 17.2 49-I r66.3 1 February 224.1 122.2 346·3 March ...... 184.6 453·0 63].6 April ...... ]80.3 1,664-3 2,444·6 20 May ...... 1,396.5 r,182.5 2,5]9.0 A June ...... 3,016.2 IJ5.6 3,191.8 July ...... 3.332.8 306.4 3.639·2 August ...... 3,20].2 246.r 3.453·3 Septcm bcr ... 2,60].] 84·9 2,692.6 October ..... 4,262.5 22.8 4,285·3 November ... 2,546.2 125. I z,67r.3 December ... I ,458.6 IJ6.] 1,635·3 Young and Total ...... 23, 134·0 4,6o8.7 2],]42·7 Adult Among the spring spawners a small decrease in 1950 1955 1960 1965 Year the relative number of the older age-groups Length (ro-n+) can be observed. Weight coeff. iOJ During the summerjautumn seasons (1957-rg66) I ' the herring catches in the Gu~f of Gdansk were 1 ' composed of many age-groups. As can be seen I from Figure 125 the total mortality was low and 0.6 rather stable. Two year-classes, the 1955 and the 1959 ones, were rich and for many years gave good catches. Autumn spawners+ - + + - + Rather numerous broods of herring hatched in Spring spawners + - + - + _ + 1953 and 1957. The rg56 year-class was poor as 1950 1955 1960 1965 Year well as the year-classes of rg6o to 1963. This is generally in accordance with the data from the Figure 122. A. Polish herring catches in the Baltic 19-+7-1966 Bornholm Basin. However, the difference between in thousand tons. the relative strength of good and poor year-classes B. Length(•xeight coefficient 1951-1966 in her ring (maturity stages II, VIII-III) in the was not so significant in the Gulf of Gdansk as in summerfautumn season. the Bornholm area. Although autumn spawners predominated in the The herring concentrations occurring in the Gulf catches of the spring/summer fishing season, the of Gdansk during the feeding season were composed admixture of spring spawners was considerable, of a mixture of different stocks. Among the younger and in the years 1965 and 1966, many spring age-groups the autumn spawners were quite spawners of the year-classes 1955, 1963 and 1964, important but their relative number was less than were found in these catches. in the Bornholm Basin during the same season. The summerjautumn season in the Bornholm Basin The admixture of local stocks of coastal spring was dominated by spring spawners (Figure 124). In spawners, which generally occur in the younger this stock the year-classes 1953, 1955, 1957 and age-groups, was small up to 1965. In the last two 1959 were numerous whereas the year-classes 1956, seasons their number increased largely owing to 1958, 1960 and 1963 were poor. the good year-class hatched in the Gulf of Gdansk The admixture of autumn spawners fluctuated in the spring of rg64. in different years. The largest relative number of The majority of the catches, as in the Bornholm this stock occurred in 1g66 with the appearance Basin, consisted of old slow-growing herring which of the excellent year-class hatched in the Bornholm migrated from different parts of the central Baltic Basin in the autumn of 1964. The large landings for feeding. of herring in October 1966 (Table 160) were mainly In the investigated period the condition of the composed of this year-class. herring changed in rather broad limits. This can 1) Catches from April to and including July, reckoned to spring-summer period; catches from and including July to December reckoned to summer-autumn period. 2) Catches from January to and including September comprise 0-group herring, while catches from and including September to December comprise I-group herring (year-class 1964(65). ------~------ -rn- Herring .,_ 9 10 11+ 3001 wr 200~ 100~~ 15 20 25 30 5556 5455 5354 5253 52 51 l.SSO 49 48 47 year class 3001 1958 !:! ~ n ~ L iJ j lLo Jj J1 ::~~_--.--__/~-----~~-~~-----=----=-----=-----,4-15 2'o 25 -~305657555651.55535452535152 ~ J 51 so 49 48 1959 3001 2001 100J 15~~~ 20 25 305657555651.55535452535152505149504849!.?!.8 1960 300-, 1960 :::~ ~ ~~'-~ Jl 1s 20 · z's 3058595758555755565455 51.5253 52 51 50 h"' =~~~':'>15 20 25 _,I, ii"' il ~s., ""' 1961 ~ m~ 1 300l ~ 200~ 0 n N :'' ;til zoo ..e 100 ~i ~~.._ ... ~ -~ I I n il ~ :£:: ..... lOOj /•, " §:;: ------······-, ,. . . II; IJ iS dJ :£, ;;U Jj _..o ....!.0 ...!.1:5 i - ~ ... ______·~ ~n o...r IJl ore 0 300 1 1962 ~ ~ 0 ' 100-j'l£ ~ ~ <0 ol~ i t2 n! I - j~i 1---.--- __ /-----::;=,~ L Is ~Li ;[] d_ NG ! -- __,_8 _._j5 ~ -·-~ 15 20 25 30 6061 5960 5859 5758 5657 5556 55 54 53 52 300l 1963 n" 2001 I ~ - ~ ~ io ~ -~ n .., Fl ~ (;; ~ ...,_ c IILJ JJ ill ,u -'.0 _,u = = .c."] '"!.~-'> ~--3o 6162 6061 ssso ssss 57 sa sss1 ss st.ss st. sJ 1964 ::1 ..-··--,._ L;!lml' ../JdS '"' j----r-, N Jl /~~--\·-~·-·_·:·;:_---,----,--,-~.----·,----~ ';;!III'SIJ~2!.E,~:::;..i:?...!..-=....'.....!_~._.~ ~~15 2Q 25 3Q626J61626Q61596Q58595758565755565!,55 -~~il,;: 5[. 15 20 25 3061626061596058595758565755565455 54 1965 1966 200--1 100_; ..Jj di .." 15 20 25 30 61,65 6364 6263 6162 6061 5960 59 Jl58 ./,,,""57 56 ~=$:20 zs 30 53~~iSisLtiJ,jj"'~"~=· 6263 5162 6061 ssw sass 5758 57 ~ -~~~ t:"' ~ -0Spring5pawners ------Autumnspawners - 0 Spnng spawners -- II Autumn spawners Figure 123. Length and age composition of herring catches Figure 124- Length and age composition of the herring in the Bornholm Basin, spring/summer feeding seasons catches in the Bornholm Basin, summer(autumn feeding 1957-1966 in °(00 • seasons 1957-1966 in •[,,. -178- em •t•• 18 300- 1 2 3 4 5 6 7 8 9 10 11 + Bornholm Bassin 200 _' m~ !1! !il - 16 ______,\\, 100~-. ~ ~ ~j ~j] _cJ il Jj iJ ,g J5 15 20 25 30 5556 5!.55 535!. 5253 5152 5051 !.950 t.at.9 t.8 t.7 year class 14 12 - Spring spawners 300 ----Autumn spawners em 1956 1961 1966 Year 18 Gulf of Gdansk 16 300~ 1959 200~ 14 s § ~~ N g 100-j ~ L~~ ml]li 'Om ~ - Sill- ~~~~~----- i'J""' ~ dJ .d dJ dJ _[] •' 12 15 20 25 30 575B565755565t.55535L 525351525051 !.950!.61.9 1956 1961 1966 Year 1960 Figure 126. l\Iean length of I-group herring in spring. 2001~ ~ 1001 ~;: ;:9 :::i ~ ------... .,, .. - -,-~ -, 13 iLl J] = 15 20 25 30 5859 57 58 5657 5556 5!.55 535~ 52 53 52 51 50 be followed in the Figure 122 B where the length/ weight coefficient in herring of maturity stages II, VIII-III in the summerfautumn season is plotted against a time scale. In the same figure the extreme ly good and poor year-classes as well as the total Polish herring catches are also indicated. In general we observe a good correlation between the feeding condition in the southern Baltic and the year-class strength. Thus, in the years 1956 and 1963 in 3001 1962 which the length/weight coefficient was low, very 8 :::1 ~ i ~ j] ~ ~ ~ ~j]£; j:: m :ii poor year-classes were produced. On the contrary, ~~ ~.S~ I,J]clJ_[}.dJ. lJdjdJ 15 20 25 3060615960565957585657$565t.55 5~ 53 52 in the years characterized by a high length/weight coefficient such as 1954, 1955, 1957 and 1964 rich year-classes appeared. 3001 1963 A very distinct negative correlation was observed 200 ~ a> ~ between the total herring catches and the feeding 100 l ~ 1'- ~~ ~ r, ill n ~ JJ- 'l ~ Sl i.=:::::~~------~____ ~, IS u lii5 i1.i .!i:! dJ ill~· ll JJ dJ condition as indicated by the lengthfweight coeffi 15 20 25 30 61 62 6061 5960 5859 5758 5657 5556 5t.55 5~ 53 cient. This correlation would have been better still if we could eliminate from the graph the influence 300, of an increasing fishing effort. There can be two possible explanations of this :::t_~ ~~ iJ ~ ~ lJ ~1 ill~~~~ fact. When the feeding conditions are poor, more 15 20 25 30 6263 6162 6061 5960 5859 5758 5657 5556 5~55 535~ herring may arrive to the southern Baltic for 1965 feeding. Or, when the stock density in the southern Baltic is large, the herring may be in a poor condi tion because of the competition for food. The first explanation is connected with changes in distribu tion, the second with changes in the abundance of the stock. In particular years, both factors can 1966 operate in various combinations. 300 ;:: 200 / n ~ The recruitment to the herring stocks of the 100 -~··~- ~JJ:;8dJl:~~~~~ .;a.A southern Baltic 15 2,0 25 306!.656364626361626061 59605859 57585657 56 -- [] Spr1n9 spawners • Autumn spawners The investigations were conducted in the same Figure 125. Length and age composition of herring catches in the Gulf of Gdansk, summer/autumn feeding seasons way as explained by ELWERTOWSKI and POPIEL 1957-1966 in °/oo· (r963). -179- Herring Table 161. Catches of 1-group spring and autumn spawned herring in weight and number per cutterfday %of weight Spring Autumn Kg per Year- Kg per ~o of fish Year- Kg per ~o of fish Year cutterfday Spring Autumn class cutter/ cutter/ class cutter/ cutter/ day day day day Bay of Gdansk I956 2.0 77-5 22.5 I956 r.6 222 I955 0-4 26 I957 I2.5 30·3 69-7 I957 3·8 339 I956 8.7 56 I I958 42.0 I6.4 83.6 I958 6.9 500 I957 35-I 2,279 I959 37·6 25-7 74·3 I959 9-7 746 I958 27-9 I,5I6 Ig6o g8.8 9-0 9!.0 I96o 8.9 65I I959 8g.g 5.73I Ig6I 70-3 6.4 93-6 I96I 4-5 375 Ig6o 65.8 5,062 I962 I23.8 I6.3 83·7 I962 20.2 I,303 Ig6I I03.6 5,788 I963 70.0 72.2 27.8 I963 50.5 3,280 I962 I9-5 I,I40 I964 I78.6 9!.0 9-0 I964 I62.6 9,29I I963 I6.o 7I4 I965 !!.3 25-3 74-7 I965 2.9 256 I964 8-4 538 Bornholm Basin I956 I956 I955 I957 I.O IO go I957 0. I IO I956 o.g 40 I958 30·7 7 93 I958 2.3 144 I957 28.4 I,264 I959 4°-5 23 77 I959 9-3 6go I958 3!.2 I,5Io I96o 57·7 99 Ig6o 0.5 48 I959 57·2 2,542 I96I I03.0 2 98 I96I 2.0 q8 I96o IOI.O 5,838 I962 93-2 I9 8I I962 I7-5 I,3I5 Ig6I 75·7 4,30I I963 g.8 72 28 I963 7-I 450 I962 2.7 I26 I964 I22.6 33 67 I964 40-3 I,658 I963 82.3 3,037 I965 9I.o 8 92 I965 7·5 593 I96+ 83.5 4,688 Table 161 gives the abundance indices of different decreased and amounted to 22,900 tons and year-classes in number per fishing day. 1,400 tons respectively. The trawl catches amounted In the Gulf of Gdansk the local spring spawning to 6,roo and the total yield to 30,400 tons. In rg66, stock dominated the catches again, after a period due to good trawl catches (8,7oo tons), especially of increased abundance of autumn spawners. In in the Gulf of Riga, the total yield increased to the Bornholm Basin the autumn spawners were 3r,8oo tons. However, decrease in coastal catches much more abundant than the spring spawners. continued (spring herring 22,100 and autumn Figure 126 shows the mean length of the I-group herring goo tons). herring (f. i. the length of the 1964/65 year-class The coastal catches of spring herring consisted in the spring of 1966). chiefly of the moderate rg62 and rg63 year-classes During the last ten years we can note an in and the rich 196r year-class (Table r62). The rg66 creasing tendency in the length per age of the recruitment, the rg64 year-class, was strong too. herring in the Gulf of Gdansk. In the Bornholm In rg65 and rg66 the spawning period of the Basin no such tendency was observed in the same spring spawning shoals was affected by a low period. water level caused by northern winds. Because of J. POPIEL, K. STRZYZEWSKA this the main part of the sea herring and the older Sea Fisheries Institute, gulf herring spawned on the grounds nearer to Aleja Zjednoczenia I, Gdynia, Poland. the open sea, off Saaremaa and Hiiumaa. On these Reference spawning grounds the percentage of sea herring ELWERTOWSKI, J. and }. POPIEL, I963. "Recruitment increased (Table r63). In the gulfs (Gulf of Finland, to the herring stock in the southern Baltic". Rapp. Parnu Bay) the importance of the sea herring as P.-v. Reun. Cons. perm. int. Explor. Mer, 154: 243-5. well as the catch per pound-net decreased. In rg65 the average number of herring larvae Herring Investigations in the North-Eastern Baltic per ro min. haul with the Hensen net was remark in 1965-1966 ably high (IIJ.O). Later on, however, young (Tables I62-I65) herring of this year-class was met with in small In rg65 the herring fishery was less successful numbers in experimental trawl catches. This in the Estonian S.S.R. as compared with rg64. suggest a high larval mortality in this summer, Coastal catches of both spring and autumn herring probably owing to a strong gale in July. In rg66 -180- Table 162. Age composition in coastal catches of spring and autumn herring off the Estonian coast in 1965/66 9 and Age 2 3 4 5 6 7 8 older Nos. Spring herring Parnu Bay ...... I965 0.4 55-2 24.2 I8.5 0.5 0.] 0.2 0.2 O.I I,5oo 1966 4·7 58.6 21.4 10.3 3·8 0.3 o.8 O.I I,300 Saarcmaa ...... I965 o.g 12.9 33·8 32.8 2.I I2.4 I.3 2.2 I.6 !,400 rg66 0.5 39·3 Ij.g I5.6 r8.2 r.8 6.2 I.O I.5 1,300 Hiiumaa ...... I965 0.6 II.] 39·7 30.I 2.8 I2.6 0.6 I.5 0.4 goo rg66 36.I I g. I I6.o !2.2 I.g II.Z 0.5 3·0 500 Gulf of Finland .. rg65 IO.O 22.9 48·5 o.g I2.1 2.] I.9 I.O 200 1966 I.O 32·7 2I.7 7·3 26.0 2.3 7·0 0.5 I.5 I,OOO Autumn herring Gulf of Riga .... 1965 2.2 46·7 23·5 o.8 r6.3 0.4 !0.2 2,8oo 1966 0.2 26-4 4·7 40.0 II.8 0.3 II.1 5·5 1,400 Table 163. Percentage of gulfs and sea herring on the spring spawning grounds off the Estonian coast I964 1965 I966 Area Gulfs Sea Gulfs Sea Gulfs Sea herring herring herring herring herring herring Parnu Bay 74·2 25.8 84·4 I5.6 go.2 g.8 Saaremaa ...... 24·9 75.1 20.6 79-4 25·7 74·3 Hiiumaa ...... 41.3 58.7 2].6 72·4 23·9 76.I Gulf of Finland ...... 63·5 36·5 6].5 32·5 7I.8 28.2 Mean ...... 62.6 37-4 65-4 34-6 7I.O 29.0 Table 164. Racial and age composition of herring in experimental trawl catches in the north-eastern Baltic in 1965/66 (%) Spring herring 9+ and %of spring Area o+ I+ 2+ 3+ 4+ ;:,,-..L 6+ 7+ 8+ older race in catches Gulf of Finland .. I965 O.I 36.0 20.9 5·3 rg.8 0.4 I4.2 0.4 I.6 I. I g8.o rg66 8.3 19.I 41.5 9-7 6.2 ].I I.7 5·3 I. I 95-6 West of Saaremaa I965 17.7 16.3 9-9 19.2 I.9 25·5 0.6 6-4 2.5 95-5 and Hiiumaa .. 1966 3·7 26.4 32-4 ].0 3·0 6.4 I. I II.2 0.] 8.1 8z.g Gulf of Riga .... I965 29.3 39.1 I6.8 II.5 0.5 2.1 0.5 ]6.I rg66 0.5 20.] 59.0 12.6 3·5 2.6 0.2 o.g 66.8 Autumn herring %of Area 8-'- g+and autumn Nos o+ r+ z+ 3+ 4+ 5+ 6+ 7+ ' older race in catches Gulf of Finland I965 12.8 23.1 5·1 r8.o 12.8 20.5 7·7 2.0 1,388 1966 8.g 50.0 r6.2 4·4 I0.3 5·9 2.9 I.4 4·4 1,595 West of Saarernaa 1965 5·0 2.5 32·5 20.0 I5.0 20.0 5-0 888 and Hiiurnaa .. rg66 8.] 63.2 10.5 0.] 5·5 3·3 I.5 r.8 0-4 4·4 1].I r,6ro Gulf of Riga .... 1965 I.3 12.3 5·8 52.1 r6.g 4·3 6.o I.3 23-9 2,198 rg66 I.1 66.4 1I.O I.2 g.2 3·8 0.2 4·2 O.I 2.8 33-2 3,686 the same figure was one-third only (36.5 per haul). In recent years commercial fishing for spawning But in this summer environmental conditions were concentrations of autumn herring was carried out favourable for the larval developement, and on this in the Gulf of Riga only. Unfavourable hydrological basis the 1966 year-class can be estimated as one conditions in the spawning period were responsible of moderate strength. for low catches in 1965, and steady gales and a At present the condition of the spring spawning considerable decrease in the commercial stock were stock is rather stable in the north-eastern Baltic. the reasons in 1966. Older age-groups dominated In 1967-1968 the moderate 1965 and 1966 year in the catches (Table 162), since poor year-classes classes will recruit the fishery, and therefore no were hatched in two successive years (1962 and substantial changes are to be expected in the 1963). The age composition of the trawl herring catches. (Table 164) suggests that the 1964 year-class of -r8r- Herring Table 165. Percentage of the autumn race in experimental In rg66, the first catch from the very first shoals herring trawl catches in the eastern Baltic in spring 1965 that had migrated to the coast for spawning was and 1966 made on 17. May. The temperatures prior to March-April April-May (r6. May) and after the first migration (23. May) Area 1965 Nos 1966 Nos were as follows: Gulf of Finland ..... 3 zo8 7 102 Gulf of Riga Pre-spawning area (eastern part) .... 4 208 38 204 in the open sea r6. May 23. May Gulf of Riga :VIiddle !ayer in which (western part) .... 12 312 21 214 the herring appeared . . 2.5° (55 m) 2.3° (55 m) West of Soela Sound 9 421 9 291 Minimum temperature West of Irben Sound 8 4Il 22 312 layer ...... 0.7° (25-30 m) 0.7° (22-31 m) Ventspils ...... I2 2II 9 139 Liepaja ...... 20 105 297 24 The occurrence of the fish on the coast was Klaipeda ...... 5 roo -t6 -t86 divided into three phases (Figure r28). The last phase autumn herring is comparatively numerous. Due was clearly connected with the upwelling and to this year-class the importance of the autumn thus the inflow of cold water in the island area race increased considerably on wintering and (Figure 127, July). This led to an extension of the feeding grounds in the eastern Baltic in rg66 (Table fishing season in the archipelago to the end of July. r65). Because of strong recruitment (the rg64 year The last spawning fish were captured on 25. July. class), better autumn herring catches are expected The spring spawners occurred during the feeding in 1967. time in August in the Bothnian Sea and in the L. RANNAK, E. OJAVEER northern Baltic proper during night in mean depths from r6 to 23 metres. In the Gulf of Finland Estonian Laboratory of Marine Ichthyology, Apteegy r-2, Tallin, USSR. the mean depth of occurrence varied from 25 to 37 metres. The mean temperature at the surface during Baltic Herring in the Seas around Finland in 1966 the feeding season in the open sea at the places (Figures 127-130; Tables 166-r68) where exploratory fishing was made by "Aranda" Distribution of the stock and hydrographical conditions in the Bothnian Sea, the northern Baltic proper and the Gulf of Finland was 14-4°, e.g. about as The occurrence of the Baltic herring during the low as in the cold summer of 1956. The low tempe pre-spawning and spawning seasons and the hydro rature in the Gulf of Finland can partly be graphical conditions have been investigated in the explained through the deep surface layer. Gulf of Finland. In rg66 the oxygen deficit was smaller in the Table 167. Stages of maturity of Baltic herring caught by Gulf of Finland than in the previous years (Table "Aranda" in August 1966 r66). Thus, Baltic herring appeared in the pre Total spawning season at the bottom in somewhat :Yiaturity I II III IV V VI % No. greater depths than earlier. 1966 . . . . 2.2 26.7 70.0 I.O 0. I 100.0 3,882 The temperature along a section from the light Table 168. Amount of intestinal fat of Baltic herring caught house "Helsinki" to the Finnish coast is shown by "Aranda" in August 1966 in Figure 127. 1966 0 ······················ I7 The catch of Baltic herring in the island spawning III area south-west of Helsinki, with a maximum I ...... 638 depth of ro metres on the coast side of the third ::VI ...... 234 innermost hydrographical station of the cross Total ...... 1,000 section, is given in Figure r28. Xumber ...... 3,884 0 Table 166. Salinity ( / 00) and oxygen content (mljl; per cent of solubility) at the bottom of a site 6o metres deep by the lighthouse "Helsinki" from the end of April to the beginning of July in 1962-1966. Mean value and lowest and highest readings according to weekly observations 1962 1963 1964 1965 1966 S 0 /oo · · ·. · · · · · · 8.o6 (7.65-8.55) 8.29 (7.95-8.51) 8.69 (8.o6-9.56) 8.92 (8-42-9.22) 8.13 (7.94-8.30) 0 2 ml/l ...... 5·72 (3·78-7.60) 2.97 (2.54-3·51) 2-42 (0.83-3.89) z.oo (1.16-2.67) +77 (3·98-5·35) 02% ...... 64·3 (43·9-8-t-3) 35·2 (29·3-40.0) 27.9 (9.80-43.8) 23·7 (13.8-31.8) 57·5 (46.9-65.3) -r8z- HAY 16 1966 ~ 11- JUNE 22 1966 29 , ___29- _ -29 L 16=:;:::::::::;-- '-+.: -1'5 I~ >-1..-..Jf ...... ,,,,' ) >I. 8 , -];;:;;--____ ,,,J ],~, ~c -.,,l JULY 6 1966 12 ..2£.._ ____ 10- >I, 7 " 17 Figure r27. Water temperatures in the Gulf of Finland in May-July rg66. Cross section between the lighthouse "Helsinki" and the Finnish coast. The three stations closest to the coast are situated on islands. The bottom profile represents the deepest channel. -I83- Herring The fishery During the spawning season (May-July) the total catch of r,o68,ooo kg of Baltic herring from the Gulf of Finland were landed in Helsinki. This was nearly the same as the landings of the two previous years. The mean daily landings each week during rg66 Figure 128. Catch of Baltic herring in the island spawning differ from the two previous years by lower values area south-west of Helsinki on the coast side of the third in the beginning of the season and higher values in innermost hydrographical station of the cross section. the end of June (Figure rzg). Three day means/examinations of the net. The composition of the stock KG Samples were collected by "Aranda" from the 30000 open sea areas of the Bothnian Sea, the northern Baltic proper and the Gulf of Finland. The fish were caught with a mid-water trawl in August 20000 during the feeding season of the spring spawners, when the shoals appear scattered in the thermocline at night. The mesh size of the cod-end of the trawl was ro mm between the knots. The material was MAY examined fresh according to the recommendations Figure 129. Mean daily landings of Baltic herring each week adopted by the Herring Committee in rg6z. in Helsinki from the Gulf of Finland during the spawning The stock of the year rg66 consisted mainly of season. three year-classes, rg6r, rg63 and rg64, from which the last one was dominant (Figure I30). The catches were composed of spring spawners •t•• y, (Table r67). 100 The amount of intestinal fat of all fish was higher r-· 30 than in the three previous years (Table r68). The 1965 20 50 -'\ . ' \ proportion of fish aged three years and older with I . I \ N = 3502 large amounts of intestinal fat (degrees + and M i \; \" together) was 55-3% in rg66. .i ···~ .... 10 15 20 25 123456789 Stomach analysis sho-wed that in the age-groups ;~; .. y, ~9§; , 30 three years old and older, 6g.8% contained little I . 1966 ' ' . \..-.. ' I or no food. I ' 1961 N = 3884 1 I .--, 20 50 9 6 The length/weight coefficient of all the herring I \. ~~~ ~ - ~ ; : 1959 (M57) aged three years and older was o.6r7 in rg66. I i'-.i. \.. : : : ~9.§~ ~9§~-; i ...... : I I 1 I I 1 1 10 15 20 1 2 3 4 5 6 6+ Summary 0 Figure 130. The length ( / 00) and age composition (%) of Baltic herring caught by "Aranda" in the Bothnian Sea, The following were typical features of the Baltic the northern Baltic proper and the Gulf of Finland. In herring in the seas around Finland in rg66: rg66, age determinations from otoliths only. (r) The spawning season of spring spawners was put off later. Spawning began in the third week of May. In the Gulf of Finland spawning continued in the island waters far into July. In the feeding season of the spring spawners, (z) The exploited stock consisted mainly of the (4) the amount of intestinal fat of immature year-classes rg6r, rg63 and rg64. The year-classes fish was large and that of spawning fish moderate, rg6o and rg62 were poor. (5) the proportion of fish aged three years and (3) The stock was almost entirely composed of older with little or no food in the stomach was high. spring spawners. (6) the length/weight coefficient was high. Typical hydrographical features of importance (c) The strong upwelling in the Gulf of Finland from the point of view of the fishery were: in summer. (a) The oxygen deficit of the bottom water in (d) The unusual deep surface layer in the Gulf the Gulf of Finland being smaller than the three of Finland in the latter part of the summer. previous years. VEIKKO SJOBLOM (b) The thin surface layer in the former part Bureau of Fisheries Investigation, Fabianinkatu 32, of the summer. Helsinki r7, Finland. -185- Sardine Sprat The English Sprat Fisheries (Figures IJI-133; Tables r69-r77) ~1 Introduction The English sprat fisheries have, until the last few years, always been relatively small scale and only locally important. This has not been due to a lack of resources, but mainly due to very limited markets. The major outlets were for canning, various types of processing and fresh sale, with surplus usually going as agricultural fertilizer. These outlets could only absorb about 3,ooo-4,ooo tons per season. Another limitation to large-scale development has been the small size of the vessels engaging in the fishery, these mainly falling in the 30-40 foot (g-r2 metres) size group, making them very restricted in relation to working range and weather conditions. The east coast of England has always (except during the war periods) supplied the major part of the sprat catch (Table r6g), the south coast fisheries coming a poor second, and although the sprat occurs quite commonly around the west 5 0 coast, regular fisheries have never developed f~r Figure 131. Principal English sprat fishing grounds. it in this region. The Thames Estuary was tradi tionally the most important east coast ground and remaining in large overwintering concentrations the principal method of capture employed there until about mid-February when they commence for at least several hundred years was the stow net breaking up into numerous smaller shoals which - a fixed gear attached to the anchor chain ~f a disperse seawards for spawning and feeding. They vessel moored in the tideway, the strong tidal then become so thinly dispersed and are also of currents carrying fish into the net. In the early such poor quality that it is no longer economic rg5o's a major development took place in this to catch them. The twin problems of changes in area with the introduction of pair-boat midwater seasonal availability and longer-term fluctuations trawling, using echo-sounders to locate the sprat in stock abundance constitute further drawbacks shoals. This new method rapidly proved so much to the regular large-scale exploitation of this species. more efficient than the old that within the space The present series of investigations on sprat of a few seasons the stow net was completely commenced in December rg58, initially to locate superseded as a method of sprat fishing. The fresh stocks for exploitation by the Thames pair Thames sprat fishery then built-up rapidly to a boats- which led to the development of the Wash peak catch in the mid-rg5o's (in 1955 there were about 22 pairs operating), but then showed an sprat fishery early in 1959 and its subsequent detailed study, which has involved echo- and egg- equally rapid decline, falling to a very low level in I959· This slump was entirely due to the non Table 169. Seasonal mean sprat catches (cwt) appearance of sprats in quantity on th~ u~~al grounds which could have been due to availability Period East coast South coast Overall changes, a general decline in abundance of the 1935-39 73,200 38,6oo r rr,Soo stock supplying this region, or a combination of 1945-49 15,200 rs,6oo 30,800 both. The English sprat fisheries are strictly 1950-54 38,8oo 32,400 71,200 1955-59 48,6oo 19,ooo 67,600 seasonal and dependent on the fish aggregating in 1960-64 128,400 29,6oo r58,ooo coastal waters, usually during November, and 1945-64 57,75° 24,150 8r,9oo -r86- Table 170. Catch statistics of the North Shields sprat fishery for the 1966/67 season (North Shields landings only) Type of fishing Number of Number of Number of Total catch C.P.E. C.P.L. :.\lonth unit vessels landings hauls (cwt) (cwtfhour) (cwtflanding) January Single 33 127 391 .j4,62I 1,052 351 Pair 8 52 I 56 33,229 2,374 639 February ...... Single 34 208 624 53,225 1,024 256 Pair r8 63 189 31,755 z,or6 504 Season ...... Single 34 335 1,015 97,846 1,037 292 Pair r8 rrs 345 64,984 2,184 565 surveys, collection of catch statistics, and regular Early in January the research vessel "Clione" sampling to assess the population structure; this was able to make a close-grid echo-survey in and work being extended later to cover the other around the immediate fishing area. At least three main fishing areas. discrete major patches were located, each of these The areas currently exploited are shown in extending between 0.5-1.0 nautical mile across Figure 131, the general details for each fishery being (0.93-1.85 km), as well as several smaller clumps, as follows:- the total trace area amounting to about 3 square nautical miles (10.3 km2), although from the wide General range of fishing positions subsequently reported it Chart Area size range :.VIain types of gear seems likely that only a portion of the total stock number of vessels and fishing methods in the area was covered by this survey. The water North 50-65ft Mid,,vater Pair and depth ranged between 40-45 fathoms (73-82 Shields (15-20 m) trawl single metres) and the fish in daylight occupied a layer 2 Humber- 50-65ft Mid water Pair and up to 5 fathoms (9 metres) thickness lying between Wash (15-20 m) trawl single 30-40 fathoms (55-73 metres) in depth. The 35-40 ft Mid water Pair (ro-12 m) trawl packing density of fish within these layers must 3 East Anglian 15-20 ft Drift (Beach have been very high, as evidenced by the occlusion coast (4-6111) boats) of seabed signals on the echo trace where the fish 30-40 ft Drift (Harbour layer was very thick and the extremely high (9-12 m) boats) catch rates reported at the time and subsequently 4 Thames 35-40 ft J\ilidwater Pair throughout the season (Table 170). At dusk the fish Estuary (ro-12 m) trawl streamed up towards the surface, and at one 5 SE Channel 20-40 ft Drift (Harbour coast (6-12 m) and beach stage fish were noted breaking surface whilst boats) extending on the echo record down to a depth of 6 Poole- 30-40 ft :.VIidwater Pair and 30 fathoms (55 metres). \Veymouth (9-12 m) and bottom single trawl The fishery rapidly developed with the number of vessels participating increasing daily, until by 7 Westbay- 35-55 ft Mid water Pair and Torbay (ro-17 m) and bottom single the end of January about 47 single and 8 pair-boat trawl midwater trawlers were involved. This led to an inevitable glut when the fish meal factories became saturated. Results- 1966/67 season An agreement between the fishermen to restrict The North Shields fishery landings by operating on a sliding quota basis The very disappointing returns shown by the Wash sprat fishery over the period when normally Table 171. Catch statistics of the \Vash sprat fishery it reaches a peak (November-December) led to most of the Grimsby vessels engaged in the fishery Boston and Wells Grimsby seiner-type giving up by mid-December. During the first 40 ft vessels vessels week of January several of these boats decided Pair trawl Single boat mid water trawl to search further north for shoals since there was evidence from research vessel hauls and commercial 1965/66 1966/67 1965/66 1966/67 (Nov. and fishing in previous years of sprat shoals off the Dec. only) north-east coast of England, although no serious Total cwt .. 25,375 7.852 94,154 q,85r commercial exploitation had previously taken place Cwtflanding 136.0 rr6.6 434·0 337·5 there. Cwtjhour .. 6r.o 83.0 r8.9 8.2 -rS7- Sardine then regulated the fishery until mid-February, Table 172. Average percentage contributions of age-groups by when a prolonged spell of very bad weather numbers and weight in the "\Vash, Thames and Torbay sprat virtually ended operations. By mid-March the fisheries main concentrations had broken up into numerous (i) Wash, 1958-66 (9 seasons) scattered small shoals. About ro per cent by A.ge-group weight of the catch consisted of immature herring. 2 3 4 5 6 (2+3) The vVash Fishery ~/~ nun1bers 12.'2 49.2 30-4 6.8 1.2 0.2 79·6 ~~·weight 3-9 4l.I 40.8 II.3 2.3 0.3 Sr.9 This fishery only produced 22,700 cwt (compared with 125,rS5 cwt the previous season), the reduction (ii) Thames, r96r-66 (6 seasons) being partly due to the fish concentrating much ·Age-group later than usual (January instead of November), 2 3 4 5 6 (2+3) 0/ and also to a considerable reduction in total stock. /0 numbers ro.S 45· I 35·8 6.s r.6 0.2 80.9 0/ Fish counter surveys (using a roo kHz echo /0 weight 4·7 41.2 41.7 9-3 2.8 0.3 82.9 sounder) indicated that the total population was (iii) Torbay, 1959-61 and 1965-67 (4 seasons) only about one-fifth that of the previous season ~.\.ge-group and the majority of these were concentrated well 2 3 4 5 6 (2+3) o• to seaward of the usual grounds, beyond the range /o numbers 2.0 33·3 38.6 17.2 7·7 1.2 71.9 0/ of the smaller vessels. In spite of this, as the catch /0 weight 0.7 26.5 40.2 20.2 ro.9 r.5 66.7 statistics for the Wash fishery show (Table IJI), the seasonal mean catch per unit effort for the smaller pair-boat units bettered that of the previous weight over the periods indicated for the 'Nash, season, being due to the high efficiency of these Thames and Torbay fisheries. vessels enabling them to locate and exploit the relatively few good shoals within their daily work It is clearly evident that the major part of the ing range. The Grimsby vessels only fished this catch has been made up of two- and three-year-old region during November and December before the fish in all areas, around So per cent in the Wash fish showed any positive concentrations, their and Thames, somewhat less in Torbay. Fish older mean catch per unit effort being considerably below than three years have made only a relatively that of the previous season. insignificant contribution to the east coast fisheries (S per cent by number, 12-13 percent by weight), The Thames fishery but make a larger showing in the Torbay fishery This fishery was a complete failure, the total (26 per cent by number, 33 per cent by weight). catch amounting to only r,5oo cwt, certainly There is some evidence from research vessel hauls the worst on record since landing statistics com that this lack of older fish in the east coast fisheries menced in rSS6. This was entirely due to a lack is probably due to emigration offshore into deeper of fish, confirmed by a research vessel echo and water and the difference in topography of the fishing survey in January which showed only very coastal water zones between the two areas might thin scattered trace over the usual grounds and help to explain the greater proportion of older fish no signs of fish concentrations beyond in the outer in the Torbay fishery. In the latter region the areas of the estuary. Fortunately for the fishermen, shallower water (below 20 fathoms depth - 36 good cod and spring spawning herring fisheries metres) is restricted to a narrow strip around the provided a reasonable alternative. coastline and deeper more open water extends The south coast fisheries (Ramsgate-Brixham) close into the coast, whereas in the east coast The total catch from these fisheries amounted areas most of the fishing takes place in depths of to 35,240 cwt, a slight improvement over the 5-15 fathoms (9-27 metres). There has also been a much higher proportion of first year fish in the previous year (31,740 cwt), but the Poole fishery was a failure (only 3,400 cwt) and the Torbay east coast catches, which may again be associated area contributed the major part of the catch with the differences in coastal water topography outlined above. The possibility of the present (31,540 cwt). greater fishing effort in the east coast fisheries being responsible for the scarcity of older fish General analysis of the relative contributions of seems unlikely since the \Vash fishery in its first different age-groups to the catch (1958-rg67) season (r95S/59) showed a predominantly one- to Table 172 shows the average percentage contribu three-year-old age structure (97 per cent by number) tions of different age-groups by numbers and after a thirty year respite from fishing. -188- Table 173. Overall mean lengths (em) in the \Vash, Thames Table 174. Extreme ranges of length for age and Torbay sprat fisheries, by age-groups in the Wash sprat fishery (1958-67) Age-group A.ge-group Range (em) 2 3 4 5 Overall 2.5- 9-5 2 ...... 6.5-13-5 \Vash ...... 6.6 9-2 10.7 1I.6 I2.I 9·7 3 ··········· ...... 7.5-15.5 Thames ..... 6.8 9.6 10.9 II.8 12.2 10.1 4 ...... 8.o-r6.o Torbay 8.7 1I.6 12.7 13-3 q.1 12.5 5 ·················· 9.5-16.5 6 10.0-16.0 Other differences are evident between the east There is also a possibility that not only do the and south-west coast fisheries in terms of mean older fish tend to move offshore, but also the length for age. Table 173 shows this for the three larger members of younger age-groups, and dis main fisheries, the Wash and Thames being persion is more likely a function of size rather similar but much smaller than the Torbay fish than age. It has been noted that the older fish which are about 2 em larger at each age. This appearing in the Wash and Thames fisheries are difference could be at least partly due to the peak usually very small for their age and it often produces spawning period in the south-west region falling an effect of decrease in mean length as the fish somewhat earlier (February-April) than in the become older. southern North Sea (April-June), thus giving The 1966/67 season has been of particular interest the fish in the south-west a longer period of growth with respect to size differences between fishing in their first year than their North Sea counterparts. areas. Figure 132 shows the length distributions The extended spawning period of sprat produces a of three-year-old fish (1964 year-class) together very wide time-base for the commencement of with the relative age compositions of the catch development in any one year and this results in a from each of the areas concerned. Table 175 also considerable overlap of length for age (Table 174). gives by areas the relative age compositions The actual period of first year's growth (feeding together with the mean length of each age-group. usually ceases at the end of October or in early The first six localities involve samples taken from November) could range from about ten months commercial fisheries, and the last three were for a fish spawned early in the year to only three covered by research vessel hauls in March 1967. months for one spawned towards the end, and in The Bayman's Hole area was fished for a few some years quantities of late spawned fish pass days in January by a few of the larger Grimsby their first winter in larval or immediate post-larval vessels then engaged in the Shields fishery. The stages (when 2.5-3.5 em in length). These fish West Bay fishery on the Dorset coast is only a lack a true first winter ring on their scales or relatively small scale affair carried out with shore otoliths, so that when subsequently aged as older seines, but is of some interest in that sprat shoals fish they will be allocated to the year-class following usually first appear close inshore along this sector the one to which they actually belong (ILES and of the coast during September and later move JOHNSON, 1962). westward towards Torbay. Table 175. Composition of the catches, by age-groups, and the average mean lengths, in the various sprat fisheries (1966/67 season) Age-group Overall 2 3 4 5 6 North Shields %numbers 43·6 25-7 26-4 4·1 0.1 L (em) ...... 7·9 9-9 12.1 12.5 14·5 9·7 Bayman's Hole %numbers .... . 0.9 12.2 76.1 10.8 L (em) ...... 8.8 10.7 12.2 13-4 12. I Wash %numbers 9.1 38·9 49·8 I.3 0.7 0.2 L (em) ...... 6.5 8.2 10.2 II.9 1I.6 13-5 9.1 Tham.es %numbers .... . q.S 37·7 44·2 I.5 I.5 0.2 L (em) ...... 6.6 9-1 9-3 rr.6 1I.9 II.7 8.9 West Bay %numbers .... . 30·5 6o.o 7·0 I.O I.5 L (em) ...... II.2 12.0 12-4 13.8 13.2 u.S Torbay %numbers .... . 13.0 48.1 21.2 13-5 4·2 [(em) ...... 1I.6 12.9 13-4 13-9 13·7 13.0 NNE Berwick %numbers .... . 28.2 64.1 3·9 (13 miles) I (em) ...... I0.7 I I -4 I3-3 II. I NNE Berwick %numbers .... . 5-I 52.2 30-4 IO.I 2.2 (16 miles) L (em) ...... II. I I2.8 q.o I4·3 I5.2 I3·3 Great Fisher Bank %numbers .... . 44·5 42.2 I3-3 [(em) ...... 1I.4 II. I II.9 II.4 -r8g- Sardine l~: j 0 6 60 40 20 West Buy -o 20 (Dorset) (l} 10 16 30 20 40 10 20 -L~~~==L---~ 0 kl~: 0 [b ' J:: 123456 ° Age groups Figure 132. Length distributions of three-year-old sprats with age compositions of the catch in different areas during the 1966/67 season. It's clear from Figure 132 that the length distribu two-year-olds in most), the proportions of first tions of three-year-old fish showed considerable year and older fish (four- to six-year-olds) varied variation between regions, being smallest in the considerably. The actual densities of fish within Wash and Thames, largest off the north-east coast each fishing area varied from very low in the and in the south-west (Torbay and West Bay). Thames to extremely high off North Shields. The age compositions also showed some differen These differences in mean size can be related to ces, and although three-year-olds were relatively the mean depth of water in each area, comparing strongly represented within each region (exceeding the North Sea samples alone there is found to be -190- absolute magnitudes of abundance, it does give the actual contribution of a brood to the catch. NS __ _2~!..______Table 176 shows the contributions by weight and GFB I total weight caught for each of the year broods ~ (POOl) I I 1959-1965 in the Wash and Thames fisheries and 1H I 0 I this provides a very approximate measure of I relative magnitudes within and between the two I areas. It underlines the outstanding contribution 10 20 JO 40 50 Mean water depth lim LWS) made by the 1961 brood in both areas and those Figure 133. Relationship between the mean length of of 1962 and 1964 in the Thames and Wash re three-year-old sprats and water depth in different fishing spectively. areas W =Wash Table 177 gives an analysis of mean length for TH =Thames age in the two fisheries over the same period. GFB =Great Fisher Bank The Thames sprat fishery had shown a marked BW I= 13 miles NNE Berwick B\:V 2 = r6 miles NNE Berwick decline over the period 1956-1961, with first NS =North Shields signs of recovery in the 1961j6z season. The Wash BH = Bayman's Hole fishery did not commence until January 1959 (after a lapse of thirty years) and the stock was a significant correlation (P. 0.01-o.oz) between then at a high level in this area. In this first Wash the mean size of two-, three- and four-year-old season a very large year brood (1958) appeared fish and the average water depth, size increasing in the catch in quantity as first year fish and then with increase of depth. (Figure 133 shows this for carried the fishery when two- and three-years old the three-year-old fish.) during the following two seasons, even making a good showing when four-years old. However, this brood did not appear in strength in the Thames Comparison between the Wash and Thames sprat area. fisheries rg6rj62 to rg66j67 The 1961j6z season saw the entry of the next Although the Wash and Thames sprat fisheries major brood (1961) as first year fish and these have on average shown very similar relative age subsequently appeared in strength when two- and compositions, there have been differences in the three-year-olds in both regions. The average size quantitative representation of individual year of fish in this brood was generally larger in the broods between the two areas. It is difficult to Thames area, especially at two years of age, but derive reliable abundance indices from the usual the difference became less when the fish were older. catch per unit effort data in a fishery of this type, The 1962 brood showed a very weak entry as and although total catch is usually the least first year fish in both areas (during the very severe satisfactory measure to use for comparison of 196zj63 winter), but showed a progressively stronger Table 176. Comparison between the Wash and Thames sprat fisheries for the years I959-65, as year-class contributions by weight (cwt) at each age Year- Age-group class 2 3 4 5 6 Totals I959 Wash ...... 733 10,803 8,013 4,514 I,oo6 25,069 Thames ..... 77 I,864 2,776 2,749 879 8,345 I960 Wash ...... 799 24,53I 9,659 7·474 689 275 43>427 Thames ..... 138 I7,950 8,975 8,789 I>486 294 37,632 I96I Wash ...... 2,793 23.3I2 65,I96 22,866 I,502 149 rr5,8I8 Thames ..... s.os8 Io,o6s 83,999 22,025 3,I50 8 I24,305 I962 Wash ...... 49 I0,536 34.759 4,807 313 50.464 Thames ..... 45 30,385 99,178 4.956 56 134,620 I963 Wash ...... I,583 3I.465 23,973 659 57,68o Thames ..... I,507 I2,026 5,040 52 I8,625 I964 Wash ...... 3,285 94>4I5 IS, I 57 I I2,857 Thames ..... 405 27,5IO 719 28,634 I965 Wash ...... 213 s.69o 5,903 Thames ..... I,oso s8s 1,635 -rgr- Sardine Table I77· Comparison between the Wash and Thames sprat somewhat larger than in the Wash- the difference fisheries for the 1961(62 to 1966(67 seasons, as mean length amounting to r em at three years of age. for age Since the rg6z and rg63 broods passed through :i\Iean length for age (em) the Thames fishery there has been a drastic decline Age-group in recruitment to this area which has resulted in 2 5 Overall 3 4 the complete failure experienced during the rg66f67 1961(62 Wash 7·7 9-3 10.6 10.8 11.5 9-6 season. Thames ... 8.2 9-4 ro-4 rr.r 12.6 9.2 The rg64 brood made a very strong entry in the 1962(63 Wash area when one and two years old, but a Wash .... . 7.0 9-3 10.4 IO.l II.4 9·7 weaker appearance than expected at three years Thames .. . 5· 7 I0.5 I I. 7 I2.0 I2.5 I I.O of age, and these mainly the smaller fish. The rg65 1963/64 Wash .... . 5·7 9.I 11.2 11.2 II.3 I0.7 brood has so far made only a modest contribution Thames .. . 6.3 9-5 I 1.6 I2.5 I 1.7 10.5 to the 'vV ash fishery and has been very weak in 1964(65 the Thames, whilst the rg66 brood, as far as can Wash .... . 6.2 8.8 I0.9 12.0 12.5 9-7 be judged from first year representation m the Thames .. . 8.2 10.3 11.9 I2.l I3-3 I2-4 catch, is probably weak. I96S/66 P. 0. ]OHKSON Wash .... . 5·0 9.2 II.! I2.3 II.I 9-7 Thames .. . 5·9 9.1 I0.7 11.3 I0.9 8.8 Fisheries Laboratory, Lowestoft, Suffolk, England. 1966(67 8.2 I0.2 II.9 rr.6 Wash .... . 6.5 9-I Reference Thames .. . 6.6 9.I 9-3 II.6 11.9 8.9 ILES, T. D. & P. 0. J OH~SON, I962. "The correlation table analysis of a sprat (Clupea sprattus L.) year-class to entry at two and three years of age, especially in separate two groups differing in growth characteristics". the Thames area where the average size was also J. Cons. perm. int. Explor. Mer, 27: (3) 287-303. -rgz- Scombriform Fish Mackerel part of the Norwegian Channel from southwest of Norwegian Mackerel Investigations in rg66 Egeroy to the west and west to north of Egeroy. (Figure 134-136; Tables r78-r8o) However, at that time the temperature in the surface layer was rather low and the mackerel, Surveys therefore, did not ascend to the upper layers. From r6. March to zg. April a cruise was under Consequently fishing with drift-nets in the upper taken with R.V. "Peder Ronnestad" in the North most surface layer was negative. However, the Sea from south of Viking Bank to the middle part purse-seiners, reaching deeper with their gears, of Skagerak. The routes of the ship and the records made some catches of mackerel and herring. obtained by echo-sounder together with the grid of stations are shown in Figures 134 and 135. During the second part of the cruise (Figure 135) To carry out fishing experiments the ship was the surface temperature had increased with 0.5° equipped with drift-net and line and hook. to I°C, but still the temperature was too low and During the first part of the cruise (Figure 134) the drift-nets operating in the surface layer did not best records of mackerel were made in the western give any catch of mackerel. I 0 HYDROGR. ST. I @DRIFT-NET ST. I " '" " """'" '"" ~'"'" I fJ 0 0 Figure 134- Grid of stations and isotherms at o m during the period r6. March-4. April rg66. The records of mackerel and herring are also shown. -Ig3- Scombriform Fish Mackerel During this period mackerel (probably mixed catch of the so-called conventional mackerel fishery with some herring) were observed from the western yielded about 23,260 tons. Skagerak to west of Feistein light-house. The In addition to the conventional Norwegian best concentrations were recorded near the "Reef" mackerel fishery a purse-seine fishery has developed west and west to north of Eger0y. during the last years in Skagerak and the North During a cruise with R.V. "Peder Ronnestad" Sea. The catch of this latter fishery in 1964 was from r8. October to 4· November the mackerel 31,050 tons, in rg65 130,828 tons and in rg66 about were found in the western part of the Norwegian 382,663 tons. (Table r78). All the catches have been Channel and on the "Reef' off Lindesnes to the taken by purse-seine in the open sea. Egersund Bank with the main concentrations in In rg64, 195 purse-seiners participated in the this latter area as far as go nautical miles off herring and mackerel fishery in the Skagerak and Eger0y. the North Sea; in rg65 the number had increased to 284 purse-seiners, and in rg66 more than 450 The fishery modern purse-seiners worked in this area. Almost all the catches from this fishery were reduced to The drift-net fishery started at the end of April oil and meal. on the "Reef" off Lindesnes and in the western part of Skagerak. Usually this fishery lasts to the Tagging experiments beginning of July. The total catch of the drift-net fishery in rg66 Tagging experiments of mackerel were continued amounted to 8,631 tons and the line-and-hook during rg66. The tagging was carried out both in fishery in summer and autumn to g,r8o tons. In open sea and in the skerries and fjords south of coastal waters the catch of the land-seine fishery Bergen. The external tags are, as in previous yielded about 5,236 tons, when the trawl fishery years, made of alcathene and dorsally fixed with in the North Sea amounted to 93 tons. (Table 178). nylon-gut. The landings of the coastal and fjord fishery for Due to the development of the purse-seine young mackerel were about r2o tons. The total fishery, also internal tags have been used. The o HYDRO GR. ST. @ DRIFT-NET ST. IIIII REC. OF MACKEREL AND HERRING so Figure 135. Grid of stations and isotherms at o m during the period 12.-29. April 1966. The records of mackerel and herring are also shown. -194- Table 178. Catch statistics in tons of mackerel 1964-1966 Gear not Year Drift-net Line-and-hook Land-seine Trawl specified Purse-seine Total 1964 ...... 6,771 8,142 5,254 249 14 3I,050 5I,480 1965 ...... 6,067 10,361 5,29I 239 103 I30,828 I52,88g I966 ...... 8,631 9,180 5,236 93 120 382,663 405,923 Table I79· Tagging experiments in rg66 and number of tagging method is the same as that applied on recaptures herring. The internal mackerel-tag has the inscrip No. No. tion: Nz and serial number. In Table 179 is shown Date Localities Type of tag tagged recapt. the tagging-localities, the date of tagging, the 14· July Breivik/Ski'mevik Yellow alcath. 250 8I number of fish tagged according to type of tag in 20. July Austevoll Yellow alcath. 450 54 21. Oct. North Sea 1966, and the returns in 1966 from these experi 58°03'N; 04 o 48'E Intern. steel 250 0 ments. 22. Oct. s8°00'N; 04 °26'E Intern. steel 1,350 0 24. Oct. 58°o8'N; 04°45'E (Yell. ale. comb. with int. steel) so 0 Biological data 24. Oct. 57°58'N; 04°47'E Intern. steel 36 0 The immature mackerel in Norwegian and 24. Oct. 57°5o'N; o5°2o'E Intern. steel 22 0 28. Oct. 57°3o'N; 04°55'E Intern. steel 2,542 0 adjacent waters usually occurs separated from the 29. Oct. 57°3o'N; 04°24'E (Intern. steel 242 I mature fish. The fishing on the young stock (in comb. w. yell. Norway called "spir", "pir" and "kuvl") goes on ale.) along the coast and in the fjords from the Oslofjord Intern. steel I,5o8 0 29. Oct. 57°3o'N; 04 °24'E to the west coast north of Bergen. Some years, Total 6,700 I36 however, this fishery also takes place further north along the coast. This fishery has since 1957 been Table r8o. Length distribution in em of mackerel rg66 according to gear poor compared with previous years (1957-1948). Purse- Drift- Hook-and- After the spawning, mackerel-shoals migrate into Length seine net Trawl line Total the coastal waters and part of the mature stock 20 penetrate into the fjords along the Norwegian west andsouthcoastand,duringsummerandearlyautumn 2 an important fishery takes place in this area. At this 3 4 7 7 25 31 3I % 6 6 75 8I 7 8 88 96 8 21 ss So A 9 12 7 I9 ~~~ II 30 I4 5 19 -=-=--- 40 I 6 I 48 ,~~~~~•~I 1 2 3 4 ~lJ!L-111~·~•·~· 5 6 7 8 9 10 11 12 13~- 14 15 16 2 145 I3 13 8 179 3 262 39 28 15 344 4 sso IOI 54 28 733 35 I,r98 I27 I03 22 IASO "lo 6 2,220 95 57 II 2,383 7 2,482 78 30 9 2,599 8 1,756 33 19 4 r,8r2 9 1,041 I] 3 I2 I,073 40 603 I3 9 IO 635 489 7 2 23 52 I 2 375 2 3 I2 392 226 I2 24I -1 2 .lllh 3 4 5 6 7 8 •.. 9 10 11 12__ 13 14 15 16 3 3 1~[, -~~~~~~~~~~~~~-8---- 4 II8 II I30 AGE 45 38 2 40 Figure I36. Age distributions (%) of mackerel in I966, all 6 r6 I I7 samples pooled. 7 5 I 6 8 (A) Samples collected during the period I7. January to 9 22. June. so (B) Samples collected during the period IS. July-27. Sept Total II,627 530 6oo r82 12,939 ember. -rgs- Scombriform Fish Mackerel time immature fish are also present in the fjords There have been 54 recaptures from the 5,845 and the gear used is purse-seine, land-seine, land mackerel tagged during rg65. Twenty of these nets and line-and-hook. During the fishery off the were made in rg66 and most showed a long period coast the catches mostly comprise adult fish. of liberation. One only was less than roo days; In Table r8o is shown the length-distribution of 8 from roo to 200 days; 5 from 200 to 300 days; mackerel in rg66 caught by different gears. In and 6 from 300 to 400 days. The more interesting Figure r36 is shown the age-distribution in two of these recaptures are: different periods of rg66. Cornwall to west coast of Scotland 4 Cornwall to Bay of Biscay 2 A. REVHEIM Cape Clear, Co. Cork, Eire to Celtic Sea rr Fiskeridirektoratets Havforslmingsinstitutt, Cape Clear, Co. Cork, Eire to French coast 5 Nordnesparken 2, Bergen, Norway. G. C. BoLSTER Fisheries Laboratory, Lowestoft, Suffolk, England. English Mackerel Tagging in rg66 Netherlands Mackerel Fishery in the North Sea in (Tables 181-182) rg66 Four mackerel tagging experiments were carried (Figure 137; Tables 183-184) out during rg66. The first of these was from R.V. "Ernest Holt", and the others, as in previous The fishery (Table 183) years, were from small inshore fishing vessels. All The total catch of mackerel in rg66 amounted the fish were caught on feathers. Those which were to IIA43·9 ton and was lower than in rg65 (r6,8rg-4 hooked lightly and not bleeding were selected to tons). be tagged. The decrease of the total catch was mainly The details of these experiments are shown in caused by the drop of the total effort from 344,597 Table r8r. hours in rg65 to 258,448 hours in rg66. This drop in effort can be observed in all areas. The main The thirteen recaptures to date are as shown in overall density in rg66 was also lower than in Table r82. rg6s. Table 181 Experiment :' Table 182 Liberated :VIonth H.ecaptured Days at liberty H..V. "Ernest Holt", Celtic Sea .-\pril S. of Botney Gut, North Sea ...... 6o 13 m S. of Kinsale, Co. Cork, Eire ...... Ioo 30m SW of Bishops H.ock ...... 235 Labadie Bank ...... 264 Near Coningbeg Lighthouse, Co. \Vexford Eire . . . . 205 24m SSW of Bishops H.ock ...... 235 Off Newhaven, Sussex ...... June Shetland ...... 13 NE of Silver Pits ...... 52 Dogger ...... 36 Off Newhaven, Sussex ...... September Off Kessingland, Suffolk ...... 33 Off Teignmouth, Devon ...... 95 Off Berry Head, Devon ...... go Off Mevagissey, Cornwall ...... October Off 'Cshant, France ...... I IS -rg6- • 597 MACKEREL 102 • August 1965 • • 116 100 •returns 31 days at liberty Figure I37· Tagging area and recaptures of the experiment in the summer 1965 along the Dutch coast, with some new recaptures added. - 1 97- Scombriform Fish Mackerel Table 183. Total catch, effort and catch per effort in four fishery areas during 1966 Numbers of hours fishing Catch in kg per roo hours Total catch in kg trawler soo BHP fishing trawler 500 BHP Month ,\rca NN NE NW s NN NE NW s NN NE NW s January 350 350 r,66r 3,721 164 39 21 9 February 3.791 6,267 300 7.955 3-467 293 48 r8r 102 :March .. 86,-'}16 +1,983 4.]90 1],239 4,]02 r,g6o 50 I 893 24+ April .... 87,730 3,38o,8or 356,8r6 50,702 r,807 21,023 r,8r8 427 4,855 r6,o8r rg,627 II ,874 :VIay .... 120,983 2,31],340 2,203,310 13,534 1,390 15,561 I0,783 I,78+ 8,704 q,8gz 20.433 759 June .... go,56z 30,389 143.920 77·274 3,7I9 2,282 I0,726 12,048 2,435 I,332 I,342 64I July .... 126,-'}8+ 943 39.39I 223,492 4,98I 352 9+4 28,ooo 2,539 z68 +,I]3 798 August .. 2I3,879 I60.-'fi3 28,593 26r,8I9 3.39° z,rg6 I ,005 28,774 6,309 7,305 2,8+5 gio September 5I,407 97.452 2II,537 3.38I 2,561 20,951 1,520 3,8o5 I,OIO October 332,040 I]4,959 224,91 I 6,286 3.579 8,042 5,282 4,888 2,797 November 61,528 I 84,800 2I,I75 4.738 5,008 r,go5 I,299 3,6go I, II2 December ],003 4.42+ I,963 5,823 357 I,0]6 Total ... I,I82,I]3 6,-'fOO, I'2 I z,776,82o I,o84,7+4 58,5ro f0,275 27,+00 102,263 Grand total I I ,+-'}3,858 kg 258,4+8 hours 4,+28 kg/Ioo hours Table 184. Age composition of the catch in numbers per roo hours fishing of a standard trawler in April and l\'lay in the area NE Month ~~\ge 2 3 4 5 6 7 8 9 >9 Total :vlay ...... 375 2,478 I,8I6 2,I87 3,062 5.737 4·754 3.348 I5,046 38,803 April ...... I,290 2,777 2,6I3 3,5I3 3,]I2 5,I-'fi 6,565 +.236 J4,329 +4.376 April-May ..... 833 2,622 2,2 I5 z,8so 3,387 5.439 5,66o 3.]92 q,687 41,639 0/ I 13.6 g. I /0 ...... 2.0 6.] 5·3 6.8 8.r 13. 35·2 Age composition (Table r84) In total zoo mackerels were tagged and liberated. In the age composition the 1958 year-class was From the tagging experiment in summer rg65 again dominant, the recruiting rg63 year-class was recaptures have been reported. Tagged mackerels very moderate in strength. were not only caught along the coast of Bretagne As usual the part formed by mackerels older than and Cornwall, but recaptures have also been made nine years was very substantial. in the Norwegian Deep. (Figure 137). Due to adversal weather conditions the tagging Tagging results programme in August rg66 along the Dutch coast A small tagging programme was carried out in was postponed to August rg67. the central North Sea south-west of the Dogger Bank, in order to compare the difference in the J. J. ZIJLSTRA, K. H. PosTuMA returning rate of internal and spaghetti tags. The Rijksinstituut voor Visserijonderzoek, Haringkade r. internal tags were fitted out with a nylon thread. IJmuiclen, Holland. Salmon and Trout Danish Research on Atlantic Salmon in West The sex ratio was 1.3 females to r male. The sea Greenland Waters 1966 trout count was the highest since the experiment: The weather conditions in the fishing season, began in 1960 and approximately two-thirds oJ which is from September to the middle of Decem the run was made up of whitling. ber, were very bad and hampered the fishery In the Spring, 3,331 salmon smolts and 4,691 severely especially in November and December. sea-trout smolts were passed down. These were all The fishery stopped in fact about the middle of measured, tagged and marked by clipping the December. adipose fin. Although there were fewer salmon smolts than in 1965 the mean length of r6.2 ems. The output of the Greenlanders' gill-net fishery was larger than usual. About 88% of the salmon for salmon in coastal waters was 1,250 tons. In smolts were 2 year old fish, the percentage of the Davis Strait the Faroese fishing vessel "Bakur" r and 3 year olds being 9 and 2 respectively. The caught about 70 tons salmon in drift-nets. number of sea-trout smolts was higher than in Electro-fishing experiments were carried out in 1965, the mean length being 20.9 em. 77% were rivers in ICNAF Division rF. In a river in which 2 year olds, the remainder being 3 year olds. Norwegian salmon eggs were planted out in 1958 The estimated spawning run of salmon in 1965, and 1959, 3 parr measuring r6-r7 em were based on the marked and unmarked kelts passed caught. Scale reading showed that these small down was 324 compared with an actual count of salmon were 4 years old and possibly second 239. Similarly, with the sea-trout, the estimated generation from eggs planted in 1958. run for 1965 was 2,946 compared with a count of Fishing experiments with drift-nets were carried 2,566. This estimate includes the small sea-trout. out in June in the Irminger Sea off South-east Six Axe salmon were caught off Greenland in Greenland. 4 salmon were caught. It is the first 1966. Five of the fish were tagged as smolts in salmon taken far from the coast in this area. They the spring of 1965 and one was tagged as a kelt, were smaller than the salmon caught in the Green after being stripped at the hatchery in November, land fishery with gill-nets in the autumn. Possibly rg65. they are salmon which have left their home rivers The first batch of hatchery-reared salmon to go to the feeding area off \Vest Greenland. smolts were released into the Axe in the spring From medio September to medio November of rg66. These were all I year olds, the total research work was carried out by Scottish, English, number released being 4.395· Canadian, and Danish salmon experts in ICNAF Division rD. Smolt tagging programme, the rivers Usk, Wye and Severn 728 salmon caught in gill-nets were tagged in No smolts have been tagged in these three inshore waters in this area. rivers since rg64 but further reports of recaptures 130 salmon tagged in foreign rivers were re were received. Forty-two fish were recaptured in captured in inshore waters in Greenland. The rg66, bringing the total to 207 by the end of the recaptures were from tagging experiments made year. Just over a third of the tagged salmon in the following countries: Canada III, England 6, recaptured in 1966 were taken in the Severn Scotland II, and U.S.A. 2. estuary and fish from all three rivers were repre P . .M. HANSEl\ sented among the catches. Unlike earlier years, Gmnlands Fiskeriundersogelser, J cegersborgalle I, all the fish caught in the non-tidal waters had Charlottenlund, Denmark. returned to their parent rivers. An Usk fish was recaptured in the sea off Co. Mayo, Eire. There British Investigations on Salmon and Sea Trout 1966 were no recaptures of Usk, \Vye and Severn fish off Greenland in rg66 but the total number caught River Axe in that area has now reached r8 - six from each In 1966, 302 salmon and 3,145 sea-trout were of the three rivers. This represents 8.7% of all counted up through the trap. An analysis of the recaptures or rr.2% of all recaptures, excluding salmon scales showed that 30.8% were grilse, grilse. 44% were small spring and summer fish and 8% A. SWAIN were large spring and summer fish. 6.3% were Salmon and Freshwater Fisheries Laboratory, previous spawners and ro.9% could not be classified. IO, "Whitehall Place, London S\\' I, England. -rgg- Salmon and Trout ;erman Investigations on Salmon and Trout rg66 oombo;%,~ (Figures 138-qo; Tables 185-187) t Sept. 66 50 l net 544 The fishery The German salmon landings amounted to [77,5 tons in rg66, which was by far the lowest J.gure since rg56. Although the number of vessels 1001 50 taking part in this particular fishery decreased :onsiderably during the last years, the decline in yield is not due to a lower effort. ·whereas the :juantity of cutters diminished from nearly So to 1001 ::487 35 by some so%, the average number of nets 50 ~66 :arried by a fishing unit grew about fourfold from I20 to soo*). Therefore a change in the stock ~onditions is thought to be responsible for the heavy decline in the yield, these variation at least 100150 partly being due to the fishery. Up to the season rg64-rg65 an average indivi dual gutted weight of more than 4 kg was charac teristical of the catch composition. In the following 1001 net 835 50 season this figure changed rapidly, now being ~65 lower than 3-5 kg. As will be seen from Table r85 this fact is due to the scarcity of large salmon. Sept. 65 Whereas salmon of more than 5 kg in weight 100 net 947 amounted to about 35% of the catch in the rg64- 50 rg65 season this figure in rg66 came to rz% only. \ l !~60 80 100 Lt em The drift-net fishery is highly selective, F being much higher in the A.z+ than in the A.r+ sea Figure I 38. Length-composition of German salmon landings age-class, as has been shown for the period 1957- I965/66. 1963. There is some evidence, however, that the selectivity has changed since then. The greatest elastic than that of the gear previously used. This part of the deep-sea fishing fleet is now applying results in shifting of the so%-retention length to Japanese drift-nets, the material of which is less smaller individuals. Furthermore, the strops be- Table 185. German landings of salmon from the Baltic proper, gutted weight % of ann. total _1\verage >5 kg, % of monthly total Month Tons Number tons number weight, kg number \Veight January ...... 19.2 5,449 Io.8 9-9 3-53 17.0 33·1 February ...... Ig.6 6,269 II.O II.4 3-13 8.5 r8.6 March ...... 20.7 6,555 II.? !2.0 3-17 Io.g 23·4 April ...... II.O 3,708 6.2 6.8 2.96 9-9 24.8 May ...... ro.5 3>447 5-9 6.3 3.06 8.o I8.7 June ...... 3·8 I,Ig6 2.1 2.2 3-17 4·0 7-9 July ...... I August ...... 3-4 g6g r.g r.8 3-49 zs.r 39·7 September ..... 20.5 6,3I3 II.6 II.5 3-24 17.2 3!.6 October ...... 17-9 5-405 IO.I g.8 3-31 q.o 28.4 November 2!.5 5,873 12.1 Io.8 3.66 24.1 43·7 December ..... 29-4 g,6o5 !6.6 17-5 3-07 15-5 34·8 Total ...... 177-5 54,790 !00.0 IOO.O Average ...... 3-24 12.2 24.2 *) The exact effort figures expressed in numbers of sets have not yet been worked out. For data until rg6z-rg63 see "Ber. Dtsch. Wiss. Kommn. 1\'leeresforsch.", 18 (3-4). -200- Table 186. Length-distribution of German salmon catches 1965/66 I965 I966 September November January April :\lay September net net hook, net hook, net net net Lt em Gotland Gotland, Danz.-T. Danziger Tiel Danziger Ticf Danziger Ticf Gotland 47 48 49 6 so 2 51 J I 52 6 53 q 54 23 2 55 28 56 32 3 I 57 45 3 2 2 8 58 26 3 4 5 7 8 59 48 ,, 7 3 34 6o 46 5 4 G 28 6I 43 IO 14 8 g 30 62 55 8 r8 II 13 3I 63 6o 9 22 IS -+ 28 6-t 6z 24 29 23 2I 20 65 35 24 34 2I 28 66 30 38 38 30 32 20 67 39 54 47 4I 3I I7 68 I8 59 54 34 49 9 69 I3 ss 53 37 54 6 70 20 69 66 27 70 I r 7I 14 73 gi 35 6I 5 72 4 62 go 26 64 9 73 8 55 83 19 55 7 74 9 47 75 23 43 5 75 7 30 63 IS 52 I2 76 IO 27 4g I7 37 8 77 I I 32 48 I5 zS 14 78 12 I3 42 10 I6 r6 7g q I6 22 6 6 IS So IS 5 I3 4 5 20 8I 14 6 23 -+ 2-f Sz I7 I3 I I 22 83 23 8 3 22 84 24 5 7 4 2 26 ss 35 7 I8 q 86 25 4 7 IS 87 I7 3 IO 13 88 II 9 I7 2 8g I2 I3 II 6 go II 6 Ill 2 tween the floating line and the net itself are now consequently causes a decline in the size of the much shorter or even absent. This has also caused A.z_:__ sea-age-class in subsequent seasons. a larger proportion of small salmon to be caught The most important fislling place for German because the small individuals inhabite the upper salmon fishermen is still the Danziger Tief. In the most water layer. Finally the season nowadays beginning of the season the fleet is scattered in starts in July already with a considerable effort. area 3 but as the seasons proceeds it will more In this time of the year most of the A. I+ salmon and more occupie southern places. It was only in are still smailer than 6o em. ::"Jovember that some of the vessels moved to the Bearing this in mind, it sounds reasonable that Danziger Tief and even to Bornholm. Later on the A. I-- sea age-class is now exploited to a all places but area 5 \\·ere of minor importance larger extent than it has been before. And this (Table I87, Fig. I39)- -201- Salmon and Trout Table r86 (continued) 1965 I966 September November January April May September net net hook, net hook, net net net Lt em Gotland Gotland, Danz.-T. Danziger Tic£ Danziger Ticf Danziger Ticf Gotland 91 ...... 4 9 27 2 92 ...... 3 12 30 3 93 2 7 I7 8 94 ...... 8 I9 4 2 9S 3 4 IS 2 96 4 IS 3 97 ...... 3 8 3 4 98 2 9 3 2 99 ...... 2 () roo I2 2 101 3 I 4 102 3 I 103 2 104 105 ro6 107 2 roS 109 2 ITO I I I II'2 II3 rq IIS 1I6 117 II8 Total 947 S44 Tagging experiments In March 1966 a number of 4,513 hatchery reared salmon smolts have been tagged and liberated in a small brook near Kiel; the fish being of a size of 13.5-25.5 em and mainly 14.5-18.0 em. Electrofishing one week after the release showed that all but about 400 smolts had left the fresh water. ~o fish was seen during a further test fishing three weeks later. In spring an important herring fishery by means of gill-nets was carried out in the coastal zone of the said place. 53 smolts were caught in the course of this fishery near the entry of the brook into the sea mainly in April. From June to December recaptures were recorded from Danish waters (Lille Bcelt, Kattegat) and one from the inner part of the Oslo Fjord. Three more fish were caught between Bornholm and Blekinge (Sweden) one each in September, November and December 1966 (Figure 140). The results so far show that salmon released in the region of the Kiel Bay tend to leave the home area in a northerly direction. As some of them seem to visit the Baltic proper, the said experiment may contribute to some extent to the stocking of Baltic salmon. Figure r 39- Statistical areas of salmon fishing in the Baltic. -202- Status of the Baltic Salmon Stocks in the Latvian Rivers rgs6-rg66 (Tables r88-r89) During the last ten years two tendencies 1vere observed in the development of the stocks of the Baltic salmon. This can be seen both from the total catches and from the average catches per unit of fishing effort (per set net) for each season in Daugava, the main salmon river. In 1956- 1961 the salmon stocks were on a low level and in 1963-1966 on a high level. This can perhaps be explained by the increased release, particularly since 1966, of smolts from the rearing stations of Latvia. The size of the yearly catches is determined by • the strength of the year-classes which constitute [j" the bulk of the catches. The strength of the year-classes of salmon depends on the abundance of the parent stock (the correlation coefficient between abundance of the parent stock and the size of the year-class of offspring is -0.72) and on the size of the spring/ summer discharge in the year in question, (the Figure r4o. Recaptures of salmon smolts tagged in .March 1966 near Kiel (The number 53 indicates recaptures in correlation coefficient between spring/summer dis the neighbourhood of the place of release). charge and year-class strength is +o.58). In 1956-1958 the salmon spawning stock Table 187. Distribution of the German fleet on the fishing consisted of the poor year-classes 1951 to 1954, places, number of vessels in % therefore the catches were low (Table r88 and 189). Statistical area In 1960-1962 when the bulk of the spawning Month 3 4 5 6 stock was composed of the rich year-classes 1955 January ...... l4 82 4 to 1958, the catches, within the low level of the February ...... 93 7 stocks, were high. March ...... roo April ...... 64 36 Within the high level of the stocks, the highest May ...... roo catches were registered in 1963 when they consisted June ...... roo mostly of fish belonging to two rich (1957 and July ...... August ...... roo 1958) year-classes and one (1959) year-class below September ...... roo average. October ...... roo Beginning from 1964, the spawning stock was November 6r 26 r3 December ...... 98 2 recruited by poor (1959-61, 1963) year-classes, and the catches declined somewhat. Another tagging experiment concerns marking of feeding fish in the sea. 500 adults of the sea Table I88. Age composition (in %) of the salmon caught in Daugava age-class A.1+ have been tagged by means of Carlin tags in November and December 1966. Age 2+ 3-f- 4+ 5+ 6+ 7+ 8+ 9+ 16 individuals recaptured by now had moved in Year fished northern and western directions. No final con r958 7·8 17·4 37·8 30.0 6.0 I.r clusions can be drawn for the time being. How r959 r3.2 r8.r 38·4 r7·9 ro.r 2.3 ever, the records seem to indicate a longer distance r96o 4·8 39·7 31.9 r9·9 3-4 0.3 of migration than found in previous experiments. r961 o.8 10.9 41.1 34·6 11.6 1.0 1962 0-4 4·1 30.2 31.9 28.5 4·1 o.8 F. THUROW 1963 o.s 5·4 21.8 34·8 24.1 11.7 I.7 Bundesforschungsanstalt fur Fischerei, r964 r.8 r6.3 29.8 28.9 17.8 4·2 0.6 o.6 Institut fiir Kiisten- und Binnenfischerei, Labor Kiel, 1965 o.8 r3·7 33·8 27·4 20.7 3·3 0.3 Kiel-Seefischmar kt, Germany. 1966 0.6 8.3 39·9 31.2 r6.r 3·9 -203- Salmon and Trout Table r8g. The strength of salmon year-classes in Daugava (in conditional units) Year-class I95I I952 I953 I954 I955 I956 1957 I958 1959 I96o rg6I I96Z 1963 Strength ...... 0·37 0.62 0.]0 o.65 I. IS 2.12 2.26 1.22 0.90 0.]8 o.95 I.02 0.46 In rg66 the catches were based on fish belonging to two poor (rg6o, rg6r) year-classes and one average (rg6z) year-class, therefore they remained relatively low (Table r88 and r8g). In 1967 the fishery will be based upon two poor (rg6r and rg63) and one average (rg6z) year classes and the catches will be on the level of rg66. B. R. EVTUHOV A l3ALTNIIIZKH, l3ezdeligu I, Riga, USSR. -204- Other Fishes Danish Observations on Halibut, Catfish, Capelin, 177 redfish caught in pound nets in the Godthat Lumpsucker and Redfish in West Greenland Waters Fjord were tagged. zr redfish tagged in previom rg66 years were caught in 1966. Two of these recapture' The catches of Greenland halibut decreased from were taken about 6 years after tagging. about 3,000 tons in 1965 to 2,500 tons in rg66. P.M. HANSEN Also the catch of catfish decreased with about Gronlands Fiskeriundersogclser, J acgersborgalle r, 1,700 tons. Charlottcnlund, Denmark, Capelin which mainly is used for fish meal, but in dry condition also for consumption and dog Soviet Investigations on Young Redfish (5. mentella food, was fished in about the same quantity as and 5. marinns) in the Barents Sea in rg66f67 in rg65, namely 1,357 tons. Samples in frozen (Tables rgo-rg3; Figures qr-r.p) condition \vere sent to the laboratory from many In the autumn-winter of rg66j67 quantitative fishing places in Greenland. analysis of young redfish was carried out on board The production of htmPsucher roe for caviar the R.V. "Tunets". For this purpose a common was 579 tons, which is nearly the double of what bottom trawl with a nylon net with 8 mm meshes was produced in the previous year. in the cod-end was used. 79° • 1-10 • 11-50 • 51-100 101-300 >300 -::. ..* • • ••• .. •• • • • lf» '8 • - . • 74° • =· .. - • • - - • -· • ••!..!-.•. 30° Figure qr. Distribution of young redfish of 6-rz em length in rg66. -zos- Other Fishes Analyses of all the material showed that the listribution of the young S. mentella in the Bear • sland/Spitsbergen (Division lib *) in 1966 was nore to the south than in previous years 1960-1965 • Table 190). Main concentrations of fishes of • • )-16 em in length were found south of West • )pitsbergen and on the southern slope of the Bear • sland Bank (Figure 141). In those catches redfish?QO • • lf 9-13 em in length and of the 1963 and 1964 rear-classes prevailed. The 1965 year-class was net with singly and the individuals of the 0-group • 1-10 ••• lCcurred only in catches taken in the Western Deep. • 11-50 In the southern Barents Sea (Sub-area I) the J. 51-100 nain part of the catches taken in December 1966 1•101-300 md in January-February 1967 consisted of the roung S. marimts. Fishes of the 1966 year-class 30° nade up more than half of the catches. Redfish Figure 142. Distribution of young redfish of up to 5 em in d a length of up to 5 em spread eastward along length in I966. Table I90. Average catch of young redfish taken per I hour-trawling in September/October I966 Number of A.. verage trawling Size in em catch per one Areas hours >5 6-8 9-II I2-I3 q-I6 hour travvling >Vest Spitsbergen ...... 4I +**) I6 26 IO 52 3outh Cape Deep ...... q 6 3 + II Western slope of the Bear Island Bank .... 9 + 8 5 I4 3outhern slope of the Bear Island Bank ... 9 + 45 97 6 q8 Hopen Island Area ...... 2I + .J_ Perseus Elevation ...... VV estern Deep ...... 5 + 6 2 9 ::entral Elevation ...... 8 ' + rota] ...... I07 + I2 I9 4 35 Table I9I. Average catch of young redfish taken per I hour-trawling in December, January and February I966/I967 Number of Size in em Average trawling <5 6-8 9-II 12-I3 catch per Areas hours one hour Western Deep ...... 3 39 5 44 88 Fugl0ybank ...... 3 29 7 36 S0r-Bank ...... 2 +**) I07 6 II..f Nordkyn Bank ...... Io 9 + II Demidov Bank ...... I I 8 8 Murmansk Tongue ...... I I 5 5 Central Plateau ...... 3 + 9 9 North-eastern slope of the Murmansk Bank . . 9 9I I29 North-western slope of the Murmansk Bank . . 3 6 + 7 Finnmarken Bank ...... 8 + 56 South-western slope of the Murmansk Bank . . 5 -;-' + + Kildin Bank ...... 5 + West-coastal Area ...... 8 + 2 + 3 East-coastal Area ...... 7 5 6 II Murmansk Shallow ...... Io I3 I2 + 25 Northern slope of the Murmansk Shallow . . . . Io 2 3 T' 6 North-central Area ...... Io 2 Central Deep ...... 23 + -,-' + West-central Area ...... 5 .J_ Western slope of the Goose Bank ...... 5 + 3 Northern slope of the Goose Bank ...... I I 6 Novozemelskaya Bank ...... 5 Northern part of the Novozemelskaya Shallow 3 Total ...... I70 3 !2 + + IS *) According to the ICES statistical divisions (Bull. Stat., 49: Sr.). * •) Occurrence of young in insignificant numbers -206- Table 192. Average catches of the young redfish taken per the coastal and main branches of the Murmans1 I hour-trawling in the southern Barents Sea in different Current (Figure I42) and were found even in inleb years at the Murman coast. Five redfishes of 4-5 em ir Number of Years trawling size in em length were caught in the Zelenetskaya Inlet. A hours <5 6-8 9-16 particularly great number of fishes of the I96E 1962 ...... 18 I year-class were caught on the north-eastern slop< 1963 ...... 55 +*) 2 of the Murmansk Bank (38 specimens per I hom 1964 ...... z8 6 + trawling), in the eastern coastal area (5 specimens) ...... 68 1965 I3 65 3 and on the Finnmarken Bank (4 specimens pel 1966 ...... 165 3 II I hour trawling) (Table I9I). Such an easterr *) Occurrence of young in insignificant numbers. distribution of young redfish had not been observe( during the last years. (Table I92). In December-January redfish of the I966 year class were eaten in great quantities by cod on th< Table 193· Frequency of occurrence of redfish yearlings in cod stomachs in January/February 1967 Nordkyn, Demidov and Murmansk Banks and in Number Frequency of the eastern coastal area (Table I93). In these area~ of cod occurrence young redfish were found in so% of the cod ,\reas stomachs of redfish stomachs. Many cod stomachs contained 20-7c analysed yearlings small redfishes. (in%) T. S. BERGER Eopytov Area ...... so z8 ·western Deep ...... 76 21 PINRO, 6, Knipovich Street, Murmansk, ·cssR. ~ ordkyn Bank ...... 400 51 Demidov Bank ...... 226 40 :VIurmansk Tongue ...... 302 +7 ?\orth-western slope of the The Age Composition of the Plaice Stocks exploited Murmansk Bank ...... g8 40 by the Dutch Fishing Fleet in rg66 Finnmarken Bank ...... 200 38 Norwegian Deep ...... So 23 (Tables 194-197) Rybach'ya Bank ...... 75 21 :Vlotovsky Bay ...... 25 16 In the Tables I94 and I95 the age composition South-western slope of the of the Dutch plaice landings is given per unit of Murmansk Bank ...... 12-J. so effort for both the otter-trawl and the beam-trawl. Kildin Bank ...... zoo 31 The data of these tables were derived from market \Vest-coastal area ...... 105 32 East-coastal area ...... 67 40 samples using length-age keys per quarter of the North-eastern slope of the year. :vlurmansk Bank ...... 1 74 7 In the first quarter the age compositions are Northern slope of the Murmansk given for three areas viz. the German Bight, the Shallow ...... 75 17 North-central Area ...... ISO 2 Cleaver Bank and the Southern Bight area. Table 194. Age composition of the catch per roo hours fishing per standardcutter of 200 BHP of plaice fished with the otter-trawl in 1966 (Upper figure: males; lower figure: females) 1955 and Year-class 1964 1963 1962 1961 1960 1959 1958 1957 1956 older 1st quarter zos 681 576 613 371 156 107 48 9 47 German Bight 242 449 334 376 399 265 92 75 29 216 1st quarter 291 883 780 8os 458 203 124 .J-2 8 55 Cleaver Bank 294 596 490 399 404 264 87 76 35 202 1st quarter 813 1,998 1,589 2,994 775 408 r28 23 0 37 Southern Bight 1,035 1-442 840 478 .J-05 zz8 134 62 18 283 znd quarter 0 1,510 702 235 231 86 r6 42 8 0 southern North Sea 24 1,755 541 177 liZ 142 57 53 21 141 3rd quarter III 1,974 1,214 400 114 67 r8 0 0 0 southern North Sea 134 2,492 727 199 129 51 59 24 9 68 4th quarter 313 1,544 264 119 96 92 40 14 0 22 southern North Sea 353 1,385 r86 II.J. 70 85 94 53 z6 90 -207- Other Fishes Table 195. Age composition of the catch per 100 hours fishing of plaice with the beam-trawl in 1966 (Upper figure: males; lower figure: females) 1955 and Year-class 1964 1963 1962 rg6r rg6o 1959 1958 1957 1956 older rst quarter 408 1,272 I,I20 1,303 710 388 272 139 r6 138 German Bight 406 847 Sro 928 1,002 720 268 298 137 537 rst quarter 590 1,385 1,067 1,055 615 279 191 48 5 6r Cleaver Bank goo 930 543 489 570 292 g8 75 37 203 rst quarter 1,166 3,311 2,922 2,846 1,627 702 427 uS 0 152 Southern Bight 1,266 2,249 1,525 1,307 1-455 693 257 roo 71 426 2nd quarter 0 2,548 1,422 480 470 r66 31 87 r6 0 southern North Sea 49 3,423 r,og8 352 200 258 84 Sr z6 144 3rd quarter 136 1,923 1,194 396 IZI 63 19 0 0 I southern North Sea 142 2,345 749 218 r6r 70 g8 45 23 152 4th quarter 489 2,298 466 175 ro8 III 63 23 0 23 southern North Sea 489 2,508 305 129 87 95 rog 65 38 q6 Table 196. Average length (em) per year-class of marketable plaice with the otter-trawl in 1966*) (Upper figure: males; lower figure: females) Year-class 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 rst quarter 29-9 30.8 33·0 34-9 35-4 36.0 35-4 40·3 German Bight 27.8 31.8 35-2 38.1 37·7 41.0 41.7 45·7 44·5 44·0 ISt quarter 30.1 31.1 32-9 34·6 35·1 35·5 35·3 40.1 Cleaver Bank 28.r 32.0 35·0 37·3 37-4 40·9 41.8 45·3 45·2 44·8 rst quarter 29.5 30.5 32·3 34·0 34·3 34·9 32.8 41.8 Southern Bight 27.6 31. I 34·3 36.8 36.6 40.8 44·3 45·2 4+6 2nd quarter 27·9 31.4 31.4 32·5 34·0 35·0 34·0 southern North Sea 29.0 29·3 32.6 34·7 37·3 36.8 40.6 42.0 42·3 45·6 3rd quarter 27-9 28.6 31.0 32·4 31.3 33·5 34·1 southern North Sea 28.o 28.5 32.6 35-0 36.8 38.g 40.0 41.5 44·2 44·0 4th quarter 26.8 28.o 31.8 35-4 36.6 35·5 36·4 36.1 southern North Sea 27·5 2g.6 35·0 37·2 38·5 38.8 40.0 42·3 42·9 43·7 *) Derived from dead fish sampled in the fishmarket, plaice smaller than 25 em is not landed. Table 197· Relative age compositions of mature male plaice caught by R.V. "vVillem Beukelsz" on four spawning grounds in January and February 1966 1955 and Year-class 1964 1963 1962 rg6r rg6o 1959 1958 1957 1956 older %of Southern Bight numbers caught 8.7% 27.8 20-4 17.6 q.r 6.1 3·0 2. I average length 22.9 Clll 26.3 32·5 33·2 35·8 33-7 36.0 37·4 %of Cleaver Bank numbers caught 2.8% II. I 35-4 33-4 ro.g 4·8 o.S 0-4 0-4 average length 2I.ICffi 26.3 30.8 34·4 37-2 %of German Bight numbers caught 3-3% 13·3 19·7 30-4 23·5 1.5 6.8 1.0 average length 2r.gcm 22.3 30.6 33·8 37·1 37·0 39·7 % of Flamborough numbers caught 12.9% 18.8 25.8 19-5 r6.6 3.6 2.9 Off Ground average length 21.6cm 26.3 30·3 31.7 35·0 35-7 35·5 It was found that plaice occupying these areas strong or poor year-classes. In the first quarter the in the first quarter (spawning season) belong more strong year-class born in rg6r is prominent, or less to three different populations. Thus the especially in the otter-trawl data for the males in age compositions for the first quarter are indications the Southern Bight (the otter-trawl fleet covers of the age compositions of these three populations. more of the spawning areas than the ships working In the rest of the year mixtures of the three with the beam-trawl). In the second quarter the populations are fished. Although only the data rg6r year-class has lost much of its importance for the first quarter are more or less representative and in the third and fourth quarters the rg6r for the populations as a whole, the data from the year-class seems to be a rather poor one. In reality other quarters are indicative of the existence of these facts reflect the movements of the year-class -208- (' 1000 in and out of the area fished by our fisherme11 when fishing for sole. In the first quarter only, thE ""ct 0 complete year-class was exploited whereas in thE rest of the year this year-class moved to the nortb ~ 1000 "' of our sole fishing area. ""<::, ~ 0 Another feature of the tables is the strong rg63 i;; II v X year-class recruiting to the fish ~tocks. <:).__ 3000 '58 In Table rg6 the average length per year-class t' is given for the otter-trawl-landings. The length "' ""'§ was measured on dead fish in the fishmarket. " In the winter of rg66 the research vessel "Willem Beukelsz" carried out local tagging and transplanta tion experiments on the spawning grounds of the 0 plaice in the southern North Sea. II X XV 3000 In Table 197 the age composition of the mature 58 male plaice on four spawning grounds is given together with the average length per year-class. In this case the length was derived from live fish. In contrast to the data given in the Tables 194 and 195 based on landings of commercial ships, the rg63 0 year-class does not appear as a strong one. The same is true of the rg6r year-class, with the 2000 exception of the German Bight, where this year class is a prominent one indeed. J. F. DE VEE]';" Rijksinstituut voor Visserijonderzoek, Haringkade I, 0 IJmuiden, Holland. II V 58 X XV 47 03~ The Age Composition of the Dutch Sole Landings in II v X XV 3000 rg66 (Figure 143; Table 198) In Table rg8 the age composition of the Dutch 58 sole landings is given per unit of effort for both otter-trawl and beam-trawl. 47 0 The data were derived from market-samples II v X XV using length-age keys per quarter of the year. It is obvious when looking at the data that the 5000 year-class born in rg63 is a very dominant one. In the first quarter of the year the catch consisted for more than go% of this strong year-class and in the fourth quarter after a beginning recruitment of the rg64 year-class 70% of all individuals still belonged to the rg63 year-class. The strong year-class rg58 which dominated the catches in rg6r and rg6z is still present but '58 has lost much of its importance. 47 0 Another feature of the age composition is the V X XV XX scarcity of the year-classes rg6r and rg6z. The year-group latter is even absent in the 4th quarter age com positions. This scarcity is caused by the severe Figure 143· Age composition of Dutch Sole landings per unit of effort for the years 1959 (top) to 1966 (bottom), winter rg6zjrg63 which almost exterminated the based on otter-trawl landings. baby soles of the year-classes rg6z and rg6r. -zog- Other Fishes Table 198. Age composition per IOO hours fishing of soles landed in The Netherlands in 1966 for otter-trawl and beam-trawl (Upper figure: males; lower figure: females) {ear-class I964 I963 I962 I96I I960 I959 I958 I957 I956 I955 I954 I953 I952 I95I 1950 1949 I948 I947 I946 and )tier-trawl older st quarter o 3,275 I6 4 I4 I3 3 4 6 I8 IO 'i' 4,309 5 I7 25 5 II II 9 7 3 I3 :nd quarter o 2,327 I4 5 34 5 26 3 24 5 5 ¥ 3,029 34 14 33 55 7I I3 45 6 2 3 2 :rd quarter o 55 I,824 I8 43 3 5 20 ¥ 295 2,689 6 z6 I2 4 5 5 6 3 .th quarter o 658 2,676 24 5 3 6 IO ¥ I,372 2,6?8 7 74 4 4 I2 6 4 3 4 '3eam-trawl st quarter o 7,870 4I I95 4 2I7 I8 I9 5 9 49 ¥ -- Io,562 Io 43 I03 33 I69 6 I2 II 9 3 nd quarter o 7,957 6o 2I 286 8I 8g8 2I 68 7 IO IO 'i' 9,969 I36 30 I66 65 867 go I05 3I 78 4 IO 4 ,rd quarter o 260 7,269 49 IIS I27 8 433 7 53 C,: I,403 8,378 I5 62 333 22 342 II 14 II I8 7 5 th quarter o I,gq 6,454 6o I03 so I2 6 20 2 I3 ¥ 3.74I 6,797 39 II II8 8 5 22 9 8 2 4 7 The present situation is not a normal one. In sole stock is more or less of a mono-year-class Figure 143 the age compositions of the Dutch sole type now. landings are given from 1959. Prior to 1964 the J. F. DE VEEN catches consisted of a number of year-classes in Rijksinstituut voor Visserijonderzoek, Haringkade I, which the strong year-class 1947 still played a IJmuiden, Holland. part. The severe winter 1962/1963 changed the situa Quantitative Fishing of Flatfish with the Standard tion. The adult stock was about halved, which Trawl in the Kiel Bay 1966 led to poor catches in the second half of 1963, in (Table I99) 1964, and the first half of 1965. In the second As in the previous years experimental trawling half of 1965 the strong year-class 1963 began to was carried out at 8 fishing places in the Kiel Bay recruit to the adult stock, with the result that the by R.V. "Hermann Wattenberg". Quantitative Table 199. Length and age distribution of plaice, dab and flounder taken with the standard trawl in 1966 Number per I hour's fishing Length Plaice Dab Flounder*) in em Jan. March :\lay July Sept. Nov. Jan. ~larch :vlay July Sept. Nov. Jan. March May 6-Io 0.2 0.3 O.I 4·5 0.2 II-IS O.I 2.2 2.3 r.6 I0.3 IS-9 I6-zo O.I O.I 7·3 8.3 9.2 I8.7 IO.I I0.6 O.I ZI-25 0-4 0-4 O.I 0.2 O.I O.I 10.2 II.3 I?.I 14·6 I5.6 I 5-9 0.6 2.7 0.2 26-30 2.0 0.7 0.5 o.g 0-4 0.4 5.I 5-4 I0.7 4·5 5-4 3-9 1.3 3·6 0.2 3I-35 2.6 0.6 0.2 o.6 O.I 0.3 0.7 o.g 2.0 0.7 0-4 0-4 I.O 2.1 36-40 2-4 0.7 0.3 O.I O.I O.I O.I O.I 0.4 0.6 41-45 I.I O.I O.I 0.2 46-57 0.3 O.I O.I Year-class Ig66 O.I O.I I965 O.I O.I 0.2 0.2 0.2 O.I I3.2 zg.S 22.2 I964 0-4 0.4 0.2 1.2 0.4 0.6 8.8 9-9 I3-4 27-9 23-5 20.0 O.I 0.2 I963 I.O 0.6 0.2 0.6 O.I I3-4 I3.8 20.6 I0-4 6.0 4·3 r.6 s.6 0.5 1962 4-9 I. I 0.3 O.I O.I 3· I 4·3 6-4 I.? I.O 0.3 1.3 2.) 0.2 Ig6r r.8 0.3 O.I O.I O.I 0.2 0.3 0.3 O.I O.I 0.3 0.7 O.I I g6o and older o. 8 0.2 O.I 0.2 0.3 Total number 8.g 2.6 o.8 2.1 0.7 I.O 25-7 28.6 40.8 53·3 3·5 9-3 o.8 Number examined I66 IO 3I II IS 8oo 990 ISI IO *)July: 2 flounder; Nov.: I flounder -210- catches were taken at the following times (number only half of the average in 1964 (86-4). The decline of hauls in brackets): 31. J anuary-3. February in the two last years was the consequence of a (19), 28.-31. March (16), 23.-25. May (8), 27.- smaller supply of fry. Taking the catches in the 29. August (14), 16.-22. September (15), 7-- second half of a year as representative for the 10. November (14). The results for plaice, dab and frequencies of the age-groups I and II, we find that flounder are given in Table 199. the strength of the 1963-65 year-classes was nearly equal, but one-third only of the 1962 year Plaice class. The commercial landings of dab in 1966 In 86 hauls 275 specimens only were caught amounted to 156 tons, a little more than in 1965 resulting in 2.9 specimens per hour, an extremely (143 tons), due to the present stock of older fish low figure. If we exclude the catches in the spawning belonging to the rich 1962 year-class. time when the plaice concentrate in deeper water and are easier to catch, an average of 1.4 specimens Flounder per hour results. The corresponding figures for In the first months of the year when the flounder March-October were 2.1 in 1965, 3.6 in 1964, concentrate in deeper water for spawning, ex and 3.8 in 1956-58 before the relatively good perimental trawlings give an insight in the length 1957 and 1959 year-classes caused an increase of and age composition of the adult stock of this the mean catch to 13.0 per hour in 1959-62 species. In 1966 more than half of the specimens outside the spawning time. The greater supply of belonged to the 1963 year-class, one-third to the these two year-classes had no permanent effect on 1962 year-class, the rest, with few exceptions, was the stock of plaice in the western Baltic, and it older. But the material collected in those years has become weaker than before the increase. The when the trawling experiments were carried out yield of the German plaice fishery in the western already in February/March, is too small to allow Baltic decreased from 264 tons in 1965 to 166 tons for estimation of the strength of the year-classes. in 1966, but was higher than the average in 1950-59 The annual yield of the German flounder fishery (rr3 tons). in the western Baltic shows a remarkable decrease Dab in the last years, from 514 tons in 1964 to 390 tons The monthly mean catches in 1966 show a in 1965 and further on to 275 tons in 1966. steady increase from January to September. R. KANDLER 86 hauls yielded an average of 42.1 specimens per Institut fur Meereskunde der Universitat Kiel, hour, more than in the previous year (35-4), but Hohenbergstraf3e 2, Kiel, Germany. -2II- Rare Fishes Rare Fishes Recorded by The Marine Research Alepocephalus bairdii Goode & Bean -I : Institute in Reykjavik during 1966 6 - I5' S-SW of Rockall, IV. Sardina pilchardtts (Walbaum) Alosa alosa (L.) - 4: 1 VII, S-Iceland, 24 em. First record from Iceland. zoo' E / 2 N of Aberdeen, I; Swatchway, I; off Stomias boa ferox (Reinhardt) Hysgeir Rock (S. Minch), I; off Canna, I. 25. VIII, E-Iceland, 12 em. Alosa finta (Cuvier) - I: Conger conger (L) 6' W of Girvan, Firth of Clyde, II. 3· XII, S-Iceland, ro8 em. Sardina pilchardus (Walbaum) - I: Scombresox sa~tnts (vValbaum) off Arran, Firth of Clyde, IV. X, S-Iceland, 29 em. Engraulis encrasicholus (L.) - r: Aphanopus schmidti (Saemundsson) I2' SxW from Dubh Artach, West of Scotland, IX. I5. VI, SW-Iceland, II4 em. Centroloph~ts britannicus (Gunther) Scomberesox saurus (Walbaum)- 6: 15. XII, E-Iceland, 49 em. NW Orkney, IX; 40' E of Balta, Shetland, IX; Bay of Ireland (Orkney) (stranded), IX; Eshaness Scophthalm~ts maxi1mts (L) (Shetland), X; Inverbervie (Kincardineshire coast) ro. II, S-Iceland, 69 em; (stranded), IX. (z) 28. IV, S-Iceland, 74 em. Ceratias holboelli (Kr0yer) Belone belone (L.) - 2: 21. VIII, E-Greenland, 121 em. so' NNE of Fraserburgh, IV; I9o-zzo' ENE of Aberdeen, V. Fuller details of these captures are given m "JEgir", 6o. (3). lVIacroramphosus scolopax (L.)- 2: G. JONSSON 26' ExN from Balta, III; Noup Deep, VIII. Hafranns6knastofnunin, Skulagata 4, Reykjavik, Iceland. Lampris guttatus (Bri.innich) 3: Muckle Flugga, Shetland, V; NE corner of Syder0 Scottish Records of Rare Fishes - 1964 Bank, Faeroes, VII (2). Trachypterus arcticus (Bri.innich) - 9: The following rare fishes were recorded in Scot Bergen Bank, IV; Faeroe Bank, VI; Faeroe Bank, land in I964. The list includes a number of records VIII (2); E. Iceland grounds, VII (z); Lerwick from areas bordering on or even within the region (Shetland) (stranded), IX; Shapinsay (Orkney) of the d1stant northern seas. (stranded) XI; W. of Rockall, XI. Oxynotus paradoxus Frade - I: Capros aper (L.) - 3: Rockall, V. Off the Butt of Lewis, V; 55° 48' N 09°00' W, VII; Scymnorhinus licha (Bonaterre) - I: 55°57' N o8a36' W, VII. St. KildajFlannan area, III. Marone labrax (L.)- 7: 1 Sq~tatina squatina (L) - 7: 5' off Aberdeen, I; off Clyth Ness, II; 3 / 2' NE of St. Kilda, III; off Barra Head, IV, V; off Eagle Macduff, II; Inchmarnoch Water (Clyde), III; Island, V; off Garlieston, Wigtownshire, - sum 3' NE of Troup Head, III; Firth of Clyde, IV; estu mer: N. Minch, IX; N.W. Orkney, IX. ary of River Ythan, VI. Torpedo nobiliana Bonaparte - 2: Sciaena aquila Risso - I: N. Minch, II and XI. 2 - 3' off Portlethen, Kincardineshire, X. Trygon pas#naca (L.) - I: .c1fullus surmttletus L. - 5: Cockenzie Bank (Firth of Forth), IX. z6' ExN of Balta Sound, IV, Tiree grounds, IV; 1VI yliobatis aquila (L.) - 3 : Dubh Artach grounds, VI; Findon Ness, VIII; Wee 30' N of Buckie, IX; 6- 7' N of St. Abb's Bankie, IX. Head, X; 40' NNE of Fraserburgh, XII. Spondyliosom:I canthants (Gmelin) - 6: Acipenser stttrio (L.) - 5: Tiree grounds, II; 45' NExE of Aberc'een, III; 30' N. Minch, V; I2' ESE of Berwick, V; 4 - 6' off NxW uf Lossiemouth, III; 5' E of Noss Head Bayble (Lewis), VI; 8' NE of Lossiemouth, VII; (Caithness), IV; Garlieston (Wigtownshire) VII; 5' 3 - 4' W. of Ardrossan, X. NNE of Lossiemouth, X. -212- Box boops (L.) - 2: M orone labrax (L) - r: W. Shetland ground, II; 3' NE of Troup Head, III. Macduff (Moray Firth), V. Cepola rHbescens L. - I: Polyprion americamtm (Schneider) - I: Ballantrae Bank (Clyde), II. 6o'WNW from Butt of Lewis, XII. GobiHs pict~ts (Maim.) - r : Brama raii (Bloch) - I5: Rousay (Orkney) (stranded), IX. 20' off Muckle Flugga, VIII; roo' NWxW from CentrolophHs niger (Gmelin) - 3: Pentland Firth, VIII, (2); Muckle Flugga, X; 3' ENE from Nun Rock, IX; 40' NW of Noup Lousy Bank, X; r6o'ExN from May Island, X; Head, X; ro' SSE of Sumburgh Head, XL Muckle Flugga, X, (6); 2'SE from Cromarty (Moray Firth), X, (2); Inverness Firth, XI. B. B. RAE, S. F. PIRIE Spondyliosoma cantharu,s (Gmelin) - r: :\Iarine Laboratorv, Victoria Street, Torrv, Scalloway Deep (Shetland), VII. " Aberdeen, Scotlan~L Cepola ntbescens, L- 2: Firth of Clyde, III; 4'SW of Hysgeir (S. Minch), Scottish Records of Rare Fishes- rg66* X. The following rare fishes were recorded in Aphanopu,s carbo, Lowe-r: Scotland in rg66. The list includes a few records Lousy Bank, V. from areas bordering on or even within the region Sarda sarda (Bloch) - I: of the distant northern seas. Montrose (E. Scottish coast), VI. 1'dugil chelo, Cuvier - 12: Hexanclnts griseus (Gmelin) - r: Cove Bay (Aberdeen), V; Cove Bay, VI (ro); Sule Skerry (N. Scottish Coast), VI. Gardenstown (Moray Firth), VIII. Sq~tatina squatina (L) - 4: B. B. RAE, S. F. PIRIE Noup Deep (W. Orkney), II; Stratl1y Point (N. Marine Laboratory, Victoria Street, Torry, Scottish Coast), III; Noup Deep (W. Orkney,) Aberdeen, Scotland. V; ro'NNE of Rudh Re (N. Minch), XL Torpedo nobiliana, Bonaparte- 3: English Observations on Rare Fishes in rg66 4'N of Macduff (Moray Firth), VIII; I4'NNE of During rg66 the following rare fish, or records Rudh Re (N. Minch), X; r2'S·W-W, 1/ W from 2 of them, were received at the Fisheries Laboratory, Fugla Ness (Shetland), XII. Lowestoft. Specimens marked (B.M.) are now in A cipenser stttrio, L - 3 : the British Museum (Natural History), London_ Moray Firth, II; North Minch, III; r5'K of Buckie (Moray Firth), XII. Distant northern seas A los a finta (Cuvier) -2: ChauliodHs sloanei Bloch & Schneider, r8or. 5'ESE from May Island (Firth of Fortll), I; One specimen, caught by S. T. "Northern Isles" 0 Gairloch (N. Minch), VII. off E. Iceland; 65°32'N II 5o'W, 220-3Io m Scomberesox saurus (Walbaum) -I: depth. Probably caught in early June, landed at Grounds unknown, X. Grimsby 14- June rg66. (B.M.) La1npris g~tttatu,s (Brtinnich, 1788); Opah. B clone bel one (L) - 2 : 1 A single specimen, weight I2 / 2 stone (79-5 kg), Mid Yell (Shetland) stranded, I; Moray Firth by the Hull trawler "William Wilberforce" about (Salmon stomach record), V. 21. September rg66 r8 n.m. NNE North Cape, Lampris guttatus (Brtinnich) - r: Iceland. Depth 77 m. Landed at Grimsby 5- Elie (Fife), VI. 0ctober rg66. Trachyptents arcticu,s (Brtinnich) - 12: Ceratias holboelli Kr0yer, 1844. Yell (Shetland) stranded, I; off Staalberg One specimen from the Dohrn Bank, 460- (Iceland), III; Lousy Bank, IV; Collieston (Aber 512 m depth. Caught by S.T. "Lord Wavell". deenshire coast) stranded, IV; Faeroe Bank, V; Landed at Grimsby 24. June Ig66. (B.M.) Butt of Lewis grounds, V; North Cape (Iceland) grounds, V; Lousy Bank, VI; S. E. Iceland Near northern seas grounds, VIII; 30'SSW from Ingolfsh0fdi Huk Chimaera monstrosa Linnaeus, 1758; Rabbit-fish. (Iceland), X; Pentland Skerries, XII; 65'NNE One specimen caught by the Lowestoft trawler from Fraserburgh, XII. "Yoxford Queen", north edge of the Dogger Bank *) A corresponding list for rg65 is published in A nnales biologiques, 22: r86. -2I3- Rare Fishes (approximately 56ooo'N o2°3o'E, 77 m depth). Non-indigenous Demersal Species caught in the Landed at Lowestoft IO. May Ig66. 1N estern Baltic 1966 Urophycis blennoides (Brtinnich, I768); Forked For information about the occurrence of fish Hake. species which are not indigenous in the western One specimen from the west of the Dogger Bank Baltic, a list is given containing foreign guests in (approximately 55o4o'N 02°30'E, 70 m depth). the catches with the standard trawl*) in the Kiel Landed by the Lowestoft trawler "Suffolk Crafts Bay in Ig66: man" 31. May Ig66. (B.M.) This species and the Chimaera are well away from their usual habitat I. January-3. February: on the Atlantic slope. 2 haddock, Ig-2o em 4 Pollachi~ts pollachius, I8-40 em Trachipterus arcticus (Brii.nnich, I788); Deal-fish. IO long rough dab, I8-23 em One landed from the North Sea in late February Ig66. No details of capture obtainable. (B.JVI.). 28.-31. March: I6 Trisopterus esmarki, 7-I4 em Brama brama (Bonnaterre, I788) Ray's Bream. I Pollachius pollachius, 38 em One specimen about 75 em total length caught 6 long rough dab, I8-24 em by set net on Snettisham beach, Norfolk (east shore of the \Vash) 28. October Ig66. (B.M.) 23.--25. May: I haddock, I3 em Labrus bergylia Ascanius, I767 Ballan Wrasse. I2 long rough dab, I2-I3 em A specimen 34 em total length caught by M. T. "Celita" on the Haddock Bank (North Sea, 27.-29. July: approximately 53°2o'N OI 0 35'E). Landed at Lowe 2 Trisopterus esmarki, II-I2 em stoft 26. January Ig66. An unusual position for a II long rough dab, II-28 em species usually found near rocky coasts. r6.-22. September: Balistes carolinensis (Gmelin, I789) Trigger-fish. II haddock, I2-I5 em One specimen trawled up ofi Newhaven, Sussex 2 Trisopterus esmarhi, I2-I3 em (English Channel) on 8. September Ig66. (B.M.) 14 long rough dab, 6-22 em Another specimen caught in Start Bay, Devon, 7.-ro. November: II. October Ig66 by the M. T. "Tudor Owen II". 6 haddock, I4-I9 em Specimen in possession of the Marine Biological 4 long rough dab, 20-28 em Association, Plymouth. I Trigla gurnard~ts, 20 em In addition the following unusual species were Compared with the findings in rg65, the number caught by the R.V. "Ernest Holt" in a deep-water of foreign guests has decreased to about half for trawl haul south of Ireland ("Ernest Holt" Cruise haddock, long rough dab and pollack. From the 5/Ig66, St. go 50°2g'N I0°53'W, soo-6I5 m big invasion of Norway pout at the end of Ig6s depth), 29. July Ig66 leading to catches of 320 and 380 specimens per Beryx decadactylus Cuvier &. Valenciennes, I82g. hour in the southern Little Belt off Alsen a con Tw·o specimens, each about 30 em total length. siderable number remained in the Kiel Bay for nearly one year. As in rg63 and I964 shoals of Echiodon drummondi Thompson, I837. small horse mackerel, 7-14 em in length were One specimen 26.8 em total length. (B.M.) found in September and November Ig66 at all Lepidorhomb~ts boscii (Risso, I8Io). trawling stations in different quantities, up to Seven specimens up to 2I em total length. 296 specimens per hour. All these species are probably residents in the R. Ki\.NDLER area but are noted here because of the rarity of Institut fur :!\Ieereskunde der universitat Eiel, records from this deep water. Hohenbergstrassc 2, Kiel, Germany. R. \V. BLACKER Fisheries Laboratory, Lo Shellfish CRUSTACEA Danish Observations on Crustacea in West Greenland Waters 1966 Fishing experiments with crab-trawl, started in rg65, were continued in rg66. At some places in Disko Bay rather good catches of crabs (Chionoecetes opilio) were made, while in other places very few crabs were found. Some trawling experiments for prawns showed larger occurrences than normal in Disko Bay, perhaps due to the high bottom temperature in rg66. The deep-sea prawn fishery continued to increase. The catch in rg66 was 5,378 tons which is more than 300 tons above the figure for rg65. P.M. HANSEN Gronlands Fiskerinnclcrsogelser, J ;:cgersborgalle r, Charlottenluncl, Denmark. -215- APPENDIX Report on the Joint Meeting on Atlanto-Scandian (r6°W) the southern boundary of the 0°C isotherm Herring Distribution, held at Akureyri at 50 m was located at about 67°3o'N which is ca 12.-14. June rg66 6o n. m. farther south than normaL North-east of 0 (Figures 144-q6) Langanes the temperature at roo m (- r C) was now the lowest observed with the exception of last Introduction year. The southern boundary of the cold water east As in previous years the investigations started of Iceland was about 65oN which is ca 6o n. nL towards the end of May and were finished on farther north than last year. The eastern boundary 12. June. Prior to this a preliminary survey of the was located at about 8°W. area north and east of Iceland had been carried The temperatures of the eastern and western out during the period 7.-25. May by Icelandic branches of the Norwegian Current were below scientists. The area investigated is shown in normal (-o.8°C and 0.7° C at o-2oom, respec Figure 146. The south-eastern part of the Norwegian tively, and- 0-4°C and- o.6°C at 20o-soom, Sea east of 2°W and south of 68°3o'N could not respectively) and comparable with the tempera be investigated due to shortage of time. tures in r959 and r965. In the north-western branch Throughout the cruises hydrographic, phyto of this current, south of Jan Mayen, the tempera plankton, zooplankton and herring observations ture was slightly above normal at o-2oom and 0-4° were carried out. Reports and charts on hydro higher than last year, but similar to last year at graphy, plankton and herring were prepared by 2oo-soom. three respective committees. During the final In the area of the north-western branch of the session the reports of these committees were Norwegian Current and in the East Iceland presented and accepted. Current the surface warming-up was slightly below It was decided that next year's meeting should normal o.2°C in r966 against - o.6°C in r965, be held at Akureyri during r8.-r9. June 1967. and - o.1°C in r966 against - I.2°C in r965, Mr. H. VILHJALMSSON convened the joint respectively). meeting. Temperature distribution at 20 m depth is Hydrography presented in Figure r44. Ice On the whole, it may be concluded that the During the surveys the ice limit was observed at temperatures in the first half of June were in 68°N 24°W (75 n. m. NNW of Ki:igur) and at general below normal in the Norwegian and Iceland 7r 0 N r2°W. This is farther north-west and north Seas. The temperatures of the Norwegian Current than normaL in the Norwegian Sea and the Irminger Current branch north of Iceland were at the lowest and the Temperature influence of the cold East Iceland Current was In May the temperature north and north-east strong. of Iceland was relatively low, 0-3°C. A slight Members of The Hydrographic Committee: thermocline had formed with a warming-up of S. AA. MALMBERG (Chairman), V.I. PAKHORUKOV, 0.5-2°, increasing eastwards. No Atlantic water V. v. PENIN, N. G. SAPRONETSKAYA, 0. DAHL, S. was observed east of Kogur. J ONSDOTTIR. In June a tongue of Atlantic water (4° C) had reached the area off Skagata (20°W). In the Plankton coastal area from Skagata to the north-east coast of Iceland, the temperature in the surface layers Phytoplankton was 3-5°C which, with a warming-up of r.s-2.5°, For estimating the phytoplankton density, all is r-2° below normaL The intensity of the Irminger the ships used Secchi disc readings. Samples were Current branch north of Iceland was low (r-2° also taken from different depths by means of water below normal) and similar to the conditions in bottles by the Icelandic and Russian ships. The r949, r958 and r963. Russian research vessels also estimated the phyto This year the influence of the East Iceland plankton and determined its qualitative com Current was relatively strong. At 0-200 m the position from Juday net hauls. On the Icelandic temperature was 0.2° below normal, but still research vessel measurements of primary production o.2° higher than last year. Off Melrakkasletta with the C14 technique were carried out. -zr6- Figure 144. The Sec chi disc readings indicate that in M a~\' Off Kogur towards the ice limit and off Hunafi6i no real growth of phytoplankton had occurred in very high density of phytoplankton was observed the tongue of relatively warm water surrounding in ] une, whereas the waters off the central part of the north-western peninsula of Iceland. In the the north coast were very poor. coastal area high density of phytoplankton was Low transparency in the Arctic and mixed observed. The oceanic area north-east of Iceland waters between Iceland and Jan Mayen indicate had a very low standing crop, although areas rich high density of phytoplankton in this area, whereas in phytoplankton appeared intermittantly in the the Atlantic water east of the East Iceland Current oceanic water east of Langanes. south of 67oN was rather poor in phytoplankton. -ZIJ- Appendix .. ...... , ~ ~ 1: 1...... 1;, 1::; ~~ '0 .,SOC\110 ~ ~.....,~0\ t::OC:.,._ o6l!;lll :, - ...... !:: c:: Q, ~::J Qle:-c:::.._,t') CIJ "S..q, 1.) ::Sc:c::: - ;, ~-.... -- v"' ~ " ~ ~I r : " '!;; "' i:: ~ :: -2r8- The "blooming" of the Arctic waters was chiefly Although the zooplankton densities were extrem induced by Thalassiothrix longissima, Rhizosolenia ly low in the waters north of Iceland and modera1 sp., Chaetoceros spp., Nitzschia sp., Thalossiosira sp. within the East Iceland Current and mixed water. and Phaeocystis Poucheti. it is suggested that the ample growth of phytc Areas with low transparency were also observed plankton observed might give rise to larger quant in Arctic and Atlantic waters east and south-east ties of zooplankton in these parts of the area. of Jan Mayen and in the waters between the Members of the plankton committee: Faroes and Iceland. In the Icelandic survey area TH. TH6RDARDOTTIR (Chairman), G. Sv. J6Nssm the density of phytoplankton was much higher in V. PETROVA, M. GOGOLEVA, K. GLUSHAKOVJ June this year than in rg65. The same seemed to R. MYHRE, A. SJEBOE, H. R. HovDE. be true for the greater part of the whole area investigated by the other ships. Herring Zooplankton Investigations carried out in the area north c The zooplankton was collected in vertical Iceland did not reveal any herring concentration~ so-o m Hensen net hauls by all participating In the northern Norwegian Sea herring shoal research vessels. In addition, the Russian vessels were recorded on the sections along JI 0 IO' an used Juday nets for hauls from the depths of 69°20' N as well as on the passage track betwee 500-200 ill, 200-IOO ill, 100-50 ill and 50-0 ill. positions I 0 E 6go35'N and 9°25'W J0°I5'N. Th The zooplankton volumes are presented in Figure 145. shoals were registered at a depth of r20-I40 r Unusually low density of zooplankton was and were of r-4 grade density. The densest shoal observed in the shallow and deep waters north-west occurred at the greatest depth. and north of the Icelandic coast. In the East The greatest number of herring shoals wa Iceland Current and the mixed waters north-east of registered in the area between 68°N and 64°15'1\ Iceland, reasonable concentrations of zooplankton from I0°W to 4°W. Shoals of I-2 grade densit were observed, whereas in the Atlantic waters predominated in this area and the majorit farther east higher densities were found. The occurred at a depth of 3-30m. Herring shoals wen highest concentrations were found north of the however, occasionally found as deep as 200 rr Faroe Islands and in an area ca rso miles east of South of 64 oN no herring concentrations wer Jan Mayen. According to the Russian results based found. on the so-o ill Juday net hauls the average It must be pointed out that when moving to th plankton biomass for the whole area is the highest north-herring shoals were met with at greater depf observed in the period rg5g-rg66. The Norwegian and near the western limit of its distribution th results show considerably poorer zooplankton herring penetrated waters with a temperatur density in the northern and western part of their below 0°C. area of investigation than the average for the years rg62-rg65, while the zooplankton in the southern Samples taken from drift-nets indicate tha and eastern parts seems to be somewhat richer than adult Norwegian spring spawners with a meaJ in previous years. length of approx. 31.5 em predominated in th western Norwegian Sea during the first half of June Two distinct zooplankton communities could be The homogeneity of the size composition and th distinguished in the area Jan Mayen and the physiological state of the herring suggest that par Faroe Islands, the border line lying roughly along of the stock had not yet reached this area afte 66°40 N. In the waters north of 66°40 N a com spawning on the Norwegian Shallows and near th munity consisting of C. hyperboreus, Metridia longa, Lofoten Islands. This herring may, however, hav, Eukrohnia hamata and adult C. finmarchicus pre been in the south-eastern Norwegian Sea, but thi dominated. South of this latitude the most import area could not be surveyed. Observations shov ant species were Pseudocalanus elongatus and that concentrations of fattening herring movec younger stages of C. finmarchicus. north and north-eastwards to reach the colde A peculiar feature of the plankton distribution waters south of Jan Mayen and Molms Ridge. this year was that the cold water species M etridia As in previous years, the western limit of distribu longa, Themisto libell~tla and C. hyperboreus were tion seemed to be at the 3° isotherm at 20 n distributed over a very extensive area in the depth (Figure 146). West ofthat, herring was practi eastern Norwegian Sea. cally absent. 2~ lr 16" 14" lr 10° 8" 2" ~ 2" ~ •• r .. .. ~ • ' 17~ ' ' ' ~' ' ' ro• • 3J8 n• u• 67° 67• N H ..0 86 ••• 8 .,. ICELAND .... ••• 0 T IN 20m AND HERRING CONCENTRATIONS 63° IOMAY-12.JUNE 1966 ~ ACADEMICIAN KNIPOV1CH VERY SCATTERED ACADEMICIAN BERG SCATTERED :1::::::: · The densest herring concentrations were found were distributed between I2° and 8°\V, but this in the mixed waters by Icelandic and Norwegian year they were found from I0° to 6°W. It is possible vessels during 23.-27. May and by Soviet vessels that better feeding conditions caused a more in the north-western Sea from 29. May-7. June easterly distribution of the shoals since zooplankton (Figure 146). biomasses were much lower in the waters along the western edge of the East Iceland Current than Conclusions farther out. The distribution of the herring concentrations 3) In spite of somewhat milder conditions in observed in late May and the first half of June and June than in May in the area north of Iceland, it their possible migrations were discussed. It was is thought that appreciable concentrations of concluded that: herring will probably not migrate to this area, r) This year a small number of herring concentra and if so, not until later in the summer. tions were observed in cold water areas (below the 4) It is suggested that the herring will stay for 3° isotherm at 20 m). The herring was mainly some weeks along the eastern edge of the East observed in the 0-30 m layer, but contacts were Iceland Current, possibly increasing in number also made in deeper waters with a temperature on account of herring coming from the south-east below 0°C. The migration of the shoals was mainly Improving feeding conditions in the East Iceland in a north-easterly direction. Current may induce a more westerly distribution of 2) In the area north of 6g 0 20'N, distribution the shoals later in the summer. seemed to be more westerlv than usual. A definite Members of the herring committee: Dr. K. A. conclusion can, however, n:'ot be reached since the LYAMIN (Chairman), A. S. SELIVERSTOV, U. LIE, area north of this latitude and east of 2°W was I. HoFF, E. JoNssoN, H. VILHJr\LMSSON. impassable. In the central part of the survey area, Edited by: S. A. MALMBEH.G viz. from 65° to 67°N, herring concentrations had T. THORDAH.DOTTIH. a more easterly distribution as compared with H. VILHJ ALMSSON previous years. In rg65 the main concentrations Marine Research Institute, Skulagata 4, Reykjavik, Iceland.