118

11. The Norwegian “Small” and “Fat” Herring Fishery Size and Age Composition of the Catches By

O l a v D r a g e s u n d Institute of Marine Research, Bergen

Introduction The Norwegian “small” and “fat” herring fishery is based on immature herring belonging to the Norwe­ gian spring spawning tribe. Although considerable fluctuations have taken place in the yield of this fishery, as shown in Figure 1, a significant increase has taken place in the “small” herring catches, especially since 1910. As the catches increased, the fishermen’s organizations have paid close attention to the possible effects of this fishery on recruitment to the adult stock, on which the Norwegian winter herring fishery is based. Because of the catastrophic decline in the latter fishery since 1957, their con­ cern has increased and several proposals for regu­ lating the “small” herring fishery have been made. Figure 1. The catch of immature herring landed in Norway from The aim of this paper is not to discuss these problems, 1900-1960. but to present data on the landings of “small” and “fat” herring in space and time, and on the age com­ positions of the catches. It should be emphasized, how­ Table 1. ever, that intensive investigations are now being car­ The average annual catch of “small” and “fat” herring ried out on the problems mentioned above ( D r a g e - in millions of hectolitres in each ten-year period from s u n d and Hognestad, 1960). 1900-1959 Period ‘‘Small” herring “Fat” herring The landings, their distribution in space and time 1900-1909 0-217740 0-405549 The average annual catches of “small” and “fat” 1910-1919 0-637056 0-462021 herring in successive decades between 1910 and 1959 1920-1929 0-768466 0-461870 are given in Table 1. These data show that in the 1930-1939 1-378653 0-517555 1940-1949 1-334320 0-372248 period 1900-1910 the average annual catch of “small” 1950-1959 1-727683 0-712396 herring was 0-217740 million hi, whereas the average catches in the following two decades were 0-637056 1950-1959, when the average catch per year was and 0-768466 million hi respectively. The main reason 0-712396 million hi, the annual landings have varied for this increase in the landing figures was the develop­ between 0-372248 and 0-517555 million hi in the other ment of the oil and meal industry which took place periods. during and after the first world war. In the next three As shown in Figure 2 the main fishing districts for decades (1930-1939, 1940-1949 and 1950-1959) the small herring have been North Trøndelag, Nordland average figures landed per year amounted to 1-378653, and Troms. Between 50 % and 65 °/0 of all the “small” 1-334320 and 1-727683 million hi respectively. herring caught have been landed in these three coun­ The yield of the “fat” herring fishery, however, has ties in the last 50 years. Before the establishment of not increased to the same extent. Excluding the period the reduction industry, most of the “small” herring were 119

[] FAT HERRING, CATCH.

PER C ENT.

I SMALL HERRING, CATCH.

PERCENT ‘FINNMARK

TOTAL AVERAGE TOTAL AVERAGE TOTAL AVERAGE

CATCH PER YEAR: CATCH PER YEAR■ CATCH PER YEAR SMALL HERRING 217740 HL. SMALL HERRING 637056 HL. SMALL HERRING 768466 HL FAT HERRING _ 405549 HL- FAT HERRING 462021 HL. FAT HERRING 461870 HL.

1900-09 1910-19. J920-29.

QsMILL. HL.

50 PER CENT.

TOTAL AVERAGE TOTAL AVERAGE TOTAL AVERAGE

CATCH PER YEAR: CATCH PER YEAR: CATCH PER YEAR:

SMALL HERRING 1378653 H I- SMALL HERRING 1334320 HL. SMALL HERRING 1727683HI FAT HERRING 577555 HL. FAT HERRING 372248 HL. FAT HERRING 712396HL

M v£ 1950-59. ■ -8

Figure 2. The average yearly catch of “small” and “fat” herring distributed between the different districts of Norway from 1900- 1959 (ten-year periods'). The histograms on the figure represent catch and percentage of the total average catch respectively. (Preliminary figures.) landed in the southern part of Norway where the Data on the distribution of the landings with time majority of the canning companies were situated. The are available only for the last twenty years. These are landing figures in the first 10-year period is therefore shown in Figure 3. It can be seen from this figure that no indication of the abundance of the herring present there seems to be a greater distinction between the in this area. spring/early summer and the autumn season in the When considering the “fat” herring, the South Trøn- last 10 years, than in the previous ten. During 1951- delag and Møre region has been the most important fish­ 1960, the “small” herring, caught in May-June were ing district during the last ten years, whereas North mainly landed in southern Norway, whereas the ma­ Trøndelag and Nordland, and to some extent Troms jority of the herring caught in the autumn were landed were the main fishing areas in former years. in the northernmost counties. This is shown in Fi­ The ‘ -'small” herring fishery takes place mainly at two gure 4. The minimum in February-April is due to the seasons in spring/early summer and during the autumn. fact that the fishermen are occupied on other fishing 120

SM ALL HERRING- FAT HERRING. M ill. h i.

THOUSAND HL.

1 9 4 H 9 5 0

500-

1951-1960 TOTAL CATCH

JA. FE.MA. AP MA. JU. JU. AU- SE.OC. NO- OE. JA. FE. MA.AP. AU. SE.OC.NO. DE Figure 3. The average catch per month of “small” and “fat” herring landed in the last two decades. 0 - GROUP \

SMALL HERRING. FAT HERRING.

I-GROUP

MORDLAND- N. TRONDELAG ROLAND" N.TRONDELAG

S. TRONDELAG-MORE 6 .TRONDELAG-MORE

50GN t FJORDANE - RCGALAND 50GN& FJORDANE-ROGALANO % s&i s%e s%0 JU. JU AU.SE.OC. NO. DE. JA. FE.MA. ARMA. JU. JU.AU. SE OC-NO. DE. Figure 5. The yield of “small” herring landed from 1950/51- Figure 4. The average catch per month of “small” and “fat” 1959/60 divided in 0- and I-groups. The yields of the 0- and I- herring landed in different districts from 1951-1960. groups landed in 1950/51 are due to the 1950 and 1949 year- classes respectively; in 1951/52 to the 1951 and 1950 year-classes, etc. grounds, and the minimum in August-September must be due to the scarcity of the “small” herring inside the Thus there are three different year-classes represented skerries at that time. In October—November, however, in the landings during each calendar year (Dragesund the herring migrate into the fjords and become avail­ and Hognestad, 1960). able to the fishing fleet. If, however, the year is divided from 1. September In the northernmost areas the “fat” herring fishery is of one year to 31. August the next, the catch consists active mainly during the second part of the year, mainly of two year-classes (dividing the year in this whereas in southern Norway most of the herring are way was first introduced by D e v o l d in an unpublished landed during the spring, as shown in Figure 4. The report). Figure 5 shows the catches of the two year- herring landed from April to June is called “forfangst- classes represented in the “small” herring fishery in these sild”, which is a mixture of the first-time spawners and periods, the 0-group and I-group including herring “fat” herring. of Va-lVa and 1 y 2-2 1/2 years old respectively. Data for splitting up the landings according to year-classes The age composition of the catches 60 The “small” herring, landed in the autumn consist 50 of the 0- and I-groups, the 0-group predominating. 40 During the following spring/early summer season these 30 P" 30 n-2625 same year-classes predominate in the catches, but the 20 m herring are now one and two years old respectively. , n I-I n n r1 n n m - _ The II-group gradually appears in the “fat” herring 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2021 22 23 24 catches during the summer, and later in the autumn Figure 6. The age composition of the Norwegian winter herring, a new year-class, as 0-group, comes into the catches. 1961. 121

% 1952. 7 0 - F 1N NMARK- N ,T RÖNDELA& ' S.. TRÔNPELAGr*OGALAND . - 60 1/1-30/6. 50- TOTAL CATCH :15252* H. 4 0 3 0 20-

. 1953,

fin -FINNMARK-N.TRÖNDELAG. S. TRÖNDELAG-ROGALAND. I I l/l -30/6. TOTAL CATCH: 206813 HL.

1 95 4 .

70- FINNMARK-N.TRÖNDELAG. S.TRONDELAG - ROGAUND. 68 50

30

FINNMARK - N .TRÖNDELAG. 1 9 5 5 , S. TRÖNDELAG - ROGALAND. 7 0

'INNM/ - ROGALAND.

30

FINNMARK-N .TRÖNDELAG. Æ fÜ S.TRONDELAG ROGALAND. I

7> FINNMARK - N.TRÖNDELAG. 1958. S.TRONDELAG ~ROGALAND.

SO 40-

•/. I i 10n-jFINNMARK - N. S i T R Ö N D E L A G -T ROGA L A N O .

5 0 TOTAL CATCH. 127000 H L . ------

» » YEAR Figure 7. The age compositions of the “fat” herring (the “forfangstsild” included) in different districts from 1952-1959. (Preliminary figures.) 122 are available only since 1949, and are mainly based the landings in the northermost county, Finnmark, on samples giving the number of herring per kg in have been a higher percentage of the total in the catches landed at oil and meal factories. last decade than in the previous one. However, no The relatively big catches in 1950/51 are due to the change has so far been detected in the distribution of 0-group (the 1950 year-class) and this year-class also the “fat” herring. gave bigger catches of I-group the next year. In 1951/ The year-classes represented in the mature stock in 52 the 0-group (the 1952 year-class) again predomi­ the last few years have all been very small, except for nated in the catches. The 0-group also dominated in the rich 1950 year-class (Fig. 6). Considering the same all succeeding years, and in 1959/60 it yielded more year-classes in the immature stock, no significant than 90 °/0 of the total landing of “small” herring. relationship has been found between the yield of a Because of the wide spread of the “fat” herring year-class as 0-group and the relative strength of the catches, both in space and time, it is difficult to obtain same year-class in the mature stock. It is likely there­ representative samples. Nevertheless, an attempt has fore, that the yield of the 0-group depends more on been made to determine the age compositions of the their availability than on year-class strength. Further “fat” herring catches in the different districts in the peri­ investigations, however, are necessary to establish this. od from 1952-1959. These are shown in Figure 7. The The case seems to be different for the I-group. To “forfangstsild” samples are regarded as representative obtain a relatively high yield of this group, a new of the catches landed in southern Norway (South migration from the open sea into the fjords must take Trøndelag/Rogaland) during the first half of the year place, and this may be the reason why a relationship ( 1 .January-30. June), whereas the “fat” herring samples between the yield of the I-group and the subsequent obtained in the rest of the year will be considered as relative strength of the year-class as adult, is found representative for the landings during the second half. (Figs. 5 and 6). In northern Norway, most of the fat herring samples The age compositions of the “fat” herring in Figure 7 are taken in the second half of the year, when the show that the strong 1950 year-class has predominated majority of the “fat” herring are caught. in the catches, followed by the 1953 year-class. The same two year-classes have also predominated in the winter herring fishery (Fig. 6) and this might indicate Conclusion that a year-class which gives a relatively high output As already pointed out by D e v o l d and Ø s t v e d t as “fat” herring, also will dominate in the winter her­ (this volume) the migration pattern of the mature ring fishery. herring has changed in recent years towards a late arrival for spawning and a shift to more northern References

spawning grounds. It is likely that these changes have D e v o l d , F., 1963. “The life history of the Atlanto-Scandian influenced the distribution of the 0-group, and one herring”. Rapp. Cons. Explor. Mer, 154: 98-108. should therefore expect to find a corresponding altera­ D r a g e s u n d , O., & H o g n e s t a d , F., 1960. “Småsildundersøkelsene tion in the output of the fishery of immature herring. og småsildfisket 1959/60” . Fisken og Havet, No. 3, 10 pp. Ø s t v e d t , O. J., 1963. “ Catch, effort and composition of the This also seems to be the case of the “small” herring Norwegian winter herring fishery”. Rapp. Cons. Explor. Mer, fishery, for a shift northwards could be the reason why 154: 109-17.