Synopsis of Information on the Oceanography of the North Sea

1stDraft FB/60/S2 CIRCULATION RESTRICTED OT ANE NORTH SEA

SYNOPSIS OF INFORMATION ON THE OCEANOGRAPHY OF THE NORTH SEA

Preparea by T. Laevastu (Fisheries Oceanographer, FAO)

FAO, Fisheries Division, Biology Branch August 1960 Purpose

This is one of a series of synopses on the oceanography of sea regions, aimed at summarizing the pertinent environmental factors af- fecting the fisheries. Whilst the primary purpose of these synopses is to contribute to the general work of the FAO Fisheries Biology Branch, on the appraisal of living aquatic resources, they also pro vide in concise form information necessary for briefing purposes, e.g. for the Use of ETAP experts. They might also serve for assessing the general state of knowledge of different sea areas and might draw attention to the need for working up of accumulated data and serve as background material for designing research programmes.

These synopses are also compiled in accordance with recommen- dation No 4, 1951of the International Council-for the Exploration of the Sea (Rapp.Cons.Int.Explor.Yer 131:5)

"It is recommended that efforts should be made to encourage the writing of monographs describing the hydrographic conditions in the seas in which fishery research workers are interested'.

Preparation

1st draft by Taivo Laevastu (11 August 1960)

Distribution

48th Statutory Meeting of ICES, Moscow 1960 FAO Fisheries Division FAO Regional Fisheries Officers UNESCO SCOR Selected collaborators

Project No 2.21/3 FB/60/52 North Sea

CONTENTS

INTRODUCTION 1.1 Data and methods 1.2 Special aspects of data treatment

GEOGRAPHICAL AND GEOLOGICAL FEATURES OF THE NORTH SEA 2.1 Coneral geographical characteristics of the North Sea 2.1.1 Boundaries, areaand volumes of the North Sea and its subdivisions 2.1.2 The coast 2.1.3 Shipping and fishing (general) 2.2Submarine geolOgy

cLirATJ ADD HYDROLOGY

4, PHYSICAL AND DYNAMICAL OCEANOGRAPHIC CHARACTERISTICS OF TI-LE NORTH SEA 4.1 Tides, tidal currents 4.2Currents 4.3 Sea and swell 4.4Water masses and their characteristics 4.5Mixing and turbulence; annual cycle of stability 4.6 Water temperature 407Heat budget 4.8 Turbidity 4.9 Ice conditions FB/60/S2 North Sea

CEETlian OCEANOGRAPHY 5.1 Salinity, major constituents 5.2 Oxyg,en and other dissolved gases 5.3Trace elements 5.4 Nutrient salts 5.5Pollution

FLORA OF TEE NORTH SEA 6.1 Seawe'eds 6.2..iiarine bacteria 6.3 Phytoplankton 6.4 Basic organic production

7. FAUNA OF THE NORTH SEA 7.1 Zooplankton 702 :Thytoplankton-zooplankton relationship 7.3Benthos 7.4Nekton FD/60/32 North . T

J. INTRONVTIflIf

It is intended. that this synopsis should be a collection of oceancwraphic an.. marine biological data for reference purposes mainly in graphic eu6. forM with a minimal amount of doscrip- tive material in the form of conden.:Jed summaries.

The present first draft contains .data which was easily available. Notes are given on data being prepared, which will be added to following editions. It must be realized that the compilation of such a synopsis and the.working up of individual data is a very large task, and the following should be considered mainly as an annotated outline with samples'ana comments on future processing of data.

In this synopsis it is intended to collect only data which is pertinent to the area. General information which can be found in text- books is exclUded and/or Worked into special subject synopses.

This draft has been coMpiled hurriedly and may therefore contain occasional errors. The bibliography and datasources referred to will be added to the next edition, when the descriptive analyses will al() be expanded.

1.1 Data ankmethods

(This.chapter will contain information of national and international standard sections routine observation routes and fixed stations. Availability of the time series data will-be indicated together with notes on the extent to which these data have been worked up for various purposes. The list. of institutions working in the area, their facili- ties and s6ipntists specialized in different fields will facilitate the 'cooperative working up of data for the Whole area as a unit. Reference list of the description of various reutine and standard methods of observation and working up Will also be added). 12 FB/60/52 North Sea

List of figures

Figure 1.1 ICES routine observations in the North Sea and adjacent waters " 1.2 ICES sections of hydrographicalbiological investigations in the North Sea

List of tables

Table 1.1 Positions of routine observations from commercial vessels, lightships and fixed stations in the North Sea 1.2 List of institutions engaged in the investigations of the North Sea, number of scientists employed and their specialities (to be added) 1.3 Date on the research vessels engaged in the investigations of the North Sea (to be added) It 1.4 List of special data reports and periodicals containing articles on the North Sea (to be added) It 1.5 References on the standard and routine methods of observations and working up of hydrographic and biological data (to he added)

1.2 Special aspects of data treatment

(This chapter will contain various conversion tables, noteson selec- tion on sections etc. and suggestions on methods for further working up of accumulated data). 'FB/ 60/ 2 North Sea 1:Figs. 1

10° 0° 5° 10° G,--1649

FIGURE 1. 1 - ICES ROUT/NE OBSERVATIONS IN THE NORTH SEA AND ADJACENT WATERS 1:Figs.2 FE3/ 60/S2 North Sea

100 5° 00 50 10° 1649 FIGURE 1. 2 -ICES SECTIONS OF HYDROGRAPHICAL - BIOLOGICAL INVESTIGATIONS IN THT NORTH SEA PB/60/S2 North Sea 1:Tables 1

TABLE 1.1.

Positions of routine observations 'rem commerciai vessels, light ships and fixed stations in the North Sea

Ney:th Seat_English_Channel and Irish Sea Reutes and Sections

Bergen-New York (Route8) Norway ( Thermograph records. Salinity

Bergen-Newcastle ( " 34) ( samples Collected (intake pipe Bergen-Rotterdam ( " 35) ( of the condenser) at fixed t Bergen-Oslo ( positions. Salinities deter-

( mined by titration

The Okaw-Croenland (Route 3) Denmark. Surface observations, as often as sLiAin,s permit (i.e. about30times o sear) of T° C and S %o at 11 points between 11°E. and 2°W. (fixed longitudes). Samples taken by bucket. Salinities: titration.

Leith-Copenhagen (Route61)England. 'reekly surface observations of 4 T C and Syooat9positions at approx. 40 mile intervals:-

56ol7IN., 1°30'W. 50o, 26IN., 0o19'W. 56°35'N., 0°52'E, ( Samples taken through the condenser ( intake in engine room at less than 56°45°N.,2°03'E. 56°541N., 3°15°E. ( 5 mdepths. 57°03'N., 4°25'E. ( Salinities determined by titration. 57°12'N., 5°30E. 57°21'N., 6°471E. 57°301N.,8°001E.

Hull-Hanstholm. (Route 32) England. Weekly surface observations of T C and0S p0at9positions:-

56°56'11., 8°0C'E. 56°301N., 7°00E, 56°05'N., 6°00'E, 55°39N., 5°00tE. 5512* N., 4°00'E. 54°45'N., 3°001E, 54°10'N., 2°00E, 54°05'7., 1°30'E, 53°51'N., 1°00'E.

Samples taken through the condenser intake in engine room at less than5m depths. Salinities determined by titration. 1:Tables 2 FB/60/S2 North Sea

O .Flamborouc,hLine.WEncland. Observations of T C and S %o at 6 fixed positions:

54°00'N., 00001 Surface observations from April to 54°131N., 0°19'E. September taken by surface sampler. 54°13N., 0°38'E. Subsurface observations in June 54°24°N., 0°57'E. every 10 m taken by NansenPettersson 54°29°H., 1°181E, water bottle. Salinities determined 54°34'N., 1°38°E.. by titration.

L24b..19).12.7Linfl.,92.. (Route 31) Denmark. 'ieekly surface observations, T C and S %o at 6 fixed positions: (Occasionally. between Esbjerg and Grimsby) _o 55o24'N., 7000'E, 55o231N., 54054'N. 6°00'E. 6oOWE. 700'E,55o09,N., 54°241N.,5°00,E. 54°52'N., 5o00tE. 53°49'N., 4°00'E, 5435111., 4oOWE, 52°54N, 3°00tE. 54o20'N., 3o 00'E. o 0. 52 10'N. 2 00'E. 54°021N,, 2oOWE.

Samples taken by bucket. Salinities determined by titration.

o IjmuidenHull. (Route 36) Netherlands. I:ieekly observations ofT C and S %o at the surface at 6 positions approximately:

53°30'N., 1°50E. 53°201N., 2°20'E. 53°10'N., 2°50'E. 53°00'N., 3°201E, 520501N., 30401E.

52°401N., 4°00°E.

Samples taken by bucket. Salinities determined by titration.

RotterdamLondon. (Route 37) Netherlands.'Weekly surface obser- -o-- vations. of T Cand S %o at4positions approximately:

51o511N., 3o15,E.

51°45'N., 2°40'E. 51°36'N., 2°05'E. 51°27°N., 1°301E.

Samples taken by the Lumby water sampler. Salinities determined by titration. FB/60/52 North Sea 1:Tables 3

HamburHull. (Route 58) Germany. Frequencyt 6 times per month.

- Observations at the surface of To C and S %o. Salinities determined by titration.

54609N., 7o32'E. 54o18'N., 6 12'E., 540 19N., 5°21E. 54°10N., 4°26'E, 54°00'N., 3°32E. 53°53N., 2°43,E, 53°45'N., I°54'E0

GravelinesDeal. Belgium.

B 13 51o02°N.,2o03E. (8 times a year water samples by r,14 i1 07'N, 1°49'E. (frameless reversing bottle at the B 15 51°10N., 1°36°E. (surface, near the bottom and at B 16 51°12'N., 1°28'E. (20 and 40 m To C,Sc/100 and alkali (nity. At 20 m observations of (oxycen, silicates, phosphates, (nitrates, calcium, magnesium and (sulphates. Salinities by titration

FolkestoneDouloc;ne. (Route 18) England and France. Weekjy surface observations o-J: Tu and S %o at 3 fixed positions at intervals of 6 miles:

51°00N., 1°17'111. 50°55'N., 1°22'E. 50°50'N., 1°28E.

Samples taken through the oondenser intake in engine room at less than 5 m depths. Salinities determined by titration.

NewhavenDieppe. (Route 23) England. Weekly surface observations 7777- of T C and S %o at 6 fixed positions at intervals of apprmcimately 10 miles.

southbound northbound 50°38'N., 50°04°N.,0°56'E. 50°30'N., 0°20E. 50°11'N.,0°48°E. 50°22N., 0°30'E, 50°19'N., 0°39E. 50°14'N., 039IE, 50°25'N., 0°30'E, 50°07N., 0°49'E, 50°32'N., 0°21E. 50°00'N., 0°58°E. 50°40'N., 0°12'E.

Samples taken through the condenserintake in engine room at Lea 5 mdepths. A thermograph is also used. Salinities determined by 11Tables4 FIV60/S2 North Sea

SouthamptonStaTalo. (Route 21) England. Tr Weekly surface observations of T C and S 'icp at9positions at intervals of about 11 miles.

50°35N.,1°401W. (1°38°W.) 50°23'N.,1°045'W. (1°,431W0) (An alternative route,occa- 5012'N.-, 1 51W. (1°47.511L) (sionally used, is shown in 500001N., o57,tt. (1°52'w.) (brackets. The latitudes e48,14.,2°021w. (1°56,w.) (are the same for both routes). 49°30N.,2°081A4 (2°01'W.) 49°24N.,2014W. 49°04N.,2°19'W. 48°50N.,,2°15'W.

Samples taken through the condenser intake in engineroom at less than5m depths. A thermograph is also used. Salinities determined by titration.

Lands EndUshant. (Route 10) England. Weekly surface observations ofTuC and S %oat9positions at intervals of about12.5miles.

50°04'N.,5°55'w. 49°52'N.,5°50,w. 49°40'N., 5°45"A% 49°28'N.,5°40'W. 49°16'N.,5°35,W 49°04'N., 5°30'w. 48°52,N., 5°25,w. 48°40'N., 5°20,w. 48°27,N., 5°15,w.

Samples taken through the condenser intake in engine room at less than5m depths. Salinities determined by titration.

FishguardWaterford. England. Surface observations 3 times a week, of T C and S %o at one fixed position:

52°04N., 5°4011L (LiP4)

Samples taken by canvas bucket. Salinities determined by titration. (potentiometric).

HolyheadKish. England. Surface observations 3 times a.week of TuC and S %o at3fixed positions:

53°20'N., 4°44'7. (LP7) 53°20'N., 5°I6'W..(L'p6) 53919'N., 5°52°L(L'p 6)

Samples taken by canvas bucket. Salinities determined by titration. (potentiometric). FB/60/S2 North Sea 1:Tables_2

Larne-Stranraer, England. Surface observations 3 timesa week ofTo C and S c»o at one fixed position:-

o, 54 771., 5o28'. (LiI) 9)

Samples taken by canvas bucket. Salinities determined by titration (potentiometric).

Lightshin Stations eLc.

Vyl (Vy) Denmark 55oo24.41W., 7 34.3'E. (Dail-sr observations at C.E.T. ER (ER) 5523.6'N., 6°57,4E0 (of T 0 and S %o (by hydrometer) in 0 (or 1) m, near the bottom and in as many of the levels 0,59 10, 15, 20, 25930 and 35 m as permitted by the depth. Knudsen's inSulating water bottle is used for temperature and water sampling determinationhh inclu(lin.e- to rn.-Inface (1 m). Every 4 hours (4 , 8 , etc. C.E.T.) the true diroction of the current (by one of the 16 points of the compass) and the s:Jeed (in knots to the first decimal place) are estimated.

Hoard Hinder (NH) Netherlands. 510.39.01N., 2°34.0'E. Terschellineerbank (TB) ti 53°29.0'N., 5°07.0'E. Texel (T3:) 53°01.4':N., 4°21.7'E. Goeree (0e) 51°55071N0, 3°39.71E.

Surface observ:tions of To C every 3 hours at 00, 03 etc 0.M.T0; of 00

surface S %,(-) da. . ly at 08 G.M.T. Samples taken by bucket. Salini- ties determined by titration. Continuous current measurements by means of the vertical log v,ith readines at 00, 019 02 etc. G.M.T.

"roes -t_incol 17'A.,e1: lam.- 51022 25"1t. 2°27' 4511E. _o Daily surface observations of I C, every three days observations of S %.;c) and alkalinity. Samples taken by bucket. Salinities determined by titration. Weekly observations of silicates, phosphateS, nitrates. Monthly observations of calcium, magnesium and sulphates.

Dyck France 51o02.41N., 1o 53,0'E. Observations continues des courants6.. 6 mètres de crofondeur par le "VerticalLoe".

8 Germany 54o 16.0'N., 7°11.5'E,(Daily at 0800 P 12 54°00.0'N., 7°51.5'E.(measurements of ',Ube 1 54°00.0'N., 8°10.7°E,(surface T° C eeser 53°51.6'N., 7°53.3'E.(and. S %o, and

Borkumriff" 53°45.01N., 6°24.2'E.(every 3 or 4 days (at hieh and Ion water surface T° C and S %o. Samples taken by bucket. Salinities deteT- mined by titration. Current measurements by cross-shaped log(Stromkrou 1:Tables 6

. . FB160/S2 North Sea

every 2 hours. At Borkumriff: Once a week'(at0800C.E.T.)N To C and S %o in 5, 10, 15 20 m. and at the bottom with the Pettersson sampler. Salinities determined by titration. Continuous current measurements by vertical log.

Varne (Va) (Surface obser- England(3°56'N.,') 1°TE. Seven Stones (SS) 50o087N0, 604.5W,(vations ofToC Galloper (Ga) 51°4405N., 1°57.8E.(and S %o every 4daYs. Samples taken by Engine Room Sampler at less than5m depths. Salinities determined by titration.

Smith's Knoll (SK) England. 52o48.5'N.,2o18.0'E. Samples taken by Surface Sampler until June 1958, and by Engine Room Sampler at less than 5 m aepths thereafter, T° Cand S %o every 4 -days.

Conic (Co) Ireland 52°02'N,, 6°40'W. Twioe daily observations ofT°C at the surface..

Eatia.00lBar (L'p 2) England 58°81.4'N., 8°19.8'W, Morecambe Baz (1'p 1) 53o54.6'N.,3o28.9"5%

Surface Observations 3 times a week of T° C and S %o. Samples taken by canvas bucket. Salinities determined by titration (potentiometric).

Station L 2 England 50°20',N.,4°10'W. (Monthly observations It , L3 50°18'N4oo11'W. (ofToC and S %o at 4 It 50°15'N.,4°13'W. (surface. Salinity 5 50°11'N.,4oo181VT. (determined by 6 It 50°06'N., (titration. 4o21117. l 50°02'N.,422'W. Monthly observations of T C, S %o and content of phosphorus and silicon at surface and subsurface depths. Samples taken by NansenPettersson water bottle. Salinities determined by titration.

Station at 3 nautical miles N6 U. of Port Brin. Weekly observations of surfaceTuC and S %o. Temperatures taken by insulated thermometers, read to001o C. Salinities determined by titration.

Coastal Stations.

Lista Norway 58°05.1N., 6°32.5'E. (Observations IV (every Utsira I 59015.21N.,59°15.4'N., 4°55.7'E. Utsira II 4046.5'E.(fortnight

Surface to bottom observations ofT° C and S %o. Samples collected by Nansen water bottles. Reversing deepsea thermometers are used: salinities are determined by titration. FB/60/82 North Sea 1:Tableo /

List (Isle of Sylt) Germany 55°03'N.,8°27'E at the "Elbow". Daily surface observations of T° '39every 2 weeks salinities at high and low water.

'o List (Isle of Sylt) Germany. 5501N., 8°27E. in the harbour. Every- 10 days 'surface observations of To C, S %o, and IDTL 02

. B 22 Belgium. 51o101N., 2o38°E. Ptimes a ycar water samples collected by the "Frameless Reversing Bottle". Salini- ties determined by titration. Observations at the surface and near the o bottom of T C9S %o, oxygen, alkalinity, silicates, phosphates, nitrates, calcium, magnesium and sulphates.

RoscoffFrance. Observations p6riodiques de T° C et S %o pr.621 de Bas.

Bardsev Island (L'p 3) England (To C and S %oat 52°45'N,,4o481';1. Chicken Rock (L'p8) 54o02N., 4°50í. (surface 3 times a Salinities determined by titration. ( week.

Port Brin 769.L. (Isle of Man) England.Taily observations of surface T F at9.m,and4p.m. GMT. Temperatures read to0.5oF.

North Atlantic

Routes, Sections (and Ocean '::eather Stations)

R...eykdávik-New York Iceland. Thermograms, once or twice monthly.

Icelandic coastal routes It Thermograms, in summer twice, in winter four times monthly.

The Skaw-Greenland. (Route3) Denmark. Surface observations as often. as sailings permit (i.e. about 30 times a year), ofTo C and S%o at 21 o o points between4U.and44 (fixed longitudes) and at8 points along the west coast of Greenland. Samples taken by bucket. Salini- ties determined by titration,

Bergen-New York (Route 8) Norway. (Thermogrp_,ph records. Samples col- Bergen-Kirkenes (lected lintake pipe in the condenser/ (at fixed positions. Salinities dote- (rmined by titration. Southampton-Canary islands. During winter: Thermograph recorcL2.. 1:Tables 8 12160/S2 North Sea

Ocean Weather Ship, Station A. (WA) Great Britain, France Netherlands, Norway. 62°00'N., 33°00'W. 00 00 (Netherlands) every three hours at 00 9 03 9 etc. GMT88route between Hoek van Holland and station and once daily at 12 GMT during stay on .stationl samples taken by bucket; daily BT observations only on station. Salinities determined by titration.

Ocean Weather Ship. Station I. (M1) Great BritainNetherlands. 59°00'N., 19ar00W, 00 00 (Netherlands) every 3 hours at 00 9 03 9.etc. Gt% en route between Hoek van Holland and station and once daily at 12 GMT during'stay on station. Samples taken by bucket; daily BT observation only on station. Salinities determined by titration.

Ocean 7ather Shi- Station J.(vis)Great Britain, France and Nether7- lands. 52'730N., 20°00'W. 00 00 (Netherlands) every 3 hours at 00 9 03 T en route between etc. GM00 Hoek van Holland and station and once daily at 12 GMT during stay on station. Samples taken by bucket; daily BT observation only on station. Salinities determined by titration.

Ocean Weather Ship. Station K. (WK) Great Britain, France, Netherlands, 00'N.,1.6u001V;. 54 00 00 (Netherlands) every 3 hours at 00, 03 et80GMT en routebetweenHoek van Holland and station and once daily at 12 GMT during stay on station. Samples taken by bucket; daily BT observations only on station. Salini- ties determined by titration.

Ocean WeatherShip. Station M. (WM) 66o00/N., 2oOWE,Norway, Nether- lands. (Netherland8)) Ob88rvations of T° C and ScAoat the surface every 3

hours at 00 , 03 9 etc. Noen route between Hoek van Holland and station and once daily at 12 GMT during stay on station. Samples taken by bucket, salinities determined by titration. Daily BT observations only on station. FT160 S2 North Sea 2:3

'GEOGRAPHICAL AD GEOLOGICAL FEATURF2 OF THE NORTH SEA

2.1 General geographical characteristics of the North Sea

There are sliht differences in the definitions of geographical boundaries of the.North Sea and. its subdivisions (see'Figure 2.1). 'In certain quantitative, comparative considerations it is necessary to determine areas and/orvolumes ofthe regions. As the names of some geographical and statistical areas are identical, it is necessary to point out which divisions are used in these quantitative considerations.. There is therefore a need. to determine uniform boundaries .in order to avoid cenfusion In Figure 2.1 proposals have been made for uniform geographic boundaries of the area which are of course different from the ICES statist'Loal boundaries (Fi(ures 2.2and2.3) which should bo. maintained for present statistical purposes.

The general natùre of the coastline is indicated in Figure 2.4. A list of geological maps, as well as national .sea charts of the 'North Sea will he added later. The north and south coasts of the North Sea are basically different. In the north, the Scottish. and Norwegian coasts are rocky and steep; the southern coaSts are low, sandy and have extensive tidal f1os.

The shipping in the North Sea is more intensive than in any other sea area. Some of the principie norts and their distances from each .other are shown in Figure 2.5. More detailed information on habouys and Shipping can be foundAbsailing directions and in G. Goodall, 1952, "The Mercantile f:Larine Atlos", published. by G. rhilip.and Son Ltd., London.

A .detailed deseription of the fishery falls outside the scope of this synopsis. A general idea of the intensity of fishing however, is given in Figure 2.5 and further general information on the types of vessele and gear used and the main commercial species will be added, partly to this chapter and partly to the last chapter of this synopsis. 2:2 FB/60/S2 North Sea

2.1.1Boundaries, areas and volumes of the North Sea and its subdivisions

List of f_Iii_e:;ures Figure 2.1Boundaries of the North Sea and its subdivisions 2.2 Boundaries and names of ICES statistical areas in the North Sea and adjacent waters I/ 2.3 Regions and fishing grounds 2.4 Chart(s) of the North Sea with the identification of detailed sea charts of the area, issued by different countries(to be added)

Lj stof1.;P1)1P Table 2.1 Areas, volumes and average depths of the North Sea and adjacent waters 2.2 Regions pd fishing Grounds and their approximate area (km-)

2.1.2The coast (The morpholoGy of the coast see Figure 2.5) List of tables Table 2.3 Length and. nature of the coastline of different countries, bordering tile North Sea and. its use by man(to be added) 2.4 List of geological maps of the coasts(to be added)

2.1.3Shipping and fishing (general) List of figures Figure 2.5 Some bigger harbours, distances between ports and nature of the coast 2.6 Relative intensity of fishing in the North Sea List of tables Table 2.5 Fishing charts and atlases of the North Sea FB/60/S2 North Sea 2:3

2.2 Submarine geology

The bathymetry and distribution of sediments are shown in Figures2.7and 2.8. The shallowest depth in the northern North Sea is 73 m9on Viking Bank and the greatest depth is ST Bressay Shoal, 190 m. In the central North Sea the shallowest depth is 13 m on the Dogger Bank, and the greatest depth is 212 m the Devil's Hole.

The sediments of the North Sea pOnSiSt mainly of sand and gravel with occaSional spots of mud in deeper holes. The average content Of organic matter is 2 to 3 % but in some muds it can rise to 25 %. The content of is usually below7% and is mainly caused by shell Qa003 fragments and benthic forms. As the North Sea has sunk during the last glaciation, in some localities peat ana tree trunks of earlier interglacial oric;in are found.

The rate of sedimentation varies locally, being greatest off the estuaries. Some sedimentation also occurs in deeper holes whereas on the shallow banks, erosion by wave action and tidal currents takes place.

List of ficuLts

Figure 27 Bathymet* and names of the banks and grounds " 2.8 Nature of the bottom

List of tables

Table 2.6 Physical and chemical data of the sediments from various localities (to be added) FB/60/S2 NortlSea 2:140. I- 7* ---

Norwegian Sea ..

/"'"r1000 m. / I

North Airlantic, s Nord Fjord

Sogne Fjorc

Shetland 0° Hardange Oslo Fjord

Orkney Is Bokn Fjord

Firth of y,- Moray .Skager Northern

Firth of Kattegat Forth North Sea

Sonthern 0 Baltic 75- 55° German y Bight leligoland Iri sh Sea umber F -isian Sound-and F3elts The Wash Dollar( Waddenzee reTlisT., or Hoofden lisselmeer Mouth of 1,'Themse Bristo fgd; Cl arm

Channel. 50° English. Seine NVINVVV1 Old ICES Area .Committe Boundarie, ICES Area Committe Boundaries I. H. B.( Names underlined ) Other boundaries "rrrr?"rrrProposed boundaries

-Bay of Biscay

10° o HD° G -1649

FIGURE 2.1 - BOUNDARIES OF THE NORTH SEA AND ITS SUBDIVISIONS 2:Figs.2 FE1/60/S2 North Sea r r r i1 1 a Norwegian, Sea

Faeroes Grounds

60°

VI a Northwe -t Northern North Sea Coast bf Scotland

Kattegat Central North Sea and Sounds

55° 'Vli a

Sea

Southern North Sea

!VII d - 50° Englih Channel

Bay of Biscay

1 109 5° 0° 5° 10° G-1649 FIGURE 2.2 - STATISTICAL AREAS OF ICES 3 FB/60/S2 Nor h----, Sea 1- 2:Figs. o 10 o 5° 4 2 10 NYENIMWI0'MPRIMANNIESMON MIINriall OT,MMIE IlA E 1 620)=11113nlinnaln¡Ingninnl,23123 2 2 3 2 13 I 2312 wimuumum IlairldlibININIblE01111111A1IMI ANIMMIIMMIMMEMOMME MOUE POBOGNE I 79 II 30il79 o1161111111111111L 111N11 NORTH SEA CEBEPHOE MOPE 1 78 HALIBUT Amrinnet Dl 1111741MMIIMENIMIIP, EMIEN 11MME 61°A 76 11111111,r0111 I8076 111 mu= ri REJONY I LOWISKA 11MIENEIkaillIMMENE.! O fr liFLINI111101111111111 nwar BRESSAY VIKING GROUND BANK .41 1111111LIII 30PEEIMEMIPMEME rf m BK REGIONS AND FISHING GROUNDS 30 11611111111111.1MBEIN 1 ...) U. BERjap_i Di 1117111111111111OEM e BR65,SAY OLD ¡Kill 60° i 70 !mum° Rum L RI R.) i GROUND VIKI BK PANOHbl N MECTA TIOBA 60° 69 II69AMENBANoK FOP,TY M LE GR NOBLES 70I GR 68 II se 1.111111!,,, B 6 301113111110 ,-- UTSIRE NORTH 30' BERGEN 166MiliVIENEB°II DUTCH ' 011iiejt 661 v.. G ÒTJND o 65 t,-,silv4.. u MENEM 01=ig6511 59°111mow oz.°, 11P1M11.1--NANIMMM I EC MINIM OMNI," 64159° I63MEN 4aegglilIZINI new= 62 6264Ii PE PENMAN sEEROGS M inaut3L....tblir ''.°''''-iIMIIIIP bi...1 ilitrialeMil6163:!11:30 .1 SO l....ti FLADEN GROUND Aro N_K Ft t o OW= 641 60 r litr1 II59II 1B111121 , LAICO G Ou SO OK 4- ...41111. Mar58° ,, hl . ow A '11E3111 As ENGLISH 1 56 MOD tal ....4KGN P ag 561 KLONDYK-F U11EIMMEMIMMI1111\,-,4 E Es SKAGEN LON30 G1.4 IrdratiMPA 1W LONG FORTIES --MINFAMBEIN IrE91:111.11ABEMRDEMIEN 1:11.' 'NI GREATFIS OT 1:1 ,. .ww. 111/2113157° im 9ANS HOLM LONG , 0 BANK LTL F SHER . inniENEompri ,, " EN GB gri-t stmo ORTIFS ID A ,a, 11BANK 8 NK e IEEIUMIMNINIMI 4 0.1.i...miEtir: s R EA TlISCI. MONKOY BK 11491111111111111M 1 . 1,0rc: L.....VF,MLi-FAII491130 IIP "BANKSOLO GR00' RO, 148.111111M1M1113111211= NI (NE MEE SChLIC,, MAElWaltill:' 11131111111111MMEEMI :;L: G U T 'AM< TURBOTi'EINGKJOBI'- /fflW/0111i - OF FORiI-1' 146NIMMPAIII ,uFo. UrER GUTH gimp. Now 461D6° - CLIC 11111 h FARNE nu NEI im CHUCK giummweirilEll BANK illiEN*riE.DINiLHAIM - AR - - WIRP. '' 4 .....1.4,' nillIMINIK411110311.:. IDÖLE ROUGH O EAST. HoRN REEFS IN DpsNE BA K Eosr,, TAIL 'ES.' ERGIlreispIll 77,

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Bergen

60°

294

kristja.TiS '''' Goteborg V \\I I / ///1 403 Aberdeen Fredrikshaven

Dundee // Edinburgh

55°

,.°1 Itona Brom4rhaven Grimsby

Lowestoft Jjmuiden o terdam

Do'ver stend Calais Sandy beach Low coast /////// Rocky,high coast 50° Tidal flats Dunes

10° 5° 0° 5° 10° G -1649 FIGURE 2.5 - SOME BIGGER HARBORS, DISTANCES BETWEEN THE PORTS AND NATURE OF THE c,oAsr 1113/60 /S2 North Sea 2:Figs.5

600

55°

Relative intensity 6f fishing

EFIEVery intens ve 50° ntensive Average VZMLow Very low

10° 5° 0° 5° 10°

FIGURE 2. 6- RELATIVE INTENSITY OF FISHING IN THE NORTH SEA ( after Klirnaj andRutkowiez ) 2:Figs. i'13/60/S2 North Sea

150 Vi king \ f 60" /co,loa; ç100

/Ç '3(22 ! ) 51 3 ' / o ()0 S-4

, - Fort ics eti) ri..it let)) ,, , r I t;iti1.

0 Cf) 13 , Diiggc r Bank . i : 55° I , , , 0 1 -....) A 14 0 ,,,"...,-...,,.;0 f rj.\.-9 :----`,',2 ,,, Oystcr ,.."0 "1,----,--1..--..t.--:.-_-.7 6rinind ' 1, -1 ..t .,

, >100 150 (i',111111 2 C;oritl iii 5k 3 NMI< 4 11,1111,7 Gr,11111(1 5 Lai(1.'i she r 6 1 >75 1.h. v i It, Heir 100 8 0111.4.1hi I vt r 9 Di., p t r 10 1 loolitcn 100 I V Li 01and 12 Bt,rkurrt Reef 13 Horns Itnet 14 Si/hilt Bank

1 ) loo no 5° 10° G -1649 E 2. 7- BATHYMETR Y AND NAMES OF THE BA11KS AND GROUNDS FB/60/S2 North Sea

Sand.

- -50° Gravel and rocks

G'1649 10° 5° 0° 5° 10° FIGURE 2.d - NATURE OF THE BOTTOM (A.fter Pratje) Areas, volumes and average depths of the North Seaand adjacent waters. TABLE 2.1 (from Kalle 1949 North Seaproper EnglishChannel Irish Sea Kattegat Area1000 in km2 Depth 0-200 m total 200 m. 575.3515.5 59.8 75.2 103.3103.2 0.1 25.2 Depth,Volume inaverage, 1000 m km3 9454 54 4.1 60 6.3 28 0,7 Regions and fishing grounds and their approximate area, TABLE 2.2 km.2 ( see Figure 5) fishing ground Region and sq.Surface km. fishing ground Region and Surfacesq. km. fishing ground Region and Surfacesq. km. fishing ground Region and Surface sq.km. 1. HalibutTheNorweaLan Patch Ground Furrow 3,1505,600 UtsireViking HoleBank 3,1505,600 UtsireOld Viking North Bank 3,5004,200 ScottishNobles Ground Klondyke 3,5002,100 2. FladenCoral BankBressay 3,500 Ling Bank 1,750 West Middle East,Bk 4,550 English Klondyke 5,250 o HalibutBressay ShoalE.Ground79000Bank 3,8503,150 BergenBressaySwatchway Ground Ground 1,0503,1504,900 NWFladenForty Flat ElleGround 18,550 2,4504,900 WitchDutch BankGround 4,2005,250 3, FairUnstThe ShetlandsBank South 1,400 2,100 TannersPobie Bank Hill 1,0502,800 FoulaThe Hole Bank 1,050 FoulaFair BankBank South 2,1001,400 4, StronsaScottishOtter Bank Firth Waters 1,0501,400 PentlandPapa Bank Skerries 3-5001,400 Moray Firth Gr. 1,400 'Little Halibut Bk 2,100 Bossies-LittleBoseys Bank Bank 1,400 700 BuchanSmith-Bittockie Deep Bk Ground 2,4501,400 AberdeenMoray Firth Ground 2,4501,400 Montrose Bank Berwick Bank 2,8001,400 5. EnglishHalibutNE Grounds WatersBank W 1,400 3,150 Mar-Wee Bankie 700 Firth of Tay 1,050 Firth of Forth 2,100 1,400 5,250 Barmade Bank 1,750 BaymansFarneFlaborough Deeps Hole Gr, - 1,0502,100 700 WithbyNorthOff GroundFarne Fine DeepGround 1,050 NELittleCastle Bank PitGround 2,10019750 OuterScarborough Dowsing Ground 1,0501,050 T...BLE 9 On t fishing ground sq. km. fishing ground sq. km. 1 fishing ground so. km. Long Forties 5,250 Long Forties S. 4,050 ;Devils T-Tole 4,200 I h.) Coal Pit 1,050 I Great Fisher Bat: 13,300 :Inner Shoal 1,050 r It'ci(1-1'cr: 8. Southern DoggerEast Bank North Gr. 4,2C) NVi Rough 1,050 1 Dogger N. Shoal 1,400 '::estBrown1estCoal Hole BankDeepPit Water 2,100 1,4001,050 700 Dogger Bight 1,050 700 SkateSouthern-most Hole Gr. 1,050 700 He ',Tills I Boulders Bk, 700 RegionNorthBrilleSandettie and FallsGr, S Surface 1,400 700 fishing ground BarfieurCalais e Channel 2,000 700 Botney',tell Bank Cut 1,050 BellGreat Role Silver Pit 2,1001,050 'Outer Dowsin=,, NE Hole 350700 S':; Patch 700 Eismost Shoal 700 1 Hospital sq. km. 6. The Gut-Fisher Bank 700 Cleaver Bank 2,450 B. :aid Hole 19050 1 UPper Scruff 2,100 RiOdileN.Elbow Zeeland RoughSpit Ground 3,500 700 OuterLower RoughScruff 3,9002,800 ISchlick Bank S I H2avy Scruff 4,2001,050 Leman Ground 1,750 Leman Bank 1,050 1 Over Bank 700 OuterTheTurbot Gut Shoal Bank 23,000 2,1001,050 .Tea KettleEastBrava' Deep HoleBank ';:ater G77. 2,1001,750 VantertonVlieijmuiden Rough TwentiesGround 2,100-1,400 ITheIkinterton Broad ForthShoal cii_exel Ground 1,4002,1001,400 Knoll Deep 700 Gabbard Gr. 700 i i Hinder Gr. 700' Dogger Bank BlighSchouven Bank Bank Region and Surface 1,400 B. Shelde Region and Surface 700 1 Huytingen Region and Surface 1,050 IN) o ioo 1 HooeBoulogne Bank 2,100 PlymouthDieppe 2,1001,400 I F6camp 2,100 ;0 BruceysDogger GardenBank 11,900 2,450 BotneyEastmost'::estS. Dogger Shoal Ground Rough Cr. 1,400 700 SchlickTailClaySouth Deep EndRoush Bank N 2,8001,05029'100 TEE L: 2.2( cont,d ) Region and Surface ! Sur'ace fis'iiYIE ground SQ. km. I fishing Eround sq. km. ¡ fishing ground Region and sq.Surface fishing round Region and Surface 10, German Eay 1,40 so. km, î rr 3orhum'Zersheling 2lat HoughGr. 2,800 Oyster Ground 11,653 -hite Bank 1,400 1 iTorderny Grouncl L,05o '- elgoand Ground 3,150 EiderVlielandOuter Ground Ground Gr. 3,150 Lister Deep 1905C, HelEoland Rouh Bern 1Leel s, ur. 1,050,2,100 Horn21=um Reef GrouncTL Ground 2,1002,000 1,_uschelSylt Outer Or. G-n, 2,450 Danish -,:aters 1 i i 11. norn Reels Horn Reefs Rough ; Horn Reef 1-orth Gr. Guroot Lank 1,050;1,400 S rl'urbot 3Enk 1,40019400 ! .1.:onhey Eanh 1,40C iRinEhjobing Gr. 2,800 Jutland Eank 1,750 Holmen Cround 2,100 ! Little 7.is-0 Eank 3,1501,400 ;Bov-uier Schlick Eh East Ground Rouh2,100 Jubilee Bank 72est "Liddie East Eh 3,350 Holmen 2,100 !1 2100 i i , 12, Shace-nrals: ! 3,500 Sha,,:en Bank 2,300 1 Sha.f:4-en ,est Zat, Jammer 1,750 i, se.::--eral-- ! - .i -, i t,i FB/60/S2 North Sea 2:Tables,5

TABLE 2.5

Fishing charts and atlases of the North Sea

Author:1 yeartitle and_publisher Remarks

I. Klimaj, A. and St.. Rutkowicz Charts on hydrographical and geological 1952, Fishing Atlas of the conditions with explanations in Polish, North Sea. Lorski instytut English and Russian and monthly charts Rybacki, Gdynia. on trawling and lugger fishery, with explanations and tabular data.

2. U.K. Admiralty. 1953. non- Monthly charts with indication of fishing thly fishory charts for the areas by type of fishery with short ex- British Isles. 37d.rogr.Dept. planatory notes. Admiralty, London.

3,I.C.E.S.19?? Fisheries of Monthly charts on occurrence of herring the Wortheast Atlantic, of different maturity stages, fishing Herring Atlas; Copenhagen groUnds, landing ports and quality, with

explanatory notes in English, l'c' ench and Danish.

4. Furnestin, J. et al. 1956 Monthly charts of fishing grounds for dif- Atlas des pêche de la Mer du ferent species with short explanations. Word. Inst.Scient.et.Techn. des Pêches Maritimes, Paris.

5, Close's Fishermans Charts. Sea charts with nOtes on type of bottom A. Close, London. and fishing conditions.

FB/60/S2 North'Sea 3:1

3. CLIY.ATI] Aul) RfDROLOGY

During the winter Many barometric minima pass from southwest to northeast over the central North Sea. The higher the sea surface temperature in the North Atlantic during the winter, the more steady and strong are the eouthwest winds over the North Sea and the warmer remains the winter in general.

The frequency of storms increases towards the northern North Sea (see Table 3.1).Because of the northwest storms there is a rise in the high water level along the coast of the southern North Sea and many floods have occured especially but not exclusively during these storms.

Detaile0_ climatological data are found in the atlases and charts listed in Table 3.2. Forecasts for shipping and fishery in the North Sea are given by most of the bordering stateS. However he forecast areas differ slightly (see Figures 3.1 and 3.2) and a unification of boundaries and nomenclatures of these forecast areas seems to be necessary. There is at present no good summary of the hydrological data available (precipitation, run-off and drainage areas) but some average run-offs are given in Table 3.3.

List of fie-ures

Figure 3.1 Meteorological forecast areas of Danish Meteorological Institute- " 3.2 Meteorological forecast areas of the Netherlands Meteoro- logical Service 3.3. Meteorological forecast areas of British Meteorological Office (to be added) 3.4 Meteorological forecast areas of German Meteorological Office (to be added) 3.5 Meteorological forecast areas of Norwegian Meteorological Service (to be added) 11 3.6 Meteorological forecast areas of French and Belgian meteorological Services (to be added) 3.7 Characteristic weather map for the North Sea area during early winter (to be added) 3.8 Characteristic weather Map for the North Sea area during early summer (to be added) 3.9 Drainage areas of rivers, flowing into the North Sea (to be added) 322 .b13/60/S2 North Sea

List of tables

Table 3.1 Frequency of storms and. fogs in the North Sea Table 3.2 List of climatological atlases and charts, covering the North Sea Table 3.3 Inflow of water to the North Sea Table 3.4 Yearly maximum and minimum runoffs of the rivers entering into the North Sea (to be added) 60°

F LADEN GROUND

55'

50°

10° 50 00 50 10° FIGURE 3. 1- IVIETEOROLOGIGAL FORECAST AREAS OFDANISH METEOROLOGICAL INSTITUTE 3:Figs.2 FB/60/S2 North Sea

i00 5° 00 50 10° G-1649 FIGURE 3.2 - METEORoLocicAL FoREcAsT AREAS OF THE NETHERLANDS METEOROLOGICAL SERVICE FB/60/S2 North Sea 3tTables

TABLE 3.1

Frequency of storms and fogs in the North Sea

North Sea Season Southern Central Northern

Frequency of storms in

Winter ,>5 10 20

Spring 1 5 10

Summer <1 <1 1

Autumn 5 8 10

Frequency offogs in, %

Winter >20 <10 <10

Spring 15 12 12

Summer 6 . 15 >20

Autumn 15 10 10 3:Tables 2 FB/60jS2 North Sea

TABLE 3.2

List c)- .climatological atlases and charts covering the North Sea

Author, year, title and_publisher Remarks

Deutscher '::ettordionst, Seewet 'Three parts published by different authors. teramt, Hamburg,1954, 1956 Detailed presentation of vario us properties Klimatologio dor kordwesteuro--as monthly averages, maximums aid minimums paischen Gewasser, Teil 1-2,3and annual changes in selected localities.

International Council for the Directions and average speeds of winds .. xploration of the Sea (ICES) during 10day periods in various localities. .6erv.Eydrogr.'Charlotteniund 1950 1,1onthly -;;ind charts.

Ileteorological Office, London, 1948. Monthly meteorological charts of the Atlantic. M.O. 483,

Deutsches Hydrorahisches Institut, Hamburg,1956. Eonatskarten far den Nord- atlantischen Ozeans.

The Royal Netherlands Meteoro- logical institute. 1931. Climatological atlas of the Atlantic Ocean.

6. U.3. iJavy. 1955. Marine climatic atlas of the World. Vol. 1 North Atlantic Ocean. Inflow of water to the North Sea (from Kalle 1949)

Origin Type of water Amount in elevation of North Sea level im am/year Relation English Channel Atlantic 3140 10 RhineMeuseScheldt FreshFresh 128 12.6 5 P Zms';:eser FreshFresh 16.5 3.3 KattegatElbeMama Baltic Sea 77. Fresh 300 43.539 1 ThamesN.':;. inflow Fresh water total FreshAtlantic 40,000 251.6 3.7 100 o o FB/60/82 North Sea 4:1

4, PHYSICAL AND DYNAMICAL OCEANOGRAPHIC CHARACTERISTICS OF THE NORTH SEA

The influence of tide generating forces on the tides within the North Sea is very minor and the tides in the area are determined by the oceanic tideS entering through the English Channel and through the area between ScotlandanaNorvray. The rotation of tidal currents i8 usually counterclockwise. The wind exercises great influence on the tidal currents and tidal heights. (see Figure4.4) The form of tidal ellipses on the surface is slightly different from that close to the bottom. (see Figure4.3)

The average net circulation is also greatly determined by the prevailing direction of winds. There are several more or lesS perma- nent centres oí eddies which. however change their positions slightly with the seasons. As seen from Figures4.3, 4.7and4.8,the surface currents in the southern North Sea are approximately parallel to the coast, whereas the bottom water flows towards the, coast, causing slow upwelling. In general the bottom currents are considerably different from the surface currents, as also indicated by the distribution of bottom temperatures. (see Figures4.34and4085) This circulation close to the bottom is controlled by the horizontal density differences close to the bottom (caused by cooling, warming and mixing processes) and by bottom toporaphy.

The wave characteristics in various offshore localities in the North Sea are greatly determined by the length of the fetch. Average relations between the wave elements in the area are given in 7igure 4.9and Table4.4,and the frequency of different sea conditions in Table4.3.Maximum recorded wave heights are between 6 ana 8 meters and the maximum length is ca. 150 meters.

In most cases it is possible to define six different water masses onthe bases of different properties. (see Table 4.5) The distribution of these water mas8es also corresponds roughly to the distribution of different biological water masses. (see Figure 7.1) There are also some similarities between these water massesand the different hydrographical regions (see Figure 4.10) which are determined mainly by the mixing by tidal currents'and the depth of the water. One of the determining characteristics of these hydrographical regions is the' depthof the summer thermooline (see Figure 4.13) which is also an important 4:2 Z76012 Torth Sea ecological factor. The influence of the bottom topography on the stratification is recognizable from Figure 4.11 and 4.12.

As seen from Figures 4.19 'Lo 4.30 the surface temperaturesare mainly determined by the inflow of water, by mixing and to a lesserex- tent, by local cooling and warming in shallower water along the coasts (especially in the south). Y.onthly surface temperature charts with brief analyses are prepared by Serv. Hydrogr. of ICES. (Figure 4.31) There are some year to year variations in average monthly temperatures (Figure 4.32). These variations however differ from locality to locality (compare Figures 4.32 and 4.33), due to the differences of surface circulation pattern, and are especially inflUences by the intensity of inflow. The close correlation between the air and sea surface temperatures (see Figure 4.32) is determined, by the sea surface temperatures and not vice versa.

There is no correspéndence between the temperature variations of surface and deep water (see Figure 4.33), nor in the general distribution of surface and bottom temperatures (see Figures 4.34 and 4.35) as the surface and bottom water circulations are different from each other, as mentionea earlier.

No reliable heat budget calculations have been made for the North Sea.

The turbidity, caused by runoff, mixing and occasionally by intensive plankton blooms, follows the distribution and'movement of water masses. (see Figure 4.39)

Ice is formed during severe winters on the shallow water along the coasts of Holland, Germany and Denmark. (see reference in ice atlas).

4.1 Tides, tidal currents

List of figures

Figure 4.1 Cotidal lines (GMT) in the North Sea " 4.2 Distribution of maximum velocities (cmsec-1)of tidal currents at spring tide

" 4.3 Hourly current vectors off Texel in 10 and 23 m depth FB/60/52 North Sea

Figure4.4 Water movements and winds in the Strait of Dover, September 1939to August 1940 tt 4.5 Heights of spring tides along the coasts of the North Sea (to be added)

4.2 Currents

Figure 4.6 Average net surface circulation in the North Sea 4.7 Surface currentsinthe southern North Sea in May 1955 (averages for 10-day periods) " 4.8 Daily residual currents near the bottom in March 1955, based on measurements with 6 paddle wheel currentmeters

List of Tables

Table4.1 List of current charts, covering the North Sea " 4.2 List of data on current measurements in the North Sea (to be added)

4.3 Sea and swell

List of figures

Figure 4.9 Average relations between wave length, height, period, speed and wind speed in the North Sea

List of tables

Table 403 Frequencies in % of different states of the sea in eastern and soUthern North Sea 4.4 Wave elements by various wind speeds at lightship "S2" (54°N,305oE) during 1949

404 Water masses and their characteristics

List of fi((lures

Figure 4.10 Hydrographical regions of the North Sea

List of tables

Table 4.5 Water masses, their characteristics and distribution in the North Sea

" 4.6 Average water exchange and half-lives of water masses in the North Sea (to be added) 4:4 FB/60/52North Sea

4.5Mixing and turbulence; annual cycle of stability

List of figures

Figure4.11Characteristic distribution of T and S in international R section during last part of April

" 4.12Characteristic distribution of T and S in a NS section over the Dogger Bank along3oEduring last part of September " 4.13Average depth of the thermocline during the summer (in m) " 4.14Distribution of T and S in three international sections to4.19 during two different seasons (to be added)

4.6Water temperature

List of figures

Figure4.20Mean surface temperatures (monthly charts) to 4.31 11 4.32 Surface temperature, December1958 4.33Monthly means of the surface temperature (solid lines) and of the air temperature (dashed lines) at Horns Rev lightvessel during the years1880-1939 " 4.34Yearly anomaly of surface temperature,56o to 60oNand .0o to3o and bottom temperature during JulyAugust, 56oto57N and1oto5oE 11 4.35Characteristic distribution of bottom temperatures during last part of May 4.36 Characteristic distribution of bottom temperatures at the beginning of Zeptember

List of tables

Table4.7 List of hydrographic atlases coverihg the North Sea

407Heat budget

List of figures

Figures4.37Average annual variations of main components of the heat to 4.39 exchange between the sea and.the atmosphere in northern, central and southern North Sea (insolation, effective back radiation, convective transfer of heat, evaporation and heat advection by currents) (to be added) 711/60/S2 North Sea 4:5

4.8 Turbidity

List of fillaLap_

Figure4.40Turbidity of the water during spring 4.41 Turbidity of the water during autumn (to be added)

List of tables

Table4.8 Seasonal mean values of extinction coefficient of different water masses in the North Sea (to be added)

4.9 Ice conditions

e-cenc

Deutsches Hydrographisches institut, Hamburg1956 Atlas der Eisverhaltnisse der Deutschen Bucht und Westlichen Ostsee FB/60/S2 North Sea

10° 5° 0° 5° 0° FIGURE 4.1 - COTIDAL LINES (G. M. T. ) FE/6O/S2 North Sea

10° 0° 5° 10° G-1649 FIGURE 4.2 - DISTRIBUTION OF MAXIMUM VELOCITIES (cm sec-I) OF TIDAL CURRENTS riT SPRING TIDE kafter DIETRICH) FB/60/S2 North Sea

,Gauss'86'1 17/18E.1952 40 53°1Z7W A. 4327

Stundenwerte noch Schaufelradstrommessor 34063407 ous zwei 77delII 0:Monddurchgang in Greenwich

28m

Texel

Figure4.3

Hourly current vectors off Texel in 10 and 28 m depth (after Dietrich) A

12 75 1782 0 09 9 65 S W L i 075 19 31VE NE 702158 1527 ; 174 14.E 020 347 SW 0 71SW: 0 7441396 CO ;; E 2058 9E s 330 854 . 9E_ 6 10 e Al 26'E o e 0 3 C7 1, 25,,s 7 00-4 e C) e o e 252 N 72'W o e3 10 s"..ThN 46.E 3-84 5824 7 10 C S 60"W E i per IIii e o o VARNE NORTH FOLKESTONE GATEWAY LYDO SOUTH FOLKESTONE GATEWAY r ses ss ,404 NORTH- EAST 5 M[1,-. p..1 SOUTH- osl, , hi," fl-h l WEST :r1 .! 111 90 100 HO 30140 150 I130 130 180 190 200 2i0 230 230 280 250 280 270 280 220 L, BA Average monthlymonthly total residual water pectivewater movement movement of direction) (the summed (the in milesnett daily travel per mileage, day. or "overall irres- NOVEMBM DEUMBER1 Key E PeckedContinuousDaily line total line water movement, in miles per day. Mean daily SW. and NE. wind travel, in miles per day.Daily residual water movement, in miles per (lay. C AverageI) Full and monthly new moon. residual windmake" strength, of the water)in miles in per miles hour, per and day direction. andNotes. the octant in which it lay. (i) All days are lunar days of 24 hrs.All miles 50 min., are seaunless miles of 6080 feet. otherwise stated. nentsCalendar;Mean are daily drawn black residual in fulland wind,line,white East inbars Beaufort and represent West scale. components weeks North of andseven in Southpecked solar compo- days.line. All directions are magnetic. (Variation = 100 W.) Figure 4.4 Water movements and winds in the Strait of Dover (after Carruthers,September Lawford, Veley) 1939 to August 1940 FB 60/S2 North Sea

FIGURE 4.6 - AVERAGE NET SURFACE CIRCULATION 4:Figs, 6 FB/60/S2, North Sea

D /TM AR It

Th. W.

larotoft

E ITGL A1T NE THERLANDS

LONDON GE RMANY

Boulogoo BELODTK

MAY 1955 eft, tZ3. CURRENT

AVERAGES FOR 10-DAY PERIODS

0 S 10

NAUT MILES PER DAY

Meridian 0' of Gronxrwich 1/).

I.C.E.S, SERVICE HYDR °GRAM DUE, CHARLOTTENLUND, DANMARK.

Figure4.7 FB/60/S2 North Sea

4° 8. d55 , -)5 ( ) ; í ') n-'. > .

'i \ ,, I ' n i ?. 7" PP ,,,c, - e . , '1, 10 13 0 .., 0 pp 551 c':-. 4 i / 3552 I ;-i'--- --) /3 , A 0 .0 IP . , J 1. g '1 / 2 , r o, \ . Po . ,, ' 1 ' ,,....2 ' C , '\,-.. ---.,a ''..--...... -' c- ,...., c,\ _I , \\,',. Q i . .

, ,...... 6,., ,-:,----- ,, Emden 1 , , , 3557 \ ' . I ,

. . 3561 ».../.. :.:73559

, ,

53° ' /2 Al r3" ± 1.-1,09,1-1Mlekr

, 42 dIS . P . TaglicheReststrbme , n , 9.3. 25.3.1955 1 25m über Grund 1 r ..., , ,I d Geschw, 144051.ftb '

Y --,,,/v , I

, . o o to cm/sec 20 .

' k

.f--00o 7,,, , , I[520! [520 , , .....,...... ,.._ ....,...,..... 52'

...... _...,...... _.....,...

Figure 4.8

Daily residuE-1 current near the bottom in March.1955, based on measurements with 6 paddle wheel currentmeters. (after Dietrich) 4:FiFs. 8 FB/60/82 North Ses;

21 10 15 20 wind speed

10 16

9 li 16 15 7 VC 14 u 6 13 g

5 .12 4 4/C) 11 mo 10ta, 3 O- 9 u) 8

7c; 6 5 4

0 20 40 60 80 100 120 140 160 180 200 220 240 460 480 300 nn vv.avelejagth Figure4.9 Average relations between wave length,height,period,speed and Wind sPeedin theNorth Sea (after Schnmaoher) FB160152 North Sea 7 4:Figs. E

60'

.-fY77

;./..:'"

Whole year homohaline;seasonally or whòle year thermally stratified 50° Whole year homohaline and homotherm Seasonally or whole year haline stratification present; annual salinity c.hanges small in surface layers, regular in hottom.layers Seasonally or whole year haline stratification present; annual salinity change pronounced, regular in'bottom layers.

10° 5° 0° G-1649 FIGURE 4.10 - HYDROGRAPHICAL REGIONS OF THE NORTH SEA (after Dietrich) 4:Figs.10 FB/2/S2 North Sea

FIGURE 4. 11 CHARACTERISTIC DISTRIBUTION OF 1` AND S IN INTERNATIONAL R SECTION DURING LAST PART OF APRIL 1173/60/S2 North Sea 4:Fis, 11

Do gge r Bank

Dogger Bank

FIGURE 4.12 CHAR.ACTERISTIG DISTRIBUTION OF T AND S IN a N.-S SECTION OVER THE DOGGEII BANK ALONG 3°E DURING LAST PART OF SEPTE1VIBER 4:Figs.12 FE3/60/S2 North Sea

......

*%. \, 15 - 50 7

60° 15 - 40 15 - 60

15 - 50

30 - 40

30 - 60 30

- 55°

- 50°

10° 5° o o 10° G-1649 FIGURE 4.13 - AVERAGE DEPTH OF THE TER MOCLINE DURING THE SUMMER (in m) (after Dietrich) i1 iI / / I r NORWAY ..". I/ /..... I I .c.q.... ,. 4,. , \ 1 ... I ,...1-. ,...... ,,,---. A.,.....42 1 i / \ .- .-- S D (' \ .;> A .COTLAN ( 7 \ // / / / __.,sz..,. ...-._ \ \ \ 7 i 6/ i ,-,4-- N t.THER LAN DS )ERMANY E LonTIL TEMPERATURE aC SURFACE FRANCE FISHERIES LABORATORYPROVISIONAL LOWESTOFT MEAN JANUARY PREPARED AT 6 ofl_ ., i 7 5.,,v,.,:-...----,-,---'---;y-7,-- -N---s 6 ( "...... 04.-, ,-- , E....0,1 , o s c - \ OTLA N D 4 \ \ 7. n I, l ' \ :.> N 0 R WA Y >`. \ / \ I -...... )- 4 / 6 1 / . L . / // 1 i / II if 4 D MI ' r / I / Err). ; i / ...'" V , / ,''''.- / i -- //NETHERLANDS / / 'r-::"3) . GERMANY % BELGIUM I - , TEMPERATURE FEBRUARYSURFACE --- FISHERIES LABORPROVISIONAL PREPARED ATORY. II *C AT LOWE MEAN STOFT

I ,..,?.. 4..-...... - a.u.,... , r'''''. ,,,_,I,,, -,--,---\i.\, .../ Dubba 1 -: 6 5 "--",. N. . / 10 IRELAND i 7 ,,i ) -`,.1 ' \ \ ,...... "`.1 i r \ I''----"7»...,,..z,,,i 7 As, '''' '5' E N- G L A N LI+ i -....e,-,8 Loti00 1 ,,f-'-'4- \," ?-----,i----,------_<;,--:.------) <45 i 10 9 8 7 /...... / ..,' / i -,--;.; FRANCE

I 1 i II 0 / *"",-.T.,te 1., ...- --_,_..= -... 7 ,n...., c.r. - to' , ,------' - .------_ ''- _,_-. 4. ,..14,...... t...: .."'". 'A. 1

4117-- 17`"(7.: gr .11..20.. 1 i I _...- 1I i i 1 .4...... _...... , . ,... t Ai,4..-r.r.: N O R W A Y i , -, --- -, ,.." .A --:.------'''.---`,...... -',4 ../ 5 ,.__'"-.. , 6 \ \ , Y.C. SCOTIATTD '' : ) \ \ ti i 11( 6 i if t' '' ".. 1 10 x:r...i.-- --/ II / i i/ r(\ , ..,4,,,,,-,,,, ' ' ' 7 - ,-" --3--- / I / 3 q \ ------..,-- ,, 7 =1P IRELAND -, , :i 6 5 ...t t__.,, 4 .--,;\ "...... ,..0, if 10 ,-- -- I ( u t,-r------' ---t° 2,- '''.-- a. _. ,,,,5 /NETHER / DS 1 L. iti-j5e I J 8 sa...... ,,, ./ ,,,,,,,,---' / / '-...i ' ? H t L Gfp-'.A ) i' / 6 k \ ! , IQ '_9 /. k.--...---.-"ei --"\ , 1 14e,r-,- TEMPERATURE SURFACE °C ) ti' , FRANCE PROMSIONAL MEAN i I 1 ... FISHEP.!,.:S 1..PAIPARAR51:0T. LO.VEST OFT 1 . _L.. . as..., 7.,..li .3,..... 12 w .,... ,...,...... , ----'- ji --.....-- lo I ------' ------.,-7- er..,-.4. }Th -- 7 A...e..., B- -. ----,, I 5. t-4,Xtz-. 'i...._.,- 7' 716 1 1 ,V' 1il 'f'" I 7ìro . V I I 1 4 - {-4:-.1."-#z fq.,1:g 7 1 4,..' N 0 R W AY <4 dt..'\ 4, , l l ..-...*-1,:.... j ,-,-, 1 --,... ,--k. , 1 i I i :',- ,---,^s. _. ..,-----z---,-----,,,,,, .,. ..; ...... 9 8 7!, , ...... / \s, i I iil v c 0 TLAND \ i )

1 1 i ...... ,... \ oCIT Il 11.2sT/...?!I''' ' _4e6v!I r ,. i .1, 10 --4...1..--, .1,..e. .. <6.5 \-.,.. o... :,, I 1 .....".". ...\ 4, 1 -1. '''' . %...... -"'''''''....------'1 -I' O. ---,-,.0).---. -,------,- ICES, SER,ICD MIYDROGRAPHIQUE, CHARLOTTENCUND DANMARK. (...< 5 5_ 1 I REL AND \ , --,,\....,r ____(.,.....," N, ...... -."'''' 0 III ' \ , i,..... r -,,-- ÌCa 8 51 .C't' .i.,,,r----\ / 7 I 1 ,...... -+ Av-._5 r___,s, . .'1'. a. ENGLAND NETHEItl.ANDS 1 ...,...,....,-, .)'°.7...... \ ,, ''"" ...... 1 'to.- 9 , -,....__ ...,_, 8 G E RMANY I 1------10 ,--- r-- Y ...... -k. 5.----<, ___. --i 11: BELGIMA - ,--..,-1 ( t) ;1` - ',.------__* ---... .4, 1 SURFACE 10\\ . _ , TEMPERATURE °C APRIL ' . 1...g...1. .r.-- 12 FRANCE F SHERIES LABORATORY.PROVISIONAL LOWESTOFT MEAN DREPA0ED AT _ S- a- - ',"--"------___-.---._ __. ./*---",..--,---- i1 . 5...... ,.. / I, : i ...._7. i \ N. ;17....- .4, ..0. ,Nrd 1I . . k ,,,,,...:,,,,...,, £6...... 4or /I t i .,, I ..-44. \ \ \ \ ,, :...... , N 0 R WAY " li \,.....i ...,--f': -3 1 I . ..,..%, \ 1 .. ,,,, f,..4 ...^."., I I , ..-il..,---.,,:"S--r-'-'------', 9 ..... , .4...... d, ,,, / 1 l S I --.,;-:, SCOTLAND .,...,...... ! !....:C5 i i'''. .I- 1 ...>. 8 1 10 Ns----.." I :.\-' I,-:',....I (777°S.,: ,..., , ""` ...--\.. '-t° 1 I 44, Tusarmw I I

11 ,:'''S 9 ----..t fr : .0 I i ..q: 1 1 ,...7 , -P------\_, , p I 1 IRELAND o 1'14_ )..' '7 .4, -

1 I! 1 i 1 6 i iDobbs 12 : ...... r.... I i ENOL A N IY N I:E.RLANDS ---

, 1 10 1 1. 70 G E R NI ANY 11 Ii i I i BE L G UM

1 1 12 1.... --- 14_, TEMPERATURE cC SURFACE - .."" N1 1,--, I1 13 ' '.- ----.:"2D - , -,' FRANCE I PROVISIONAL MEAN MAY I PREPARED AT FP -...--.....- tt.. 6- ...... I CES, SERVICE t FISHERIES LABORATORY. LONSSTOFT UND, DAMP. r . I ti 10 ! ! Baragtor Fl! if: , N OR WAY Cn UTLAND 4 s, ; ;;;;-!. !!! " !". - , .., -..'--1,..-...... 12 T ,=....- .....- \ \-:. \ /(_ ' L.. I R E L AN D , I 1 1.2 ' 13 ; ..ft, : IX..b.2< i \\ .,-/- ,..',,, 14 -x!, 40--e.,-_,- ,--,' II, 1 1,...., w...... Ar,...... ,4 1, . _ ly- 14 A, . -.!31 i F. N-GL ANA) 13 12 ','!"-' ,,--°- 'e--,- ,.. ,.-.. , 13 ----6-: I Somilwor.,...t 9* a tße..., at' B E L G III4AL SURFACE FRANCE TEMPERATUREPROVISfONAL MEAN °C jUNE 5 -15 , s. FISHET,IE.S LA5ORATORY . LOWESTOFT PREPARED AT L.nguud. ..z *Is C. E S , SERVICE MYDROGRAPHIQUE, CHARLOTTEHLUNO, SAMBAS E RMANY! . 11

.- _ 1 2 / 147'E..ft' `;" Sop. . r 1. ...::::',. ,,,,, ,..:,--,-5,-Y- , .1.....4.,N ORWAY .7., f. ft,..-44. ' :I-!..--; '-v )1,..{..: , i 12 ''. ji ) I1 ,---- i ::: '; / ' - ,---;" -; (7 ; I 11,!A 14 , '''. .. ' S ,.' I., T L A N 1$ 1-44 t -1 / I i '4:1. / - 11111 II I i \. J / I 1 7 ) , \ , V ,211 / I .---°°' I i I :': U- ' .' 1 \ \ .1.1.-,..,i ', - - ,-.,--, !--- 1 \ s's1 \ \ CO \ i 1 f \ \ \ I a E I. A. N D 1....,-..' .., ' L'' / \ : 14'' 15 \ - \ ;- I 13 i'T 1 GERMANY '' ' . .."-14 _-< .,5 :` "'Le..., .,,,,'' ,- E N ,. L A 7, 1 = LI-,1,441d. '7-I'''.....,".' :J:',.e.',.." ' '." f e ' / 4- ! --!-1151)155 (16 , TEMPERATURE °C SURFACE JUI FRANCE PROVISIONAL MEAN LABORATORY.PkEPARLD LOWESTOFT rI It FiUE C E Sf 04,E ii,..:,OGRAPPAGJE, CF,ARLOT7ERL.,,D, II 12 --"-- -13 S C T L A ND 13

(i 35- $ $ .46, ...... ,. ----z - I.- 15 ) i I,....., '-': -15 I R E L. A 1.1 D .'t 'it14 14)16 \ 17,5i ---,

I,: + - -r" -. , i ,./,, .../ '__"- -,--"- LongKu, Ì I r-,,ess. s..... z.s.s..s 7.,..-F., :."---- ''""".±..Z,-!--'4:- r E N DL AND . ;,-- , _, ,.. 1 ! GE RMANY -.:_--- - - B ELGIL-k 17 16 <15.5 --- :-- IT TEMPERATURE °C SURFACE F rtANcE F!SHERIES LAIIICFATORY.PROMSIONAL LOWESTOFT MEAN AUGUSTPREPAT,E) cts, SEU,CE NY CR OGRAPHI QUE, CHARLOSI ES lutD, 0.-aaagwre S.COTLAND

15 NETHERLANDS GE R MANY TEMPERATURE °C SURFACE F ISHE RIESPROVISIONAL L A DDRATOPY.LOKESTOF T SEPTEMBER PREPARED AT MEAN

Cll CD

16 16 5 5 Ova.. I C E S, SERV/CE JYOROGRAPJJJQUÇ CHARLOTTEHLU AR SCOTLAND 12 : 4 ., - t 13 14 IRELAND ENGL .15 4+ - 14 15

14 1 11 BELGICif GE RMANY ) 15 ' TEMPERATURE °C SURFACE RANCE FIS/TER'ESPP?), LAS,T3PATORY /13:ONAL OCTOBER LCWESTC..TMEAN í C: C`, L1MD, --- ,-,--_ ....-, - - , YO , 0..., .., o i >9.5 \\ 1 1.,. - 1 r,..--,-----r----) \ I ... .-Th '-k-) 1 .../ : i --4 I ..------L._ _-- ..------. ------'---- / - . 'Ì N 0 R WAY ' S? \ ! \4 \,.... \ I \.....,(t.,.....+7'...' I \..., ....''' : / ,r, I . SCOTLAND \ J 10 - . . " " - - , I, 1 k 9 .. 9 .-/- 1 1 ' ... \ 0".. 9 / o ,- R E r I - ..v. . .. 1 r...--'N V / / .1 /V I , i / I I-) / jr / <7 5LA Crq i 0 3 10/ ta -I ,---- T.,- ----5. vs, \ ..-3... i:- --- 4 1 R E L. AN D 12. 4-- . ..- - . , o ,..., E IT G L A -N LI - , s ,...--- LONO,.11,,, ,---,;---- 10i, -- 12 , 2 CE RM.ANY ( .,. ,....-----. :, 9 ...._, - ad...4n, I --"--C ...) e.-..------...... i 3 ...... BELateM H..--"- -.--,N_____..,.....,...... 13 i ---",-,-,"-::::\d-,..;-pr,-..\- cb--..j ..'::' 1 , 2'-5 ' o"k., 5 \---" ^ "------,: ,./--- '.:4-4/ TEMPERATURE °C NOVEMBERSURFACE ' F RANCE PROVISIONAL MEAN PRE PARED AT 1 ----, ---- ., FISHERIES LABORATORY. LOWESTOFT 1'''. j Ww. LASV,I.C., -,,-H---- , _,-.---, --,,=...... ,-.H------HH-..., sgsympx...... , 1 .. I --,., , ,.. E ...... A. - I I :, --, , 4p.,___,------J-A-- .". .1, Salaa 7:Ioni , ,. ''''''' 9 i ' p.-nfr, f Sardiaa. ear Fi 1 / i / ( i 1 N OR WAY -.1 -'".:.,../4 \ 1 8 / . 4:777.7"7-77777.77,\ 7 \ 1 / / I 'Ì // i I I \ ----, -,. .2 ' I I "1 S C 0 TLAND ( \ , i t,.. ,tf.,:k 4 q ,..6..' ."--71 7 ..\ i i I 1 , \ \ i 5 ..i4. I, 311,-1, , . ---1 . 10 x , ..., : - '-iP, -- IRELAND '4 7 ,, ,-:"---- \,...... -'' ' 4". 1 ''4 ,1 .."' / I -s-% ' - ' ) 7 . .ti. ,...... :,,,, 1 V '''' E N- G L .A N D / '7,,a.... 11Fk LANDS

I ,-,-34.-- ,-- , . 7 A---/ -.. , GERMANY I

I I 1 -;',0 e',.------i I - ,....- i.,,vot.,,,,,, ,,, ,.....----- 11....,... B £ I. G. TUX ..}-...... ,...., 10 I." I --... '..., -...... 4,,....1 .^...... - a I. 7. TEMPERATURE °C SURFACE , !I - ...... ft..... ,...:L.-:-.- -,. _,---,,-. ' ,./ F RA N C E DECEMBER I1 r----j ; flSHERES L A BOR AT PROVISIONALC,R-r. LOY: EST'D,T MEAN PRE PA P.,:C. AT . - sr.. ..g ----- __-,7,7.- _ I112 C EC , SERICE MYDROGRAPHQUE, CHARCO ---- CURD, DAHHARK. FIB/60192 North Sea 4:1F' ge. ,_. - r 9 . .

. I.' .. . . sI. 9 , . . 'If .

et >95 -.ir :44Yr e Vil. ., ' 95 - -..-. * t9.5 -....-<-7--- r. 10 9.5 ' sly,.,' i NO R WAY . !.1 re' 1 ...... : IF)

(1/2-N, y >95 7'4 ' ;10 ....v .5 11 00 ..5 ...... 1 - FO'FLANI)i *8 /

1 -' ' :1-': ' ..... 1 (v. . I ! --i--.---- . 17/,,MAIlft- 6 ii, '1 1,..,a - q -1. _ 5 , ...,.. . ..,,,', ,! 1, 1 1 il 11 '' ,

$ . 1 . 5 9' 1 a t: t. AN O ,s 0 1..,-1'i-17 0.. .. ( ...... f.. - I... i . 10 ii ' ' i-/...6,.,,... , te....-4 I - E N G L AN 1 `4,11113.1.,11. ... 2 . ° . ..,,,, ' .:1,,-1 1 GF;RMANY 11

10.5 ,6---; .,>. ,--'If' . 11, BELGIUM , ...... 12 ,13 x .. . . DECEMBER 1958 1 SURFACE 12' , ,..,-,.y/0-.5, FRANCE TEMPERATURE °C . ^-, f. . ° , '. .. . SINGLE OBSERVATIONS x MULTIPLE , ' . _ . _ ,V1VI IYUP,NAPillOUE, CI1A000,,V1111,10, FIGUItE 4.32 OFLgs. 26 FB/60/52 North Sea

ocl 1885 1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 :. rr--r 5 ' MIPINIPM1111111,Ili, Air 1 3 / , V 1 , v i \ / \ ! \,' 1 ' V \ i 1 \ 4 ! , 4 AR AIWt ;'' \ -- -- , 1 , WI 2 , ,, , ,/ v o v

5 ii

AtgI'vl, Audetib... 3 um"Ii 1 IT A 7

5 II e 111111111111111111111 V I NpoNsv \,1 3 v

11 9 Al Pik. WE ill w limly 1 15 13kAh... i W 11111.11=1111 IlkilliMMINKAlIAL ! I ----., 17 ,, s \ A A \ f\ / ' ' ./\\. -.A ,s, /A&I, 15 ,v, PIAM Imo , 13 18 II,

VI A 4 i 16 NiMr , / Illirillmom" NIMIVUMIIIINMIWM/ 14 v 17I k A MA 11,11..111M 15 ,/ , ,v; , \ \v/ I \ ',,' ' Ì 13 u,f / ME 14X ...... 11.11111111= /\ 12 ,--,T,---7-v-' 1 / 1 I ' V v V 1 i 10 \' 1101111'W 10 ak -INIMNIIIIIIIIrA------Or 'I/ i\ v .__, , 801,14 t V - 4 v , ' \1 6 / v ,3 1 A , A. NV V A . i , ,. , , , \I1 i \ , - 4 -L__L 1 V _J2Ii_L _i__L_LI_ 1 t 1_ ' i 1 I 1 _L_l 1880 1885 'IMO 1895 1900 1905 1910 1915 1920 1925V1930 1935

FIGURE 4033 lEnthly means of the surface temperature (solid linep) and of the airtem- perature (dashed lines) at Horns Rev LightVessel during the years 1880-1939 (after Smed) YEARLY ANOMALY OF SURFACE TEMPERATURE, 564ia 60°N ; 0°to 3°W BOTTOM TEMPERATURE DURING JULY - AUGUST 56° to 57° N ;1° to 5o E. A % 5 %_- 1950 1910 1910 1920 1930 1940 4-14. Ijcn 4:Flge.23 F13160182 Nor h Sea

1 /

60°

o t:1 .30 \ 7 O \ '

55°

50°

5° 10° G-I649

FIGURE 4.35 - CHARACTERISTIC DISTRIBUTION OF BOTTOM TEMPERATURES DURING LAST PART OF M.A.Y FB/60/S2 North Sea

600

55°

50"

10° 50 10° FIGUlik; 4. bo CHARACTERISTIC DISTRIBUTION5°O OF BOTTOM TEMPERATURES AT THE BEGINNING OF SEPTEMBER FE/60/S2 North Sea

60'

55°

50° Relative turb'clitY Very high

10° 5° 0° 5° 10° C-1649 FIGURE 4.40 TURBIDITY OF THE WATER DURING SPRING (Incomplete) F13/60.22 North Sea 4:Tables 1

TABLI13 4.1

List of current charts, covering the North Sea (incomplete)

International Council for the Exploration of the Sea. Serv. Hydrogr. Charlottenlund. 1950

Monthly charts of surface currents, averages for 10day periods.

Böhnecke, C. 1922, Salzgehalt und Stromungen der Nordsee. Veröff.Inst.Meeresk. Berlin, NF. A.10.

Deutsche Seewarte,1905. Atlas der Gezeiten und Gezeilen- ströme für das Gobiet der Norasee und der Britischen Gewasser. 4:Tables 2 FB/60/S2 North Sea

TABLE4.3

Freouencies (in %) of different states of the sea in eastern and southern North Sea

State of the sea code

Eastern North Sea

March-May 7 24 22 22 1.3 0,7 0

June-August 6 8 24 32 18 8 3 1.5 0 0

September-November 3 8 20 26 21 7 2.5 2.5 1.5

5 16 22 10 2 0.5 December-February 3 24 J 14 4

Average 5 8 21 26 21 10 6 2 1 0.5

Southern North Sea

0 March-May 9 11 24 23 18 i 12 2 0.50.5

June-August 8 15 23 28 5 2 1 0

$eptemter-November 7 6 19 28 18 12 6 2 1.5 0.5

December-February 3 6 17 21 25 14 10 2 1.5 0.5

Average 7 10 21 25 20 11 5 1.4 0.90.2 FB/60/S2 North Sea 4:Tables3

TAP1,.]4.4

';:ave elements by various wind speeds at li:htship"S2"5o4. N93.5Edurinu 1949 (after Rol)

1-- ,i no cpeea SLate of i rea3ured Computed Number 3 t 1.3f1, m sec Lhe sea \,,ave heiii)t vave lencth of code m m ob-,ervctlons

1-2 0.3 3.3 J 2 0.4 26 251

) 3 3.4 - 5.4 2 0.( 35 239

4 5.5 - 7.9 3 1.0 38 193

) 8.0 - 10.7 4 1.5 50 758

6 10.8 - 13.8 5 1.9 58 80

7 73.9 - 17.1 6 2.z 70 32

8 17.2 20.7 7 2.9 Wl 36

9 20. 24.» 8 3./ 81 26

10 24.5 2;. -.( 82 16 North Atlantic Water Channel Water

Central North Sea Water

Skagerrak Water

Highlow salinity,turbidity, poor relatively in nutrients warm Characteristics EnglishWater Coastal inwinterLowturbidity, winter, salinity, cool /ow nutrient intemperature summer rich, inhigh Continental Highlow salinity,turbidity, poor relativelY in.nutrients, warm Mediumin nutrients, salinity, medium medium turbidity to poor Coastal Water

Water masses, their characteristicsin the and North distribution Sea (after Malle TABLE 4.5 1953, moddfied) Entering partly between Orkney and Shetland, but mainly Distribution Low salinity, poor in nutrients, north from Shetland, flowing to south along British East lowlow temperature turbidity and medium to coast to Norfolk coast, turning to East and mixing in winter,Lowturbidity, salinity, warm relatively innutrient summer rich, cool high-in the three gyrals in the central part of .the North Sea

Entering through DoverCalais strait, distributing in _Coveringnarrownortheast strip the Dart tocentral northeast,of Dogger North BankreachingSea, especially the gyral over in Doggerthe Bankwater and masses northeast of it. A mixture of five other

A mixture of Baltic water, flowing out along the Nor- reacheswegian coast. the central part of the northern North Sea About 59oN a tongue of this water often Keelshapedand some mixing enclosure takes betweenplace also Channel between water and North 57-58°N Atlantic water, reaching the centre of a gyral south of Dogger Bank

gyralNarrow instrip the offGerman the Bightcontinental and flowing coast. North into Skager- Mixed in the rakKattegat along the Danish Coast FB/60/S2 North Sea 4:Tables 1:".

TABLE 4.7 List of hydroc;raphic atlases of the North Sea

7ii1mooke, C. and G. Dietrich, 1951.Lbnatsharten dor Ober- flUchentomporatur far die Hord und Ostsee;Dtsch.Hydrour. Inst. Hamburc;.

Dullig, U.J. and P. Dint:IL, 1954.TemporaturDiLTeronz Luftassor.ill Klimato]ogio der Nordl:osteuropKjschon Gewasser.D.sclotterdienst, SeooUterant, Einzolverof- fent1.4., Deutsche Soewarto, 1927.Atlas far Ter,12eratur, Salzgehalt und Dichto der Nordsee und Ostsee, Hambur(j,

4,ICES, Service ITTdro;zrapld.ouo.Eonthly charts of surface toTerature and salinity.. Lumby, Jon*, 1935.S1inity ond towor,:ture of Lho EnLlish Channel (aLos of cbarbs).Toishorlos Invost, London, Sor, 1', Vol. ;:IV No. 3

Fp/60/S2 North Sea

5, CHEMI CAL 0 CEANO GRAPHY

There are very slight differences in the mean values of some major chemical constituents in the North Sea water (see Table 5.1) as compared to the recognized mean values for the oceans as a whole. The distribution of surface salinities is determined by inflow, runoff and mixing (see "Fi-jures 5.1 to 5.12). The inflow of Atlantic high salinity water is at a maximum in February and at a minimum in August. The inflow of low salinity Baltic water is at a maximum at the end of July and at a minimum in January. ICES issues monthly surface salinity charts with analyses-similar to those for temperature (see Figure5.13)

The surface water is slightly supersaturated with oxygen especially during May and the bottom waters are slightly undersaturated, especially durin,:: 17ovraber. Otherwiie no great differences in saturation between surface and bottom waters occurs, because of rather intensive mixing in the area by tides and waves.

The amounts of trace elements reported in the water from the North Sea are given in Table5.3.Many of the data are unreliable be cause of the use of unreliable and improper methods of analysis. Ave- rage recognizedvaluesfor sea water are also given in this table.

Although numerous individual data on nutrients in the North Sea are available, no systematic working up of these data has been done.

The Si-0 content is usually 0 from July to.November and reaches a maximumusualYyin March to May with ca.4.3mg/1 (caused mainly by runoff). Nitrates are usually at a maximr in January (360 mg NO3/m3) and at a minimum in September (90 mg NO3 /m ). Phosphates are the main limiting nutrients in the North Sea, being at a maximum during the winter (ca 0.6 ug at/l) and almost exhausted during the summer. The phosphate/nitrate ratio varies with season, depending on the higher degeneration speed of phosphates. So also does the phosphate/silicate ratio, which in addition depends on the distance from the coast and estuaries.

There is some severe domestic and industrial pollution along several coasts, especially close to big cities and estuaries. Oil pollution is decreasing because of various regulations. At present, it is allowed to dump oil into a limited area in the centralNorth Sea. 5:2 t1B/60/S2 North Sea

5.1 Salinity, major constituents

List of figures

Figures 5.1 Mean monthly surface salinities to 5.12 5.13 Surface salinity, December 1958 5.14 Characteristic distribution of salinity near bottom during spring (to be added) 5.15 Characteristic distribution of salinity near bottom during autumn (to be added)

List of tables

Table i Lican values of the major constituents of the sea water at the lightship "West Hinder" during 1951 to 1955

5.2 Oyen and other dissolved_fases

List of f-ji,ures

Figures 5.16 Characteristic distribution of oxygen saturation near to 5.17 the bobtom during early spring and autumn (to be added)

List of tables

Table 5.2 Results of analyses of dissolved gases other than oxygen in the waters of the North Sea (to be added)

503 Trace elements

List of tables

Table 5.3 Amounts of trace elements reported from the North Sea and adjacent waters It 5.4 Amounts of elements reported in the runoff, in plankton, benthos, fish and sediments and calculations of half- lives of these elements in the North Sea (to be added)

5.4 Nutrient salts

List ofgures

Figures 5.18Amounts of PO 9 and Si in surface and bottom layers NO3 to 5.23 duringspring4andsummer (to be added) 5.24 Seasonal variations of NOand Si in surface waters PO4, tO 5.26 in selected localities(to be added) FB/60/S2 North Sea 5:3

Figure 5.27Relations between different nutrient salts in various parts of the North Sea (to be added)

List of tables

Table5.5 Estiations of the amounts of nutrients carried into and out of the North Sea (to be added)

5.5Pollution

List of figures

Figure5.28 NatuTe and extent of pollution of the coastal areas of tice Trth Sea (to be added) . 1 ° i _. 1 1 3525 _ _ 3525 .,. .4.,5t t,-- . .:.14.?!g I ir .:',37.'-fa,: ,,,,- nhe "Yard Il ,-.1-- 3525 350 -<.-- II 3475 34.5 -7...... ,...,...,, A.,j= r, ,' fro...tred;- 4,- .'.t,-.,', N 0 R W A Y to -" ... -, ',, , _,,-_ 345 A...... ,,} 4 ----:, SCOTLAND, { i k 1 3453425 340 i ,--,-- , l , fr- 35.5 3525 ,-,-...r! ..,,,,* ..,---7 .,:>. . 3475 350 34:75 33 S Ind A . 4 .. 35.0 D 32-0 -,.. ,--- - . ,7,- } . -, :34.5 30 031.0 ' , i I 'y--- ,,,

- , . , 1 I 1 REL AND ' '. ' 3403425 330 i 1 .1 5. .',0-, =:-`4,,_._:.-,-.... - , )34 3475 :"'-,,,,,,,,,,.. A.,, _ i ENGLAND 34.0 3475 ....-?.. , 33Or -I I 350. 1_------i 345 34 0-- ''''''"4 At.-,-, GE RMANY 1I i ..111 ;1 3525 ...--4,..2.,.....------350 -1"-----1-5.--4-,J ;34.0 34 25 WELG r I A-1" V 35 25 . 1347 , 350 ....._ CE YDROGPAPMIQUE, CHARLOTTENLUND DAYNARr SURFACE I .. SALINITY 1 III 355 35-0 % 35-75 35.5. ------`-/---.1,<, ---- -.., FRANCE JANUARY i . PROVISIONAL MEAN PREPARED AT Ii ,-----,... FISHER:ES LABORATORY. LOWESTOFT ,-. r ' - I--3- v4. LeagttadrP. --- 35-25 350 34:75 345 O R WAY 35.5 34-25 34.0 33.aiaj SoNArss Fjord ,rz,...,, 35 34 0 .,_±, 6 ' - I 34-75 'f----Y-- IRELAND r...... ,' t 3425 e - ,' i/, \\ \ 340)330 \ V-1 ,eir...... 34-5, 35.5 34 4"--,.., , -..------7 ,...., 3475 " 350 3475 ( , EN-GLANI 34 25, 340,',-.. e ,.... a Lom...4.....,,...- 34 5 3475 33-0'A A.Aamwvr, , 35.5 3525 - K,,.,....____4.../..., .-17-- --- 4;34'5 ,i 3425 i 1"" NETHENI..nMDM GE RM.ANY Ifr------.. :7-3s,., '-' ,..,...... / ,.., A.34 25 g 34 0 B E L GIL-11 isa....,... ". 35 SALINITY SURFACE `Yea FRAN CE Fl PROVISIONAL MEAN RIES LABORATORY. LOWESTOFTFEBRUARYPREPARED AT ICES, SERVICE HYDROGRAPHIQUE, CHARLOTTEKLUND, DANMARK. ------s ----- _____ 11

00. ,

CES , SERV/CE HYDROGRAPHIQUE, CHARLOTT FULL.

I 3525 r'7,, -&.'N- i 3525 35 '0-5-,,,-> ..,,,,-,° ,(4-,"----es,-,..------' 25.4::' ,t, ! 3 4'll 33.0'2'1- 355 . V 1111 2s. 1 ,.:_!-:S 35-25 .. 4.---.,-- --,2 " ! 35.0 3475sei _,-,^ ''' 1 7-1,,. 340 , ..,,- 35-0 i i 3525 1 j -7T N2-- N OR WAY s. ,4'44.1efil 1 .-,4--7t.--- _,-,.....4., I 33 0 .,. ,. 3 3 ' 0 k.S{) l' 1, 3 3 0 ..f"' : 34-75 .i T3:0 .32 0 rUETren A I 260 ,_ ,,,, 4 ,.... ff i C 0 TLAND -4 (.."-N.0, ---, 2 *5 A--", ' . " . I , 355 I' ,,... ' I

,_ Ildr..." -...... ,:' ,.....\`-'' 340 , , 330 32 0 ,),-- ,,,,. ,; -,----- 34-75 4 5 . 11 '''',/ IRELAND ./. 345 ',. 7 ,..1., , w.,,,,-... ---'-`, Is.,...,,t .7.'"'''''' E NGL AND, LOICJON,.,, 34.25 . 34 0 / ,,,,,;.= 355 1 330 .:5,?j, >,...... , GERMANY ' ¡ 34 5 3 342 5 34 0' h 3525 .-/34-75 '.-. \J J------.."ZT,,...._2__....--'-':-.---4 s'''''''''....,,,...... **"`". 35 0 :3475 j" v:// 2..34 0 4/13 425^T. 45 BELGIUM 355 I 3525 - c--...--e35 0 _'-.--.--/ 1 SURFACE 3575 - ; 350 .,e."- J., 1 ,^ SALIN ITY MARCH c/o° , 1 ''''S , FRANCE PROVISIONAL MEAN PREA'A.P.ED AT 3575 -- _ -.. ... -, ----- ...... 0.5 ....mpek ______FISHERCES LAWDP,' ATOM". 12.YNF_STOFT m - - -_ __._ r4rr''S ''''\ 3 525 35-25 35-25 35-0 ':,',.:---J------a 34-5 34-2.ci5.,-1, ,7---,--: -.4.-,"",-,-,--z, __tr.,:l.-- ,f4i,,...... :..-eT ./ ,.,Z 1 .. 0. 4 i 3ao, t i 31.0 Y . ...,_.1..,-`4 -.4.--, ti 0 R W A Y A ..., 33 0 32.0 SCOTLAND , - / 34 5 , 35-5 ...... 7" 3475 / i 3525 %- . rIlIGNIALAR.31-0 .. VA 6 . -,.3.-, 25, 1 : 300*1 ) 517' -.--'2 .''''' ' ` i a a.,...e..: - .... - "., . -,2 cis,A\ ' 3425 ,,,, .-- / 5';' -,-,. 1 I a E L A N D ....,i) , 34-53425 - 30 - \:.'' <-- , --,---- 1..34.5 34'75 34 75 '.... rr .7 , 3-4/..../ 75 St . G L A N D .//, NI -,1 -...... ),- S...,,,,...... :...... ,...... 7 35 3I3 ..> . . GE R MANY t :3-475 _5 / <....._ 3525 -,1"----'-'`i--3 :,-5 0 35 C...... -477\ , ,../ ..34 4534 0 BELGIC3i 3575 35.5 - 35.25 - ,'."---,..----_,,,,--,,_ -..--7.------, SURFACE I --y SALINITY %e _.---,--,1,:f `,"--,,,,e---:," Ii PROVISAIOPNRAL1L : : I i FRANCE ! FISHEPS.S 1.1.50RATOPY.LOWESTOFT.. PRE PARZE; AT MEAN ------....f. . as...... 6 IC ES, SER, CE HIED& OSMA Uf, iki*SLOT TEN LUND, DANMARK. lo ,I 6-. , to 352 . 35.25 A.-,...... , ,, I. \...... :>35,25 '..1 350 3475 345 334-0 425 11 i sop. Fjor4 330 3 ' , 4'2 ..-. ' 3525 '1 4"-t,--';'''''' .,-.'-. .j'e N 0 R W A Y ---..4..- , ,,.. 30-0 t ¡ 1 / --,-, ,t, 355 , .. 350 250 , 3525 _ 35-0 - -/

' --..-. SCOTLAND ' ' ,.."....".... '---44?-1, --,-.4 z ., - ,r 34-75 3475 ...,, , i1 H 4 ,... tr:-. ,..g ------3 330 ' L.,, ---- t''i 4 q ''''''''t"-.43' ..:4_,...... :-.2 I - i 342 A .3 330 \ 32,0-v;... 345 320 -!. ,i '-'7- .7 IL E L. A Is: D Dal.; ', '2>4°( 34 5 34 0 1 I / i --r v-"T-':' ' --'-342 5 h . = H .._.,:...... L:L.---,/ -:. . er----- . , - , - \ . . , 4 7' '777.4'..L"' K.-4, A ,,,,,,,:_i . 3475 fr E N G I- A N D , ---,',I.,,,,,,,- E It I ,AND, t -- LOsntom,,,,....34 - c-,-;--- -..,it-----...... ___,..,...... , ;:------e -,..., r ,-,...... : Somaamp.N. ....-- 25 is.,,..,.... 330 3 20 ,s, `- NAat77.1" , GE RMANY 3525 , 4-- .c. .4 .-\"-` ../-,------5---...-' 34-7 350 35-Q¡ *34 3475 5 e^' -----/ BELGITI'M i 35-5 1 SURFACE ; -,- 4.4, 34-& PRANCE PROVISIONALSALINITY MEAN %o M A Y sv I, mi. 3575 --r===",'------.----"--.=------,,,- ---,.=, ...--... '--,-,---, ,,..7...... '.....".7.1.- , FISHERIES LABORATORY,LOWESTOFT PREPARED AT , MY 7F OtiRAVIi1.1 LO' , ,

, , 111 5-0 355 III',!75

35-25 3525 5-25 _ 3525 3525 35.0 , .) 3E0 3525 't't F;Kin 35.0 S C TLAND Abas' 34-75 3 350 " /3475 34.5 35-0 34-25\ 3425 34Ì 330/ DC7fliAR 36-0 , 3475 N O R WAY 32-0 31- k *.5 I RE L AN D43/4.25 10330 3425 34-5 34.5 ,. 350 34 5 ' -z.- E NGL AN ;NETHERLANDS JO' M. 3475 , 342S 340 345 20 "Nes...350 35-25 s , ,..,_ 475-'sliW,'344.0.25 , 34.0 33-0 B EL GIITM 35-5 ( 34 75 : ,---7,__H.,..3.5 ,_--! SURFACE GERMANY 3515 3575 Ae Q'''''-- 1 SALINITY °/00 ; Nto val., 0 FRANCE PROVISIONAL MEAN JUNE i FISHERIES LABORATORY. LOWESTOFT PREPARED AT ;,

I C E.S, SERVICE NTH OGRAPHIQU CSARLOTT SHENK`, DANMARK. ._ iT ___ _ '1 35.0 ---=--- 3525 ,,,,,,..4.14...... 1 Al -----, -- 1,, 4;<------'.: ...., ----7--- - 3525 3525 35-0 .,,, .:, 3475 '4:-S'.:..;;,.: -. : -I. 4 , 1 1345 .,,,,,),Lpa,..'L .- ,- 1 SanisVer l', ' I i .34-0 11 I 3525 i 32-0 1.2 ,,...., N OR WAY "----4 0.. t, x ,.. ,.....--k. i :1 I ,. ,...., § ...,, SCGTLAN'.- D ." 32-0-77--'---- , - 1 3525 1 35.0 1-1 i 3-i5 34'- 0- - .1, _- ....----J.- 32 0/ 1 % It A ILtt:Itr. As ,f ..: 35 5 ,, , 3! 0 ! En

1 ----..,-A 1 ,s3,,...1., , ,,,,:k_ -..-- IRELAND '' 33 12-0 '''. .,. -", 34 25 .,_7.,_..1_30-0 , 1 ,.. I' 33 0 it 5-4 ,-Z--__, -- ...r 1. 34.5 1 ' . ,..,,.. 34 0 ".,. -- 32CT. :1"'-y' ...... ---"L' 34'75 .--/ 7,1...... , ENGLAND ...... , -1.. y ,, '`.: :::, LAND, G E R AA A N Y ) Socious,cs. '34 75! -- 3/4-344 2534 0 B E L GLUM...... rp 1 --- . , 34 SURFACE ' II

! ,,,...; 1 35:75 .. N C E SALINITY J Ui_Y %a ii 1 35-75 ...----e...... --""^--f-> FR A ! PISHERIESPROVISIONAL LABORATORY, LOWESTOFT MEAN PREPARED AT .....6. I'S. 3575 ICES, SESW10E fre 002 A 0U [HARLOT MONO, DANMARK. -- 'i I1N s i I . 3 5.0 4,350 :,.,4.,e- `..,'--H,,,:f:4"----3 , 350 .., 3475 345 3425 -;--, 1.-Y.,:I.- 4 ,i , -k. '--=-°''' I-I.. I I 35-25 'i1'2; '' 340 3 30 32-0 3 10-.., ....,.4.-, ?...{:-.E "` -ts, .s..0. Iry.... -i 1 3525 -!:::',',.. ,if- 1..6 s ,..'',. .' ...---' ,..----tr"4 i " ;1 P.,.,--,4. ;,' ., 35-25 . , . -,...,.s '.:;_i. 3525 ' -P' - ';'..,3.,VrRf---, ...ay.- re so : ..: ''"---.' N O R WAY . 350:7 rl'a Iry .....zrA., , '`,- ' .,--?* 7 '-' r... 29-Or 270/ 260; y - ...L"' '--- ''--"-', 34-75 ..., . 30 0 ill -, ,5', C ,,-";', --f------", I.7,91.,"5--, 310 sr.,-J' ,i,--is,...----,,,?..,-, ., _....-...... I c o TLAND .. 342 -,"v It., Th 1 ; ; / . - r's-r ' i , ' 350 .. - ,, vr .-,', .../. .4,:-' 4', , ....e ""-_,.-,- 350 DEFMAR I 34.5 -, ; f , , %,.:;',./ 2 --TIi41' i, ... -----'-' - - ,N,..., '--- r ' 34-Cr ,. 1 3475 I *' II . 34 5 345 3 40 3.30 , 3525 - L, \ vt,.. ICES, SERVICE htDROGRAPHIQUE CHARLOTTERLURD, DANMARK, 320 : . -1. 34Q 330 5,..._..., 1,I 1 1 RELAND "1"-. \ 3I \ 34-2 5 1\ 3-4-25t ) 4 ,/," )= 1I TI.or,,, ',j nYambs Avc.,..3 ...... _., 34.5 , EN-GL AND 34,0 Ls., NE;THERLANDs- Jill' """'...... i 345 Lowoox.,.....-1° ,a,- GERMANY I ; I 35-5 .."1 \ ,---¡ Smasskass,,, 34.75 1...1... >....--,, I I III . 350 ,-,if,`7-V, f ' 350 BE L GTIIII I! per- , .4 . 350 ''-`", `.7.345 , ''"`-`-' 3475 ... , .., ,,, 3525 - ( ir, ``. 3472-5-----1- - , ,-.., SAL! N I TY %a SURFACEAUGUST ; ',.., 35-75 .--3.., ,-:-.,,.,,,,si FRANCE PROVISIONAL MEAN PREPARED AT fI 1 . FISI-ERES LABORATORY, LOWESTOFT ' . ,,, L . .. . , ._ II O, . , .__ --'4 0-/----etc,'------::-4. \ `-`" 1 3525 '. , ,- .,.- . " i, S,g,.. ,Yord 3525 , .,1 . . o ° I 350 l i 34534e 41 ,, 6 o 340 3 $5' .' .., N 0 R W A Y :., ,s,6:1. ., 300 ---1-- 1:"-''.....-- 355 f, S C TLAND .. 350 3475 3425 330 320 , .. -_,,H, ...,--, . 3525 350 `' 4 3451 ' I - '" D II e . , .//9...,42 , v1,1tasa. , 340/ 20 -at y---- I P. E L AN D ji14o t_., ,33-0 iVu5Illfr 32 ,, , . -.,__- ,\ 34-75 34 3425 330 ._ -- 3 3 0 ' 3425 345 ) ) l': 345 34.25 1 3525 N / i ENGL AN ' 3475 NI-, MERL, DS , 3475 i ' D .1 1.07DION \ 'OM GE RIMANY 355 "?."...." ri'' Doss.ax,,,,,,,_____. 320/!: BELGI1TAS .,1/..--4.._ \.! 3425/-1- .,,../-3475 350 340 ALINITY SURFACE % 0 z 3525 ,e FRANCE PROVISIONALS MEAN SEPTEMBER PREPARED Al 3575 35-5 ,J, ',, FISHERIES LABORATORY, LOWESTOFT -"-- --,-- --- _a --- .. . --.,- --, -- L ,------. W A Y

.-' \3425 ENGLAND. , 320 GERMANY ' CM 3525) 35-25 -"34 5 3475 4 I BELGIUM SALINITY SURFACE %o 3575 FRANCE PROVISIONALFI5,IEPES LABOAATORY MEAN, LOWESTCFr OCTOBER E..D AT , - 'C E C SG., CS 0,,,,,QUE, [HARLOT' ENL,C. s ,.. -' '2,7' ' '''<., , 3525 I 35-250 35 i 1 , I, 1 345 ... AX '340 - 3525 ,-... : 31-on------t 1:-...e. C'n..&,,'" ''' 'EAJ4AA,(..-JTI ---)-4 : . 1 ,..-1 ; i WAY II v-';'Y "k ' ....-____Nj - "-,z.\: ! 1 1.,... .,... N OR I 350 ' 7<-,,..' . , e....:4, -2704 :I 240280s; ' 1 r ../ ,f 3O O '' 1 ''''''fi. 320 I...... ,:,.., ' ::. -... , ..... :.: -.---- A,,s,,e1,.' P..-.-. 33 0 ) ,"' .;'' SCOTLAND ; I 3425 \F>1), EIPEIARIS : .. I , _ ---v., I . ; , 7.' 7t A-- 345 - ' . \340 33 0( ,J.? --..,P.- - ' t 1 I0 - 3475 ICES, SEAVICEST.::..7..... C-I 26 'Ic - . I I'''' ':-.'-'3-4 3,40 33.0 i .., J, : 1 1 - I RE L AND i''./. 0 ) /320-7 - 34 75 , . ,, 25 , 'I. A ,. I . .., ....., ..,.., r ..-4-.s. KA,. A, ..,_,I.,...... , ,..---".."' ...... ,,v, 344\ ENGL AND \ 3 75 .32 ,/.. I .E.ir t I , Du 0 I GERMANY! I _---__, - -..: . 1 , _4- Saarisa,.., - i -- 1 . ,..----2,-.. i 3525 , e, ---.3. 350 ---,, ,;- 's---:._..,,--'-'- - ,,,,.. ,-.,..--- 350 '342534 5 BELGILT`AC . t ' I

i , i-34 ..,--. I ,.z. .1 .1 350 II 34 , !' i. : i 35 5 i - ,. - - rr-,.- 34 -, ' SURFACE 3575 3525 ,-,-,:-.:-. ,...- 35 a 0 6-.? ....--r.,/ , '''''' ' " S ALIN i TY %0NO\IEMBER , ... FRANCE F,SHERESPPOVISJONAL LABOPATORT LOYFISTOT MRAN opEPARED AT '4. 1.,..,...,, ___ - \ -- ..r. I ! I I .....,.. , ' 3525 I

,.., 1 I 35-25 Ni-~ t

I ' I 3525 r .., I I 350 ,j4`.-bt. - ' --.) -Th Sagrog rp.4

I I C ES, SEAANCE HYDRO4RAPHISUE, CMARLO,TEkLuND, DAkMARK I ..--t, 35.25 347S i B.r./..d.r.r4 I I 34 5 -.,5 - ,,- ea' 1 I .-., U : 1 . ,,,...r ' . - N 0 R W A Y ,' ..A.,. 1 i I1 f...`",y , \ ',. \ ' 33-C) I ,. .-P - ,- .;1 I s c o T L .A N 1.) 35.0 . 1 : 1 ,_-- . / te\ 1.:.,Z, ' I 35-25 / i / . DE1,11.4RA , - C: ...... ,..,<=34' ., I I

'. ' 34 5 */ - cp '4,"., -.; --..- -.¡''''''''eZ1.-2! "-- -..._-, 1 d -....--- 34 0 ,- 34-75 --.- e.4- -4' , r , ,- -1 .. c. ' ---i- I ,-''.''''' 'A.,..,a.. e s.e.... r''' 340 A ' 1I *C- ''' 1,.,' - r".' -- . 342 ,7.";:: - It .355 -1.- I RELAND ...nu- 5,,V A 34 25 3320 30t - ,3'_.,-". -,---..-. 3475 ,,,1"----""----, i 34 5 \ 4 ', ..-: 1 i1 ..4.4 , n.....,li -,..,,,,,,_.c.-., 4, 75 . ----,.---4, 'iq-` ../3 ./f1 "...\\:\\-- ' ,.' '. '.. t. , q r al k,L,, '' ------3-7r- 3525 EELLo hi-35C r , /4 , .,/ 1"/".:.4 0 -S ...... , ., , R.MANY t 3525 , _ ..,.. ' = SURFACE N. 1 3 BEI.G.1U-2. : . ket I-- \L 350 i - ,..., .: pii , 3525 ' ,--,..-,,,I.,,_ - ,-- ...., I ,-, k._. 1 35-75 35-5 1 ...------l .ef F P., ,,,, N C E :, PROVISIONAL MEAN !SALINITY DECEMBER %. , r \- ! PPEPARED AT le. FIS.,. .E..5 LABORATY.LOWESTOrt I " MG 0/S2 North Sea 5:ngs. 13 ___ , __ _

. FVt! '''',s% 11 1(- Il 353 352 * ' t1 353 .,'.11:-.

353 \ t: ..'1.j -2 ',,'' :.). ty,..,, I 1 354, 353 3.2 v \t., ------_., _ . 35.0 35.4 ,..... I . . 51 346 , t ' PI, ,1 . 4 4 4,. NORWAY 5. 3 1" .1.1. 34 0",,"R1:1. ..,-.,,:,(.1.:,r. ., . '''.1.1.' 352 w1y ' 3203° ° . /- ,,, I ,,,...,/). -

. , \ " \ 354 il r'l ,11,,` ,, ,s, <35.4 e 1.330

1 1 554, ' . 0 I ...`,...... ''Y . ^J 10 "'/P . " 3344:34 34 1't '''' I) 346 / ..." Stt' o /' I, A N J.:i t . 3..15 I, ." ,I/ 370 v/ -Vv. ' //,...,,,i,' (rfr,,f-'-,-; "'1, I i '.» '...,,,...:_if i 1,%,..(' ... 35.0 ! 351)* ' " 3{ ..3..rf, - 352'0i4,'¡,.4 j340 i3.8 ,,l, 1, ,--.,. . --,4-,,,-,--,:,,,-, y, 353 1 ,, \' I .11 i ' 34.8 34 .. ,,i

/!,320 , , 1 , / , 346 346 i , t,1 34.4 I **l . ' *.*\1.) X -4 t? ' 330 I RE: LAND 338 ? - ', ' ,,,,,t--32.0 ' II' (I ,_,... ..0' r '344 ..,117-ii.--.:(*1-**'S dil ' 34.2 ,... r f i 34.4 34.6 348-2 '' ./ ,. _....-r E N I I, A N I 344 , l ._....r724-t,..,.5111.../0 348 3445!14.0t ' 356 358 -, /- '' 0+; GERMANY . ., \ ( ""'"'" -.',..- I 35.3 35 0' f .,--- , '' 350- 348..2:4---- 340 liEl,(711.12el ' 1...., or :I 351 _ ------_ t 5.3 52 33.0 _ 35.118* DEC E M BER 1958 ..' 1 SURFACE 1 ,,..352** \ /_,..).:511,., FRANCE SALI NI TY %.

SINGLE OBSERVATIONS . MULTIPLE .. -- 35.6 355 35.4 353' ''/- " ,, C , SERVI We. 06R/41110K, C11.1.01-1(Htl0.,

11' 1G 1.113 E 5. 13 FB/60/S2 NorthSea 5sTables 1

TABLE 5.1

Mean values of the major constituents of the sea water at the lightship "WestHinder" during1951to1955 (after van Meel1956)

Salinity %o 34.19

Alkalinity HC1 N%o cm3 2.919

Specific Alkalinity o.1539

Sulphates SOmg %o 2672.0

Ratio SO /C1 0.1412 4 Camg %o 452.3

Ratio Ca/C1 0.02393

Mg mg %o 1303.3

,Ratio ITE/C1 0.06895 51..Tables 2 FB/601S2 North Sea

TABLE5.3

Amounts of trace elements reported from North Sea and adjacent waters

(Note: Below eách element is given a generally accepted rep- resentative value for sea water in general; designated ARV)

ARSENIC

Place of collection ug/kg ug-at/kg Investigator

English Channel 30 .4 Barnes,1932 30 .4 Orton,1924 Skagerrak (Gullmarfjord) 3 .04 I. and W. Noddack,1939

ARV 3

COBALT

Skagerrak (Gullmarfjord) .1 .0017 I. and W. Noddack,1939 English Charnel 03 .005 Black and Mitchell,1952

ARV 0.2

COPPER

English Channel 200 3.15 Orton,1924 North Sea 64 .95 Ter-Meulen,1931 English Channel 1.3-24 .02-.38 Atkins, 1953 Skagerrak (Gullmarfjord 4 .063 I. and W. Noddack,1939 Baltic and North Sea 6-26 .095-.41 Meyer,1938 Baltic 3-8 .032-.13 Buch,1944

ARV 3

Baltic .7 .037 Forchhammer, 1850 Atlantic Ocean 1019- 00625- Thompson, Taylor,1933 1.23 00645

ARV 1.3

GOLD

mdt

North Sea 6 Minster,1891 Sea water(1500 spl) .004 Haber,1927 .1 Glazunow,1928 Atlantic Ocean Glaude,1936

ARV .004 FB/60/S2 North:Itnr, 5 Tab

:1: ODIE

Place of collection uLatihg Investic,ator

North.Sea 18 ,14 Heymann,1925 tt 17 .13 Bleyer,1927 It 32 .25 Isenbruch,1927 11 .09 Matthes, ',7allrabo,1927 11 45 .35 Reith,1925 tt N.' .16 Glose, 1921 llorth Sea 45 .35 Reith, 1930

ARN 50

'Mglish Channel 20 .37 Ortos,1923 6 .1 Ij:':Irvey, 1925 15 .27 Cooper, 1935

11.1.1UUM

North Sea 70 10.1 Goldschmidt, Berman, Hauptmann, Peters, 1933 ti 120 17.3 Strock,1936

ARV 200

'MANGY:II:ESE

Skagerrak (Gulimarfjord). 3.0 .055 I. and V:. Noddack,1939

Ervjish Channel . 3000 55 Black and Mitchell,1952

ARV 2

MOLYBDENUM

North Sea .) .005 Ernst, h3rmann, 1936 Skagerrak (Guilmarfjord) .5 .005 I. and \:;. Noddack,1939 Enrzlish Channel 12 Black., Mitchell,1952

LiV IC

North Sea .12 .002 Ernst and Hörmann, 1936 Ardencapie Bay 1.5 .025 Black and Ilitchell,1952 ARV 1,5 5:Tables 4 FB/60/S2 North Sea

RADIUM

Place of collection Investigator

North Sea 10 Satterly, 1911 Kattegat, Skaerrak .87 Föyn, Karlik, Pettersson, Rona,1939

ARV 30

RUE IDIIJIT

Place of collection - Investicator

English Channel .24 .0028 Burksep, Kovaleva,1940 North. Sea .20 Goldschmidt, Berman, Hauptman, Peters,1933 English Channel .12 .0014 Smales, Salmon (unpubl.)

ARV .12

SILVER.

Place of collection Pdt, Investip'ator

North Sea 20 Mister,1891

ARV 0.3

STROZTIUM

Place of collection mcrati?c, investigator

English Channel 13.5 .154 Desgres, Meunier, 1921 Atlantic Ocean 13.3 .152 Webb,1938 Atlantic Ocean 6.6 .093 Odum, 1951

ARV 8

VANADIUM

Place of collection ugikg uo. at/17 Investigator

North Sea .3 .006 Ernst, Hörmann,1936 English Channel 2-7 .039.137Black, Mitchell,1952

ARV 2 FB/60/52. North Sea 5:Tables5 ZINC

Place of collection ug/kg ug.-atJ investigator

English Channel 100 1.5 Orton,1924 5 .08 Atkins, 1936 Skagerrak (Gullmarfjord) 14 .21 I. and 'J. Noddack,1939 English Channel 10- .15- Black and Mitchell, 1952 20 .31

ARV 2 PB/60/S2 North Sea 6:1

6. FLORA OF THE NORTH SEA

6.1 Seaweeds

Considerable crops of seaweeds occur along the rocky coasts in the north, but along the southern sandy coasts very little seaweed grows. Although the tidal flats have spotty algal vegetation, the quantities are small and the typical zonation absent.

The species Of seaweeds occuring in the North Sea can be divided into several groups,.depending on.their geographical distribution (see Table 6.1). The maximum depth of occurrence of sessile algae is determined by the turbidity conditions in specific localities during the growing season. (see Table 6.2). Although some quantitative surveys of seaweed resources have been made in some countries, no good summaries forthe North Sea as a whole are available.

List of figures

Figure6.1 Schematic zonation of seaweeds along the coast of English Channel 6.2 Distribution and densities of commercially important seaweeds along the coasts of the North Sea (to be added)'

List of tables

Table 6.1 Species in benthic vegetation occuring in the North Sea " 6.2 Maximum depth of occurrence of sessile algae

6.2Marine bacteria

There is extremely little data specifically for the North Sed available on marine bacteria.

6.3 Phytoplankton

The phytoplankton in the North Sea can be divided into certain communities by the occurrence of certain dominant species(see Table 6.3 and Figure 6.3). A more detailed community division is sometimes possible (see Figure 6.4), but in view of seasonal and year to year changes in the dominant species (see Table 6.4) this detailed divisionis impracticable. 62 FB/60/S2 North Sea

The standing crop of phytoplankton shows considerable local, seasonal and year to year Nariation. Although a considerable amount of individual quantitative and qualitative data are available, no systematic working up of these data has been done. Tables 6.6 and 6.8 give some of the data available on the average standing crops of phytoplankton in the North Sea.

List of Figures

Figure 6.3 Distribution of characteristic phytoplankton communities during spring 6.4 Distribution of plankton communities in the German Bight, MaY 1933

List of tables

Table 6.3 Characteristic and dominant species of (spring) phytoplankton communities in the North Sea Table6.4 Example of seasonal succession of dominant phytoplankton organisms in the northern North Sea " 6.5 Seasonal succession of dominant phytoplankton organisms in the southern North Sea (to be added) " 6.6 Some data on the standing crop of phytoplankton in the Borth Sea

6.4 Basic

Many estimations of production of organic matter in the North Sea have been made, using various methods and approaches (see Table 6.7). There are also some data on seasonal variation of production available (Table 6.9), as well as experimental data on the influence of temperature on the rate of production (Table 6.10). The general knowledge on the factors determining the rate of production is at present sufficient for attempts to estimate the areal 'distribution of the basic organic production in the North Sea,

List of figures

Figure6.5 Distribution of average annual basic organic production in the North Sea (to be added) FB/60/S2North Sea 6:3

List of tables

Table 6.7 Estimations of basic organic production in the North Sea " 6.8 Standing stock of organic carbon and its of pro- rate3 duction in the North Sea in spring in mg C m- 6.9 Production on Fladen Ground (glm-2) 6.10 Carbon oroauotion in the sea at the Smith's Knoll lightvessel 113/60/52 North Sea 6:Fis. 1

Kruslen-AlgenRechienlierreeariá-.0pasnYal

radenatsen(dane-art1400/19) -Sprirzg 11.W

06ere Flächena(genlibrphy...7-fulere,700,49)

(Pe/ve/fe)

OW,71yearpuS) Nr»-ifkg

(Evesiculosus)

--(Ascophyllum) Z

Thementange Un ere Flàchenalgen íPhodymenia?

serraiusl

eri blor Buscha/yen Kalkkru- - -Spring - NW,

SchnuraIgen

\\St./6///o-Riemetilan9e

( Halydr4.9- Lederfange CystosiPal

(thyperAorea)

SubbZ 8uscholgen Ifal4hno/len

FIGURE 6.1

Schematic zonation ofseaweedz along the coast of EnglishChannel (after Nienburg) 6;Figs. 2 F13160152 North Sea

600

55°

VID

Proposed names of thei communitjes

1 Central Atlantic Il Southern Norwegian Sea IllFaeroes IV Orkney - Shetlary Atlantic -Southward ,Exten.sion 50° VI Western Coastal VII East Anglia GoaLtal VIII Southern Bight IX German Bight X Dogger Bank XI Viking Bank - CUt XII South Norwegian1Coas a

10' 5° 50 10° G 649 FIGURE 6.3 DISTRIBUTION OF CHARACTERISTIC PHYTOPLANKTON COMMUNITIES DURLNG SPRING FB/60/S2 North Sea 6:Figs. 3

, 60 10 20' MP 40 so'7 ° a' ow 4)° w'so' so'oo so' Er' .a5======,---- ,....., r n

I t g 4, , . o N. 2.,... . ,,, 11 1 - I .--.. .1, El ° °:..... - -- ...»1' r.: ':,.`147ix .4,'R..' 15- , * 1 , 4. % +-4 -,;;'-- i4fo.o.,k ,., \ 44,-40 18b Re.%,-1- 'il, ' e '11, 201 inA , I 20 7 1 . °,,Orles ; ,tir I I , ,,. , I t' -"V 'h u Iti - L. 'IF 4,22..._--- , 70 C i, .-1. .-w. ....1" . \ ''tc3 \ .., J I ' -___ , 1 I' vo? . , - - ..knI ;' -im---,,.------. . ; +, , i i.,,,...... d. t . I 5t % Y i ---' ì - lir:ET4--=z----.4*- \ , so'

...... -.\ - "' a N. , ,'" t 1 - 4 :L ,-.'' ,, ---...=.... .:--1, ) 4' .1 f tt' ' '' -r.In / Ì ni:,--- , ,.

' 20 ,, , ?' 2T...... 4 ; ' V Mlimmmil /, ,}. Zt ...:,:,1,.,A1,..';ihl. ,..1 .: ' ,4777. s5..,' i70'

. ...,

...... 1 Ivirf. 4 ,..24 : i :di0'4 .'...... ,0.4ry' " h/lit // - A r./.2 I, f0 ,i44471'004,'"40P04 II

111 30 , - n ...,,,,,,,a,i',.:.) '1! 11:P41 1 Eiji ,: ,'i', ''''L'1 . 411 I +466-1 l i Cd, ie.'''''''' ti , 40 ",:4:""

o .-,. av9-peztaw ctr . ,,, i -- '. -' \ i .'s"YkitS71-93[;1.8.1Rd'e ,. 1, Ned 133 ' J .. .. r , 1 .. 0 I. TR 2tea-412,-:6/4 /2,7 ,t , d .ceimak:120. ,la, -- -es.bhf. ..wJ iliv,,w6,..-- 'F. E6tvadneirdabreeigI Mazzeta2a4-an62: II 2- PIIII ggo-'-f-22ce''' , g 2 a Hioi6,4°,46,i/or.4w>. /311°,44-j* ':40latest&dtga aloe,- P 7 1 /---77--.--;,.--- 3 e.?"74.,,,....I.A2z i:71twd.-,,:li'lIff SuclOuitine-gef.m: 110. I w. ,t ,., ) prak,s;, ,V97-4e, iq4 > Undr"k-d

53 ';,. . 6° 70' 20' 30' 40 ' SO' 7 . 70' 20 ' 30' /' 50 ' 8 -, 70 ' 20 ' 30'40 ' 50 ' e -

FIGUE E 64 Distribution of plankton communities in the German Bight9 May 1933 (after Wulff) FB/60/S2. North Sea 6:Tables 1

TALLE 6.1

Species in benthic vegetation occurring in the North Sea (from Nienburg 1930, slightly modifiea)

10 Cosmopolitan socias Ulva lactuca, E4teromorpha compressa, Ceramium rubrum, fascia Arctic - boreal species I:onostroma Grevillei, Ulothrix flacca, Uros.i)ora penicilliformis, nelagoniom, Lithoderma jatiacens, »yrionema globosum, .;:!Atoco,r» Chaetopteris plumosa, a7,1feia clavata, Ecto- carpus tomentosoides, iL'lachista foci cola, Punctaria plantaginea, Ietnofilea sphaerophora, ,'ftiotyosiPhon tortilis, Dictyposiphon foeniculaceue, je8mare-s-tia viridie, D. aculeata, Litosiphon fili- forme, Chordaria flagolliformis, Chorda tomentosa, Porphyra miniata, _Phyllophora Prodiaei, ,3thora cristata, Rhodymenia palmata, Delesseria sinuosa, Hildenbrandtia rosea, Odonthalia dentate, Igiodomela lycopodioides, Lithothemnion glaciale.

North European ODOCieS (boreal) Valonia ooalio, Calfia verrocosa, :::ctoCarpos tomentosue, E% dasycarpus, ,:phacelaria radicans, S cirrhosa, Cladostephus spongiosus, pictyosiphon Chordaria, Castagnea vireecens, ùperma- tochnos paradoxoe, Laminaria eacciy2.rina, L.'hyperborea, -eeculenta, Pocos platserpos, Pelvetia canaliculata, Nimanthalia lorea, 5,igartina ìiaraiilosa, Phyllophora membranifolia, ,:ysto- cloniumpurporascene, oelesseria alata, D. sangUinea, Polysi- phonia urceolata, violaca, P. artrorubeecens, 12hodomela sub- fusca, Cali t thaani on roseum, Plumaria cl gano, Oeramiom Desiong- champsii aznontia filiformie, FOrcellaria fastigiata, Polyides rotuncItz.13, Petrocelis Henedyi, Lithothamnion Lenormandi, Corailina

4- Subtropical - boreal species 1Xteromorbha Linza, Ohaetomorpha aerea, Dryopsis plomosa, Asco- cylus orbicularis, Cladootephao verticillatue, Deomotrichum ticum, Asperococcus compressus, Leathesia difformis, Punctaria latifolia, Chordania divaricata, ,]tilophora rhi4:odeo, ,,accorhiza bulbosa, Diloptenis Zertensii, Dictyota dichotoma, Outieria multifida, Balidrys siliguosarphyra leocosticta, Chondroe crispus, P/ocanium cocoinean,Yema/i.on muitifidom, Oelidium corneum, Laurencia pinnatifida, .L'hodophyllis Oracilaria confervoides, ¡Ji tophyllum ponctatom, Drogniartella byssoides, ,Intithc.nnion cruciatom, Oallithannion corymbosum, Cruoria peljita, Lithothamnion 6"onderi. 6:Tables FB/60/S2 North 'Sea

Subtropical species

Chaetomorpha crassa, Ectocarpus irregularis, llyriactis pulyinata, Cystosira ericoides, Colpomenia sinuosa, ,(Jcinaia furcellata Naccaria I2igghii Bypnea musciformis, Dostrychia scorpioides, Lasya elegans,Polysiphoniavariegata, Griffithsia barbata, Lithophyllum lichenoides,Corallinasguamata. 11T/64/S2 North Sea 6:Tables 3

TABLE 6.2

Maximum depth of occurrence of sessile algae

(from Gessner1955)

Locality _Depths in m.

Danish coast 38

Swedish W'coast 35

Faroe Isands 40 - 60

Oslo Fjord 45

Heligoland 15 6:Tables4 FB/60/S2 North Sea

TABLE,6.3

Characteristic and dominant species of (spring) phytoplankton communities in the North Sea

Central Atlantic Community

Coccolithus RUxleY and ..Euviaella baltica

Southern Norwegian Sea Community

Thalassiosira gravida and Anthosphaera robusta

III, Faeroes Community

Thalassiosira gravida, iceletonema costatum, chaetoceros debilis and Nitzschia delicatissima

OrkneyShetland Community

Asterionella japonica, Chaetoceros debilis, C. decipiens, Thalassiosira gravida, Oceletonima costatum

Atlantic Southward Extension Community

Few diatoms, dominant of them Chaetoceros sPID. Small populations ofdino flagellatis dominant of them Exuviaella baltica. Coccolithus Huxley relatively abundant

Western Coastal Community

Asterionella Chaetoceros, Nitschia and 67íeletonema are leading genera

East Anglia Coastal Community

Benthic diatoms and Ohaetocerus danicus, Asterio- nella spp. Biddulphia mobiliensis f. regia, Pty- chocylis urnala

VIII, Southern Bight Community

Large variety of diatoms and dinopagellates. High number of bottom diatoms, e.g. krelosirasulcata. Biddulphia ainensis (in the Channel water) faralia sulcata, Coscinodiscusspp. Bellarochea malleus, Guinardia paccida, Thalassiothrix nitzschioides, Ceratium fusus andC. ¡urea FB/60/S2 North Sea 6:Tables5

German Bight Community

Asterionella japonica, Chactoceros debilis Phaecyatis

Dogger-Bank Community

Dinollagellates characteristic; also 2hizosolenia atyliformis, Yhalassiociraand ,leptocylindrieus Durinc summer: Ceratium longipes, C. macrocerus, C. tripoc and C. bucophalun

Viking Bank Cut Community

Nixed communities, dinolagellates dominate in S. part

XII. South Norwegian Coastal Community

Extreme poverty of diatoms. Main components are Cymnoainians. Ceratiumsppo,acuviaella baltica, Peridinium trochoideun, and Coccolithus organisms in the northern NorthExample Sea of seasonal succession of dominant phytoplankton TABLE 6.4 (after Fraser, modified) 01 0.

4.1

Onshore Offshore Cn FebruarySeason Abundance Dominant Species Abundance Dominant Species

March

April

May June

July Duringdiatoms spring, dominant bloom Thalasstothrix nitzchtoldes Dinopagellatesbecome doMinant Sceletbnema costatum Dinollagellatesphytoplanktonform ca. 80 % of the dinoflagellatestomsSummer very-scarce, mirimum. less Dia- August Dinollagellatesnumerousincrease rapidly Sbeletonemadominant costatum

costatumIndied addition down:. which Thalasstosirato has partly S. RhizosoleniarosCeratiumgraoida innear the in Shetland Fair spp. stylifbrmisNIV, Isle and area. Chactoce-

Cerattum longtpes

Diatomsdominant J Ceratium fUsus and C. Dinoilagel2atesdominant with some Malassiothrixhioides with Coscino-nitzsc- Rhtzosolentalongipes near alata Shetland amount of diatoms occurs Summer minimum I spp. in N.discus and Chactoceros NitzschtaRhtzosolentaCentralthe Norwegian seriata North hebetata Coast,Sea in off Diatoms scarce decipiensFehtzosoleniavolutusgractllima and alataC. con_ var0 Chaetoceros Dinopagellatesincrease Cerattum longtpes and with PeridiniumtriposChaetoclerosSeain the in N. Central deciptens North spp0 Ceratium Ceratium iripos SeptemberSeason

Dinopagellatesreach their peak Abundance NovemberOctober

Autumn bloom died Onshore TALLE 6.4(contd) Ceratium macroceros, Dominant Species down particularly E of Fair Isle

Coscinodisous concinnus Abundance Dinoilagellatesreach their peak . lizalassiothrixand nitzschoides Halosphaera diatoms increase As in coastal Offshore -- Ceratiz,:777,1,01-11.1nanT r,acroceros waters and 0C.,e,t00;37'0,5' spp, 1727izooleniaCerc-7. spp. /:..22,croceros 6:Tables 8 FB 60 S2 North Sea

TABLE 6.6

Some data on the standing crop of phytoplankton

Place and Season Standing Crop Author

N. Sea and adjacent waters 460 mg dry organic matter m Cushing1955

English Channel June 150mg dry organic matter/m )Atkins and April, 1,320 mg dry orgaaic Itter/ )Jenkins 1553

North Sea / Beginning April1949 0.192g C/m3.a )Cushing

End April1949 0.063 g Chu"' ) 1955 Estimations of basic organic production TABLE 6.i Locality Method other remarksSeason and Amount Unit* Author Romsdalsfjord prod. In weeks in eary ,o, .,_ av d ) Gran, 1929 West coast of 02 summer 4 0,13:,56 56 2 ) Norway 02 prod. - In 4 weeks in early summer 0.2 gC/m/day ) * 1 g. carbon . 42 g. phytoplankton biomass. ) NorwegianScottish coastcoast 02 prod. Prod. Short period 0.160.14 gC/m2/day MarshallOrr,Gran, 19301927 and. English Channel Change in P 02 7060 gC/m2/year Riley (Atkins, 1956 NorthEnglish Sea Channel P-consumption Annual average 84 0.045 or mgP/cm2/yeargC/m2year (Atkins, 1923) 1923) North-Sea Changes in 7.5 mg,org.subst./cm /year Malle, 1942 population April 1949 0.073 gC/m3/day Cushing, 1955 North Sea PopulationChanges in May, 1949 0.014 gC/m3/day , Cushing, 1955 TABLE 6.7(cont 18'iM Locality Method other remarl:sSeason and Amount I I Unit* Author i Fladen Ground Annual production 82 1 gO/m-/year ,.) I . Inshore water, 54 - North Sea i , 104 - 127 1 / 1 )/\Ster.1 `-' '-'9 =' -,- NEEnglish Coast Channel of England C14 Annual average 1 _/../ '-7, - 01.- / 14 1 80 1 gC/m2 , /year, Cushing, Kattegat C ) ! i 1957 \Gross annual 61 1 / ) Limfjord C14 \production/ / 105 )gC/m year Melsen,)Steemann- 1957 Seaweeds I , Scotland Anualof Laminaria production 1 10 kg/m year 2 Blinks, 1955 i

- 1I FB/60/S2 North Sea 0:Tables 11

TABLE 6.8

Standing stock of organic carbon and its rate oproduction in the North Sea in spring in mg. C/m

(from Cushing,1957,Production of Carbon in the Sea, Nature, 179(4565:876)

Period Standing Stock Daily Production Production per day

10-30April1949 44.1 16.7 38

23Apr.-16 May 1949 15.8 3.6 22

8-15 April1954 16.6 3.6 21.7

24-28April1954 37.5 10.7 28.7

4-14May1954 12.4. 7.6 61.3

23-26May1954 16.0 13.2 82.5

1mm3m 0.086mg. C

TABLE 6.9

Production on Fladen Ground(gC/m2) (Steele1956)

Spring Sumner Autumn Total

1951 28.0 8.0 26.0 64.9

1952 30.4 22.4 29.5 82.3

1953 26.1 17.6 13.7 57.4 6:Tables 12 F13/60/52 North Sea

TABLE 6.10

Carbon production in the sea at the Smithts Knoll lightvessel (after Wimpenny)

Water collected from the surface over the Eastern Deep water on 22.3.56 and illuminated at 5o9 10o 15oC. at 16,000 lux forthree hours

Uptake of C in1N4 per hours using C

Experiments at 15o 1.25 Mean 0.607 1.026 Experiments at 10o 0.803 Mean 0.697 0.750 Experiments at 5° 0.350 Mean 0.327 0.338 Standing crop of phytoplankton from counts as mg.0 perm3 6.12

% daily increase at 15° 168

% daily increase at 10° 122.

% daily increase at 5° 55.2 F12/60/S2 North Sea 71

70 FAUNA OF THE NORTH SEA

7.1 Zoollankton

The distribution of zooplankton is greatly influenced by current transport. There are species carried into the area from the north, through the Engjish Channel and:from the Skagerrak. (see Table 7.2). In autumn oceanic plankton enters with the current from the north and main- tains its character until the Moray Firth (Sagitta serratodentata, Chel- ophyes, Agalma, Galetta and Rhincalanus). In April, a rich population of Calanus usually develops and is maintained until July.There are certain species characteristic of different North Sea areas and water masses (Tables7.1 and 7.3 and Figure 7.1). Some species are especially sensitive to changing environmental conditions (see Figure 7.2). Inshore waters are usually poor in crustaceans but Meurobranchia is usually abundant there in ,the autumn.

The standing crop of zooplankton varies considerably from year to year, both in quantity and quality. (Figure 703 and Table 7.4). A considerable amount of information is available on the quantitative distribution (see Table 7.5) but ho attempt has yet been made to summarize it on maps.

List of figures

Figure 7.1 Biological water masses of the North Sea on the basis of planktonic indicator species " 7.2 Distribution of Chaetognatha in 1947 7.3 U The relative seasonal abundance of the plankton of the Buchanan fishing ground

" 704 Distribution of average standing crop of zooplankton in to 7.5 the North Sea during early spring and autumn(to be added)

List of tables

Table 7.1 Zooplankton species, characteristic for different North Sea regions 7.2 Zooplankton species transported into the North Sea and indigenous species

" 7.3 List of planktonic indicator species in the North ea in " 7.4 The dry weight of Hensen eggnet plankton as mg m June to September at the Flamborough line and north of it from 1947 to 1954 " 7.5a Standing crops of zooplankton biomass in the North Sea

" 7.5b Average plankton biomass in the North Sea and adjacent waters 7:2 FB/60/S2 North Sea

7.2Phytoulankton-zooplankton relaILInEhlp.

As mentioned earlier, the quantities of phyto- and zooplankton .vary considerably from year to year and from locality to locality.In general there is a seasonally changing quantitative relation between these standing crops (see Table7.6and Figures 7.6 and 7.8), controlled by a predator-prey system. This relation is not however constant in detail because there are many additional influencing factors. (transport, patchiness and changes in environmental conditions)

List of figures

Figure 7,6 Histograms showing the mean monthly values of phytoplankton and zooplankton between Flamborough Head and DoEger Bank It 7.7 Routes along which the continuous plankton recorder was towed monthly during1952 " 7.8 Estimated densities of phytoplankton and relative numbers of total copepoda along the K line of Scottish plankton recorder survey 1952 to1955

List of tables

Table7.6 Quantitative relation between standing crops of phyto- and zooplankton

7.3Benthos

The species composition of benthos communities and its biomass per unit area is much more stable thanthat of plankton and nekton. Although the benthos communities are well defined inNorth European waters, their distribution is not yet mapped in detail(see Figure7.9 and Table 7.7). Data are available on the quantities of behthos in various localities, their seasonal and year to year variationsand the content of fish food. The available quantitative data would allow rough mapping of the average quantitative distribution.

Very little data are available on the productivity ofbenthos. Some estimatesshr,e.g. that on the Dogger Bank6 to7g fish food is produced per mper year. FBN/S2 Nox-th Sea 7:3

List of ficljures

Figure 7.9 Distribution of benthic communities in the North Sea " 7.10 Variation of the 9mber of various groups of benthic animals (per OT m )in the German Bight,1949to1957 " 7.11 Variation of benthos biomass in Horns Reef area !V 7.12 DistrilTution of average benthos biomass in the North Sea (to be added) List of tables

Table7.7 Composition of benthic communities in the North Sea " 7.8 Frequent benthic animals and their importance as fish food in German Bight " 7.9 Quantities of benthos and the amounts of plaice food in it in some localities in north European waters " 7.10 Standing crops of benthos biomass in the North Sea " 7.11 Average nuMber and biomass of benthic organisms in German Bight,1955to1957 " 7.12 Average number of benthic animals per square meter in Moray Firth " 7.13 Changeinthe composition of the bottom fauna of the Dogger Bank area 7,14 Plaice food in Kattegat

7.4Nekton

The fisheries problems will be summarized in another synopsis. The present one is conserned only with fish egg and larvae; the latter usually classified under nekton.

The catches of different commercial fish species in the North Sea are given in Table7.15. The spawning areas of these species are known, some approximately, some in greater detail, but no summary mapping of these areas, with indication of spawning seasons, exists. Although there are some data available on the denSities of eggs and larvae of various species on the spawning areas (see Table 7.16), again no detailed summary exists on the areal distribution of the eggs and larvae, although a considerable amount of detailed information has accumulated during the last 50 years. 7:4 VB/60/S2 North Sea

List of fiures

Figure 7.13 Distribution ofplaiceeggs during FebruaryMarch Figures on the spawning grounds and distribution of eggs.and fry of different species during different months (to be added)

List of tablee

Table7.15 Catches of different species in the North Sea " 7.16 Densities of eggs and fTy of various species on the spawning areas of the southeastern North Sea F13/60/S2 North Sea

5° 0° 5° 10° G-1649 BIOLOGICAL WATER MASSES OF THE NORTHSEA BY PLANKTONIC INDICATOR SPECIES 7:Fius. 2 FB/60/S2 North Sea

Ill O b 4° I TT la.; VVWWXX YYZJA'13 Et:Gil 24 Jo

1 J 0 oç.-) 2.3 r '), , --\"\) JD 0 L 1 , -- ','-,\)7{O_J if --A4k____,, G Jl:`-?, J 22 l',. - A at A . _ _ . jOk° Vj ' , ' \ , 46:-."-",- L------e JO -', 21 pi ,pre 0 #1. ' J p_vp_ 9; FT° 6( 4.....0-...-- AI& Y 0 i y YY' YWV"I'r fit J ." J . 20 .0 ... 1 At 1...... _I ! j 0 KS * i d'pO 19 A , e , A I LO A I la Y Y '',, --- A 4 r()), e 0 6, A t T. .6., 18 t Y Y 9 V _ -rite aie CY) 0:A,,,, Peet. 17 & -11111 -'° kt JE. .' - Q P .. SS O O AA 9 0.°A I , iik.,...... 2,N J2kA J,'9,,2,--f _.) O e

4 J A v 1 5 ' t Ye 0 !.13 /AO : ' .¡A NI i t - - % 0 i 5. .\S ---I'l A Ce 14 Ai i t,t . --AA ; - -'',,'\''---) ,,,e 4.,--:, 13 , Ms ../ 51 _MS : e

' f g --A- A 12 A A i .,, I' ,- :;2-:,-:',,,-,...,---- A 1 . `, c..--M - OS i-1 .,....¡-, e els e ( ilb' "'°i'ci ,..- f 1 :,(i',': " Mki'US al ..,:// ,_ \,1?) . elvgans 0 t,',_,k, i... serratoAr .!-,t,JA j.,1 .,, el) NI ! , m:,,,,, , -s\> e,-' O 5 5F; I'') ?,...... , VII, gill 't --6 5!:., I, hq,w, 1947 ,A --,--')' la , 1 --lit , --, et . 10. v, t; 4° t 6° Figure 7. 2 The distributionof Clittog,nat ha.in 1917.In this chart, and inFigs. 4.and 5, the posifions of the Plankton stations are shown hv a letter inilicatina: the month of the vear: 1 April, M s= May, .1 ;June, Y ,1111Y, A ..ellletitlo.t, Dmober, November, I/ December. The .positions are given only to the nedrcsi sn1)-inme and svilibills reurcsyniiiig titeliccsiince of orizilnisttr: are placed conveniently1hear the ap- PriiPrialc statiimpo-ition. The domedii110 indicatesthe hypothetical northerly limitof distributions of .'a! setus,1iiVOZ1r,iitiiiirni,t1 Atlantic inflow into tlic northern North :.1ea.'['he thsfribution of one species'-8. scrrolo- denla I" ill"'Piing- Ole broken line as an example of Imw the chart may be real, (after Fraser) FB/60/S2 North Sea 7:10icp0 3

1947 1948 1949 /950 1951 1952 1953 1954 i955 Pseudo. a Paroco/anus Appendicularia Cladocera remora long/corms Centropages homotus Acart,o spp. Ca/anos star, 1.1V Centropages typtcus DInotlagellata Tomopterts,pp. Metric:halucens Candoc/o armoto Ca/onusstogr, V .a VI 1../macmaspp. Euphausuds Cl/one//moc/no So/palust/on-1,1s Abundant MON Most abundant

FIGURE 7.3 The relative seasonal abundance of the plankton of the Buchan fishing ground. (after Glover) 11Figs. 4 FV691S2 North Sea

25 20 IS Phytoplankton per m3 10 scale in 10,000's 9 8 7 6 5 4

3 2

1 MAMJJAS AMJJAS AMJJAS AMJJAS Zooplankton per rn? 28 24 scale in loo's 20- 6 12 8 _.21 4

rho_ r- 1 1 7 1 MAMJJAS AMJJAS AMJJAS AMJJAS 19 50 19 51 1952 1953

FIGURE 7.6 Histograms showing the mean monthly values of six stations between Flamborough Head and the Dogger Bank for phytoplankton and zooplankton (after Cattley) FB/60/S2 NorthSea_72..Fis. 5

FIGURE7.7

Routes along which the continuous plankton recorder vías towed monthly during1952 (after Rae) 7:Figs. 6 FB/60/S2. North Sea

2000 80

1500 60

1000 40

500 20

1500 60

100071) 40

500 220

o 0 80 ,24 1954 -81500 60_ OD g'1000 ,P 40- u

500 4-,20- o

cr; 150071.0 60

1000 a,40 1955

500 20 % / rTh J F A J J A SOND Phytoplankton - pale green Slightly smoothed 70: green line s constructed from monthly histograms dark green Total copepuda ESTIMATED DENSITIES OF PETYTOPLANKTON AND RELATIVE NUMBERS OF TOTAL COPEPODA ALONG THE K LINE OF SCOTTISH PLANKTON RECORDER. SURVEY 1952 - 55

FIGURE 7.8 FB/60/S2 North Sea 7:Figs.7

60°

55°

50° rté/%4Macoma community Venus community TFTMVitreus community Brissopsis-Amphiura clommunity

loo 5° 5° 10° G -1649 FIGURE 7.9DISTR/BUTION OF BENTHIC COMMUNITIES (alter Petersen) FV91S2 North Sea

ZOO

.190 TO

120 A 1110 I 150 I

1,40 110

11t) 110

, I I / \ A so I I I\ I 2-P / \ 1 'i 1 //\ /, I \ / / \ r 8,0 \ / \ \ I E \ I V 50 o 0I /1 / \ I / \I \/ / / V 30 ekes 10 PO\ siC"-a 'I 10

t t 11 t 1 t t t -t AutumnSpringAS AS AS AS A 5 A SA S A 19491950 1951 1952 1953 1954 1955 1956 1957

FIGURE 7.10 Variation of the Tambers of various croups of benthic animals G.1 m in tho German Bigh:b 1949 to 1957 (after Zie,y;elmeier) FB/60LS2 North Sea

500

200

X SS 100 SS SS

Tj 10 o o 2)

5 o o ..tme .ftft00ft o S Horns Reef N. Horns Reef 2 Plaice food o Non plaice food X

1 1934 35 36 Year37 38 39 FIGURE 7.11 VARIATION OF BENTHOS BIOMASS IN HORNS REEF AREA (after Blegvad ) FB/60/52 North Se

Relative amounts of the eggs

10° 5° 0° 5° 10° G--I649 FIGUR E 7. 13DISTRIBUTION OF PLAICE EGGS DURING FEBRUARY - MARCH (Incomplete) FB/60/S2 North Sea 7:Tables 1

TABLE 7.1

Zooplankton species characteristic for different North Sea Regions (Ostenfeld)

S - summor, A autumn, - winter, Sp. - spring

Flemish Sea

Very. frequent 6b.gitta bipunctata, Copepods: !femora longicornis, Pseudocalanua elongatus, Acartia clausi, Centropagea hamatus, Para- calanus parvus, Oithona nana, Calanua finmarchicus, Copepods and copepod larvae (S). Oill:opleura, frequent the copepod EUterpe acutifrons (S), Pleurabrachia pilcas (Sp. and S).Noctiluca miliaria (S), Hydromeduse (S-A), not rare are: 2chinoderme larvae (S), Labiaocera (S); as frequent, are also mentioned:hemipelwsic crustaceans: Phtisica 'marina, Oastrosaccus, Paramysis apiritus.

H. Southern North Sea

Frequent: Oithona similis (S), Pseuaocalanua elongatus, Oithonanana,. Acartia clausi, (s), Tintinnopsia ventri cosa (A), Noctiluca miliaria (s), Oagitta bipunctata (S, A), as well Echinoderme and Ladn6llibranch'larvae; not rare are: (kopleura, Euterpe acutifrona (A).

III. Northern North Sea

Very frequent: Netriaia lucens, Calanus finmarchicus, frequentneisto abyssorum (A),Nicrosetella noroegica, Anomalocera patersoni(s), Tamara longicornis Paeudocalanus elongatua (Sp./S), Centropages typicus, Cyttarocylis denticulata, O. gigantea(U), Zvadne nordmanni (S),Acartia clausi,as well as Decapode and Schizopode larvae; not rare are the Acanthometrides (S), Protocyatis tridena (S), and Poden intermedius (s).

IV. Skagerrak

Ver,), frequent: Poeudocalanus elongatua, Temora longicornis, Calanus finmarchicus, gitta elegana, Ecartia longiremis, Centropages hamatus, Oithona similia, Aglantha digitalis. 7:Tables FB169/S2 North Sea

TABLE 7.2

Zooplankton species, transported into the North Sea and indigenous species (after Remane 1940)

Warm water species entering through English Ghannel

Medusaa:Ytzrritopsis polycirrha, T. nutricola, Gossea'corynetes, Amphinema dinetaa, .:11abberia halterata, Octorchis gegenbauri Gastropod larvae: Laaellaria perspicua Tunicats:. b.lpa democratica, Cyclosalpa baizeri, Doliolumnationalis, D.gegenbauri Siphonophores: -aea atiantica

Warm water species entering North of Scotland

Medusae: Cosaetira pilosella

Tunicates: Do/to/um tritonts, acdpa fu3iforrais, Appendicularia oicula venusta, Oihcpler.cra parva, Salpa asyfiwietrica Gastropod: C/topyromidata Ostracod: Conchoecia daphnoide6 Copepods:Eucalanus elongatus, Rhincalanus nasutus Chaetognaths:eagitta serrata dentaa, ±i:yphaena malmii Trachymedusae: ,lo.Zaaris corona

Siphonophores:Physophora hydrostatica, CUpulita sarsi, Arachnactislarvae, etc.

Temperate water species entering Northern North Sea

Radiolarians: Challengeron araatum, C. diocLon, Choenicosphaera murrayana, Cladoscenium tricolpium, Clathrocyclas orospedota, Dictyophimus cleoei, Echinoaaa trinacrium, Plagiacantha'arachnoides, Protocystis tridens, xiphodon, _riA.ochodiscus echinodiscus, T. helioides Tintinne: Dictycysta elegans Ceriantharier larvae: Arachnactis albi da and. A. Bournei

Copepods: Actidev-3 araatusCanaacia araata , Cgraci limn a,C n,orive g ca C.rotunda, Chiridius armatus, Lietrictia lucens, Oithona at_Zantica, O. Pleuroaaaaa robusta

Amphipod: Saína borealis FB/60/52 North Sea 7:Tab1es3

TABLE 7.2 (contd.)

Indigenous species present in whole North Sea

Copepods: Acartia Clausi, Anomalocera Patereoni, Oentropages typicus, Euterpe acutifrons, Labidocera vollastonii, iiicrosetella norwegica, ...;agitta bipunctata (elegans) 7:Tables4 FB./60/S2 North Sea TABLE7.3

List of planktonic indicator species in the North Sea (after Russell, modified)

North Atlantic Water

la. North Atlantic Water

Warm water forms:

Hydromedusae: siphonophores: Physophora hydrostatica, Agalma ele gans and Galeolaria truncata

Chaetognatha: Oagitta serratodentata

Crustacea: copepods: Rhincalanus nasutua and several other species

Pteropoda: Cito pyramiaata

Tunicata: various salps and doliolids

Temperate water foil's:

Hydromedusae: siphonophores: Dimophyes arctica

Chaetognatha: Sdgitta maxima and Etarohnia hamata

Crustacea: copepods: CalanUs hyperboreus. and Metridia longa

Pteropoda: Limacina heticina

Ib. Mixed Scottish Coastal Water

Hydromedusae: Neoturris pileata, raodicea undulata, ,Ualopsis ocellata, Cosmeira, Tima bairdi and Aglantha Chaetognatha: 61agitta elegans

Crustacea: amphipods: Themisto (Calanus finmarchius abundant)

Pteropoda: Limacina retroversa

11. Channel Water

Hydromedusae: Ilwritopsia and Gossea corynetes

Mollusca: Lamellaria perspicua larvae FB/60/52 North Sea 7tTables5

TABLE7.3(Contd.)

III. Central North Sea Water

lila. North-Central

Chaetognata: Sbtgittasetosa

IIIb. South-Central

Hydromedusae:Tima barrdi, Cosmetira,Aglantha,and the siphono- phore Agalmaele gans

Chaetognatha: aigitta elegans elegans

Crustacea: amphipods: euphasids:Ryctiphanes couchi,Thysanoessa gregaria, Themisto abyssorum

Pteropods: Clione limacina andLimacina retroversa

Echinoderms: Luidia sarsi larvae

Appendicularia: Oihopleuralabradoriensis

Skagerrak Water

Complex community with frequent occurrence of Pseudocalanus, Temora, Calanus, Acartia,Centropages, Oithona, Aglanthaand 6hgitta spp.

English Coastal Water

Hydromedusae: Turri-topsis

Chaetognatha: Oagittasetosa

Continental Coastal Water

VIa, Flemish Coastal Water

Pelagic hydroid: Clytia

Medusa: -arsia tubulosa.(late winter and spring)

711). German Bight Water

Medusa: ::"arsia tubulosa DTables 6 FB/60/S2 North Sea

TABLE 7.4

The Dry Uoic;ht of Hensen EugNet Plankton as m6, form3. (june, July, jept.) (afterUimpenny),

Stat. North of FlamborouLh Plamborouzh Line Line (mean of 6 (mean of 11-12 stations) 6tations)

1947 55 66 1948 zi 6 36

1949 /1/4 47 1950 43 6d 1951 43 53 1952, 63 1953 81 1954 L)) FBJ6Q/S2 North 7:Tables

TABLE 7.5a

Standing crops of Zooplankton biomass in the North Sea (Mainly on the basis of Neilsen net catches)

Locality Season mg/m3 Author Remarks

North Sea Average 55 .Wimpenny,1953 Recalculated assuming 50 m depth

SW North Sea Febr.March 152 397Kroy, 1953

TABLE 7.5b

Average plankton biomass in the North Sea and adjacent waters according to the data compiled by Bigelow and Sears (1939) (Recalculated assuming 1 ml displacement volume= 0.8 g biomass)

Locality Season Authority Plankton 1T)mass in mg /m

North Sea June 1926 Savage 1931 460 August 1926 400 November 1926 480

Jespersen 1923 10

English Channel April 1925 Russell 1927 8 May 1925 80 June 1925 16 July 1925 40 August 1925 40

Skagerrak February 1903 Cons.Perm.Intern, 32 August 1903 p, l'Explor de la 40 November 1903 Mer (1904-1907) 112 May 1904 72 August 1904 40 November 1904 128 August 1906 16 7:Tables 8 FB/60/S2 North Sea

TABLE 7.6

Quantitative relation between phytoplankton and zooplankton

Biomass inmem3 Phytoplankton Locality Time Author Phyto- Zoo- Zopplankton plankton plankton relation

SW North Sea Fo-hru:lry- 27 241 0.1 Krey,1953 March

gC/m2 Locality Time Author and. remarks Phyto- Zoo- plankton plankton

North Sea Jan, 3.4 1.3 1.2gCm2higher animals. Kane,1950

Fladen Ground (Max.) 1.2 5 ) ) Inshore waters ) Steel,1956(Phytoplankton North Sea (Max.) 2.1 5 ) recalculated)

)

English )

Channel (Max.) 2.5 5 ) FB/60/52 North Sea 7:Tables9

TABLE7.7

Composition of benthic communities in the North Sea (after Petersen)

1. The.Eacomabalticacommunity, with gacoMa balticay gya arenaria, Cardium edule, Arenicola marina etc, as the ,most evenly distributed characteristic species.

2. The Venus communities withSpatangidaefound mainlyonsandy bottom Echinocardium cordatum, Venus gallina, Tellina :tabula, Ilactra subtruncata,in shallow water. Spatangus purpureus, Echinocardium flavescens, Abra prismatica, Psarambbia faerensis, iiactra ellipticaetc., in deeper water. Cyprind islandicais frequently found as an attendant species in both a) and b). Venuscommunities which have not yet been subjected to valuation may doubtless be found in still deeper water, together withf'Jpatangus raschiietc.

3. The brissopsis Amphiuracommunity, on soft clay bottom with Drissopsis lyrifera, Amphiura chiajei, Calocarts miandrea, flUculd sulcata, amenia crassaetc.

4. Communities from deeper water than the a-issopsiS, presumably on soft clay bottom, with Pecten vitreus, Abra longiCallis,and various other species as characteristic types or at least as important attendant species. Future investigations will doubtless reveal the necessity of further subdivision here, and possibly a revised classification (Amphilepsis norwegica). 7:Tables 10 FB/60/S2 North Sea

TABLE7.8

Frequent benthic animals and their importance as fish food in German Bight (after Ziegelmeier)

Polychaetes: - all important as fish. food

6.piophanes bombyx ) Pectinaria koreni Most abundant Lanice conchilega ) Nephthys hombergi On muddy bottom Ocoloplos armiger Nagelona papillicornts On sandy bottom ;./ca/tbreme'inflatum On muddy bottom in deep water

Crustacea: Amphipods: Urothoë poseidoni On sandy bottom Dathyporeia guiZliamsoniana Ampelisca brevicornis On all bottoms

Cumaceans: Diastylis rathker bradyi Iphinoë trispinosa

Echinoderms:

Echinocardium cordatum Ophiura texturata albida All echinoderms are sensitive Amphiura filifOrmis to cold winters

Lamellibranchs Angulus *tabula Most important lamellibranch as food Nucula nitida for plaice llontacuta bidentata Phaxa pellucidus Lunatica nitida Nydrobia alvae Abra nitida On muddy bottom Abra alba On sandy bottom, further offshore Quantities of benthos and the amounts of plaice food in it in TABLE 7.9 some Region Benthos Community localities in north European waters. LoCality and its (after Smidt 1951) Characteristics Number of indi- viduals(av) m2 Total weight plaice 1st class food Source Danish Macoma Vaddens, Southern area g/m(alq Aver§ge g/ra Max&ena Z Waddensea at Skallingen,Aug.July-Aug. 1942 1941 31,000

63,000 497174 249 84 200 Smidt,1951 Ringkbing Fjord Nacoma Tidal areasJuly-Aug. Julyat the1938 Tipper: 1937 3,1903,176 42.426.7 42.426.7 Sparck(unpubl). 1Dybso Fjord Macoma Depth ca.0.1June - 1939 10.9 m 2,427 844 55.245.0 55.245.0 Larsen(1936) ,uxhaven Nacoma America Harbour, depth 7 m 75,300 270 73 Hagmeier(1925) Heligoland Bay hacoma RichPoor localities 358 59 .30.8 6.9 18.2 5.4 Hagmeier(1925) TALLE 7.9(contd) Region Benthos Community LocalityCharacteristics and its Fumberof indi- weight .....". Total _._, plaice food1st class Source Heligoland Bay Syndosmya viduals(ay). m2 em 700 (av. Averre g/m g/mMax Venus NortheasternSouthwestern area area 113 105.4 28.2 12.476.0 Amphiura Mixed with elements ofVenus-community 273 25.1 4.8 Hagmeier(1925). Limfjord Syndosmya Thisted Bredning Syndosmya-community 1,770 406 232.8 98.1 33.914.6

oCs%

SallingsunsLovns Bredning(18 (13 years years invest.)invest.) years 48.944.7 279.6136.6 Blegvad(1928) Venus Several years investi- invest.) (12 62.2 336.8 Kattegat gations in-various 808 46.3 23.9 97.0 localities 368344- 121 26.8 100.6 71.0 10.7 16.8 Blegvad Amphiura Several years investi- 18.2 8.8 88.7 9.1 (1930) gationslocalities in various 309277657 216.6 219.5 138.6 21.6 10.122.0 30.6 13.830.5 Blegvad(1930) Hanloöps Two years investigations 1,458 54.9 34.4 R ' A,9 - B legvad( 1 cYzn1 FB/60/S2 lorth Sea 7:Tables 13

TABLE 7.10

Standing crops of benthos biomass in the North Sea

g/m2 Community and Author other remarks

Venus gallina comm. Nucula nitida var. 30-130 _anon.A Tollina fabula var. 5-10 Echinocardium cordatum var. 500 1934 Aonides var. 10

346 Demeland Mulicki, 1954 244 (Zernov, 1934), Moiseev,1955 260 Petersen,Jensen, 1911

Macoma comm. 7-31 Hagmeier,1925 Syndosmya comm. 105 (acc.Sparck Venus comm. 25-28 1935) Amphiura comm. 98-233 Average number and biomass of benthic or;zan:sms in TABLE 7.11 German Bight 1955-57 (after Ziegelmeier) 1955 1956 1957 Average numbers on 1/10 m.2 at all stations Lamellibranches ISDring 30.4 52.9Aut, Spring 26.6 Aut,37.0 Spring Aut. i 34.6 74.9 AbraAngelzzs . i3. .0.4- 17.5 5.3 0.69.3 8.08.7 1.79.4 19.1 4.1 PolychaetesofEchinodermsCrustacea which E. cordatun 40.8 4.91.06.7 168.5 17.632.320.1 54.9 0.55.8.8.6 0.6 20.085.3 6.6 45.5 0.46.29.9 195.7 16.225.4 6.1 Average total sto2k on 1/10(biomass m.2 in mm. ) 5.0. Average stock on 1/10 m. E. cordatum 2 Opiomass, in cm.")) excepted , Lamellibranchs 1,93.2 1.6 1.32.7 4.61.7 4.82.2 3.28.1 Polychaetes 1.1 j , 2.5 1.1 2.0 2.1 4.1 Average number of benthic animals per souare metre in Moray Firth (after Stephen) TABLE 7.12 Organisms TypeDepth of rangeBottom Under. Sand Over 20-45 LIud. Kinnaird Echinoderms 20 10.5 fms. 20 fms. 35.6fms. 109.7 Deep PolychaetsEolluscs 10.233.4 22.025.614.6 52.1 61.825.0 OtherCrustacea forms 0.66.5 16.5 8.0 16.447.1 7.1 15.5 9.7 Change in the composition of the bottom fauna of the Dogr Bank area TABLE 7.13 (after Ursin) (Oct. 1922) Davis Number per sauare meter (hay Ursin 1951) Spisula subtruncata 272 11 15 ZactraPolychaetsOther corallina.species of bivalves 4 7043 OtherEchinoderms groups 84 6528 Total 303 212 ,co o rt`s :o ;f1 FB/60/S2 NorthSea 7:Tables 17

TABLE7.14

PLAICE FOOD IN KATTEGATT (after Blegvad, 1930)

A B C I class plaice food II class plaice food No plaice food

All Lamellibranchia except Bhcoma cal carca 2cm Pecten sp. 2 cm those under II class and No All species of the genera Cyprina ialandica 2cm plaice food Venus, Astarte, Lucina, Qia sp. 3 cm Dosinia, Ledo, Corbula and Mccula

Psammobia faerensis 2 cm Zactra solida.2 cm Abdiolaria nigra2 cm

Batica all sp. Buccinumunctatum 005 g Buccinum undatum 005 Pela turricola ilassa reticulata

Lacuna, all sp0 liassa pygmaea i?isaca, all sp. Aporrhata pea Jelecani ilporrhata pes pelecani 0.5 g 0.5g Phi]ine, all sp. L/calaria cinerareus litrritella terebra Acera bullata YA'ochus festudinalis Dental ion entalis Cylichna cylindracea Chinton, all sp. iludibranchia Chaetodermaintidulum

All worms with exception Aphrodi,te acaleata PomatoCeros trigueter of thoSe under B and C Phascolion stronbi Amphiura chiajei All Echinoderms with It filiformis exception of those Ophiura all sp, mentioned in B Zchinocardium cordatun (Small 0 - Gr.) Lbhinocyanua pusillus

All Crustacea with Small Paguridae Big Eupagurus bernh. exception of those under " Carcinus maen,aa B and C u ligas " Eephrops novegicuo Ltlardaia chrysanthellum Rydroidae Act ¿ni idae with excep- Cerianthus danieloseni tion of those mentioned Amphioxus lanceolatus in A Ascidiae Foraminif era ---- 7:Tables 18

TABLE 7.15

Catches of different species in the North Sea1957

milltlsgst °A.

Herring 19047.8 57.6

Haddock 105.3 5.8

Cod 95.9 5.2

Uhiting 84.3 4.6

Plaice 69.3 3.8

Mackerel 68.9 3.8

Saithe 51.8 2.9

Dogfish 26.4 1.5

Sprat 22.4 1.2

Ling 15.1 .8

Sole 11.7 .6

Skateand Ray 11.5 .6 FB/60/S2 North Sea 7:Tab1es. 19_

Table7.16

Density of fry on the spawning places of the southeastern North, Sea, (after Aurich 1954)

Average Maximum

February 1936 35 -56 116 - 176 eggs/m02 Cod March 1926, 1937 / March 1953 75 192 eggs/m02

, February 1936 75 111 - 294 eggs/mo,2 2 4 9

Plaice March 1926, 1935, 14 4 - 9 - 35 2' 1937 4 - 11 15 - 51 :7larvae/m.

. 2 March 1953 47 159 eggs/m. 8 12 larvae/m.2

2 February 1936 370 821 eggs/m02 Dab March 1926, 1935,1937 300 1185 eggs/m.0 March 1953 300 - 765 eggs/m.'