r~,

International Council for theExploration of the Sea

PAPER

ICES CM 19951L:15Biological OceanographyCommittee

•ZOOPLANKTON INVESTIGATIONS OFF WEST GREENLAND, 1956-1984

by

S.A. Pedersen and E.L.E. SmidtGreenland Institute of Natural Resources

(former: Greenland Fisheries Research Institute),Tagensvej 135, l.tv., DK-2200 Copenhagen N, Denmark

Abstract

The available data on the density and composition of zooplankton obtained in offshoreplankton surveys carried out annuaHy during 1956-1984, except in 1965 and 1967, in June­July off West Greenland by the Danish Institute of Fisheries and Marine Research and theGreenland Fisheries Research Institute have been analysed. The average densities have beencalculated and inter-annual changes in the densities and of the most important speciesinvestigated. There was a decreasing trend in both the CPUEs of plankton volume and selectedspecies e.g. the eopepod, Ca/anus finmarchicus, as weH as a positive associations to seatemperature measurements from the late 1950s and early 1960s to the 1970s. These trendsmay be indicative for a decrease in the zooplankton productivity and ehanges in the eeosystemfood-web structure in the same time period. A very weak positive association between themean number of eod (Gadus morhua) larvae caught and the mean sea temperatures werefound. The failure of the 1982 year-class and the inability to relate the eatches of eod larvaeto subsequent recruitment were the main reasons that put the end to the zooplankton time­series from off West Greenland in 1985.

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Introduction

In the prescnt century there have been major changes in thc abundance of commerciallyimportant fish species in \Vest Greenland waters. Historically, Atlantic cod (Gadus morhua)has been the most important commercial fish species in Greenland waters, with annualinternational1<mdings peaking at levels between 400,000 and 500,000 tons in the early 1960s(Fig. 1). In the late 1960s the annual landings showed a drastie decline. After 1970, therecruitment to the \Vest Greenland cod stock has shown large variations and all importantyear-classes in West Greenland waters have been of Icelandic origin (Buch et al. 1994,Hovgard and \Vieland in press). After 1990 the Atlantic cod has been very sparse in WestGreenland waters (Anon. 1994). In the 1980s and 1990s the northern shrimp (Pandalusborealis) has been the far most important fishery resource at West Greenland with annuallanding peaking at 87,000 tons in 1992 (Anon. 1995). The low productivity of the WestGreenland cod stock is assumed to be duc mainly to decreased and unfavourable watertemperature conditions for spawning, eggllarvae survival and to changes in thc whole •ecosystem productivity (food-web structtirc) (Hermann et al. 1965, Pcdersen 1994).

In thc North Atlantic analogous biologieal seasons occur at different times of the year indifferent parts of the same aquatory, as if they moved together with the water of warmcurrents and this phenomenon often determines the direction of the feeding migrations ofpelagic fishes (Pavshtiks 1968, 1972). Davis Strait resembles the other northem regions of theAtlantic in many ways in its complex circulation, clearly defined frontal zones, and otherhydrologieal factores (pavshtiks l.c.). Seasonal and inter-annual variability in thehydrographieal conditions and fauna of the upper ocean layer along \Vest Greenland is ­governed mainly by inflow of water from other parts of the North Atlantic (pavshtiks l.c., Lee1968, Buch 1984, 1990, 1993). The surface layer (0-150 m) of the \Vest Greenland Currentis dominated by cold, relatively fresh Polar Water carried to the area by the East GreenlandCurrent, while the underlying layer (150-800 m) consists totally of water originating from thewarm, salty Irminger Current (Fig. 2). Mixing and heat diffusion between the two layers areimportant factors for the temperature conditions whieh among other things are dependent onthe flow intensity. Years with a strong East Greenland Current will tend to show up as coldones and viee versa. A description of annual and inter-annual variation in the iee conditionsis given in Buch (1990).

The most recent general publication on zooplankton in \Vest Greenland waters, including aprotracted list of references is by Smidt (1979). Smidt (l.c.) presents results of zooplanktonsampling in inshore and coastal waters throughout the years 1950-66, mainly in the Nuuk(Godthab) district.

From 1956 to 1984 aseries of offshore plankton surveys were carried out annually, except in1965 and 1967, in June-July off \Vest Greenland by the Danish Institute of Fisheries andMarine Research and the Greenland Fisheries Research Institute. Some of the main aims ofthese surveys and zooplankton collections were: 1) to collect and possibly quantify fish eggand larvae, especially of Atlantic cod, in order to get information on the strength of the newyear-classes, 2) to evaluate the amount of zooplankton and quality (species composition) asfood for the recruiting year-classes of fish, 3) to identify indicator species for differenthydrographieal conditions in the area, 4) to compare variations in the zooplankton by year and

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possibly to ideritify trends over the ycars in the species eomposition rind productivity. Thezooplankton data (invertebrates and fish eggs and larvae) have reeently been eompiled in adatabase together with sea temperature and salinity measurements. The purpose of the presentpaper is to give a deseription of the information in the zooplankton database and to presentresults froin analyses of the zooplankton data (species eomposition, oeeurreriee, abundaneeindices) for variations, trends and associations with e.g. temperature. Of special interest is thelong-term variations or trend between the period before 1970 (1956-1970, relatively walmpedod) and after 1970 (1970-1984, relativcly eold period).

Materials and methods

MethodS of samplirig

By far most of the zooplankton, 1956-1984, was eollected on stations along three transects[hydrographie areas/sections, (SI,S2 and S3)] off \Vest Greenland in June-July in conjunctionwith collectioris of hydrography data from standard depths (Fig. 2-5). Zooplankton and seawater temperature data from these transeets have been analyzed for annual variations.

Sampling was carried out with the RJV "Adolf Jensen" and "DANA". Tbc zooplanktonsampling gear used was a 2 m (diameter) stramin-ring-net with 1 mm mesh size. Tbc towingspeed was about 1.5 to 2.0 knots during the whole tow duration of about 30 min. During theyears two different hauling proeedures were employed. Before 1963, all hauls were horizon­taHy, stratified with two nets on the same wire in three times 10 min. and with wire lengths200, 150, 125 and 100, 50, 25 m for the two nets, respectivcly.

In 1963 (the NOR\VESTLANT survey), aH hauls were made obliquely with only one nethauled from about 50 m depth to the stirface at 1.5 knots, wire length 225-0 m, durationabout 30 min.

In 1964 and 1966, stratificd hauls with two nets were again made, but in a11 the fo11owingyears, 1967-1984, hauls with only one net wcre made obliquely as in 1963.

Analysis of sampIes

In order to make the zooplankton sampies comparable haul by haul, between years, arid henceby hauling method (stratified vs. oblique hauls) all figures in the present paper are caiculatedto 30 inin.· hauis. Tbe figures from the two nets in the stratified hauls (before 1963 and in1964 and 1966) have been averaged. Because of soine extra hauling time a conversion faetorof roughly 0.75 is used for the stratified hauls before 1963 and roughly 0.85 for hauls in theyears 1964 arid 1966. Only data from hauls with a ma'dmum wire length less than 251 m havebeeri included in the preserit paper. .

Calibration experiments pcrformed in 1984 with flO\vmeter attached to the opening of the 2m stramin riet showed that a haul duration of 30 rriiri. at towirig speed 2 knots equals a filteredvolume of water of about 6125 m3 (Hovgard and Wieland in press).

The mcthod uscd for sorting and counting was first to pick out and eount the largcr animals

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from the total sampie before taking an aliquot subsampie to identify and count the smaller andmore numerous animals. The plankton volume in ml is the displacement volume measured atsea exclusive salps and schyphomedusae, adjusted to 30 min. haul . All other zooplankton datapresented in this paper are expressed in numbers per 30 min. hau!.

The zooplankton groups and specics sclected and analyzed in the paper are listed in Table 1.Very small animals are not caught by the 1 mm mesh size in the ring net used, and manysma1l development stages and sma1l species are therefore not included in the species list Table1. For more complete lists of specics including also sma11 development stages and species seeJ"rgensen et al. (1978a,b) and Smidt (1979). In some years not a11 sampIes were sorted forinvertebrates, aIthough sorted for fish eggs and larvae and in 1965 and 1967 there were nosampling at a1l (Table 2).

Analysis of variance and associations

The zooplankton CPUE data (volume and numbers per 30 min. haul) showed non-normalityand were, therefore, analyzed for variations (effects of sampling section and year) using ranktests. Kruskal-Wallis tests and two-way ANOVAs on ranked data were performed (Anon.1985, NPARl\VAY, RANK and GLM p'rocedures).

Thc sea temperature and salinity at the sampling stations were calculated as simple means oftemperature and salinity measurements in the range 10-50 m (norma1ly the standard depths10, 25, and SO m or 10, 20, 30, and SO m). Effects of sampling locations and year on themean temperature and salinity were analyzed by a two-way ANOVA. The number oftemperature, salinity and zooplankton observatioris (sampled stations with data) by section andyear are given in Table 2.

Associations between temperature, salinity and logarithmic transformed CPUE-values ofzooplankton [Ln (volume and animal numbers per 30 min. haul)+l] were investigated byPersons product-moment correlations (Anon. 1985).

Results

Distribution of the zooplankton CPUEs (Fig. 5-27)

The zooplankton CPUE-values, June-July 1956-1984, show not surprisingly largedistributional variations, however, some general trends are apparent. Comparing the "white"and "red" form of Aglantha digitale it appears that the "white" form becomes less abundantin the northem survey area around Disko Island whereas the "red" form is found only in thenorthem and westernmost sampies (Fig. 7 and Fig. 8). The copepods Calanus finmarchicusand C. hyperboreus show aUke distribution and the largest quantities are taken at thewesternmost stations and in the Disko Bay (Fig. 9 and Fig. 10). Euchaeta (Pareuchaeta)nonvegica is most abundant at the western and southern haul stations (Fig. 11). Comparisonsof the distributions of Limacina (Spiratella) lzelicüia and Limacina (Spiratella) retroversashow a clear trend of thc former being more northeinly distributcd than thc lattcr (Fig. 15 andFig. 16). Clione limacina shows no c1ear distributional trends (Fig. 17). Shrimp Iarvae arecaught on most of thc sampling locations with a trend of the Iargest catches being taken inthe Disko bay (Fig. 19). Crab larvae are most abundant in hauls riear the coast and in the

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Disko Bay (Fig. 20). LarVae of Atlantie eod, Greenlarid halibut, long rough dab, arid catfisheshavc beeri eaught in highcst numbers in hauls from seetion S1, S2 and S3 (Fig. 21, Fig. 22,Fig. 26 and Fig. 27). The highest CPUE-values of redfish larvae havc been observed on thcsouthern and southwestemmost haul stations (Fig. 23). Highest CPUE-values of sarideell<irvachave bceri obserVcd over thc so-ealled fishing banks dosest to thc shore arid in thc Disko Bay(Fig. 24). Capeliri larvae have been taken mainly in inshore hauls in the Godthäosfjord areaand just south of Disko island (Fig. 25).

Analysis Qf varianCe und associations

Mea~ sea temperat~r~ (MTEMP) and salinity (MSAL): ,.Tbc MTEMP and MSAL, shows large inter-annual.fluetuatioris (Fig. 28a,b). A tWo-wayANOyA with scetiori and year as dass variables showed ci significant e.ffe~t. of year ori~1TEMP (F=10.64, p<O.01), but no sigiIificant <:ifeet of sampling section (F=2.37, p=0.10).A two-way ANOVA with section and year as dass variables. showed a significant effeets ofboth year and seetion on MSAL (F=39.26, p<O.Ol and F=14.95, p<:O.Ol, respeetively). Scetiori1 gcnerelly had thc highest inean salinity followed by seetion 2 und 3. MTEMP showed thchighest association with MSAL (r=0.46, p<O.Ol, ri=540) followed by log. transforrned CPUEsof the "white" forni Aglantha digitale (r=0.32, p<O.Ol, n=186). MSAL showed the highestassociatiori with MTEMP (r=0.46, p<O.Ol, n=540) followed by log. transformed CPUEs ofGonatUs fabricii (r=0.28, p<O.Ol, n=306), and Euphausiaeea (r=0.27, p<O.Ol, n=312).

Plankton volume (PLVOL):A two-way ANOVA on the ranked PLVOL data with seetiori and year as dass variablesshowed a significant dfeet of year (F=6.98, p<O.01), and seetion (F=2L58, p<0~01) (Fig. 30).Tbc log. transformed PLVOL showed positive but weak associatioris to MTEMP (r=0.29,p<O.Ol, n=446) with a trend of higher PLVOL in thc latc 19505 and early 19605 with meantemperatures abovc 2° C. eompared to thc, 1970s and 1980s with more fltictuating mearitemperatures (I:'ig..30). The log. trarisfomled PLVOL showed the highest associations with log.transformed CPUES of Aglantha digitale (r=0.84, p<O.Ol, n=315), Limacinti sp~ (r=0.52,p<O.Ol, n=314), Gonatusfabricii (r=0.51, p<0.01, n=306), euphausids (r=0.50, p<:O.Ol, ri=314),etenophores (r=0.49, p<O.01, n=262), Calanus Izyperboreu.s (r=0.47, p<O.01, n=271) andnegative associaiions with sandeellarvae (r=-0.26, p<O.Ol, n=532) and crab laivae (r=-0.19,p<O.Ol, n=315).

AglantJui digitale (HAGLA="white" form and RAGLA="red" form):A two-way ANOVA \\ith section and year as dass variables showed a significant effeet Qfyear on the ra~ked HAGLA data (F=10.07, p<O.01), but not on thc ranked RAGLA data(F=1.35, p=0.17) (Fig. 29). For, both rankcd HAGLA and RAGLA data thc sampling scctionhad a significant effcet (F=10.29, p<O.Ol and F=19.30, p<0.01, respeetively). LOg. transformediIAGLA was posiÜvely associated with MTEMP (r=0.32, p<0.01, n=186), whereas log.RAGLA was negatively associated with MTEMP (r=-0.26, p<O.Ol, n=186). Tbe latter showsthat RAGLA is a eold water iridicator.

Caltinus jinniarchicus (indudes also C. glacialis) (CALFI):A two-way' ANOVA on thc ranked CALFI data with scction and year as dass variablesshO\vcd a significant cffcet of scetion (F=12.27, p<O.Ol) aridyear (F=7.11~ P<O.Oi)(Fig. 31and Fig. 32) LOg. CALFI showed thc highcst association with log. transformed CPUES of

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Chaetognatha (r=O.81, p<O.01, n=272), Calanus hyperboreus (r=O.73, p<O.01, n=273),Euchaeta (Pareuchaetiz) nonvegica (r=O.68, p<O.01, n=268), and Euphausiacca (r=O.67,p<O.01, n=272), but no significant association with MTEMP (r=-O.OO, p=O.96, n=230).

Calanus hyperboreus (CALHY):A two-way ANOVA on the ranked CALHY data with section and year as dass variablesshowed a significant effect of section (F=8.44, p<O.01) and year (F=9.73, p<O.01)(Fig. 31 andFig. 32) Log. CALHY showed thc highcst association with log. transformcd CPUEs ofCalanus jinmarchicus (r=O.73, p<O.01, n=273), Euphausiacea (r=O.69, p<O.01, n=272), andEuclzaeta (Pareuchaeta) nonvegica (r=O.67, p<O.01, n=272), but no significant associationwith MTEMP (r=-O.01, p=O.94, n=230).

Euchaeta (Pareuchaeta) nonvegica (EUCH):. . A two-way ANOVA on thc rankcd EUCH data with scction and ycar as dass variables

showcd a significant cffect of section (F=5.39, p<O.01) and year (F=6.07, p<O.01) (Fig. 32)Log. EUCH showed thc highest association with log. transformed CPUEs of Chactognatha •(r=O.68, p<O.01, n=277), Calanus jinmarclzicus (r=O.68, p<O.01, n=268), and Euphausiacca(r=O.60, p<O.01, n=276), but no significant association with MTEMP (r=-O.01, p=O.82,n=269).

Hypcriidac (HYPER):A two-way ANOVA on the ranked HYPER data with section and year as dass variablesshowcd a significant effcct of year (F=2.21, p<O.002), but not of section (F=3.10, p=O.05)(Fig.32). Log. HYPER showed the highest association with log. transformed CPUEs of Euchaeta(Pareuclzaeta) nonvegica (r=O.57, p<O.01, n=276), but no significant association with MTEMP(r=-O.09, p=O.12, n=269).

Euphausiacea (EUPH): .A two-way ANOVA on the ranked EUPH data with section and year as dass variablesshowcd a significant effect of section (F=9.28, p<O.01) and year (F=6.68, p=O.01)(Fig. 32).Log. EUPH showed thc highest association with log. transformed CPUEs of CalanusIzyperboreus (r=O.69, p<O.01, n=272), and Calanus jinmarclzicus (r=O.67, p<O.01, n=272). Log.EUPH showed a weak positive association with MTEMP (r=O.22, p<O.01j n=268).

Chaetognatha(CHAE):A two-way ANOVA on the ranked CHAE data with seetion and year as dass variablesshowed a significant effect of section (F=7.36, p<O.01) and year (F=4.41, p=O.Ol)(Fig. 32).Log. CHAE showed the highest association with log. transformed CPUEs of CalanusjinmarcJzicus (r=O.81, p<O.01, n=272), Euclzaeta (Pareuclzaeta) nonvegica (r=O.68, p<O.01,n=277), Calanus hyperboreus (r=O.67, p<O.Ol, n=272), and Euphausiacea (r=O.62, p<O.Ol,n=315), but no significant association with MTEMP (r=-O.Ol, p=O.86, n=269).

Limacina (Spiratella) Izelicina (LIMH):A two-way ANOVA on the ranked LIMH data with seetion and year as class variablesshowcd a significant effect of section (F=17.76, p<O.Ol) and ycar (F=6.93, p<O.Ol)(Fig. 33).Log. LIMH showed the highest association with log. transformed CPUES of Limacina(Spiratella) retroversa (r=O.63, p<O.Ol, n=304), Calanus Izyperboreus (r=O.59, p<O.01, n=264),and Hypcriidac (r=0.52, p<O.Ol, n=305), but no significant association with MTEMP (r=-O.06,

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p=0.35, n=258).

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Limacina (Spiratella) retroversa (LlMR):A two-way ANOVA on the ranked LIMR data with seetion arid year as dass variablesshowcd a significant cffcet of scetion (F=26.17, p<:O.Ol) arid year (F=7.22, p=O.Ol)(Fig. 33).LOg. LlMR showed thc highest association. with log. transformed CPUEs of Limacina(Spiratel/a) he/icina (r=0.63, p<O.Ol, n=304), Greenland . halibut larvae (ReirihardtiuShippog/ossoides) (r=0.60, p<O.01, n=304), juvenile squids (Gonatus fabricii) (r=0.60, p<O.Ol,n=294), "white" form Ag/antha digitale (r=0.52; p=<O.01~ n=204), ~md depth. to bottom(r=0.54, p<O.01, n=303). Log. LIMR showed a wcak positive association with MTEMP .(r=0.15, p=0.02, n=257).

Clione limacina (CLlO):A two-way ANOVA on the rrinked CLIO data with seetion and year aS daSs variables showeda signifieant cffeet of year (F=6.57, p<O.Ol) but not of seetion (F=0.91, p=0.40)(Fig. 33). Log.CLIO showed the highest association with log. transformcd CPUEs of Limqcina .. .(Spiratel/a) retroversa (r=0.50, p<O.Ol, n=304), and Limacina (Spiratella) heIicina (r=0.49,p<:O.Ol, n=305), but rio significant associatiori with MTEMP (r=0.09, p=0.16, n=269).

Gonatus fabricii juv., (GONA):A two-way ANOVA on the ranked GONA data with seetion and year as dass variablesshowed a signifieant effeet of seetion (F=10.00, p<O.Ol) arid yeal' (F=5.42, p<O.Ol)(Fig. 33).Log. GONA showed the highest association with log. transfoinied CPUEs of Limacina(Spiratel/a) retroversa (r=0.60, p<O.Ol, n=294), Greenland halibut larvae (Reinhardtiushippoglossoides) (r=0.56, p<o.oi, n=308), and depth to bottom (r=0.53, p<O.Ol, n=307). Log.GONA showed a weak positive association with MTEMP (r=0.25, p=O.01, n=260).

Shrimp (Pandalus sp.), mainly Panda/zis borealis (SHR):A two-way ANOVA on thc rankcd SHR data with scetion and year as dass,variables showeda sigriificant cffcet of seetion (F=3.59, p=0.03) and ycar (F;=3.88, p<O.Ol)(Fig. 33). Log. SHR ,showed thc highest association with log. transformed CPUEs of Ca/anus[ininarchicus (r=0.39,p<O.Ol, n=264), Ca/anus hyperboreus (r=0.38, p<O.Ol, n=264), ~md Euphausiaeea (r=0.37,p<O.Ol, n=307), but no significant association with MTEMP (r=O.OO, p=0.96, n=262).

Crab (Zoea stage). Braehytira: Hyas sp. ,and Chiofwecetes sp.(CRAB): .A two-way ANOVA on the ranked CRAB data with seetion arid year as dass variablesshowed a significant effeet of seetion (F=23.61, p<O.Ol) and year (F=5.05, p<O.Ol)(Fig. 33).Log. CRAB showed the highest association with log. transfo~ed CPUEs of sarideel larvae(Ammodytes sp.) (r=0.45, p<O.Ol, n=317), "white" forriiAglantha digitale (r=-0.29; p=<O.Ol,n=209), arid depth to bottom (r=-0.24, p<O.Ol, n=316). Log. CRAB showed rio significantassociation \vith MTEMP (r=-~.Ol, p=0:82, n=269).

Fish larvae:

Gadus inorhua (COD): 'A two-way ANOVA on the ranked eOD data with seeiion and year as dass variables showeda signifieant cffeet of seetion (F=12.49, p<O.Ol), and )'car (F=5.07, p<O.Ol) (Fig. 34 and Fig.

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35). Log. COD showed the highest association with log. transformed CPUEs of long roughdab larvae (Hippoglossiodes platessoides)(r=0.37, p=<O.01, n=540), "white" form Aglanthadigitale (r=0.37, p=<O.01, ri=209), rcdfish larvac (Sebastes sp.)(r=0.31, p=<O.Ol, n=S40),Grccnland halibut larvac (Reinhardtius hippoglossoides) (r=0.30, p<O.01, n=540), CalanusfinmarcJzicus (r=0.26, p<O.01, n=273), and Calanus hyperboreus (r=0.24, p<o.oi, n=273). Log.COD showcd a weak positive association with MTEMP (r=0.20, p=O.Ol, n=452).

Reinhardtius hippoglossoides (GHL):A two-way ANOVA on the rankcd GHL dab with seetion and year as dass variables showeda significant effcet of seetion (F=30.31, p<O.Ol), and year (F=2.5, p<O.Ol) (Fig. 35). Log.GHL showed the highest association with log. transformed CPUEs of Limacina (Spiratella)retroversa (r=0.60, p<O.Ol, n=304), juvenile squids (Gonatus jabricii) (r=0.56, p<O.Ol, n=308),"white" form Aglantha digitale (r=0.52, p=<O.01, n=209), lang rough dab larvae (Hippoglos­siodes platessoides)(r=0.51, p=<O.Ol, n=S40), plankton volume (r=0.46, p=<O.Ol, n=533),Limacina (Spiratella) heUcina (r=0.43, p<O.Ol, n=305),. eatfish larvae (Anarhichas sp.)(r=0.39,p<0.01, n=S40), and depth to bottom (r=0.36, p<O.01, n=538). Log. GHL showed a •weak positive association with MTEMP (r=0.13, p=0.006, n=452).

Sebastes sp. (RED): J

A two-way ANOVA on the ranked RED data with scetion and ycar as dass variables showcda significant cffcet of scetion (F=3.51, p=0.03), and ycar (F=5.16, p<O.01) (Fig. 35). Log.RED showcd thc highcst association with log. transformcd CPUEs of eod larvac (Gadusmorhua)(r=0.31, p<O.01, n=S40), Calanusfinmarchicus (r=0.30, p<O.01, n=273), Euphausiaeea(r=0.29, p<O.Ol, n=316), Limacina (Spiratella) retroversa (r=0.27, p<O.Ol, n=304), Euchaeta(Pareuchaeta) nonvegica(r=0.2S, p<O.Ol, n=277). Log. RED showcd no significant associ­ation with MTEMP (r=0.06, p=0.21, n=452).

Ammodytes sp. (SAND):A two-way ANOVA on the ranked SAND data with seetion and year. as dass variablesshowcd a significant cffcet of seetion (F=2S.44, p<O.Ol), and year (F=8.84, p<O.Ol) (Fig. 35).Log. SAND showcd the highcst. association with log., transformcd CPUEs of Crab (Zocastage)(r=0.45, p<O.Ol, n=317), dcpth to bottoin (r=-0.35, p<O.Ol, n=538), "white" form eAglantha digitale (r=-0.30, p<O.Ol, ri=209). juvenile squids (Gonatus jabricii) (r=-0.29, .p<O.Ol, n=308). Log SAND showcd a wcak ncgative association with MTEMP (r=-0.16,p=0.0006, n=452).

Hippoglossiodes platessoides (PLA):A two-way ANOVA on the ranked PLA data with seetion and ycar as dass variables showeda significant cffcet of scetion (F=48.74, p<O.Ol). and year (F=4.33, p<:O.Ol) (Fig. 35). Log.PLA showcd the highcst association with log. transformed CPUEs of Greenland halibut larvae(Reinlzardtius hippoglossoides) (r=0.51, p<O.Ol, n=540), juvcnile squids (Gonatus jabricii)(r=0.39, p<O.Ol, n=308), "white" form Aglantha digitale (r=0.39, p=<O.Ol, n=209), planktonvolumc (r=0.37, p=<O.01, n=533). and ead larvae (Gadus mo;hua) (r=0.37, p<O.Ol, n=540).Log. PLA showed a weak positive association with MTEMP (r=0.15, p=0.002, n=452).

Anarlziclzas sp. (CATF):A two-way ANOVA on the rankcd CATF data with scetion and year as dass variablesshowed a signifieant cffcet of seetion (F=12.64. p<O.Ol), and ycar (F=2.62, p<O.Ol) (Fig. 35).

9

Log. CATF showed the highest association with log. transfoimed CPUEs of Limacina(Spiratella) retroversa (r=OAO, p<0.01, n=304), Greenland halibut larVae (Re,inJuirdtiushippoglossoides) (r=0.39, p<0.01"n=540), juvenile squids (Goriatus fabTicii) (r=0.38, p<0.01,n=308), and Limacina., (Spiratella) hel~cina (r=0.35,' p<O.01; ri=305), but no significantassociation with MTEMP (r=0.08, p=0.08, n=452).

Discussiori

General rem3rks on tbe sampling

There is lrirge seasorial and inter-annual variability in the abundance and patchiiiess formationof zooplarikton off \Vest Greenland and this may causc difficulties in the interpretation of theresults of thc data comparisons between years. Howcvcr, by taking the same stations on aparticular section at approximately the same time each year and calculating the average densityfor that section one should get a measure of each year's conditions arid the most markedch~inges taking place (Astth6rsson et al. 1983). This has not completely been fulfilled dtiiing·tbe\Vest Greenland zooplanktori surveys. BCfore 1968 the stations sampled were situated 'further offshore in section si arid S3 as~ompared to the stations after 1968 (Fig. 4a,b - onlysome sclected years are presented). This may ,cause difficulties in thc interpretation of theresults of the data comparisons betWeen sampling years for, soine of thc species with highCPUEs far offshore e.g. Calanus finmarchicus and, C. hyperbore'us (Fig. 9 and Fig. 10), butnot for others e.g. nortberri shrimp arid Greenland halibut (Fig. 19 arid Fig. 22).

Trends in species cOIl1positjon and productjvity

There was a decreasing trend in both the CPUEs of plankton volume ~d copcpods as weIlas a positive association to sea temperature measurements from thelate 19505 and early 1960sio tbe 1970s (Fig. 30 and Fig. 31). These trends may be indicative for a deciease inzooplankton produciivity and changes in thc ecosystem food-web structure in thc same timeperiod. ,Similar dccreasing trend in CPUEs. of plankton volume and especially Calanusfinmarchicus have also been observed in riorthern Icelaridie waters in spring from the early1960s .to 1970 (Astth6rsson et al. 1983, Stefansson and Jakohsson 1989). According toAstth6rsSon et al. (l.e.) a reduced iriflux of Atlantcie water to thc areas llorth of Icelandprobably delayed the onset of the spring primary production and thus the zooplanktoriproduction. The same may have happcnd off \Vest Greenland duririg approxirriately thc sametinie periocl.

Wami and cold ,vater inclicators

Boreal speeies (Calanus finmarc/zicus, Euchaeta (Pareuchaeta) nonvegica, Limacinaretrol1ersa) and Arctie forms (Ca/anus hyperboreus, C. glacialis, Metridia longa, Limacinahelicina) occur in tbc Davis Strait zooplankton dunng tbc greater part of tbc year (Pavshtiks1968, 1972). ArcHe forms enter thc Davis Strait with thc cold Briffin Larid Current (LabradorCurreIlt), and with the Bast Greenland Current (Fig. 2). Thc boreal species oecur throughoutthe strait together with thc cold water forms from the Arctie; ihey overwiritcr in thc deep partof the strait (Pavshtiks l.e.)~ In t~c daia presented in this paper no .. reliablc diseriiniriationbehveen C. finmarchicus and C. glclcialis have been made, therefore, the C. finmarchicus data

10

may include an unknown number of C. giacialis. According to Pavshtiks (I.c.) C. jinmarchicusand C. glacialis form the bulk of the Davis Strait zooplankton during the greater part of theyear and it is assumcd that sevcral populations of Calanus exist and spawn in this area.Howevcr, the most abundant C. finmarchicus population is brought into thc Davis Strait withthe Irmingcr Current (Atlantic water) during spring (Pavshtiks I.c.). Spawning of C.jinmarclzicus takes place from May to July both in thc Atlantic water of thc Irminger currentand in the \Vest Greenland coastal waters whereas C. glacialis is associated with cold waterin the Baffin Land Current and spawns iri the coastal waters of Canada (Pavshtiks l.c.).Therefore, the C. finmarchicus data in this paper from section SI-S3 are assumed to includeonly a relative1y small number of C. glacialis.

The "white" form ofAglantha occurs almost everywhere in the Davis Strait, but in decreasingnumbers the colder the water, and it is replaced by the "red" form in arctic waters (Bainbridgeand Corlett 1968). According to Smidt (1979) Limacina (Spiratella) retroversa is a warm­water species found only off southem \Vest Greenland whereas Limacina (Spiratella) helicinais a cold water species found further to the north and with similar distribution as ariother cold •water species Clione limacina. These findings were also indicated by the prcsent study anddata analysis.

Monitoring ycar-class strcngth of fishes [rom larval surveys

The year-class strength (given at number at age 3) of Atlantic cod off \Vest Greenland hasbeen found to be positively correlated with the mean water temperature (surface to 45 m overFylla Bank in June) duririg the larval phase (Hermann et al. 1965, Hansen and Buch 1986).Hansen and Buch (I.c.) also found ycar-class strength to be positive1y correlated with larvalabundance (mean number of cod larvae caught per 30 min. stramin net haui). However, theyconclude that although temperature and larval abundance off \Vest Greenland provide someinformation on the size of cod year-classes better estimates of recruitment may be obtairiedfrom young fish surveys. In the present study we found a very weak positive associatioribetween the mean number of cod laivae caught and the mean sea temperature (Fig. 34). Thesea temperature, the drift of larvae by surface currcnts, and the stability of the water masses(hydrographic fronts) are important oceanographic factors affecting recruitrrient to fish andshellfish stocks in West Greenland waters as in waters elsewhere (Horsted et al. 1978, Buchet ai. 1994, Stein and Llort 1994, Tande et ai. 1994, Rassmussen and Tande 1995, Munk etai. in prcss, Sinclair and Page 1995).

Recruitment success for fish and shellfish larvae depend on mainly two (controlling) biologicalprocesses - predation and food availability (the right food in sufficient amount at the righttime). An assessment of the possible intensity of predation on fish larvae is difficult since Httleis known of the relative importance of the various carnivorous species as predatörs of youngfish (Bainbridge and Corlett 1968). Coclenterates, especially Aglanta, together withctenophores, chaetognaths, and siphonophores are serious predators of fish larvae (Frascr1961). Among other forms kriown to be voracious feeders on a wide vadety of zooplanktonare the hyperiid amphipods, adult Meganyctiphanes, Euchaeta, Tomopteris, and smallcephalopods (Bainbridge and Corlett I.c.). An other common camivorous specics in the NorthAtlantic is Clione but this gastropod may be ci selective feeder in Spiratella (Bainbridge andCorlctt 1968, after Bigclow 1924). Thc latter phcnomcnon is also indicated in the prcscntstudy by high associations between Clione limacina and both Limacina (Spiratella) retroversa

11

and Limacina (Spiratella) helicina. The fish larvae show both associations with potential foodspccies and prcdator species e.g. Greenland halibut larvae showed positive associations withLimacina (Spiratella) retroversa, small squids (Gonatus fabricii), "white" formAglanthadigitale, long rough dab larvae (Hippoglossiodes platessoides), and Limacina (Spiratella)helicina. Cod, redfish, Greenland halibut and long rough dao larvae showed relativdy highassociations with Calanus ftnmarchicus and this prey species may be of crucial importancefor the larvae survival (Bainbridge and McKay 1968). However, there is a need to establishwhether inter-annual variability in fish stock recruitment depends directly upon variations ofCcila;züs produetivity (Miller 1995). High associations between 'predators and their prey inaynot be expcctcd to show up as high correlation cocfficients of CPUE survey datri, especiallynot in cascs wcre the predators very Cffectively are grazing their prey. Similarly, thecorrclation coefficients of sea tcmperature, salinity and zooplankton CPUE data can bedifficult to interpret because the data are integrated over e.g. hydrographical fronts and patchy .zooplankton distributions.

Attempts to monitor the strength of new year-classes of fish and shellfish already in tbe larvalphase are known from many areas, however, with moderate success due to the many and

, . 0

highly fluctuating variables (Cushing 1990, Adlandsvik and Sundby 1994, Sundby et aI. 1994,Sinclair and Page 1995). According to Sinclair and Page (1995) thcre is a need for increasedconsensus by the scientific community on which of the competirig hypotheses on populationregulation bcst capture the critical mechanisms. Prediction of the impacts of climate changeare dependent upon which hypothisis or hypotheses best capturc thc realistic dynamics for agiven population and time (Sinclair and Page l.c.).

In 1982, the relatively high mean number of cod larvae caught in the stramin net h~lUls on the\Vest Greenland sampling sections SI-S3 indicated a good prospect for a large codrecruitment, however, the 1982 year-class becaine poor. It has been assumcd that the failureof thc 1982 year-class mainly was caused by the extremely low winter temperatures in WestGreenland during 1982-1984 (Buch 1990). Thc failure of thc 1982 ycar-class and the inabilityto relate the catches of cod larvae to subsequent recruitment were the main reasoris that putthe end to the time-series and zooplankton collections off \Vest Greenland in 1985.

We hope the present pap~r will stimulate and add direction to future studies on pelagicecology, and critical recruitmerit mechanisms for fish and shellfish stocks in West Greenlandmarine waters.

Acknowledgement

A large part of the work compiling the zooplankton database was made by E.L.B. Smidt andH. Hovgard. Thanks to thc ICES Secretariat and J.R. Nielsen (Danish Fisheries ResearchInstitute) for help with the hydrographical data. Thanks also to S.Aa. Horsted for a criticalreview of an earlier draft of this paper. .

-'.

12

References

Anon. 1985. SAS User's Guide: Basics/Statistics Version 5. Edition. SAS Institute Inc.,Raleigh, North Carolina 1985.

Anon. 1994. Report of the North-westem \Vorking Group. ICES C.M. 1994/Assess:19.Anon. 1995. NAFO Scientific Council Reports 1994. 234 pp.Astth6rsson, O.S., Hallgrimsson, 1. and J6nsson, G.S. 1983. Variations in zooplankton

densities in Icelandic waters in spring during the years 1961-1982. RitFiskideildar 7,2:73-113.

Bainbridge, V and Corlett, J. 1968. The zooplankton of the NORWESTLANT surveys. Spee.Publ. Int. Comm. Northwest Atl..Fish. 7 (1):101-122.

Bainbridge, V. and McKay, BJ. 1968. The feeding of cod and redfish larvae. Spec. Publ. Int.Comm. Northwest Atl. Fish. 7 (1):187-217.

Bigelow, H.B. 1924. Plankton of the offshore waters of the Gulf of Maine. Bull. Bur. Fish.,\Vash., 40(pt. 2), 509 p.

Buch, E. 1984. Variations in temperature and salinity of West Greenland waters, 1970-82.NAFO Sei. Coun. Studies, 7: 39-43.

Buch, E. 1990. A monograph on the physical environment of Greenland waters. GreenlandFisheries Research Institute, 405 pp.

Buch, E. 1993. The North Atlantic watercomponent of the West Greenland current. ICES CM1993/C:20.

Buch, E., Horsted, S.Aa. and Hovgärd, H. 1994. Fluctuations in the occurrence of eod inGreenland waters and their possible causes.-ICES mar. Sei. Symp.,198:158-174. .

Fraser, J.H. 1961. The oceanic and bathypelagic plankton of the Northeast Atlantic. Mar. Res.Seot., 4: 40 p.

Hansen, H. and Buch, E. 1986. Prediction of year-class strength of Atlantie cod (Gadusmorlzua) off West Greenland. NAFO Sci. Coun. Studies, 10: 7-11.

Hermann, F, Hansen, P.M. and Horsted, S.A. 1965. The effect of temperature and currents onthe distribution and survival of cod larvae at \Vest Greenland. -Spec. PubLint. Comm. Northw. Atl. Fish. 6: 389-395.

Horsted, S.A. 1994. A review with some proposals for amendments of the catch statistics forthc eod fishcrics in Greenland watcrs sinee 1911. NAFO SCR Doeument No.38, serial No. N2407. 33 pp.

Horsted, S.A., Johansen, P. and Smidt, E. 1978. On the possiblc drift of shrimp larvae in theDavis Strait. ICNAF(NAFO) Res. Doe. 78fXI/93, Serial No. 5309. 13 pp.

Hovgärd, H. and \Vieland, K in press. Spawning and larval drift of eod (Gadus morhua) inGreenland waters. J. Northw. Atl. Fish. Sci.

Jorgenscn, KF., Jensen, K, Andersen, O.N. and Hansen, L.M. 1978a. A survey ofzooplankton in thc upper 100 m at drilling site Ikermiut I (66°56'N,56°35'\V) from July 20 to September 8, 1977. Report for Chevron PetroleumCompany of Greenland by BIOKON Aps.

Jorgcnsen, K.F., Jensen, K., Andersen, O.N. and Pctcrsen, G.P. 1978b. A survey ofzooplankton in the uppcr 100 m at drilling site Nukik I & 11 (65°38'N,54°46'\V) from August 2 to 29, 1977. Rcport for Mobil ExplorationGreenland by BIOKON Aps.

Lee, A.J. 1968. NOR\VESTLANT Surveys: Physical Oceanography. Spee. Publ. Int.

•

13

Comm. Northwest Atl. Fish. 7 (1):31-54. .Miller, C. 1995. TransAtlantie studies of Calanus (TASC) working group.

V.S. GLOBEC NEWS No. 8 -- March 1995.Munk, P., Larsson, P.O., Oanielsen, 0., and Moksness, E. in press. Larval and juvenile eod

(Gadus morhua) eoncentrated in the highly produetive areas of a shelf breakfront. Mar. Ecol. Prog. Sero

Pavshtiks, E.A. 1968. The influence of currents upon seasonal fluctations in the plankton ofthe Davis Strait. Sarsia 34: 383-392.

Pavshtiks, E.A. 1972. Biological scasons in thc zooplankton of Davis Strait. Akad. Nauk.SSSR, Zool. Inst., Explor. Mar. Fauna. 12(20). Israel Prog. Sci. Transl.,Jerusalem 1975: 200-247.

Pederscn, S.A. 1994. Multispccics interactions on the offshore West Greenland shrimpgrounds. ICES C.M. 1994/P:2.

Rasmussen, T. and Tandc, K. 1995. Temperature-dependent dcvelopment, growth andmortality in larvae of the deep-water prawn Pandalus borealis reared in thelaboratory. Mar. Ecol. Prog. Sero Vol. 118:149-157.

SincIair, M. and Page, F. 1995. Cod fishery collapses and North Atlantie GLOBEC.V.S. GLOBEC NEWS No. 8 -- March 1995.

Smidt, E.L.B. 1979. Annual eycles of primary praduction and of zooplankton at SouthwestGreenland. Meddelelscr om Gronland, Bioscience No. 1. 53 pp.

Stefansson, V. and Jakobsson, J. 1989. Occanographical variations inthe Iccland Sea and theirimpact on biological eonditions - a brief review. In Proeeedings of the sixth .conference of the cornite arctique international 13-15 May 1985,427-455.Edited by Louis Rey and Vera Alexander. E.J. BrilI. Leiden, New York,Kobenhavn, Köln.

Stein, M. and LIort, J. 1994~ Stability of water masses - impact on eod reeruitment off WestGreenland? NAFO SCR Doe. 94/67, Serial No. N2445. 13 pp .

Sundby, S., Ellertsen, B. and Fossum, P. 1994. Encountcr rates between first-feeding eodlarvae and their prey during moderate to strang turbulent mixing.-ICES mareScLSymp., 198:398-405.

Tande, KS., Rasmussen, .T., and Pedersen, G. 1994. Thermal Inerease Enhaneement: apossible link between recruitment and cIimate in high latitude environ­ments.-lCES mar. Sei. Symp., 198:502-509.

Alandsvik, B. and Sundby, S. 1994. Modelling the transport of cod larvae from the Lofotenarea.-lCES mar. Sci. Symp., 198:379-392.

Table 1.

14

List of species in the West Greenland zooplanktonsampies. X - indicate selected group or species indudedin the database, abbreviations given in brackets.

X Ctenophora (CTEN):Beroe cucumisMertensia ovum

Hydromedusae :X Aglantha digitale (HAGLA="white" form and RAGIA="red"

form)(red individuals are cold water indicators)Sarsia tubulosaSarsia princepsEuphysa sp.Bougainvillia superciliarisRatkea ocopunctataCatablema vesicariumCatablema multicirrataHalitholus cirratusLaodicea undulataStaurophora mertensiPtychogena lacteaHalopsis ocellataOblia sp.Aeginopsis laurentii

Scyphomedusae: (Discarded, not ind. in plankton volume)Aurelia auritaAurelia limbataCyanea capillataPeriphylla periphylla

Siphonophora :Physophora hydrostaticaDimophyes arctica

PolychaetaTomopteris spp.Autolytus sp.

OstracodaConcoecia elegansConcoecia obtusata

Table 1.

X CopepodaXXX

15

continued.

(COP):Calanus hyperboreus (cold water indicator)(CALHY)Calanus finmarchicus (include also C. glacialis)(CALFI)Euchaeta (Pareuchaeta) norwegica(EUCH)Other species in total copepoda:Pleuromamma robustaEucalanus elongatusRhincalanus nastutusEuchirella rostrataCentropages sp.Metridia longaHeterorhabdus norwegicus

X Hyperiidae (HYPER):Parathemisto abyssorum .Parathemisto gadicaudiParathemisto libellulaHyperoche medusarumHyperia galbaHyperia medusarum

Gammaridea :Gammarus willdtald and others

X Euphausiacea (EUPH):Thysanoessa longicaudataThysanoessa inermisThysanoessa raschiiMeganyctiphanes norwegica

MysidaceaBoreomysis nobilis

PteropodaXXX

Limacina (Spiratella) retroversa (LlMR)Limacina (Spiratella) helicina (cold water indicator)(LIMH)Clione limacina (eLlO)

X Chaetognatha (CHAE):Eukrohnia hamataSagitta elegansSagitta maxima

Table 1.

Copelata

continued.

Oikopleura spp.Fritillaria borealis

16

Pelagic bottom invertebrate laryae: Only bigger larvae were taken with the stramin net.Smaller larvae were taken with microplankton and Hensen nets.

Decapod crustacean laryae:X Shrimp (Pandalus sp.), mainly Pandalus borealis (SHR).

Other shrimp larvae: Spirontocaris sp., Sabinea septemcarinata,and Pontophilus norvegicus.

X

Gastropoda

Crab (Zoea stage). Brachyura: Hyas sp. and Chionoecetes sp.(CRAB) .

Veluntina veluntina

Cephalopoda :X Gonatus fabricii juv. (GONA)

Fish egg and laryae:X Gadus morhua (COD)X Anarhichas sp. (CATE)X Sebastes sp. (RED)X Reinhardtius hippoglossoides (GHL)X Ammodytes sp. (SAND)X Hippoglossiodes platessoides (PLA)X Mallotus villosus (CAP)

Table 2.

17

The number (station sampled) of temperature and zooplanktonobservations by section and year.

MTEMP M8AL PLVOL HAGLA RAGLA CALFI CALHY

8ection 8ection 8ection 8ection 8ection 8ection 8ection

81 82 83 81 82 83 81 82 83 81 82 83 81 82 83 81 82 83 81 82 83

N N N N N N N N' N N N N N N N N N N N N N

YEAR56 3 4 7 '3 4 7 3 5 8 3 5 5 3 5 5 3 5 5 3 5 557 4 4 6 4 4 6 5 5 7 2 4 2 2 4 2 2 4 3 2 4 358 4 5 7 4 5 7 4 7 8 2 3 4 2 3 4 2 3 4 2 3 459 5 5 7 5 5 6 5 5 960 2 2 2 261 6 7 5 6 7 5 6 ,7 6 6 7 6 6 7 6 6 7 6 6 7 662 1 3 3 163 6 20 21 6 20 21 12 33 33 12 26 15 12 26 1564 5 7 10 5 7 10 6 9 11 6 8 8 6 8 8 6 9 8 6 9 866 5 7 7 5 7 7 7 10 8 6 9 8 6 9 8 7 9 8 7 9 868 4 5 8 4 5 8 6 7 ,969 6 8 6 6 8 6 6 8 670 5 5 15 5 5 15 6 7 16 4 4 12 1271 8 8 14 8 8 14 8 9 14 4 4 10 1072 6 4 8 6 4 8 7 7 10 7 6 5 7 6 5 7 7 10 7 7 1073 5 5 5 5 5 5 5 5 5 1 1 4 474 5 5 5 5 5 5 7 6 5 4 4 3 375 6 6 4 6 6 4 6 6 4 4 476 6 6 5 6 6 5 6 6 5 5 5 1 5 1 577 4 6 4 4 6 4 4 6 5 4 4 4 478 6 6 5 5 5 5 6 6 5 5 6 5 5 6 5 6 6 5 6 6 579 7 6 6 7 6 6 7 6 5 7 6 5 7 6 5 7 6 580 3 4 5 3 4 5 5 5 5 5 5 5 5 5 581 5 4 5 5 4 5 5 5 5 5 5 5 5 5 582 2 5 4 2 5 4 2 5 5 2 5 5 2 5 5 4 5 4 583 3 4 3 4 4 4 2 1 2 1 4 4 4 484 5 3 4 5 3 4 5 5 4

(CONTlNUED)

---------

Table 2. continued.

18

EUCH HYPER EUPH CHAE LlMR LlMH CLlO

8ection 8ection 8ection 8ection 8ection 8ection 8ection

S1 82 83 81 82 83 81 82 83 81 S2 83 81 82 83 S1 82 83 S1 S2 S3

N N N N N N N N N N N N N N N N N N N N N

YEAR56 3 5 2 3 5 5 3 5 5 3 5 5 3 5 5 3 5 5 3 5 557 2 4 3 2 4 3 2 4 3 2 4 3 2 4 3 2 4 3 2 4 358 2 3 4 2 3 4 2 3 4 2 3 4 2 3 3 2 3 4 2 3 4596061 6 7 5 6 7 6 6 7 6 6 7 6 5 7 6 5 7 6 6 7 66263 12 26 15 12 26 15 12 26 15 12 26 15 12 26 15 12 26 15 12 26 1564 6 9 8 6 9 8 6 '9 8 6 9 8 6 9 8 6 9 8 6 9 866 7 8 8 7 9 8 7 8 8 7 9 8 7 9 8 7 9 8 7 9 8686970 14 14 14 14 14 14 1471 10 10 10 10 10 10 1072 7 7 10 7 7 10 7 7 10 7 7 10 7 7 10 7 7 10 7 7 1073 5 5 5 5 5 5 574 5 5 5 5 5 5 575 5 5 5 5 3 3 576 1 5 1 5 1 5 1 5 1 2 1 2 1 577 4 4 3 5 5 3 5 5 3 5 5 2 3 2 2 3 2 3 5 578 6 6 5 6 6 5 6 6 5 6 6 5 6 6 5 6 6 5 6 6 579 7 6 5 7 6 5 7 6 5 7 6 5 7 6 5 7 6 5 7 6 580 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 l::

81 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 582 2 5 5 2 5 5 2 5 5 2 5 5 2 5 5 2 5 5 2 5 583 4 4 4 4 4 4 4 4 4 4 4 4 4 484

(CONTlNUED)

Table 2. continued.

19

FishGONA 5HR CRAB larvae

5ection 5ection 5ection 5ection

51 52 53 51 52 53 51 52 53 51 52 53

N N N N N N N N N N N N

YEAR56 3 5 5 3 5 5 3 5 5 3 5 857 2 4 3 2 4 3 2 4 3 5 5 758 2 3 4 2 3 4 2 3 4 4 7 859 5 6 960 2 2 261 6 7 6 6 7 6 6 7 6 6 7 662 1 363 12 26 15 12 26 15 12 26 15 13 33 3464 6 9 8 6 9 8 6 9 8 6 9 1166 7 10 8 7 9 8 7 9 8 7 10 868 6 7 969 6 8 670 14 14 14 6 7 1671 10 10 8 9 1472 7 7 10 7 7 10 7 7 10 7 7 1073 5 5 5 5 5 574 5 5 5 7 6 575 5 5 5 6 6 576 1 5 1 5 1 5 6 6 577 3 5 5 3 5 5 3 5 5 4 6 578 6 6 5 6 6 5 6 6 5 6 6 579 7 6 5 7 6 5 7 6 5 7 6 680 5 5 5 5 5 5 5 5 5 5 5 581 5 5 5 5 5 5 5 5 5 5 5 582 2 5 5 2 5 5 2 5 5 2 5 583 4 4 4 4 4 484 5 5 4

20

500000

450000

400000

350000

300000

250000

200000

150000

100000

50000

o

-f- -

--r-

r- f-

- r-

f-

_r-

-

f-r-i-r0-

hYear

Fig.1. Nominal eateh in tons of Atlantic eod in Subarea 1, 1956-1994(Data from Horstcd 1994).

_0 Baffin Land and East Greenland West Greenland Current ••••Currents Subarctic Mixed Current .-.)

C' ••••• lrminger Current

73°

F· ..,19..... The currents around Greenland, and the locations of the threehydrographie seetions off West Greenland (From Buch 1984)(simplified after Kiicrich 1939, Hermann and Thomsen 1946).

Map showing the major physiographie features (depths in m) off WestGreenland :ll1d loeations of the thrcc scetions 51, 52 and 53.

21

GREENLAND

52(II~

t'1.,,

./

70~

Fig.3.

oo

000

195

196

22

Fig. 4a. Sampling position of hydrography and zooplankton data in June-Julyby section and year.

23

197

198 1982 o

Fig. 4b. Sampling position of hydrography and zooplankton data in lune-lulyby sectioll and year.

24

ro©o

o

o

Plankton volume (30 min. hau)June-July 1956-1984

g5000 10 9300 (45)

500 10 5000 (509)o 50 10 500 (461)o t 10 50 (147)+ 0 (3) o

o 0 0

ocY

Fig.5. Plankton volume in ml per 30 min. stramin net haul a11 samples inJune-July, 1956-1984, off West Greenland. Frequency of occurrencein brackets.

~--------------

o

e

©

..

©o

e

CtenoforesJune-July 1956-1984

()3 (126)

02 (181)01 (136)+ 0 (85)

25

@

+ 0 eo ©

o

Fig.6. Numbcr of Ctenoforcs per 30 min. stramin net haul a11 samples inJune-July, 1956-1984, off West Greenland. Frequency of occurrencein brackets.

26

o

©

White AglanthaJune-July 1956-1984

85000 1016500 (51)

1000 10 5000 (98) :o 50 10 1000 (179)o 110 50 (99)+ 0 (23)

c .g

o

o

J

J

Fig.7. Number of white AglantJza digitale per 30 min. stramin net haul allsamples in June-July, 1956-1984, off West Greenland. Frequency ofoccurrence in brackets. Only stations sorted for red and white individ-

UJls are presented.

27

o;.~(§) @O@....,

o

+

o®

Red AglanthaJune-Ju~I956-1984

81000104131 (21)

100 to 1000 (74)

o 20 to 100 (481o 110 20 (5i)+ 0 (250)

+

+ +

+

Fig.8. Number of red Aglantha digitale per 30 min. stramin net haul allsamp!es in lune-lu!y, 1956-1984, off \Vest Greenland. Frequenc)' ofoccurrence in brackets. On!)' stations sorted for red and white individ­uals are presented.

28

+

• l,'.

'.o 0ooo

+

o

o

o

o

o

o

oe

io

oo

@

CaJanus IinmarchiasJune-July 1956-1984

~500000101070000 (4)

50000 to 500000 (14)

5000 to 50000 (47)

o 500 to 5000 (59)o 110 500 (169)+ 0 (226)

Fig.9. Number of Ca/anus finmarcllieus (C. g/acialis) per 30 min. stramin nethaul alt samples in June-July, 1956-1984, off West Greenland.Frequcncy of occurrence in brackets.

29

@GD ,~

Cl)00 + 0

0

~ i ci

©~00

00 +

+

0

Calanus hyperboreus@) 0

June-July 1956-1984 0

~"""'."""" '"0 0

50000 to 500000 (31)

5000 to 50000 (48) 00 500 to 5000 (67) o 00 Ho 500 (197) 0

+ 0 (175) 0 0

0 0+

Fig. 10. Number cf Ca/anus hyperboreus per 30 min. stramin net haul allsamples in lune-luly, 1956-1984, off West Greenland. Frequency ofoccurrence in brackets.

30

o

@o

o + +o

o

o

+e + ..

oo +

o

+ +

+ ++

+

,.+e 4- *+ ...

+ ++~

o \

+

+

~o

e

EuchaetaJune-July 1956-1984

810000 10 22000 (12)

5000 10 10000 (14)

o 100 10 5000 (74)o 110 100 (110)+ 0 (311)

Fig. 11. Number of Euchaeta (Pareuchaeta) norwegica per 30 min. stramin nethaul a11 samples in June-July, 1956-1984, off West Greenland.Frequency of occurrence in brackets.

31

o @o

o

o

HypenldsJune-July 1956-1984

~20000 10 49650 (3)

5000 10 20000 (12)

1000 10 5000 (66)

300 10 1000 (49)o 1 10 300 (440).,. 0 to 0 (47)

o

o

J

Fig. 12. Number of hyperiids per 30 min. stramin net haul all samples in June­July, 1956-1984, off West Greenland. Frequency of occurrence in

brackets.

32

-'

o

0 +

0

+

EIl

e~d) eOoo\il+

.EuphausidsJune-July 1956-1984

81oooot091800 (161

1000 to 10000 (31)

o 100 to 1000 (60)o 1 to 100 (261)+ 0 (223)

Fig. 13. Number of euphausids per 30 min. stramin net haul all sampies inJune-July, 1956-1984, off West Greenland. Frequency of occurrencein brackcts.

ChaetognathaJunEhJuly 1950-1984

8SOOO 10 18600 (8)

500 10 5000 (72)

o 50 to SOO (90)o 1 to SO (179)+ 0 (258)

o

33

Fig. 14. Number oi Chaetognatha per 30 min. stramin net haul all sampies inJune-July) 1956-1984) off West Greenland. Frequcncy of occurrencein brackets.

34

+

o 0 0o 0

+

+

+

©

,I +

r+

@

I +/e'-'

+ +

'?

~~(~

oe

0 e

+o 0

Umacina (Spiratella) helicinaJune-July 1956-1984

()5000 to 2Z32O (14)

Ö 500 10 5000 (86)

o 50 10 500 (96)o 110 50 (103)+ 0 (301)

I 0

Fig. 15. Number of Limacilla (Spiratella) Izelicina per 30 min. stramin net haulall samp!es in lune-lu!)', 1956-1984, off 'West Green!and. Frequencyof occurrence in brackets.

Fig. 16. Number of Limacina (Spiratella) retroversa per 30 min. stramin nethaul a11 samples in June-July, 1956-1984, off West Greenland.Frequency of occurrence in brackcts.

e

>.

oo

o

o

35

®

© ~o@ I 0 0

Umacina (Spiratella) retreNersaJune-July 1958-1984

850001031600 (23)

500 10 5000 (102)o 5010 500 (117)o 1 10 50 (134)+ 0 (224)

Cliane limacinaJune-July 1956-1984

n2000 10 4040 (1)

o 200 10 2000 (31)o 20 10 200 (221)o I 10 20 (306)+ 0 (57) I

I

oo@o ~

36

o

00 0 ,

0

0 0

00

0

Fig. 17. Number of CLione limacirza per 30 min. stramin net haul all samples inJune-July, 1956-1984, off West Greenland. Frequency of occurrence

in brackcts.

37

+

+

o

o

o

o

+o +

oGonatus fabriciiJun~1956-1984

nSO tc 224 (24)

010:0 50 (102)o 1:0 10 (170)+ 0 (313)

~

©

+ ~

Fig. 18. Number of juvenile Gonatus fabricii per 30 min. stramin net haul allsampies in Junc-July, 1956-1984, off West Greenland. Frequency ofoccurrencc in brackets.

.-------------------- ---- ---------

38

o

o

o

o

o

e e e

0 00

0

0cPC> eOa:>g

l+

II

I

I•

0(3l

-I

e -+e

o

o

Northem shrimp laNaeJune-July 1958-1984

850001014700 (3)

1000 to 5000 (23)o 50 to 1000 (182)o 110 50 (281)+ 0 (117)

Fig. 19. Number of shrimp larvae (mainly Northem shrimp) per 30 min. straminnet haul all sampies in June-July, 1956-1984, off West Greenland.Frequency of occurrcncc in brackcts.

Fig. 20. Number of crab larvae per 30 min. stramin net hau1 a11 sampIes inJune-July, 1956-1984, off West Greenland. Frequency of occurrencein brackets.

l

l

l

o+

oo +

o

+

~+ +

EB

"-

e

~

oo

®o

'~6,~'- ~iSlJ~)

39

+

+ 0

o

+ el

Crab larvae (zoea stage)June-July 1956-1984

()5ooo 10 52000 (17)

Ö 500 10 5000 (47)o 1010 500 (190)o 110 10 (13:3)+ 0 (230)

40

+

@

+

Atlantic cod larvaeJune-July 1956-1984

8200 to 1890 (5)

2Oto 200 (41)o 510 20 (116)o 1 to 5 (357)+ 0 (696)

s+ + +

~0

...

e+a il4 e-"'~~0

+

+

0

ee

...

...+ 0

......... 0

+

++

Fig. 21. Number of Atlantie eod larvae per 30 min. stramin net haul all samplesin June-July, 1956-1984, off West Greenland. Frequency of occurrencein brackets.

-------1

41

...+ ...

...+

++ ~

o

o

+

+

++

Greenland haJibut larvaeJune-JuJy 1956-1984

810010416 (14)

5010100 (18)o 1010 50 (130)o 1 10 10 (337)+ 0 (716)

+

F· ..,..,19........ Number of Greenland halibut larvae per 30 min. stramin net haul allsampies in June-July, 1956-1984, off West Greenland. Frequency ofoccurrence in brackets.

42

l

+

+

Redfish larvaeJune-July 1956-1984

()SOIO 182 (10)

Öl010 50 (36)o 310 10 (46)o 1 to 3 (61)+ 0 (10621

+.,. +

+

.+ .:F++

...

+

++

e

+ + +

o

Fig. 23. Number of redfish larvae (Sebastes sp.) per 30 min. stramin net haulall sampies in June-July, 1956-1984, off 'West Greenland. Frequencyof occurrencc in brackets.

43

~~ eo

+

SandeeilaNaeJune-JWy1956-1984

81000 to 8120 (12)

100 to 1000 (44lo 1010 100 (131)o 110 10 (279)+ 0 (749) I

+

+

++ +

++

... ...

Fig. 24. Number of sandeel larvac per 30 min. stramin net haul all sampies inJune-luly, 1956-1984, off \Vest Greenland. Frequency of occurrencein brackcts.

+...~ ... l

...

...

Capelin larvaeJune-JuIy 1956-1984

8100 10 730 (5)

1010100 (14)o 310 10 (15)o 110 3 (19)... 0 (1153)

... + +

-I-

-I-

...

...

-I-

44

...

+ + + .+ •+

... +... I...

Fig.25. Number of capelin larvae per 30 min. stramin net haul all samplesin June-July, 1956-1984, off West Greenland. Frequency of occur­rcnce in brackcts.

+

+

o

o ~CO +

+

Leng rough dab (aNaeJune-JUIy 1956-1984

()100 10 296 (81

Ö so 10100 (20)

o 510 50 (1731o 110 5 (221)+ 0 (781)

+

e+

e

45

++

+ + + ++

+

+

Fig. 26. Number of long rough dab larvae per 30 min. stramin net haul allsamples in June-July, 1956-1984, off West Greenland. Frequency ofoccurrence in brackets.

46

1-

-t-

+

e

+

Catfish larvaeJune--JUIy 1956-1984

0151045 (2)

o 51020 (19)o 1 to 5 (2551+ 0 (939)

+

...

...- +

o+ + +

+.+

+

Fig. 27. Number of catfish larvae per 30 min. stramin net haul aU samples inJune-July. 1956-1984. off West Greenland. Frequency of occurrencein brackets.

0.50

47

5.00

4.50 a4.00

""":' ,U

3.50L.- I

u...~ 3.00(;j

0...u

2.500.E !~ 2.00

.., :c: ·.C': · .u

1.50::E1.00 ,

0.00 +--""--1--1--1--1--+-_�_-+--+-'_--+------+-+-+--1--1....................._+--+--+--1--1--...+--156 57 58 59 60 61 52 53 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

Year

~\

.? .::.'.'.Q ! f•••• I :. \.. ..~ .~ :. ,

qp

\>'-q :i, '..! \:1' ......~/ ••~ :, <l'. \ P.0- .... .. "i: ".11' 0

·0··4. .....»

o

..'0 0,

/\:, !.A· .. ,.: :-::. :~ }'

:~.\~

34,10 r--------;:=:::::====;:::;--------------,b ~o-seclionsl

A ........ Section S2

--SeclionS3_._------33,90

33.70-0.g 33.50-.q.S 33,30"(;j

'"c:33,10C':

u::E

32.90

32.70

32.50 1--0000""- _I_-I--I--+-_1_-+--+-_------+--+-+-+--I--I..................._+--+-+--1----...o.-J

58~58~60~5253646566~6869MnnnN~~77M~80~8283M

Year

Fig..28. Mean sea temperatures (a) and salinities (b) of the 10-50 m layerin June-luly by section and year.

a

6 ....\\

5

a \4 \ a a \\ \

3 \ • , a, \ \ /:2 I \ i!!\ i \,:

I j • \! !

\ ·L \!\~ Io-l .J../::,J.56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

YeorSeclion ~ SI •._. 52 __ 53

LRAGLA~----------------, 7~----------------"

3

2\--.---.--..---T-,.--..__....-..........-..----r---.~..__...,._._r'56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

YeorSeclion ~ SI.·.·. S2 - S3

LHAGLA9

8a

7a

6 •a

5

4

+:;«J.cCEo(')...Q)a.cicc«JQ)

.§.Cl

.3

­....

Fig.29. Mean number of white (LHAGLA) and red (LRAGLA) Aglanthadigitale per 30 min. stramin net haul in June-July by sampling section;md )'car.

48

·5,00

4,50

4,00

3,50

3,00

-·2,50

·2,00

1,50

1,00

0,50

0,00

3,50 e3,00

g"<:;

·2,50<3

vvw(l)

~C""

- 2,00 "-'-c

~c

1,50 bC-

E(l)t-

1,00

0,50

0,00

4,00

3,50

3,00

2,50

2.00

•1,50

1,00

0,50

5ection 51

5ection 52

5ection 53

•

•/

o ' 0,0056 57 58 59 60 61 62 63 64 55 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

Year

3000

2500

2000

•1500

1000

500

0

sJ •

4000

........~

CL> 3000E=>

Ci:>

2000

1000

0

3000

2500

2000

1500

1000

500

Fig. 30. Mean plankton volume (mi) per 30 min. stramin net haul and meantempcrarUfc (thc 10-50 m Iaycr) in June-July by sampling sectionand year.

49

,56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

57 59 61 63 65 67 69 71 73 75 77 79 81 83

20000

15000

10000

5000

0

250000

200000::::lCU.cc: 150000'E0('t) 100000...Q)C-

o 50000c:c:CUQ)

0E

35000

30000

25000

20000• 15000

10000

5000

0

I0 Oth. cop.~ Calfi _ Calhy _ Euch

Fig. 31. Mean number of Calanus finmarchicus (include also C. glacialis)(Calfi), Ca/anus hyperboreus(Calhy), Euchaeta· (Pareucllaeta)norwegica(Euch) and other copepod species (Oth. cop.) per 30 min.stramin net haul in June-July by sampling seetion and year.

YeorSeclion G-8-<J 51 ..... S2 __ 53

•

o

A

o

,,!

fi

I1\

LCALHY12 +

t 1 i A

t0 i .:

9 i?\ :'

8 \ I.7 \; I6 I5 I4 i3 I2 i

\ .t ~oi,-.-...--.......,.--.-.......,...........-...,.....~::;:::~T"""'""",__,........,I56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

LCALFI13r---------------,12 .. ~ t11 \ i !10 \ j9 \ f I~IH : I · t

6V/i \5 .i' g \

}: i '

4 f ~ i~ \

~ I J,' \1 \ I D iO

\; .e • ~

50

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84Year

Section 11-+-0 S1 .·.·.52 -- S3LEUCH

gr----------------,

r.~ii!

o

LHYPER10r--------------.....,,

i9 j

f8 i:

i

7 \ !6 \]1 A

5 ;i

4 i •! D

3 \ ;\i

2 ~

1'r--..,.-....,......-,--...........,..-...-,-~_....,..........,r__..__._,........,........,.....-T

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

i '•

8~ t

:M ·\ ·5 f /f

; D i

4 i ii i

3 i I! dI

2 iI

1 iio .J ...... '8- ......

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

+"Sco.c

c'EoCf)

.occCOQ)

E-...Cl

.5Year

Section D-ü-O Sl •.•.• S2 -- S3Year

Section o-e-o Sl ...... S2 -- S3

o

•o

:~IAi

3 II

2 i;

iIo .J

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

•

LCHAE8 ,

jA 7 2I• \ fl

6 : !i1

i':;!\: \

} I .1ii\! \1-,",+I \ I 0-.1

D i i io . 'i56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

LEUPH10r--------------~

9

86

7 I

j6 f~

i5 ! i4 ! i

. I;

3 iI

2 J!

1 !

YearSection D-öHJ Sl •.•.• S2 -- S3

Yeor

Section G-8-<J SI.·..·• S2 -- S3

Fig. 32. Mean number of Calanus finmarchicus (include also C. glacialis)(LCALFI), Calanus hyperboreus (LCALHY), Euchaeta (Pareuchaeta)norwegica(LEUCH), hyperiids (LHYPER), euphausids (LEUPH),Chaetognatha (LCHAE) per 30 min. stramin net haul in June-July bysampling section and year.

~/.i \i \i \• 1

l.

a

a

•

a

~/~iiiiiie

rt',a

3L! 1\

in!i i ;! I11; ! i.:. !:~! 1\[I \111 iii !• Io • a ~ ~

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

.-...~-

.~

iii

j ii;' i

f r' i;,' \1 1" P'i \ i

a \ i

o ~

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

4 i3 ~. :\

H2. \i

ii~

\o ~ ~56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

YearSec!ion ........ Sl •.•.• S2 - 53

YearSeclion o-e-o 51 •.•.• S2 - 53

LlIMR9..----------------,8

\7 \ \.

\ \i \

6 \ 'I

5 \ a\ /

4 \ ii!

3 i2.

1

LGONA4r---------------.....,

LCRAB8r---------------.....,7

6

5

,•

,

•2

X11iiii :

.' i 4 ~!4! "t , ij, -I : • >. ,. ~ i \ ~/ ~ • ., j; \ I \:.- \ .! a...~iii;

o ~

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

Year5eetion lHl-O 51 •.•.• S2 - S3

1M[J

a \N//\ \• f: ~ '\ \.: \ ,.1 lJ

I/.

l,1'r--..,..........,..........-......,........................-.-,,.......-,............,....................'"T""""'..,..........,...~56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

51

6

LUMH9.r-------------------.

8

7

6 " Iv\5 \ i ?4 !, ,.... ! i

~ i ii i a: i3 1 I • \}l ';i i i

i ! i2 I I ,

i i 1 i1 i j \ 'V \ )o i a II56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

YearSection o-<H1 51 •.•.• S2 - S3

LCUO6

5• a

4

~.3a

2 ,

LSHR7r------------------,

­.-

....Q)a.occroQ)

E........Cl

.3

+•.cc'EoCf)

YearSection lH-O Sl .·.·.52. - 53

YearSeelion ........ 51 •.•·.52 - S3

Fig. 33. Mean number of Limacina (Spiratella) helicina (LLIMH), Limacina(Spiratella) retroversa (LLIMR), Clione limacina(LCLIO» GonatzLSjabricii(LGONA), Shrimp (Pandalus sp.), mainly Pandalus borealis(LSHR), Crab (LCRAB) per 30 min. stramin net haul in Junc-July bysampling scction and ycar.

5230 r--n--------------------------~5,00

2,00

25

25

:;.,g 20c::oE

g'-- 150.>Cl..

cic::

§ 100.>

::::E

5

72

90

•

/ •

Section 51

Section 52

4,50

.- 4,00

- 3,50

4,50

4,00

3,50 ~

e;;,3,00 ~

~.32,50 2

0.>0..E

2c::o

1,50 ~

1,00

0,50

25

20

15

10

5

212

•

Section 53

•

4,50

4,00

3,50

3,00

2,50

2,00

1,50

1,00

0,50

56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

Year

Fig. 34. Mean number of Atlantic cod larvae per 30 min. stramin net haul andmean temperature (the 10-50 m layer) in June-July by sampling sectionand year.

53

/\;::;,:

YearSectien o-a-o Sl ..... S2 _ 53

4

3 •.... \~ \ /

2. \

'-I \ Q-.& \ \

\ •\

'. ~D

\

\

LGHL5.---------------...,

/\/! l

~ IXJ't, i'i

,; i\i! i.: \". it \Y' i. \ .

t. i \o •56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

YearSeetien .........., Sl •.•.• S2 --- S3

,.

LeOD6

5

4 I.i

3 i2

11

&

1 .D

lSAND5~--------------...,

•1\ Jihf

iV'

'1 ti \! 1\

,/ l \r1 \... l· I~ \ i ~ !!, \ j;'\ i

4' 5 \'1 !,.! ~ \ . ! .:\' i : \:i E • I ! \•. ! !; : iH \j ! \" & ,: .,lV : i !.:: :./ \• ;: :11 \

:,j \ \Ä-.-

Q4

2

3

YearSeetion lHHJ S1 ..... S2 - S3

~i \; \i \i hji

• i

1\ f(! V\ ! !.

\rI:JJ:'\ X~\ - ·; !: i ! !o ~., l

56 58 60 62 64 66.68 70 72 74 76 78 80 82 84

lCATF3r---------------------,

A. [1 .

56 58 60 62 64 66 68 70 72 74 76 78 80 82 84Year

Sectien IH-O Sl •.•.• 52 --- S3

2

LRED3.-----------------,

LPLA5r----------------,

L-a>C-

occroa>E-Cl

.9

YearSecHen .......... Sl .·.·.52 --- 53

2

':I

iII:!

\/o -;l-;lj56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

YearSecHen o-a-o Sl ..... S2 - S3

D

4

2

3

•fi

t H:, li

• H :I

:fi\.: i~ 1\:'.: : :'\1 :'~ : :

••-~!foj ){ Ii',i!\ !'E . . :; i i

'11 i\ f \ ~ '\ lit i :i f~\ 1:J'iii, \ .~ .!'! \l !

i \ :? •.,t\ " 1\\ f

D7\ I!JA/~ ! ~ a ~Io 1'f'fU \VJLI56 58 60 62 64 66 68 70 72 74 76 78 80 82 84

Fig. 35.' Mean number of Atlantic cod larvae (LCOD), Greenland halibut larvae(LGHL), redfish larvae (LRED), sandeellarvae (LSA1~D), long roughdab Iarvae (LPLA) and catfish larvae (LCATF) per 30 min. stramin nethaul in lune-luly by sampling scction and year.