•Ihis report not to be guoted without prior reference to the Council"

International Council for theExploration of the Sea

C.M.1989/Assess:8

REPGRT OF THE tiORKING GROUP ON CGD STOCKS OFF EAST GREENLAND

Copenhaqen. 22 - 28 February 1989

Ihis document is areport of a Workinq Group of theInternational Council for the Exploration of the Seaand does not necessarily represent the views of theCouncil. Iherefore. it should not be quoted withoutconsultation with the General Secretary.

"General SecretaryICESPal<egade 2-4DK-1261 Copenhaqen KDENMARK

< i >

TAB L E

Section

PARTICIPANTS

o F C 0 N T E N T S

Page

2 TERMS OF REFERENCE

3 THE COD STOCK COMPLEX IN GREENLAND AND ICELANDIC WATERS

4

5

ENVIRONMENTAL CONDITIONS IN 1988

SURVEYS AND RESEARCH

2

3

5.1

5.25.35.3.15.3.25.3.3

The Federal Republic of Germany Groundfish SurveyDesign .Japanese Groundfish SurveyGreenland Survey and Research .

Shrimp survey . . . . . . . .West Greenland longline surveyWest Greenland young cod survey

334444

6

6.16.26.36.46.56.66.76.86.9

6.10

7

7.17.27.37.47.57.67.7

STOCK AT WEST GREENLAND (NAFO SUBAREA 1)

Trends in Catch and EffortCatch in Numbers at Age and Catch compositionMean Weight at Age in the CatchesMaturity Ogive . . . . . . . . . . . . . . .Groundfish Survey Results . . . . . .....The Inshore Stock in Proportion to the Offshore StockDistribution Pattern of the Stock . • . . . .Future Recruitment . . . . . . . . . . . • . .Estimating the Size of the 1984 Year Class byComparing the Catch Rates of 1988 With Those of 1977Conclusions . . . . . . . . . . . . . . . . . .

THE COD STOCK AT EAST GREENLAND

Trends in Catch and EffortCatch in NumbersMean Weight At AgeMaturity OgiveGroundfish Survey ResultsFuture RecruitmentEstimation of Stock Size

5

5677799

10

1011

11

11121212121313

-- ----------1

« ii

Sectjon

7.8

7.9

Total Biomass, spawning Stock Biomass, and FishingMortality .Catch Projection and Management Options . . . . . .

Page

1516

8 REFERENCES 18

TABLES 3.1 - 7.7.2

FIGURES 3.1 - 7.9.1

---00000---

19

38

1 PARTICIPANTS

The Working Group on Cod Stocks off East Greenland met in Copen­hagen from 22-28 February 1989, with the following participants:

H.P. CornusH. HovgArd (Chairman)SV.Aa. HorstedH. LassenJ. MesstorffK. NygArdF.F. RigetS.A. Schopka (until 26 February)

Fed. Rep. of GermanyGreenlandGreenlandGreenlandFed. Rep. of GermanyGreenlandGreenlandIceland

2 TERMS OF REFERENCE

At the 1988 Statutory Meeting, it was decided (C.Res.1988/2:4:2)that the Workinq Group on Cod Stocks off East Greenland shouldmeet at ICES Headquarters from 22-28 February 1989 to:

i) analyze the results of the latest groundfish survey;

ii) assess the status of and provide catch options for 1989within safe bioloqical limits for East Greenland cod.

Oue to the interrelationship between the West Greenland and EastGreenland cod stocks, it is necessary to use data derived fromthe assessment of the West Greenland cod stock in order to make aproper assessment of the East Greenland cod stock. In Section 3,the interrelationships of these two cod stocks are discussed, andit is obvious that there are sound scientific reaSOns for carry­inq out the two assessments simultaneously and presenting them inone report. There are also practical reasons for this.

The assessments in the two areas are based on data from a ground­fish survey which is designed in almost the same way for bothareas, and the scientists involved are the same.

Management advice on the two areas is given by two differentinternational organizations. In the.case of West Greenland, theScientific Council of NAFO scrutinizes the assessment and formu­lates the advice; in the case of East Greenland, the ACFM of ICEShandles the advice.

In 1988, the West Greenland assessment was not carried fullythrough (see Section 6.10), but fisheries and research data areqiven. The West Greenland part of the report will be presented byparticipants of the meetinq as a workinq document to the NAFOScientific Council for its further discussion and for assessment,catch projections, and manaqement advice.

3 THE COO STOCK COMPLEX IN GREENLANO ANP ICELANpIC WATERS

It has been known for several decades that there is an inter­relationship between the cod stocks at West and East Greenlandand at Iceland (Fiqure 3.1). Taqging experiments carried out at

2

Greenland and Iceland show that apart of the mature cod at WestGreenland migrates to East Greenland and some of them further toIceland. Results of tagging experiments carried out in EastGreenland waters also show that mature cod and sometimes immaturecod from that area migrate to Iceland. At Iceland, taggingexperiments show that migration of cod from Icelandic toGreenland waters hardly occurs and, therefore, the migrationsfrom Greenland waters to Iceland can be regarded as one-waymigration.

The magnitude of emigration from West Greenland to East Greenlandand Iceland also seems to vary from year to year and between yearclasses. Up to 1984, the Working Group used an emigration coeffi­cient of E = 0.05 for the West Greenland stock as a whole, whichwas based on results from tagging experiments carried out mainlyin the period 1945-1970. Information from the groundfish surveysfrom 1982-1988 indicates that the emigration varies considerablyfrom year to year and between year classes.

Also at East Greenland, the emigration to Iceland varies fromyear to year. From Danish tagging experiments, the North-Westernworking Group concluded (Anon., 1971) that about 45' of the ma­ture cod from East Greenland migrate to Iceland. However, theNorth-Western Working Group considered the East Greenland stockand the cod in NAFO Divisions 1E-F at West Greenland as beingcombined and estimated the coefficient of emigration as 0.29,which corresponds to an emigration of 25' per year.

It is also weIl known that larvae drift with currents from Eastto West Greenland and from Iceland via East Greenland waters tothe banks off West Greenland.

The magnitude of this larval drift seems to vary much from yearto year. In some years, the drift seems negligible, while inother years, as in 1973 and 1984, considerable numbers of codlarvae seem to have drifted from Iceland to East Greenland and tothe southern part of West Greenland (Table 3.1).

4 ENYIRONMENTAL CONDITIONS IN 1988

In 1988, the air temperatures over the West Greenland area werebelow normal from April to October and in DeCembe! with negativeanomalies experienced in May-June of more than 2.0 C below nor­mal.

The surface layerotemperatures were below normal throughout theyear with about 0.5 C. Surface layer salinities were slightlyabove normal during the first half of the year, while they weremarkedly below during the second half.

At medium depths west of the banks, there were clear signs of agreat inflow of East Greenland polar water during spring andearly summer~

From September to November, the water column below 200 m showedtemperature and salinity values indicating the strongest inflowof warm, high salinity Irminger water experienced in recentyears.

3

5 SURYEYS ANP RESEARCH

5.1 The Federal Republic of Germany Groundfish Survey Design

The parameters of the standard bottom trawl used in all surveysremained the same as given in previous reports of the WorkingGroup.

The true catchability coefficient is unknown. For the calculationof survey estimates, it was, however, taken as 1.0. Therefore,the results are expressed in terms of "trawlable biomass or abun­dance" and refer to the part of the offshore population availableto the gear at the time of the survey.

The survey areas off East Greenland (lCES Division XlVb) and offWest Greenland (NAFO Subarea 1) are shown in Figure 5.1.

The ~urvey areas are composed of statistical rectangles (30' lat.x 1 long.), as used throughout the ICES area, which form thebasis of the stratification schemes. However, according to area­specific reasons, the construction of strata is different in thetwo survey areas.

The stratification scheme of the West Greenland surveyweIL as the procedures for random selection of fishingremained the same as giyen in previous reports of theGroup. Strata areas (nm) are given in Table 5.1.1.

area asstations

Working

Groundfish surveys conducted in Division XIVb by the Federal Rep­ublic of Germany from 1980-1986 have been fairly consistent interms of area covered, method of selection of fishing stations,and analysis. In 1980-1982, and in 1987, a 4-depth zone stratifi­cation was used.

For the time period 1983-198~ stratification was done by pre­viously observed density distribution. In 1988, stratificationwas adjusted to that used off West Greenland (i.e., by regionalareas and depth zones, Table 5.1.2).

5.2 Japanese Groundfish Suryey

In 1988, a groundfish survey was carried out by the Japanese re­search trawler 'Shinkai Maru" in a joint programme between theJapanese Marine Resources Research Centre (JAMARC) and theGreenland Home Rule Trawling Company (GHT).

The survey covered both East and West Greenland waters. The WestGreenland survey was carriedoout in Se~tember and October cover­ing the areas between 73 and 62 30'N latitude. Only in thenorthern part of the area were hauls made at depths lesser than400 m. A total of 109 valid hauls was made. The survey showedthat only very few cod were found below 400 m and in the northernpart of the area covered.

In East Greenland, the areas between 65°30' and 630 30'N latitudewas covered in July. The area was divided into four depth zones.A total of 34 valid hauls was made. The estimated abundance ac­counted for only 48\ of the abundance found by the Federal Rep­ublic of Germany survey in the same area. However, the Japanese

4

survey had a low coverage of high density areas. Therefore, theWorkinq Group decided to base the assessment of East Greenlandcod stocks on the survey results of the Federal Republic ofGermany only.

5.3 Greenland Survey and Research

5.3.1 Shrimp survey

In 1988, a shrimp survey was carried out by the Greenland trawler"Elias Kleist". The purpose of the survey was to qet an abundanceestimate of the shrimp stocks, but all by-catches were recor~ed.

The sur~ey was carried out in July coverinq areas between 72 30'and 63 52.5'N latitude. The shrimp survey showed that only a fewcod were found in the offshore area outside the survey area ofthe Federal Republic of Germany.

5.3.2 West Greenland longline survey

In October-November 1988, Greenland conducted a lonqline surveyoff West Greenland. The results were discussed in a workinq paperpresented at the meetinq (Lehmann and Nyqaard, 1989). The surveywas carried out in inshore and offshore areas of NAFO Divisions1e, 1D, and 1E, with the purpose of describinq the relative dis­tribution and abundance of cod inside and outside the areacovered by the concurrent Federal Republic of Germany trawl sur­vey.

Within the survey area, which included fjords, coast, and banks(offshore), fishinq was conducted usinq a random stratificationmethod of fishinq site selection. Strata were selected within thedepth range 0-300 m at 100-m depth intervals. There were sometime restrictions which influenced the randomization of stationsin that they had to be fished on a daily basis and be permittedsufficient fishing time on the bottom. This restricted the dis­tance between stations covered the same day.

The offshore area was defined as the area outside the 3-milelimit, i.e., the same area as covered by the Federal Republic ofGermany trawl survey. The coastal area was defined as beinq be­tween the 3-mile limit and straiqht lines drawn across the en­trance of the fjords. The area inside these lines was defined asfjords. The areas are qiven in Anon. (1988; Table 5.3.1.1).

The low catchability of srnall cod by the longline fishery causesproblems when interpretinq results, and small and larqe cod weretreated separately to avoid bias. The division of the two qroupswas at aqe 4, as this separates the outstandinq 1984 year classfrom the eIder cod.

Mean density (catch per 100 hooks) is given by all strata inTables 5.3.2.1 and 5.3.2.2 for small and larqe cod, respectively.

5.3.3 West Greenland young cod survey

Durinq July 1988, Greenland carried out a survey on younq cod inthree inshore areas of West Greenland: Qaqortoq (Division 1F),Nuuk (Division lD), and Sisimiut (Division 18). The results of

5

the survey were presented in a working document at the meeting(Nygaard ~ ~., 1989).

Links of gillnets containing separate sections with five differ­ent mesh sizes (16-33 mm, bar length) arranged in random orderwere used. With these mesh sizes, fish between 15 and 35 cm areefficiently caught, whereas the catchability of larger andsmaller fish is substantially lower.

A total of 189 net settings was made. Nets were set at depthsranging from 2-35 m, and the mean catch rate (number caught perhour) for each age group was used as an index of abundance.

During the survey, a total of 1,979 cod was caught. Catches weredominated by 4- and 3-year-old cod, i.e., the 1984 and 1985 yearclasses. The 1984 year class was caught mainly in the northernarea, whereas the 1985 year class was more evenly distributed.Age 2 cod (1986 year class) were caught in some numbers in Div­ision lB, whereas catches were lower in Division lD and very lowin Division lF. Only one 1-year-old cod was taken in the survey.

In 1985 and 1986, only three mesh sizes were used, and for com­parison, indices using the catch from both three and five meshsizes were computed, as shown in the text table below:

Indices of year-class strength

Survey Age 1 Age 2

Three mesh sizes 1985 0.74 +(16, 24, and 33 mm) 1986 0.09 1.61

1987 + 0.361988 + 0.09

Five mesh sizes 1987 + 0.93(16, 18, 24, 28, and 33 mm) 1988 + 0.25

As 1-year-old cod (13-20 cm) are caught efficiently by thismethod (Hansen and Lehmann, 1986), the present results indicate avery low abundance of the 1987 year class at West Greenland.

The 1986 year class is estimated to be around 25\ of the 1985year class.

6 STOCK AT WEST GREENLAND (NAFO SUBAREA 1)

6.1 Trends in Catch and Effort

The fishery for cod in NAFO Subarea 1 is partly an offshore fish­ery carried out mainly by large trawlers, and partly a coastaland fjord fishery, usually domina ted by pound net.

The nominal catch in 1988 was 61,618 t (provisional figures)(Tables 6.1.1 6.1.5), which is more than three times greaterthan the 1987 landings.

6

Greenland vessels landed 51,237 t or 83% of the total; the re­mainder was taken by the Federal Republic of Germany, UK, andJapan (only 2 t).

In 1987, a new statistics programme was introduced for vesselsbelow 80 GRT. This programme supplied statistics of the landingsby division, gear, and month. In 1988, this programme covered 80\of the landings from those vessels. The remaining landinqs weregiven by division and month only. The breakdown by gear given inTable 6.1.2 refers to the total reported landinqs of small ves­sels raised according to the data from the detailed, new pro­gramme.

Trawl catches constituted 66\ of the total catch, whereas poundnets accounted for 21%, and longlines, handlines, and gillnetsfor less than 5\ each.

The trawlers operated throughout the year and mainlY in Divisions10 and 1E. The overall catch per unit effort (Table 6.1.6) forthe Greenlandic trawlers nearly doubled compared to 1987.

Pound nets were mainly used in the summer period (May-August) andmainly in Divisions 1B, 10, 1E, and 1~. Longlines were usedthroughout the year with highest catches ~n May-July, whereascatches from handlines and gillnets were taken mainly from May­November. This fishery took place in all of the Divisions 1B-F.

6.2 Catch in Numbers at Age and Catch Composition

The catch statistics from the fisheries by Greenland now supplyinformation on the gears used. The breakdown of catches by gearsallows improved accuracy when converting catch by weiqht intocatch by number. Further, more biological samples were taken in1988 than in 1987.

The trawl fishery was well sampled in the first half of the year,while catches from the last two quarters were raised according tosamples from December 1988 and January 1969. Pound nets and hand­lines were well sampled, whereas gillnets and longliners werecovered by few samples only.

Trawl catches in the first quarter from Division 1F were domi­nated by age groups 4 (60\), 7, and 9, whereas in Divisions 10and 1E, catches were almost exclusively age 4 (95\). For the lasttwo quarters, aqe group 4 dominated in all divisions (80-90\),but in Divisions 1e, 10, and 1~ aqe qroup 3 was also cauqht insome amounts.

Longline catches were dominated by the 1984 year class, the re­maining part being older cod.

Pound net and handline catches were heavilY dominated by the 1984year class (more than 90\ by number). There seems to have been ahigh rate of discard of fish below the Greenland minimum landingsize (40 cm), mainly fish of the 1985 year class.

7

The 1984 year class seems to have accounted for about 90% (bynumber) of the nominal catch in 1988 (Tables 6.2.1 and 6.2.2). Interms of catch by weight, the year class accounted for about 86\of the landings.

Among the older year classes, only the 1979 year class is of someimportance in the total catch (4\ by weight).

6.3 Mean Weight at Age in the Catches

The mean weights at age of cod in the major fisheries in 1988 arelisted in Table 6.3. For each gear, the mean weights were calcu­lated by weighting the observed mean weights at age by the num­bers in each age group in the catch represented by the individualsampies. Mean weight of the total was likewise calculated byweighting by the numbers caught in each gear and age group.

Mean weights in landings were highest for those from longlinesand gillnets and lowest for those fram German trawl and poundnets.

The mean weights found in 1988 are generally below those of lastyear, except for the 4-year-olds which are alike.

6.4 Maturity Qgive

Data on maturity by age were available from the commercial fish­ery of the Federal Republic of Germany in the first quarter of1988. These data were smoothed by a sigmoid curve and given inthe text table below:

Age % mature

3 24 85 236 527 798 939 98

10+ 99

6.5 Groundfish Suryey Results

The number of randomly distributed fishing stations occupied dur­ing the surveys from 1982-1988 arnounted to:

Year

TotalValid sets

1982 1983 1984 1985 1986 1987 1988

111 153 162 133 155 150 17698 142 158 114 142 140 162

Cod biomass and abundance ettimates for the total survey area offWest Greenland of 19,864 nrn in 1982 and 1983 and of 20,133 nmafter inclusion of stratum 4 since 1984 amounted to:

8

Year Tonnes Number ('000) w kq

1982 189,934 ± 37.0\ 109,039 ± 36.1\ 1.651983 98,843 ± 28.5\ 59,362 ± 26.5\ 1.671984 24,945 ± 39.7\ 16,104 ± 39.1\ 1.551985 31,860 ± 60.1\ 52,466 ± 33.3\ 0.611986 76,220 ± 30.8\ 134,716 ± 31.8\ 0.571987 464,286 ± 47.0\ 582,868 ± 42.6\ 0.801988 547,566 ± 42.1\ 563,601 ± 42.3\ 0.97

The confidence intervals are qiven at the 95\level of siqnificance.

The surveys were carried out in November-December in 1982, 1983,and 1985 and in October-November in 1984 and 1986-1988. The R/V'Walther Herwiq' was used each year except in 1984 when, fortechnical reasons, she had to be replaced by R/V 'Anton Dohrn".However, experience from a 13-year time series of bottom trawlsurveys in Division 2J (Labrador) has confirmed that the fishinqpower of both vessels did not differ siqnificantly provided thatequal standard survey qears as well as towinq speeds were used.

From 1982-1984, the survey results reveal a drastic decline incod biomass and abundance which was observed not only for thewhole survey area (Fiqure 6.5.1), but for all divisions, as shownin detail in Table 6.5.1.

The total survey biomass and abundance, however, increased con­siderably since 1984 and very steeply in 1987 due to increasinqrecruitment, mainly of the outstandinq 1984 year class.

The survey results of 1988 reveal a further increase in biomassof aqe 4 and younqer cod by 122,000 t, but a decrease in aqe 5+cod by 39,000 t. The resultinq increase in total biomass of83,000 t is less steep than in the previous year.

The recruitment mainly of the 1985 year class and younqer codcaused an increase in abundance by 57 million fish in 1988. How­ever, the number of 1984 year-class cod, as well as the 1983 andolder year classes, decreased by 53 (10\) and 23 (74\) millionfish, respectively. Althouqh the resultinq decrease in totalabundance amounted to only 19 million cod, the proportional re­duction in older fish from 31 million in 1987 to only 8 millionin 1988 was extremely high and led to the 'lowest estimate ofspawning stock level observed since 1982.

The regional distribution of cod biomass and abundance was lowfor Divisions lB+C but very hiqh for Division 1D.

The chanqes in length frequency distributions and age compo­sitions of the West Creenland cod stock over the survey periodfrom 1984-1988 are illustrated in Fiqure 6.5.2.

9

6.6 The Inshore Stock in Proportion to the Offshore stock

In 1987, Greenland conducted a longline survey in inshore andoffshore areas of Divisions lC-E at the same time as the trawlsurvey of the Federal Republic of Germany took place off WestGreenland.

The results of the longline survey were used to estimate thatproportion of the total stock which occupies inshore areas notcovered by the trawl survey. For 198~ it was found that the off­shore cod biomass and abundance, as estimated from the trawl sur­vey, accounted for only about 75\ of the total stock size. Conse­quently, the trawl survey estimates for 1987 were raised by fac­tors calculated for each division to correct for the stock pro­portions outside the trawlable areas. The raising factors aregiven in last year's report (Anon., 1988; Table 6.5.3), and theraised total abundance is given in Table 6.5.2 of last year's re­port.

In 1988, Greenland again carried out a longline survey in Div­~sions 1C-E at the same time as the Federal Republic of Germanyconducted its trawl survey. The longline survey is described inSection 5.3.2 and the results are listed in Tables 5.3.2.1 and5.3.2.2.

Trying to use the 1987 method on these results, the working Groupfound that, for Divisions lD-E, the stock outside the trawl sur­vey area was of almost the same proportion as found last year.However, for Division lC, the method of calculating a raisingfactor for 1988 seems to lead to quite unreasonable results.

The offshore longline survey effort in Division 1C is 10 sets,altogether 3,300 hooks, which gave a total catch of only 3 cod.Also, the trawl survey showed very low abundance in this area.

The inshore longline CPUE in Division 1C compared to that ofDivision 1D is quite high. Using the Division 1D comparison be­tween the trawl survey and the longline survey would lead toabout 200 million cod in the inshore areas of Division 1C. Thisresult is not considered valid because the longline survey prob­ably hit a high local concentration of cod close to Sukkertoppen.

During aperiod at the beginning of the trawl survey, high con­centrations of cod were found off Sukkertoppen. Several trawlersoperated here. However, when the research vessel covered thisarea only a few days later, no commercial fishing took place andcod density was very low (waste from the former fishery wascaught during the survey (J. Messtorff, verbal information).

6.7 Distribution Pattern of the stock

All evidence points to the fact that the commercially fishablestock (i.e., the 1984 and older year classes and to some extentthe 1985 year class) is found offshore at West Greenland from thevery southernmost part of Division lC and southwards, includi~q

Division 1E. Further, it occurs at East Greenland south of 63 Nalthough much less abundant than at West Greenland. The inshoredistribution at West Greenland, however, seems to cover not onlythe same latitudes as the offshore distribution, but also the in-

10

shore area of Division 1C and Division 1a, at least its southernpart (Holsteinsborg/Sisimiut), as evidenced by commercial catches(Table 6.1.2).

6.8 Future Recruitment

1985 year class

The 1988 trawl survey showed an abundance of the 1985 year classof 93 million fish. This corresponds to 18' of the survey abun­dance found for the 1984 year class when this age group was 3years old. Although this is slightly below last year's estimate,the survey confirmed that the year class is above the average forthe later years.

1986 year class

From the inshore young cod survey as weIl as from the trawl sur­vey, the size of the 1986 year class can be estimated to be low,in the size range of 1-5' of the 1984 year class. However, inboth surveys, this year class showed up in highest densities inthe northernmost areas, and some proportion of this year class isprobably not covered by the surveys. Nevertheless, the 1986 yearclass must be expected to be small.

1987 year class

The 1987 year class showed up in only small densities in both theyoung cod survey and the trawl survey, and it must, therefore, beconsidered small.

1988 year class

No O-group cod we:e found in the Icelandic O-group survey offEast Greenland 1n August 1988 indicating that the larval inflowfrom Iceland must have been negligible. In the trawl survey offWest Greenland, there were also no recordings of O-group cod, andthe year class must, therefore, be expected to be small.

6.9 Estimating the Size of the 1984 Tear Class by Comparing theCatch Rates of 1988 With Those of 1977

The following section is based on a paper by HovgArd and Riget(1989).

The West Greenland cod is strongly dominated by the 1984 yearclass. The trawl survey estimate of that year class using acatchability coefficient of 1.0 is approximately 800 million atage 3. The NAFO Scientific Council IAnon., 1988) has analyzed theavailable data and concluded that the best available estimate is500 million cod at age 3, thus implying a catchability caef­ficient of a little less than 2.

In 1988, the stock situation closely resembled that in 1977 witha strong year class (1984 and 1973, respectively) recruitingafter years of very poar recruitment. These two year classes arethe largest seen at West Greenland since the mid 19605 and bothdominated the fisheries at age 4.

11

The Greenland Horne Rule trawlers had a directed cod fishery inthe first half of 1977 with a mean CPUE of 1.21 tons per hour. Inthe first half of 1988, the same trawlers had a mean CPUE of2.30, i.e., 90\ higher than that of 1977. There has been a changein the trawls used in the two periods. The trawls used in 1988are estimated to be 10-20\ more efficient than those in 1977.Also, there are differences in fishing sites between the twoperiods.

Assuming an emigration coefficient of 0.30 from age 6 and onwardsand M 0.2, the 1973 year class at age 3 was calculated to be232 million applying VPA.

Using the CPUE ratio estimated above (1.9), the size of the 1984year class is found to be 441 million, which compares weIl withthe 500 million adopted by NAFO.

6.10 Conclusions

The Working Group noted that, for the assessment of the EastGreenland cod in 1989, the estimate of the size of the stock atWest Greenland was of minor importance since spawning migrationis thought to occur only for the relatively few fish of age 6 andolder, and individuals of the 1984 year class are, therefore, notlikely to contribute much to spawning migration in 1989.

The Working Group,therefore, decided not to conduct a further as­sessment of the West Greenland stock component, but to leave thatto the NAFO Scientific Council in June 1989 and to consider themigration from West to East Greenland as neqliqible in 1989. TheWorking Group is, however, aware of the qreat importance for theEast Greenland assessment of estimates of the West Greenlandstock and"its spawning stock component and likely emigration from1990.

7 THE COP STOCK AT EAST GREENLANP

7.1 Trends in Catch and Effort

The major part of the cod catches from East Greenland waters istaken by trawlers either in a directed cod fishery or as by-catchin the redfish fishery. Both of these fisheries are to some ex­tent mixed fisheries which take place on the offshore banks andalong the slopes of the Greenland shelf from Pohrn Bank southwardto Cape Farewell.

Total catches from Sub-area XIV (Table 7.1), which include esti­mates of unreported catches in 1977-1979 and discards in 1980­1982, fluctuated without trend during the period 1976-1982. Sincethen, however, the catches have decreased sharply trom 27,000 tin 1982 to only 2,000 t in 1985. From 1986, the catches have in­creased gradually to 9,000 t in 1988.

In 1988, more than 95\ of the catch was taken by trawlers fromthe Federal Republic of Germany. Of these catc~es, 65\ were takentrom January-June at ~he banks south of 63 30'N, and 24\ tromJanuary-June north of 63 30'. The remaining 11\ caught in thesecond half of the year was equally distributed between north and

12

south. The catches of other countries were small: Greenland, 380t (202 toffshore, 178 tinshore) and USSR, 65 t.

7.2 Catch in Numbers

Catch in numbers at age for the trawl fisheries of the FederalRepublic of Germany from January-May were based on age compo­sitions and lengthofrequencies from the commercial fishery northand south of 63 30'N for the same period. For the period June­December, no length frequencies were available. The catch at agefor that period was, therefore, based on age and length infor­mation from the commercial fisheries in May.

As no age/length information was available for the Greenlandoffshore catches, the catch at age from these fisheries was cal­culated by assuming the same age composition as in the FederalRefublic of Germany catches from January-May in the area south of63 30'N. Catch in numbers for the inshore Greenland fisheries wascalculated by the age composition in the trawl survey taking intoaccount the difference in selection of survey gear and commercialgear. The USSR catch was raised by the total of the Greenland andFederal Republic of Germany catches.

The catch in numbers is given in Table 7.2.

7.3 Mean Weight At Age

Unfortunately, no direct information on weight at age was avail­able this year. However, a length-weight relationship from atrawler which was operating in January in southwest and southeastGreenland was use8 to calculate mean weight at age for thecatches south of 63 N. Length-weight relationships do not differsignificantly between East and West Greenland. Therefore, a com­bined length-weight relationship obtained from the trawl surveywas used to calc~late mean weight at age for the commercialcatches north of 63 N. The SOP for the total catches in 1988 was4.7\ less than the reported catches. For the catch projections,the Working Group decided to use the year-class weight at agefound in the autumn survey (Table 7.3).

7.4 Maturity Qgive

In previous assessments, data on maturity were based on materialcollected during the trawl surveys. As these surveys take placein autumn and the ripening of the gonads for the coming spawningseason has hardly started then, estimation of maturity is diffi­cult. For the present assessment, data on maturity at age werecollected from the fishery of the Federal Republic of Germany inthe first quarter of 1988, i.e., just before spawning. The Work­ing Group decided to use these data for the catch projections(Table 7.7.2).

7.5 Groundfish Suryey Results

Estimates of the trawlable biomass of cod obtained from the 1980­1988 surveys off East Greenland are given in Table 7.5.1. Thehigh value of 88,000 t for 1981 may be an overestimate due to thelate timing of the survey (November-December) as pre-spawning ag­gregations may have influenced the survey results.

13

In 1988, the older year classes duminated in the northern part,while in the middle part, the 1984 and 1985 year classes are mostabundant. In the southern part, older cod are almost lacking, andthe 1984 and 1985 year classes are dominating in the depth zones200-400 m and 0-200 m, respectively. The length distributions areshown in Figure 7.5.

Separate age/length keys and length distributions were availablefor the northern, middle, and southern parts of the survey areaseparately. The resultant age composition (Table 7.5.2) was com­bined with the total abundance estimate which is used for assess­ment purposes (Table 7.5.3).

In total, in relation to 1987, the biomass was increased by 8,000t, whereas the abundance was reduced by about 7 million fish.

7.6 Future Recruitment

1985 year class

This year class was observed as O-group fish in the1985. Surveys in the following years have confirmed ittively abundant one. In 1988, the year class accountednumber of the survey stock.

1986 year class

survey inas a rela­for 33\ by

This year class was not found as O-group in the trawl survey of1986, and was only found in very low numbers in the 1987 and 1988surveys. The year class is thus judged to be small.

1987 year class

This year class was not observed as O-group fish in 1987, nor as1-group fish in the 1988 survey. The year class, therefore, isestimated as small.

1988 year class

This year class was observed, although in very low abundance, inthe 1988 survey. From the Icelandic O-group survey (Table 3.1~ itis estimated to be extremely low. Pending further information,the initial suggestion is a small year class.

7.7 Estimation of Stock Size

The population estimated in the autumn bottom trawl survey of theFederal Republic of Germany represents the fishable stock at thetime of the survey (column E in Table 7.7.1). Applying the catchin numbers of the different year classes taken during the monthsprior to the survey (column 0) to the "survey stock" togetherwith the corresponding fraction of the coefficients of naturalmortality and emigration, results in an estimate of the number offish per year class in the sea during that per iod which is re­quired to account for:

14

il losses due to fishing

iil losses due to emigration

iiil los ses due to natural mortality

ivl numbers estimated from the survey.

For computational reasons, it is assumed that these fish are pre­sent in the area at 1 January, an assumption which is not un­reasonable since emigration from West Greenland takes placemainly before the main fishinq season starts at Greenland, i.e.,in the first two months of the year. The results of these calcu­lations are qiven in column B. They can be used to compare stocksizes over a ranqe of years and to calculate fishing mortalities(column GI.

Shifting aqes by one year, the size of the stock was estimated atthe beqinninq of the followinq year based on the catches of theperiod followinq the survey (column Fl and of the respectivefraction of the coefficients.

The results of these calculations, which are given in column A,do not include estimates of the number of expected immigrants andof additional recruitment to the younger age groups from EastGreenland. In a situation without considerable immiqration andemiqration, the estimates in columns A and B should be almostidentical for each year.

In the East Greenland area, however, the situation is quite dif­ferent since considerable miqration takes place into as weIl asout of the area.

Furthermore, it is not possible to estimate the abundance ofyounq year classes, although it is evident from the Greenlandicpound net fishery as weIl as from the survey results that somenursery grounds do exist at East Greenland. Some of these groundsare accessible only under favourable ice and weather conditions,and it is, therefore, not possible to obtain recruitment esti­mates from young fish surveys. Consequently, for the EastGreenland cod population, the estimate derived from the autumnsurvey (column Al cannot be used directly for projections inthe year following the latest survey.

In order to estimate the size of the population and its composi­tion for projection purposes, the basic idea was to use the stockcalculated for the beginning of the year from the survey resultsin the autumn of the same year (column BI as the proportion ofthe stock calculated from the survey in the preceding year(column Al. In this way, a factor for each age group could bedeveloped, which would allow the most recent autumn survey stock(column Al to be raised to account tor partial recruitment fromEast Greenland. The theoretical requirement for this approach isthat the proportion of each age group recruiting to the fisheryis relativelY stable over the years.

Results of nine surveys are now available, from which seven setsof factors have been calculated (column Cl:

Age 1981 1982 1983 1984 1985 1986

4 6.56 1.60 2.32 1.56 1.84 11.475 2.10 0.79 1.83 2.53 3.20 1.88

lExcluding 1986.

1987 1988 Mean1

1.47 1.47 2.401.23 0.56 1.75

15

The factor for age group 4 in 1986 is unrealistically high to beincluded in the average. This is due to the fact that the abun­dance estimate of age group 3 in the 1985 survey is very low andfar below the level observed in previous surveys, even of weakyear classes. The working Group considered this value to be anunderestimate and decided not to use the 1986 survey correctionfactor. Therefore, the mean of the 1981-1988 factors (excluding1986 values) was applied to the stock estimate for the beginningof 1989 derived from the 1988 autumn survey to give the initial1989 abundance of age groups 4 and 5 for the projection.

This methodfrom the Westthe size ofpopulation at

cannot be used to project the number of immigrantsGreenland stock since the immigration is related tothat population and independent of the size of the

East Greenland.

The difference, however, between columns A and B (column H) ac­counts for the number of immigrants at age 6 and older in therespective year.

The net immigration in 1985 of 0.8 million (Anon., 1987) is con­siderably smaller than in the preceding years, while in 1986, asubstantial immigration of particularly the 1977 and 1979 yearclasses in the order of 5 million fish was estimated. For 1987,the number of immigrants estimated in this way is negative forall age groups. For 1988, a net immigration of about 1 millionfish was estimated.

The reasons for these fluctuations are not known, and althoughthey can be the result of biological or environmental factors, itcannot be excluded that they are partly an effect of variation inthe survey estimates.

7.8 Total Biomass. Spawninq Stock Biomass. and Fishinq Mortality

The results of the assessments as described in Section 7.7 aresummarized in the text table below for the years 1980-1989.

16

East Greenland Cod, Summary of the Assessments

Total Total Spawn. Spawn.stock stock stock stock Catch Catch

Year no. biom. no. biom. F(5-10) no. weight(4+) (4+)

1980 25 67 14.3 51 0.21 3.7 12'1981 23 70 13.6 55 0.21 3.9 16'1982 15 54 10.9 49 1.40 7.7 27'1983 13 34 8.4 27 0.53 4.7 131984 10 31 6.9 25 0.40 2.8 81985 9 22 5.0 16 0.13 0.7 21986 14 49 9.4 42 0.14 1.8 51987 9 27 4.9 21 0.38 2.5 71988· 20 35 4.7 20 0.32 5.1 91989 32 51 10.0 22

, Including discards of marketable cod.Estimates of stock size refer to 1 January.Weights in '000 t, numbers in millions.

Total biomass decreased continuously from 70,000 t in 1981 to22,000 t in 1985. The spawning stock biomass declined rapidlyduring this period from 55,000 t in 1981 to only 16,000 t in1985. This development was a result of a combination of factors,of which the high fishing mortality in 1982 undoubtedly played amajor role in the reduction which was estimated as 37\ of thetotal stock biomass and 45\ of the spawning stock biomass in thatyear. Total biomass and spawning stock biomass increased in 1986as a result of immigration of older fish from West Greenland.However, due to both fishing and emigration, the spawning stockbiomass in 1987 and 1988 decreased again to a comparatively lowlevel. The 1984 year class will, although only 35\ mature, con­stitute the major part of the 1989 spawning stock. This is calcu­lated to increase by 2,000 t to 22,000 t.

Fishing mortality was very high in 1982 and decreased continu­ously to a low level in 1985-1986. In 1987, the fishing mortalitymore than doubled. For 1988, the level of fishing mortality isslightly less than that of 1987.

The very abundant 1984 year class was already exploited in 1987at age 3 when it contributed about 30\ to the total catch in num­bers; in 1988, it contributed 73\. The 1984 and 1985 year classeswill dominate the fishery for the coming years.

7.9 Catch Pro;ectiQn and Management Options

The data used for the projection of catches in 1989 are given inTable 7.7.2. Natural mortality is assumed to be 0.2, and to ac­count for emigration to Iceland, an emigration coefficient of0.29 was applied for age groups 7 and older. No projection isgiven for 1990 or beyond because this would require a reliableestimate of future migration from West Greenland.

The projection is calculated by using the same fishing mortalityfor all age groups, since partial recruitment is already con­sidered when estimating the initial stock size for 1989, and the

17

youngest age group in the catches is virtually out of the sizerange where mesh selection takes place.

From the present assessment, a net immigration of 1 million fishduring 1988 from West Greenland was estimated. The results of theFederal Republic of Germany bottom trawl survey off West Green­land indicated a very low abundance of fish at age 6+ which wereregarded as potential emigrants and, therefore, few migrants areexpected to contribute to the East Greenland stock in 1989. TheWorking Group, therefore, decided not to incorporate any immi­gration from West Greenland in the catch projection for 1989.calculating the catch projection with half of the immigrants of1988 (0.5 million) results in only very slight differences intotal stock and spawning stock size in 1989 and spawning stocksize at the beginning of 1990.

The results of the catch projections are illustrated in Figure7.9.1. Three management options are given in the following texttable: a) the maintenance of the 1988 fis hing mortality, b) theconsequences of the agreed TAC of 11,500 t,and c) the ACFM rec­ommended TAC of 5,000 t.

Management Options for Cod in ICES Sub-area XIV

1989 1990

Total Spawn. Management Spawn.stock stock options F(5-10) Catch stockbiom. biom. biom.

50 21 F(88) 0.32 12 29TAC= 5 t 0.12 5 35TAC=11.5 t 0.30 11.5 29

Estimates of stock size refer to 1 January.Weights in '000 t.Resulting spawning stock biomass figures for 1990 donot include immigrants in 1989.

As discussed in Section 7.9 of Anon. (1988), the basic theoreti­cal requirement for the use of the Y/R curve for management isnot met. Therefore, management options related to FO. 1 or Fmaxare not applicable.

For these reasons, the Working Group has suggested that manage­ment objectives be based on spawning size considerations.

Estimates of total stock and spawning stock biomass of the codstock at East Greenland are now available for nine years (texttable in Section 7.8). The spawning stock biomass has declinedfrom about 55,000 t in 1981 to about 16,000 t in 1985 with an im­provement in 1986 to 42,000 t. The level for the last three yearshas been around 20,000 t.

No information is available to indicate a lower limit, belowwhich the spawning stock should not be allowed to fall, eitherfrom stock-recruitment considerations or from analysis of thehis tory of the stock.

18

lt would, however, seem prudent to not allow the spawning stockto decline further in order to make at least some recruitmentpossible from East Greenland to the East Greenland stock. Withthe current level of exploitation (F = 0.32), the spawning stockbiomass is expected to increase in 1989. lt would be an advantageto reduce the current level of fishing mortality to let thestrong 1984 and 1985 year classes contribute to the current smallspawning stock, especially since no other good year classes arein sight (see Section 7.6).

8 REFERENCES

Anon. 1971. Report of the North-Western Working Group 1970. lCES,Doc. C.M.1971/F:2.

Anon. 1987. Report of the Working Group on Cod Stocks off EastGreenland. lCES, Doc. C.M.1987/Assess:10.

Anon. 1988. Report of the Working Group on Cod Stocks off EastGreenland. lCES, Doc. C.M.1988/Assess:11.

Anon. 1988. Report of the NAFO Scientific Council, June 1988.

Hansen, H.H. and Lehmann, K. 1986. Distribution of Young Cod inCoastal Regions of West Greenland, 1985. NAFO SCR. Doc. 86/42.

HovgArd. H. and Riget. F. 1989. An estimation of the size of the1984 year class of cod of West Greenland by the use of CPUEdata from the trawl fisheries. (Paper to be presented at NAFOmeeting 1989.)

Lehmann. K.M. and Nygaard. K.H. 1989. Inshore and Offshore Dis­tribution and Abundance of the West Greenland Cod Stock,Autumn 1988. (Paper to be presented at NAFO meeting 1989.)

Nygaard. K.H., Lehmann. K.M., and HovgArd. H. 1989. Young CodDistribution and Abundance in West Greenland Inshore Areas,1988. (Paper to be presented at NAFO meeting 1989.)

19

Table 3,1 Abundance indices of O-group cod from the international andIcelandic O-group survey in the East Greenland/lceland area,1971-1988 (except 1972).

Year Dohrn Bank SE SW W N E Totalclass East Greenland Iceland Iceland Ieeland Iceland Ieeland

1971 + 60 214 2831973 135 10 107 96 757 86 1,1911974 2 22 30 + 541975 + 2 50 73 5 1301976 5 9 30 102 2,015 584 2,7431977 7 2 + 26 305 94 4351978 2 + 169 335 47 5521979 2 + 1 22 345 + 3701980 1 2 + 38 507 10 5571981 19 41 19 781982 + + 7 4 111983 + + 85 66 2 1531984 372 5 + 200 826 369 1,7721985 32 + + 581 197 2 8121986 + 1 2 15 32 + 501987 7 1 2 61 10 811988 0 1 7 12 + 20

20

Table 5 1,1 Strata areas in square nautical miles off WestGreenland (NAFO Subarea 1) .

Division/stratum numberDepth

1F'zone 18 1C lC lC/D 10 1E Tott- l(meters) (nm )

2 3 4 5 6 7

0-100 865 593 598 0 1,475 276 + 3,807+101-200 1,256 1,574 1,902 17 875 1,662 + 7,268+

0-200 2,121 2,167 2,500 17 2,350 1,938 2,568 13,661

201-300 297 259 708 29 628 464 + 2,385+301-400 209 54 280 45 390 278 + 1,256+

201-400 506 313 988 74 1,018 742 971 4,612

401-500 149 122 156 60 176 33 + 696+501-600 215 293 78 118 83 24 + 811+

401-600 364 415 234 178 259 57 353 1,860

Total 2,991 2,895 3,722 269 3,627 2,737 3,892 20,133

, Strata areas only available by 200-m depth zones.

Table 5 1,2 Strata areas in square nautical miles offEast Greenland (leES Division XlVb).

Substrata = depth zones (m)Stratum

0-200 201-400 401-600 601-800 Total

1 25 3,073 998 345 4,4412 322 5,160 1,826 334 7,6423 1,562 2,495 1,011 226 5,294

Total 1,909 10,728 3,835 905 17,377

21

Table 5.3.2,1 NAFO Subarea 1 cod.Mean catch per unit of effort (100hooks) for small cod (ages 3-4). Numberof valid sets in brackets.

Division 0-100 m 100-200 m 200-300 m

1C Bank 0.29 (4) 0.00 (5 ) 0.00 (1)Coast 8.81 (10) 4.19 (7 ) 2.83 (3)Fjord 1.35 (3 ) 1. 64 (3) 0.18 (2)

1D Bank 6.60 (7) 7.50 (8) 2.30 (4)Coast 3.79 ( 10) 2.29 (12) 0.47 (2)Fjord 0.14 (2) 0.04 (4) 0.14 (2)

1E Bank 21.57 ( 1 ) - (0) 0.00 (2)Coast 0.00 (1) 0.00 (2) 0.06 (1)Fjord 2.60 ( 1 ) 0,00 (1) - (0)

Tab1e 5 3 2 2 NAFO Subarea 1. Cod.Mean catch per unit of effort (100hooks) for large cod (age 5+). Numberof valid sets in brackets.

Division 0-100 m 100-200 m 200-300 m

1C Bank 0.00 (4) 0.00 (5) 0.00 (1)Coast 0.56 (10) 0.16 (7 ) 0.10 (3)Fjord 0.19 (3) 0.05 (3) 0.00 (2)

1D Bank 3.15 (7 ) 3.43 (8) 1.03 (4)Coast 3.20 (10) 0.94 (12) 0.14 (2 )Fjord 0.00 (2) 0.09 (4) 0.00 (2)

1E Bank 1.80 (1) - (0) 0.00 (2)Coast 0.30 ( 1 ) 0.00 (2) 0.81 (1)Fjord 0.93 (1) 0.00 (1) - (0)

22

Table 6.1.1 Nominal catches of cod in NAFO Subarea 1 (1979-1988).

Country 1979 1980 1981 1982 1983

Faroe Islands 38 1,339Fed. Rep. of Germany 1,344 1,024 417 8,139 10,158France - M 139Greenland 46,384 45,838 53,039 47,693 44,970JapanNorwayUni ted Kingdom 1,174

Total 47,9051 46,862' 53,456' 55,832' 57,641

working Group estimate 99,000 54,000

Country 1984 1985' 198641987

41988

4

Faroe IslandsFed. Rep. of Germany 8,941 2,170 37 68 6,352France - MGreenland 22,041 12,319 6,546 18,477 51,237Japan 13 9 2Norway 5Uni ted Kingdom 1,027

Total 31,0002 14,5443 6,583 18,554 58,618

Working Group estimate 61,618

, ICNAF/NAFO Statistieal Bulletin.2NAFO SCS Doe. 85/22.3NAFO ses Doe. 86/22.4provisional data.

23

Table 6,1.2 NAFO Subarea 1 Cod. Nominal catch by division and qear in1988 (Workinq Group estimate) (provisional fiqures intonnes) .

Division Pound net Longlines Handlines Gillnet Otter trawl Total

1A 2 218 3,869 393 1,036 790 214 6,3021C 706 145 199 129 2,336 3,5151D 2,159 562 453 245 17,134 20,5551E 3,455 780 832 297 13,330 18,6941F 2,626 81 603 493 6,173 9,9761NK 2,574 2,574

Total 12,817 1,963 3,123 1,954 41,761 61,618

Table 6 1,3 NAFO Subarea 1 Cod. Nominal catches 1988 (WorkinqGroup estimate) (provisional fiqures in tonnes) permonth and division.

Month 1A 1B 1C 10 1E 1F 1NK Total

Jan 56 280 826 4,050 5,213Feb 13 18 1,092 240 1,363Mar 13 12 984 466 1,475Apr 15 2,455 841 840 4,151May 255 79 3,423 1,466 853 6,076Jun 1,782 524 1,608 2,943 858 7,715Jul 2,282 286 2,420 1,450 901 7,339Auq 464 144 995 1,296 923 3,822Sep 418 83 1,540 1,132 232 365 3,770Oct 311 2,324 1,256 182 179 4,252Nov 466 59 3,586 2,459 171 2,207 8,948Oec 227 16 2,962 4,026 260 7,491NK 2 2

Total 2 6,302 3,515 20,555 18,697 9,973 2,572 61,618

24

Table 6.1.4 NAFO Subarea 1 Cod. Nominal catches 1988 (Working Groupestimate) (provisional figures in tonnes) by gear permonth.

Month Pound net Longlines Handlines Gillnet Otter trawl Total

Jan 197 8 19 4,956 5,180Feb 103 13 14 1,352 1,482Mar 159 11 11 1,412 1,593Apr 138 78 45 3,691 3,952May 2,103 270 171 299 3,251 6,094Jun 3,989 281 268 276 2,883 7,697Jul 4,175 404 447 299 2,013 7,338Aug 1,847 131 975 129 740 3,822Sep 591 61 587 50 2,481 3,770Oct 110 63 274 192 3,613 4,252Nov 88 217 468 8,172 8,945Dec 68 74 152 7,197 7,491NK 2 2

Total 12,817 1,963 3,123 1,954 41,761 61,618

Table 6 1 5 Nominal catches of NAFO Subarea 1 cod for 1977-1988 ('000 tl.

Category 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988

Trawlers 463 533 573 16 14 29 42 18 7 1~ 6~ 426

Other 27 20 42 38 39 26 16 12 8 4~ 13~ 20~

Total 733 733 993 543 53 55 58 30 15 5~ 19~ 626

TAC 312 1 1 20' 50' 62 62 68 28.5 12.55 12.5 53

;Catches limited to Greenlander's fishery and to by-catches.3Quota for offshore fishery only.~Estimates used for stock assessments.5Provisional data.

net tishing (with someDirect trawling prohibited. Ban on pound exemptions) trom6mid-July.

data . Estimates used for stock assessments.Provisional

25

Table 6.1.6 NAFO Subarea 1 cod. Effort (hours fished) and catch per unit effort (CPUE ;kqjhour) for Greenland trawlers (500-999 GRT class) in 1975-1966. Only fiq-ures for directed cod fishinq are used.

lB lc 10 lE lF TotalYear

Hours CPUE Hours CPUE Hours CPUE Hours CPUE Hours CPUE Hours CPUE

1975 1,132 57 6,666 1,467 4,696 293 3,154 422 243 346 16,091 7691976 236 36 5,071 594 5,912 541 6,319 753 17,536 6261977 - 2,432 1,019 1,531 966 3,446 1,564 121 2,421 7,530 1,2931976 - 3,562 3,314 615 2,962 673 3,743 70 3,029 5,320 3,3271979 - 2,963 2,155 1,163 3,063 365 1,946 9 2,667 4,520 2,3761960 727 2,461 1,513 1,068 1,963 692 1,092 1,277 31 613 5,346 1,2381961 1,279 3,326 1,656 2,533 952 4,602 5 4,092 3,2591962 100 1,330 1,937 2,077 4,064 1,760 3,221 2,903 17 647 9,359 2,2121963 927 315 593 946 4,039 984 6,295 1,608 114 962 11,968 1,3641964 51 20 19 + 1,926 1,004 2,246 1,055 317 564 4,561 96519851 10 376 370 2,050 160 113 962 2,551 70919661967

21,549 1 5,794 457 1,704 11 604 473 1,690

1988 564 2,185 4,679 2,765 1,634 3,149 337 4,396 7,212 2,663

;NO directed trawl fishery for cod allowed in 1966.Provisional data.

Table 6.2.1 COD OFF WEST GREENLAND - CATEGORY: TOTAL. N0>

CATCH IN NUMBERS UNIT: thousands----------------

1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977

3 1530 1727 3764 662 49 272 51 131 343 275 10760 6344 7872 15091 7976 12399 2768 2519 10039 2302 1079 3595 4026 466495 62130 30457 36670 8709 10342 10172 9786 16378 2384 2677 2243 60536 26941 61848 29824 27433 6465 9283 12020 3065 6938 1803 1216 15157 5915 24562 34591 14664 13985 5237 4081 2605 1135 5855 302 6J.88 4955 2700 10005 12411 4365 9158 2550 1406 1806 1388 1594 4259 6912 1996 1725 4784 2810 2077 2660 1203 800 619 139 446

10 1289 5237 833 513 1280 1841 624 552 194 291 148 16811 283 352 2348 237 149 953 954 165 177 84 53 7912 130 93 187 704 85 78 709 237 152 38 27 8813 981 166 37 41 201 51 130 93 272 9 17 2214 139 453 42 62 27 134 57 37 147 12 14 1

15t 247 85 303 8 41 56 122 44 11 10 26 1

TOTAL 119324 144767 128305 82627 42567 41831 43783 28218 15438 16656 20565 56699

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988

3 287 286 2999 12 1204 77 595 456 12 8626 8324 5494 10656 4513 16864 1210 12356 2018 1266 113 2474 497665 30039 12505 4580 6374 17960 2011 10384 1303 706 415 10606 1004 18970 1978 2391 2965 17228 688 4915 318 1001 4977 509 709 8014 1053 2078 1581 3656 161 1193 641 6468 83 400 125 3382 807 995 106 750 12 1037 5199 41 78 60 45 610 344 365 42 332 11 744

10 13 52 24 65 45 343 97 140 80 45 2111 7 55 1 1 88 3 69 15 13 2 8312 7 80 16 1 9 22 0 8 35 3 013 7 5 3 0 4 0 3 0 0 0 014 1 5 1 0 1 2 0 0 0 1 0

15t 1 16 2 7 13 19 0 14 0 17 0

TOTAL 37493 43817 22316 30195 26994 34981 17981 9070 2814 14273 54168

Table 6.2.2 West Greenland Cod, NAFO Sub-area 1. Total internationalcatches by age groups. Jan-Octand Nov-Dec 1988. Numbers in'000.

Age Jan-Oct Nov-Dec Total

3 642 190 8324 37,354 12,412 49,7665 735 325 1,0606 364 133 4977 472 174 6468 439 80 5199 675 69 744

10+ 88 16 104

Total 40,769 13,399 54,168

27

Table 6.3 Mean weight at age in the main fisheries at WestGreenland in 1988 (kg whole, round fish).

German Greenland Long- Gill- Pound Weight\,dAge trawl trawl line net net Handling total

2 0.216 0.2163 0.461 0.700 0.810 0.810 0.713 0.740 0.5504 0.868 1.114 1.402 1.267 1.053 1.209 1.0815 1.208 1. 349 1. 970 2.000 1.078 1.430 1.2796 1.318 1.964 2.274 1.910 1.346 1.420 1.8937 2.086 2.643 2.658 2.850 1.508 2.770 2.3818 2.060 2.491 3.238 3.280 2.428 2.6619 2.603 2.847 3.839 3.610 2.328 2.904 3.128

10 3.095 3.970 3.961 4.720 4.07311 3.060 3.060

weight\,d 0.929 1.173 1.921 1.838 1.053 1. 212 1.143mean

1Weighted by catch in numbers in each age group and gear category.

West Greenland cod. Autumn survey abundance estimates (no. x 103) by age and division,

N

Table 6.5.1 1982-1988. The <Xl

respective survey biomass estimates (tonnes) and mean weights are below.

Divisions lB+C Division lDAge

1982 1983 1984 1985 1986 1987 1988 1982 1983 1984 1985 1986 1987 1988

0 104 124 32 68 131 131 60 18,148 1,193 363 244 16 4 7,765 2,752 23 122 610 166 78 725 35,014 6,774 1,911 90 395 11 349 33,830 8,237 7823 3,686 228 29 249 737 142,759 1,522 18,862 2,915 282 300 1,582 227,042 65,1024 292 352 36 133 43 2,745 470 4,151 15,059 847 898 197 4,012 388,4995 96 4 107 64 51 1,267 3 21,238 683 3,203 1,340 482 1,903 3,0386 11 13 7 74 31 1,811 + 3,903 2,779 151 2,766 363 3,801 7307 2 80 3 85 222 2 1,082 203 625 81 512 501 7678 13 1 330 + 270 271 20 155 8 1,431 3259 36 20 1 335 60 97 25 688

10 1 30 30 52 7 2 15011 7512 7013 1514NK 39 27

Total 4,757 763 477 19,533 37,176 156,333 4,133 50,161 22,459 5,315 13,785 39,753 247,113 459,943Tonnes 2,387 393 789 2,378 13,333 131,909 1,188 60,757 29,666 8,383 11,447 19,483 198,252 452,870w (kg) 0.502 0.515 1. 651 0.122 0.359 0.844 0.287 1.211 1. 321 1.577 0.830 0.490 0.802 0.985

NQll: The age compositions for the northern Divisions lB+C and lD and for the southern Divisions lE and Ir are basedon separate age/length keys comprising ageing material from the respective groups of divisions.

(cont'd)

Table 6 (cont'd)

Division lE Division IrAge

1982 1983 1984 1985 1986 1987 1988 1982 1983 1984 1985 1986 1987 1988

0 10 149 40 4381 65 4,622 3,488 10 19 3,856 2,797 142 15 658 5 195 26,096 10,072 7 516 4 146 13,056 12,582 183 8,951 111 826 37 768 108,967 9,887 5,191 72 850 11 580 34,754 16,0524 2,854 9,302 333 3,503 188 4,377 32,452 3,523 6,733 241 1,195 146 1,597 39,1145 6,214 2,463 3,172 599 4,037 707 309 11,241 2,709 2,635 195 3,051 328 5666 2,613 3,718 299 2,510 256 2,342 13 7,091 6,448 350 945 270 1,424 347 627 752 586 122 1,062 307 191 3,046 1,268 768 145 1,429 197 1838 115 393 30 180 27 955 71 661 508 36 260 68 651 659 227 157 49 4 91 254 1,443 158 59 18 316 246

10 22 84 4 5 3 50 15 74 62 11 13 14 86 1111 5 2 6 23 12 5 2 17 81213 2114 13NK 67 32 20

Total 21,775 17,646 5,316 11,926 36,022 127,803 43,214 32,346 18,494 4,996 7,222 21,765 51,619 56,311Tonnes 29,599 31,056 7,526 11,934 23,675 96,433 40,698 87,191 37,728 8,247 6,101 19,729 37,692 52,810W(kg) 1.359 1. 760 1. 416 1.001 0.657 0.755 0.942 2.696 2.040 1. 651 0.845 0.906 0.730 0.938

(cont'd. )

wTable 6 5 (cont'd) 0

TotalAge

1982 1983 1984 1985 1986 1981 1988

0 222 842 481 160 4 34,391 10,230 386 2602 122 1,135 98 1,415 101,996 31,665 2,1113 36,690 3,326 1,981 591 3,661 513,522 92,5634 10,820 31,446 1,451 5,129 514 12,731 460,5355 38,789 5,859 9,117 2,198 7,621 4,205 3,9166 13,618 12,958 801 6,295 920 9,378 1111 4,751 2,223 2,059 351 3,088 1,227 1,1438 1,046 1,112 86 608 104 3,361 4619 2,005 375 241 22 452 1,189

10 126 198 22 18 20 316 2611 85 4 23 23 2012 7013 15 2114 13NK 138 55

Total 109,039 59,362 16,104 52,466 134,116 582,868 563,601Tonnes 119,934 98,843 24,945 31,860 16,220 464,286 547,566w (kg) 1.650 1.665 1. 549 0.607 0.566 0.791 0.912

31

Iable 1.1 Nominal catches (in tonnes) of cod in ICES Sub-area XIV,1919-1988. (Data for 1918-1981 broken down by countries arefrom Bulletin Statistique.)

Country 1919 1980 1981 1982 1983

Faroe Islands 292 368Germany, Fed. Rep. 1,062 3,193 1,367 8,940 8,231Greenland 2,755 1,778 890 893 438Ieeland 3 19 1

Total 3,820 4,990 8,550 9,833 9,043

Workinq Group estimate 34,OOO~+ 12,0002) 16,0002,3 21,0002,3 13,3773

Country 1984 1985 1986 19811 19881

Faroe Islands 2Germany, Fed. Rep. 6,981 2,006 4,0655 5,1176 11,7021Greenland 1,047 106 601 1,541 380IeelandUSSR 65

Total 8,034 2,112 4,668 6,658 12,147

workinq Group estimate 8,0683 2,112 4,668 6,658 9,1478

1Preliminary.~InClUdinq estimates of discards.

Includinq catches reported from ICES Sub-area XII and Division Vb.+Includinq estimates of unreported catches.5InclUdinq 91 t by chartered trawlers.6Includinq 74 t by chartered trawlers.1Includinq 42 t by chartered trawlers.8Excludinq 3,000 t assumed to be from NAFO Division lF.

Table 7.2 COD OFF EAST GREENLAND - CATEGORY: TOTAL. wN

CATCH IN NUM8ERS UNIT: thousands----------------

1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976

3 0 28 0 0 0 0 0 0 4 4 57 2574 131 21 145 104 31 66 25 27 25 63 57 1755 35 470 302 630 252 76 171 85 197 22 339 1626 91 89 2346 502 849 500 159 254 126 488 86 5907 879 137 564 2505 770 1539 1051 295 250 176 783 2288 661 1071 210 238 2103 1060 3785 1299 82 185 155 15469 1484 359 1292 62 170 1715 1580 3184 710 52 82 158

10 59 418 492 144 38 237 1326 818 959 329 21 11611 27 23 371 69 82 32 171 470 222 259 66 5312 139 3 37 27 68 63 19 136 72 65 52 1313 29 27 17 5 24 48 4 26 19 11 16 30

14' 178 36 81 25 86 27 14 53 7 2 4 2

TOTAL 3713 2682 5857 4311 4473 5363 8305 6647 2673 1656 1718 3330

1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988

3 0 0 5 14 0 0 0 13 0 68 737 4014 4635 427 145 78 5 0 104 97 34 50 145 37415 1205 6808 1184 235 72 458 593 334 111 432 59 1686 513 1828 4700 223 252 1335 2376 436 242 287 303 407 652 188 2755 2330 378 2012 962 1485 105 738 148 3768 208 205 797 695 2898 1605 321 290 196 66 651 499 424 Ul 121 77 231 2123 116 93 19 122 56 226

10 164 278 51 9 22 146 229 39 12 5 294 1011 77 130 18 2 9 18 10 55 4 4 12 11412 29 93 11 5 5 6 2 1 4 0 26 813 9 56 1 1 5 3 2 1 0 0 0 9

14' 1 19 1 6 3 0 0 0 0 0 0 5

TOTAL 7917 10143 9789 3675 3880 7706 4715 2844 727 1772 2431 5147

33

Table 7.3 East Greenland cod. Mean weiqht at aqe (kq).

Survey Nov-Dec Survey 0ft-NoV Survey Oct-Nov Survey OftoberAqe 1981 1982 1983 1984

Applied for 1982 Applied for 1983 Applied for 1984 Applied for 1985

3 0.352 0.200 0.294 0.525 0.700 0.562 0.815 1. 116 1.273 1.132 1.526 1. 954 2.158 2.569 2.337 3.182 3.071 3.403 3.158 4.209 3.713 4.899 3.949 6.161 4.680 5.310 4.67

10 9.173 6.234 6.946 5.3311 9.390 5.350

18.974 5.89

12 12.981 6.806 7.000 6.3813+ 7.5551 14.500 6.79

AgeSurvey Oftober Survey Seftember Survey Seftember Survey Seftember

1985 1986 1987 1988Applied for 1986 Applied for 1987 APplied for 1988 Applied for 1989

3 0.25 0.30 0.32 0.2354 0.78 0.93 0.90 0.7755 1. 58 1. 79 1. 74 1. 7316 2.60 2.75 2.76 3.0287 3.73 3.70 3.88 3.5838 4.91 4.58 5.02 4.9659 6.09 5.36 6.14 5.235

10 7.21 6.03 7.20 6.58811 8.27 6.59 8.17 7.07712 9.23 7.05 9.06 8.97513+ 10.11 7.42 9.84 9.975

;Estimated from linear reqression of w on aqe 3-11 cod.Calculated value based on the observed values usinq the von Bertalanffy

3qrowth equation.Calculated from combined lenqth-weiqht relationship from East and WestGreenland survey.

34

Table 7 5.1 East Greenland cod. Estirnates of trawlable bio­rnass, based on the Federal Republic of Germanytrawl surveys from 1980-1988.

Biomass Stock numbersYear Season Ship

Tonnes ±\ No. x 103 ±\

1980 Oct-Nov "Karlsburg" 62,944 33 15,425 341981 Nov-Dec "w. Herwiq" 88,336 43 19,448 351982 Sep-Oct "w. Herwig" 19,782 35 6,106 5219831 Sep-Oct "W. Herwig" 26,980 38 6,730 331984 Oct "A. Dohrn" 21,151 42 6,488 511985 Oct "w. Herwiqll 21,842 26 7,815 271986 Sep-Oct "w. Herwig" 44,288 34 17,554 321987 Sep-Oct "w. Herwig" 33,929 36 25,296 371988 Sep-Oct "w. Herwig" 41,817 47 18,859 40

ronfidence intervals are given at the 95\ significance level.only 36 valid hauls.

Table 7 5 2

Northern:

Middle:

Southern:

Age composition of cod in the northern,middle, and southern p~rts of the sur­veyarea (numbers x 10 ).

North of 640 30'NEast of 35° W

North of 630 NWest of 35° W

590 N - 630 N400

W - 430W

Age Northern

0 412 43 44 2045 3016 377 17589 8

101112131415

Total 737

Middle

27662

1,338387

32648

44307

42183

624

12

3,712

Southern

145,5158,044

26430

2561887

3159

14,410

Total

4

456,1819,606

95299

1,07962

40245

3426

24

12

18,859

35

Table 7,5,3 East Greenland cod. Aqe composition in numbers x 103, based on the results ofthe Federal Republic of Germany's autumn trawl surveys from 1980-1988.

Year class 1980 1961 1982 1963 1964 1985 1986 1967 1988

1988 419811986 9 451985 126 2,219 8,631 6,1861984 775 4,373 10,911 9,6061983 15 481 2,035 2,422 9521982 77 68 610 597 991981 12 345 1,174 1,733 2,473 961 1,0791980 252 508 559 1,363 1,108 248 621979 105 495 846 1,449 1,207 2,173 798 4021978 128 786 1,029 997 885 470 575 79 451917 492 2,632 1,296 1,784 1,528 1,279 1,666 570 3421976 1,067 1,798 913 1,080 505 185 127 15 61975 1,318 1,676 279 253 157 50 107 43 241974 1,712 2,496 105 222 46 24 11 31973 8,270 6,537 1,462 590 62 29 77 3 121972 2,154 973 142 581971 122 179 73 271910 51 26 81969 68

Residual 19 239 40 20 31 19

Sum 15,425 19,448 6,106 6,730 6,488 7,815 17,554 25,296 18,859

Confidence limits51.17'in \ at 95\ siqni- 33.87 35.29 52.5 33.08 26.80 31. 94 36.60 33.80

ficance level

'Only 36 valid hauls.

36

Iable 7 East Greenland Cod, Assessment Table.

A B C 0 E F G H

Calculated stockSurvey Survey Diff.

Year From 86 From 87 corr. Catch results Catch immigr.Age class survey survey factor Jan-Oct Sep-Oct Nov-Dec F age 6+

illl

2 1985 10,028 8,631 32 <0.013 1964 13,156 439 10,917 298 0.074 1983 1,957 2,876 1. 47 56 2,422 87 0.065 1982 585 721 1.23 25 597 34 0.106 1981 2,172 1,373 239 961 64 0.28 -7997 1960 1,042 514 132 248 16 0.43 -5288 1979 1,853 1,849 591 798 60 0.56 -49 1978 527 173 50 79 6 0.50 -354

10 1977 1,507 1,125 255 570 39 0.39 -38211 1976 117 35 11 15 1 0.54 -8212+ <1976 178 99 24 49 2 0.38 -79

Iotal - F(5-10l = 0.38 -2,228

Calculated stockSurvey Survey oiff. =

Year From 87 From 88 corr. Catch results Catch immigr.Age claS5 survey survey factor Jan-Oct Sep-Oct Nov-Dec F age 6+

.ill.1

2 1986 453 1985 8,179 7,573 0.926 364 6,186 37 0.064 1984 10,094 14,837 1,470 3,426 9,606 315 0.325 1963 2,219 1,239 0.556 124 952 44 0.166 1982 535 154 36 99 4 0.34 -3817 1981 852 1,939 320 1,079 46 0.28 1,0878 1980 204 144 46 62 3 0.55 -609 1979 650 803 186 402 36 0.43 153

10 1978 64 77 10 45 0.17 1311 1977 468 611 98 342 16 0.27 14312+ <1977 53 86 21 42 1 0.38 33

Total F(5-10) 0.32 988

(cont'd)

37

Table 7 (cont'dl

Stock Mean Immigr. Stockfrom survey from for

Year 5urvey corr. West projec- Re!. Re!. Prop.Age class (Al factor Greenl. tion F M mat. w

llll

3 1986 434 1985 5,843 2.40 14,023 1.0 1.00 0.18 0.785 1984 8,830 1. 75 15,453 1.0 1.00 0.35 1. 736 1983 863 863 1.0 1.00 0.56 3.037 1982 90 90 1.0 2.45 0.76 3.588 1981 902 902 1.0 2.45 0.88 4.979 1980 52 52 1.0 2.45 0.95 5.24

10 1979 320 320 1.0 2.45 0.98 6.5911 1978 40 40 1.0 2.45 1.00 7.0812~ <1978 323 323 1.0 2.45 1.00 8.98

Jan-Oct Nov-Dec

Age 3-6 M= 10/12 of 0.20 =0.167 2/12 of 0.20 = 0.033Age 7+ E~M = 10/12 of 0.49 =0.408 2/12 of 0.49 = 0.082

Jan-Sep Oct-Dec

Age 3-6 M = 9/12 of 0.20 =0.150 3/12 of 0.20 =0.050Age 7+ E~M = 9/12 of 0.49 = 0.368 3/12 of 0.49 = 0.123

Estimates of stock size refer to 1 January. Numbers in thousands.

(Al = Stock calculated from previous year's survey using catchesfrom the post survey per iod of that year and the appropriatefractions of Mand E.

Table 7 7,2 East Greenland Cod. Input variables byagegroup for catch projection for 1989. Numbersin '000 and weight in kg.

Stock sjze Rel. prop.2Age at 1 Jan 1988 F M' mat. w

4 14,043 1.0 0.20 0.18 0.785 15,453 1.0 0.20 0.35 1. 736 863 1.0 0.20 0.56 3.037 90 1.0 0.49 0.76 3.588 902 1.0 0.49 0.88 4.979 52 1.0 0.49 0.95 5.24

10 320 1.0 0.49 0.98 6.5911 40 1.0 0.49 1.00 7.0812~ 323 1.0 0.49 1.00 8.98

'The emigration factor of 0.29 is lncorporated in the M2values from age group 7 onwards.

Values are smoothed by a sigmoid curve.

Figure 3.1 Main spawning grounds, migrations of mature fish and larval drift of theead stocks at West Greenland, East Greenland and Ieeland .

w00

•--7-4

MAIN SPAWNING GROUNDS

LARVAL DRIFTMIGRATIONS OF MATURECOD

39

'0

~ k~

~-~

~iJC

lA - -.t;;:; ~

"r"'!-'"

b.~ ~ '"~

. ,., .l>',.' D~,;K

~.- <:i

:-5 I;;.- ...b-' -

rJ 11>

~L~

1\.,..•

NAFO SA'

~.Figure 5.1 Survey areas and stratification off East and West Greenland.

40

Biomass('000 t)

Abundance(no. in millions)

600

500

400

300

200

100

Abundance

j---.

j.L:'IIIIIIIII

.~ //',. /

' .......~ //.'. /......., ......-',:?'< .

600

500

400

300

200

100

o.l----l-_---'L---__.L-__.l-__...l-__....l...__-L.__......J

1982 1983 1984 1985 1986 1987 1988

Figure 6.5.1 West Greenland cod. Trends in survey biomass andabundance estimates, 1982-1988.

20

40

60

--.I·IIllIo=>J2........,---1- 0­

80

20

40

~o 2 4 6 8 10 1280604020

41Per mille Percent

150 198460

100 40

50 20

-0 ~--- 0-

200 801985

150[GO

100 40

50 ~ 20

-0 I 0-

f200 1986 L 80

150 ~ 60

100 - 40

50 20

• P7J0-80

198760

Length Age

Dominant [[IJ ~ ~ 11.Year classes: 77 79 81 8485

Figure 6.5.2 West Greenland cod. Length frequencies (per mille) and agecompositions (percent) from survey results, 1984-1988.

42

150

100

50

Figure 7.5 East Greenland cod. Regional length distributions fromtrawl survey results in 1988.

area

N = 181

O+---L..L--LL...-,---l...L-_.L.L4-Ll.JL..U...L.L...LL+..LLLLL_--,- -----,

150area 2

N = 1242

100

50

O+------l....Lf...Ll....LL.L.LLLLf-lL..U-l-l.L.LLLj.-LLUL..U.l::1:::J..,------,

150area 3

N = 2731

100

50

o+----=l=4-J...LLLJ....L.l..LL+-LUJ.J:::r:i.1:=p===::b....---, --,

o 30 60 90 120 150 cm

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

•43

Fi gure 7.9.1 FISH STOCK SUMMARYSTOCK: East Greenland Cod

03-03-1989

Short-term yield and spawning stock biomass

_ Yield •••• SSB

10 c.~

o01m

>­'­ro:Jc

40 roJ

aJUJUJ

50

30U;QlCCo....,o

20;5

+

V'" V

V'" . V'"

~'" 1/'" K./ '.

'/V '" ".

"

//

/

/Io 0

o.00 O. 10 0 . 20 0 . 30 0 . 40 0 . 50 0 . 60

Average fishing mortal ity (ages 5-10, u)

25

20U;QlCC0....,0 1500

01aJ01- 10c.~

"0.-.Ql.~

>- 5

The calculated SSB in 1990 does not include estimatesof immi grants in 1990.