r

FISHERIES AND MARINE SERVICE

Translation Saries No. 3 13I !ARCHIVES

Iceland scallop, Chiamys islandica (0,F. Muller), at Spitsbergen and Bear Island.- Investigation in 1973

by K.F. Wiborg, k.Hansen, and H.E. Olsen'

Original title: Haneskjell (Chlamys ialandica Muller) ved Spitsbergen og Bjç4rny6ya Underskelser i 1973

From: Fiskets Gang (FisberiesMigration), 60(11) : 209-217, 1974

• Translated by the Translation BureaueMJ) Multilingual Services Division

Department of the Secretary of State of Canada

Department of the Environment Fisheries and Marine Service

Biological Station, St. Andrews, N.B. Biological Station, St. John's', Nfld.

1974

18 pages typescript

• MULTILINGUAL SERVICES CANADA

SECRÉTARIAT D'ÉTAT

BUREAU DES TRADUCTIONS

DIVISION DES SERVICES

(7'

a.,

DEPARTMENT OF THE SECRETARY OF STATE

TRANSLATION BUREAU

INTO — EN

English

TRANSLATED FROM — TRADUCTION DE

Norwegian

PUBLISHER — ÉDITEUR

Directorate of Fisheries

PLACE OF PUBLICATION LIEU DE PUBLICATION

DATE OF PUBLICATION DATE DE PUBLICATION'

YEAR ANNjE

PAGE NUMBERS IN ORIGINAL NUMÉROS DES PAGES DANS

L'ORIGINAL

209-217 NUMBER OF TYPED PAGES

NOMBRE DE PAGES DACTYLOGRAPHIÉES

ISSUE NO. HUME RD

VOLUME

'Bergen, Norway 1974 60 18

PERSON REQUESTING DEMANDE. PAR JIP 7 4 r7A —

Allan T. Reid.

DIVISION MULTILINGUES

ts • - 11.4 3131

AUTHOR — AUTEUR

K.F. Wiborg, K. Hansen and H.E. Olsen

TITLE IN ENGLISH — TITRE ANGLAIS

Iceland Scallop, Ghlamys Islandica (0.F. Muller) at ,Spitsbergen and Bear Island - Investigations in 1973 •

TITLE IN FOREIGN LANGUAGE (TRANSLITERATE FOREIGN CHARACTERS) • TITRE EN LANGUE ÉTRANGÈRE (TRANSCRIRE EN CARACTèRES ROMAINS)

Haneskjell (Chlamys Islandica Muller) Ved Spitsbergen og BjernOya - Undersekelser i 1973

REFERENCE IN FOREIGN LANGUAGE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHARACTERS.

RÉFÉRENCE EN LANGUE ÉTRANGÉRE (NOM DU LIVRE OU PUBLICATION), AU COMPLET, TRANSCRIRE EN CARACTÉRES ROMAINS.

Fiskets Gang

REFERENCE IN ENGLISH — RÉFÉRENCE EN ANGLAIS

REQUEsTING DEPARTMENT Environment TRANSLATION BUREAU NO.

MINIST .ERE-CLIENT NOTRE DOSSIER N ci 66iO37

Fisheries Services PMJ • TRANSLATOR (INITIALS) BRANCH OR DIVISION TRADUCTEUR (INITIALES) DIRECTION OU DIVISION

.YOUR NUMBER •

VOTRE DOSSIER NO

DATE OF REQUEST DATE DE LA DEMANDE

50s-200-10.6 tHEy. z/e6)

7030-21.020-I5 3 3 3

I

DEPARTMENT OF THE SECRETARY DF STATE

TRANSLATION BUREAU

MULTILINGUAL SERVICES

DIVISION CANADA

SECRÉTARIAT D'ÉTAT

BUREAU DES TRADUCTIONS

DIVISION DES SERVICES

MULTILINGUES

CLIENT'S N0.NO DU CLIENT

D'PARTMENT DIVISION/BRANCH CITYMINISTERE DIVISION/DIRECTION VILLE

Environment Fi.sheries Services Otta;,a, `?nt.BUREAU NO.

NO DU BUREAULANGUAGE TRANSLATOR(INITtALS)LANGUE TRADUCTEUR ( INITIALES)

663037 Nor<<vegian PSITJ : `T I ';

Iceland Scallop, Chlamys Islandica (O.F. Nlüller) at Spitsbergen

and Bear Island -Investigations in 1973

Haneskj ell •(Chlamys - Is larrdi ca Alüller) Ved Spitsbergen

og Bj¢rnOya - Unders¢kelser i 1973

by

Kristian Fredrik Wiborg and Karsten HansenNorwegian Institùte for Marine Research, Bergen

and

Hans Edvard OlsenOffice for Experimental Fishing and Vessels, Directorate of Fisheries

Fidkets Gang 60 (11) : - 209-217 (1974)

ABSTRACT

WIBORG, K. F., HANsr•.N, K. o(,^ Otsr•.N,1•I. E. 1974. Haneskjcll(Cklamys isGmtlica N^IÜllcr) vcd Spitsbergen og 13jcornoya -Undersokelser i 1973. [Iceland scallop, C.'lrlamys islandica (O. F.MUller), at Spitsbergen and Bear Island -- Investigations in1973]. Ffskets Canq, 60: 209-217.

In August 1973 experimental fishing for Chlarays islandica offSpitsbergen revealed extensive fields north of the island andalso some concentrations on the western hanks. L'p to 1700scallops were t:ucen in '?U minute hnuls usitl;, a sc•allr,li c!n.-d,r

with an opening of 3.6 nt. At Bear Island fields discovered inprevious years were fished, viclding up to'?U00 scalloll< per h:lul.

Owing to the selectivity of the gear. mitinly sc•:Iil,)la (it) -

90 nim in diarneter were c.ilght. The age of the u•nllups wasestitnc:ted to hi• 10--15 ycars. C;rowth. ;!s deeluced fi•uru

ti(^iu:u r,r nzones, was nioderate at Bear Island and north ofand slower at the Mitra Bank.

ghts of aclductor muscle were'lii<^hest at Bcar'island, 913 and 18 g for scallops 70, 80 and 90 mm respectivch•. ASpitsbergen the, corresponding weights were mostly 7, 1O an13 g, but at the Mitra Bank only 4.5 g for scallops of 70 min

The scallops supposedly spa%^•ned in July; the regeneratingonads in 70-90 mm scallops .veighitig about 4-5 g at BeaIsland, 2-4 g at Spitsbergen and below one ,, on the \Iitr•Bank. The gonads «•eighecl more in male, than, in fenialscallops.

The scallop banl<s north of Spitsbcrgen and at Bear Islam

are supposed tci be very rich, but with it slow rate of rcgencra

tion. Commercial fishcrv is not vet profitable, Inainlv bcc:iwd

of the high costs related to the fishing and to the procrssin;

of the scallop meats. Future mCchanisatlon may diminish thi

cxhenses.

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2

Introduction

The distribution of Iceland scallop around Bear Island and toward Hope

Island has been determined earlier (iUborg 1970) . Stocks of Iceland scallop off

Spitsbergen are known both from the literature (see Wiborg 1963) and from obser-

vations from trawlers and research vessels, but not in detail. Urider the

direction of H.E. Olsen, experimental fishing for Iceland scallop was carried out

off the west and north coasts of Spitsbergen and off Bear.Island with R/V

"FEIEBAS" (Hansen, Husa and Olsen 1974) in August 1973.

Material and Nethods '

The gear used for most of the trip was a commercial scallop dredge

("large dredge") bought in Iceland. It was described by Hansen, Husa and Olsen

(1974). The large dredge is.of triple construction (Fig. 1). Each part has an

.opening of 120 x19 cm, a flat iron with spikes underneath and a bag which on

the underside consists of steel rings linked together, 80 mm in diameter, and on

the top a net of nylon with 120 mm meshes. Shells smaller thari 80 mm will not be

taken nuant'itatirely, and seine large ^1^ellS will p robably aiSo go through the

- meshes in the nylon net.

On some stations a modified Baird-mussel dredge ("small dredge") was used,

and this had an opening of 100 x 26 ,cm and 120 x 26 cm (Niborg 1963). It had a

smaller mesh,size than the large rake.

The large dredge was to^•ved fo.r 200 minutes, the small dredge for 5-10 p-210

minutes. By comparing the catches off Bear Is land in 1968-69 (iViborg 1970) taken

with a small dredge, and from the same place in 1973 with a large dredge, it could

appear as if the latter is 4-5 times as effective, but this value must be taken

with reservations.

When the catches had been taken on board, rocks, debris and empty shells

were sorted out. and the scallops frozen whole in boxes or sacks. Before freezing

1

— During later processing the height of the shells (distance from umbo, the

was of the shell to the opposite outer edge of the shell) measured with calipers

Fig. 1. Tredelt shetlandsskrape (storskrape) til fangst av hane- skjcll. Pryer del liar z-ipning 120 x 19 cm. Foto: K. Hansen.

. [Triple Shetland scallop dredge used for catching Iceland scallops. Each part has an opening 120 x 19 cm. Photograph:

K. Hansen]. • .

tip

carried out up to 10-15 mautical miles from was

the size (height) of the shèlls was neasured in representative samples.

3

to the nearest mm, and the measurements grouped in 5 mm groups (eiborg 1963).

After thawing, the muscles and gonads were separated from the rest of the

animal and weighed to the nearest 0.1 g in'groups for each 5 .mm group. The gonads

from males and females were then weighed separately for each individual group.

In a sample from Spitsbergen and one from Bear Island, the muscles were

weighed individually for each 5mm group.

Age and growth were determined by counting and measuring growth zones.

Mrs. S. Johannesen assisted in working up the naterial.

Bottom Topography

Off Spitsbergen, dragging

shore at 40-90 m depth. The bottom consists mostly of rocks, also Mffle she115,

in some areas with growths of horn corals and barnacles. Conditions for dritgglng

.were difficult and the use of heavy duty gear was necessary. Off Bear 15.1a4çl

4

the bottom conditions were characterized as good (Hansen, Husa and Olsen 1974).

In 1968 and 1969 the bottom conditions were found to be variable (Wiborg 1970).

Temperature Condition

From the areas off Spitsbergen, sea temperature measurements are available p.211

for 1955-1963 (Blindheim and Ljiien 1972), for August-September 1966-1969 (Dickson

and Doddington 1969-1970), and August-September 1973 (Midttun, personal communica-

tion). In the areas where Iceland scallop are fished, the temperatures in August-

September at 30-100 m depth are up to 4.5 °C while in the winter off Ny-Aalesund the

temperatures have been measured down to -1.5 °C at 40-100 m. On the Iceland

scallop grounds off Bear Island the bottom temperatures are approximately within

the saine limits (Wiborg 1970).

The Extent of the Iceland Scallop Beds

The cruise with "FEIEBAS" was classified as experimental fishing and no

systematic mapping was carried out. A list of dragging station and catches was

given by Hansen, Husa and Olsen (1974). The areas fished and maximum catches

are shown in Figs. 2-5.

North of Spitsbergen catches of up tb 1600 s

were obtained at . 50-55 m depth with the large dredge and 240 scallops in 7

minute drags with the small dredge (Fig. 3A).. Further towards the southeast

(Fig. 3B), up to 1200 scallops were taken with the large dredge at 40 . m depth.

On Sjubreflaket >(Fig. 3C) the fishing was carried out at 59-73 m, and at 60 m up

to 1700 scallops were taken'in a haul. However, the catches were uneven and the

dredge was often caught on the bottom.

On Mitragrunnen ("Mitra Shallows") (Fig. 4 D, E) there were mostly small

or no catches made except for a single haul yielding 1600 scallops. In the area

around Forlandet (Fig. 4 F, G) the catches were also small.

scallops per 20 minute drag

5

Off Bear Island the fishery was carried out at a depth of 90 m in areas

mapped in 1968-69. Southeast of the Island (Fig. 5 H, I) the catches were un-

even, up to 2000 scallops per haul. East of the Island (Fig..S K), the catclies

were smaller, 50-200 scallops per haul. At Spitsbergen the Iceland scallops

were most often strongly colored and had thin shells, similar to those found in

Balsfjord near Tromsd,, while those off Bear Island were greyish white with thicker

shel ls .-

Size Distribution

North of Spitsbergen in area A (Fig. 3) scallops with a shell diameter of

60-95 mm, mostly 75-80 imn, were taken (Fig. 6). The difference in selection

between the large and the small dredge is most^clearly shown in the size-distri-

bution. More scallops under 60 mm were taken with thesmall dredge and the maxi-

mum size was about 70 mm.(Fig. 6, A22 x). In area B (Fig. 3) scallops taken with

a small dredge (Fig. 6, B 4 x) were smal ler than thos e-taken further north

(Fig. 6, A 2 x), maximum 60 mm, while the large dredge took catches with a

variable size distribution. 'j'hPre was no si.."2Dle cQrrelation of shell sizes with -P -. 212

denth.

On Sjubreflaket (Fig. 3 C) there were large differènces between shell

sizes in catches taken with the large dredge and the small dredge while the dif-

ferences are not so obvious in Mitragrunnen (Fig. 4 D,'E),where the scallops were

$ Ÿ ler in catches takell with botii types of gear. Near aTcsjief j iet ( icsJ ï c

Mountain) (Fig. 4 G), the Iceland scallops were 65-95 mm with a maximum of 80 mm.

At Bear Island the shells in the southeast measured 70-95 mm with a maximum of

80-85 mm (Fig. 5 H, I); in the east a little smaller. Since no hauls were made

with the small dredge at Bear Island, it is difficult to make a comparison with

the conditions in 1968-69. In those years scallops with a shell size of 60-85 mm,

maximum 75 mm, were found in the southeast (IVâ.borg 1970).

6

• MOF FEN

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NORSKOVANE OA e.

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8 0° Od

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g° 11° 13°

Fig. 2. Provefiske etter haneskjell ved Spitsbergen i aug-ust 1973 med F/F «Feicbas». I) lugea fangst, 2) fangst, 3) omràde

" med to eller fiere trekk med fangst. [Experimental fishery for Iceland scallops at Spitsbergen in August 1973 with the R/V «Feiebas». 1) No catch, 2) catch,

3) area with two or more hauls with catch].

10° 11°i .

12° 13°

Fig. 3. Provefiskc ctter harieskjell ved Spitsbergen i aug-ust 1973. Antall skjcil pr. 20 ininutters trekk. 1) 0, 2) 1-10, 3) 11-100, 4) 101 —500, 5) 501 —1000, 6) over 1000, 7) omràde rued

rniddel ay to eller flere trekk. [Experimental fishery for, keland seaiiops at Spitsbergen in August 1973. Nuïnbcr of •scanops per 20 minute hauls. 1) 0, 2) 1-10, 3) 1 i —100, 4) 101-500, 5) 01-10O0, 6) more

i• - than IGGO, 7) a.:ca with average Of two or more hauls].

er.

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*>:01. V-2•1 ,

• Fig. 4. Provefiske etter haneskjell vecl SPitsbergen i august 1973. Syrnboler som pà Fig. 3.

[Experimental fishery for Iceland scailops at Spitsbergen in August 1973. Symbols as in Fig. 3].

74° 00'

Fig. 5. Provefiske etter haneskjell vcd Bjornnya i august 1973. Symboler sorn pà Fig. 3.

[Experimental fisher-y for iceiand scallops at Bear Island in August 1973: Symbols as in Fig. 3].

30'

20'

10' -I

--r- 19' 20°

8

Age Determinations

As earlier discussed (Wiborg 1963, 1970), it has been assumed that a

dark and light zone in the shell corresponds.to a growth zone (year). Johannessen

(1973) found two groups of small Iceland scallops near Troms'd in February-April

that measured 1.1-2.8 min and 7.140.7 mm respectively, and concluded that the

• smallest had come from the previous year's spawning in . June-July while the others .

were one year older. He demonstrated that growth zones existed both on shells

and ligaments, and found that alight winter zone was formed on the shell in

December-February. On the basis of this study, the shell meterial from the Bear -

Island area in 1968-69 was re-examined and it was found that what was earlier

thought to be the first growth zone consists of two zones with one ending 3-5 mm

from uMbo. The current experimental material has been similarly evaluated. A

correlation between the zones on the ligament and on the upper shell has also .

• •been found (Fig. 7). In some shell samples the growth zones of 50 upper shells

with same relative size distribution as the whole sample have been counted

(Fig. 8).

Few shells have less than 10 growth zones (year). Most have 10-14 with

an upper reliable limit of 16-17 zones. Also in samples taken with the small

rake the scallops seem to be old, although some shells have less than 10 zones.

Growth

The distance from umbo to the outer edge of each zone has been • measured

to the nearest mm.

Fig. 9 shows growth curves for Iceland scallops from some - localities. The

lbest growth was found southeast of Bear Island with 8-9 growth zones of 60 mm and

16 zones of 90 mm. The values are very close to those measured in 1968-69

(Wiborg 1970) when corrected for the nuMber of zones.

9

The second best growth was found north of Spitsbergen on Sjubreflaket

and east of Bear Island where 9-10 growth zones corresponded to 60 mm and 13-14

zones to 80 mm, while the shells from the outer part of Mitragrunnen (D 1) had

13 zones of 60 mm. Assuming that the scallops off Spitsbergen and Beâr Island

spawn in June-July, it could be assumed that the first growth zone corresponds

to the growth the rest of the year and, for instance, 9 growth.zones to an age

of. 8 1/2 years.

Muscle Weight

The weights of the adductor muscle in'relation to shell size are shown

in Fig. 10. The highest weights were found in the Bear Island_ area where -55 mm

p.214

shells had muscles weighing ca. 5 g; 70 mm - 9 g; 80 mm - 13 g.and 90 mm - 18 g.

These are similar to the weights found in -1.969 (Niborg 1970).. The weights are.

lower off Spitsbergen - 55 min -3.0 to 4.5 g; 70 mm - 7 g and 90 mm - 13 g. On

Mitragrunnen the weights were especially low; for 70 mm sheIls only 3.9 - 4.9 g.

The individual variations in weight can be c{uite large. At Bear Island

the following maximum weights were X:ound: - 6J. mm - 6.5 g; 70 mm - 11.5 g; .

80 rma - 17 g and 90 mm - .24. 5 g.

The scallops from the Bear Island area had a little higher inuscle weight

than those from the Andam Fjord in northern Norway (Wiborg 1970), while the

muscle weight in scallops from Spitsbergen can be compared to those from fjords

in Troms (Wiborg, not published). Fig. 11 shows that the adductor muscles from

Iceland scallops from Bear Island (B) were larger in relation to the shell size p.215

than those from Spitsbergen ( C) and Balsfjord (A).

Gonad Weight^; .

Fig. 12 shows the average gonad weight for some areas. The2

scallops southeast of Bear Island had the highest gonad weight, for shell size

60 nun - 2 g; 70 mm - 4 g; 90 mm - 5 g, while the weights from the areas north

10

80 20 40 60 80 100 20 40 60

STORRELSE 1 MM

Fig. 6. Storrelsesfordelinger av haneskjell ira Spitsbergen (ornràde A —G, Fig. 3. -4) og Djornoya (ornrAde H—K, Fig. 5). A 1 64 ni E I 44 m) skrapestasjoner og dyp, x) prover ira

smeiskrape. - [Size distribution oi :iceiand scallops (rom Spitsbergen- (area A —G in Fig. 3-4) and Bear Island (area H—K in Fig. 5.

I 64 E I 44 ni) stations and depth, x) sarripis irom small dredge).

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Fig. 7. Overskall og ligament av haneskjell fra Spitsbergen (omretcle F i Fig. 4). Ligament Prepare« etter jouANNEssEel (1973). .Overst: Skall 59 mm, ligament 3,0 mm, 9 vekstsoner. Nederst: Skall 70 mm, ligament 3,5 mm, 14 vekstsoner. NB. Siste sone nmr kanten av • skjellet. Foto: K. Hansen. [Upper shell and ligament (hinge) from Iceland scallops at Spitsbergen (area F in Fig. 4). Ligament prepared after joilANtsn:sszbt (1973). Top: Shell 59 mm, ligament 3,0. mm, 9 growth zones. Bottom: Shell 70 mm, ligament 3.5 mm, 14 growth zones. Note: Last zone near the edge of the ficli.

Photograph: K. Hansen]. . I ; . , I

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Fig. O. Aldersfordeling av hancskjcll fra Spitsbergen (omrAdzA-F i Fig. 3-4) og Bjornoya (omr3dc H-K i;"ig. 5).

Syinboler som p.% Fig. 3-6.[Age distribution of Iceland scallops from Spitsbergen (areaA-F in Fig. 3-4) and Bear îsland (area H-K in Fig. 5).

Symbols as in Fig. 3-6].

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8

4

â

soin pA Fig. 3-5.

40 60 80 tOG 40 60 80 100ST9RRELSE i MM

Fig. 10. Veict av luïcKCmuskcl i forhold til sl ^.lis.6rrclsc hoshaneskjelL 'f'il venstre: IN•liddelverdier for Spitsbergen (omrlde

A-F) og Bjornoya (omrâde H-K). Innsirklct: Enkeltverdi.Til hoyre: Ivlidçiclverdicr og standardavvik for en prove IraSpitsbergen (kryss) og en fra Bjornoya (fyilte sirkier). Bokstavcr

[Weight of adductôr muscle in relation to shell size in Icelandscallops. Left: Mean values at Spitsbergen (area A-F) andBear Island (area 2-3-K). In circle: Single value. Right: Meanvalues and standard deviations in single samples from Sp'sts-eergen (crosses) and Bear Island (black dots). Letters as in

Fig. 3-51.

9d

80-

70

60

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H o-pt( p............A

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17NTALL VEKSTSONER

, . ^ .

Fig. 9. Vekstkurver for hancskjcïl ved Spitsbergen og Bjornoyabasert p.î m3linger av vèkstsoncr. Bokstaver og tall som p.I

Fig. 3 -6.[Growth curves or Tcelanci scallops at Spitsberben and BearIsland based on measurcrnents of growth zones. Symbois as in

:i.ïg. 3 -6].

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-` -

I • Fig. 11. Lukkemuskel og gonade av haneskjell. A) Balsi'jorden 26. mai 1962, B) Bjornoya (omrà.cle, H i Fig. 5) 21.'august 1973, 0) Spitsbergen (omràde A i Fig. 3) 11. august 1973. Merk gorskjellen i storrclsen av gonader og : muskier i forhold til skall-

storrelse. Foto: K. Hansen:. [Adductor muscle and gonad from Iceland scallops. A) Balsgjord 25 May 1952, 13) 1973, C) Spitsbergen (area A in Fig. 3) 11 August 1973. Note the difference in size

to shell size. Photograph: K. Hansen]:

• e.e:

; • Bear Island (area H in Fig. 5) 21 August of gonads and. adductor muscles in relation

! ; !

I

60 7 .0 8;0 90 100 50 60 70 eo 90 100

6

—5

+ A

el A

A A

50 STORRELSE bms4

- . Fig. 12; Gonadevekt hos haneskjell i august 1973: Til hoyre:

( 6' + --- r) Lra • 9

Spitsbergen (omràde A —F i Fig. 3-4) og Bjornoya (omdtde H—K i Fig. 5). l'il venstre: Gjennomsnittsvekt av hann- og hunngonader fra Spi tsbergen (oturâile A i Fig. 3) og 11;ornoya

(omràde H i Fig; 5). Innsirklet: Enkeliverdier. [Weight of gonads from Iceland scallops in August 1973.

Right: Average weight of male and female gonads (

from Spitsbergen (area A— le in Fig. 3 --I) and Bear Island

(area H—K in Fig. 5). Left: Average weights of male and female gonads from Spitsbergen (area A in Fig. 3) and Bear

Island (area H in Fig. 5). In circle: Single values 1.

and west of Spitsbergen were lower, .60..mm - ca • 1.5-1.7; 70 mm - 2 g and 90 mm -

3 g. An exception is Mitragrunnen where the gonad weights were especially low,

- below 1 g.

The male gonads weighed more. than the female and the difference could at

times be quite large (Fig. 12). At Bear Island the female gonads, shell size .

70 mm, weighed 4 g; the male gonads over 5.5 g; 80 MU - ca. 4 g and 6 g; 90 mm -

ca. 5.5 g and a little over 7 g. There were large individual variations. The

differences are note quite as distinct at Spitsbergen. It is not known if the

difference is constant the whole year. Male gonads possibly need a shorter

period to regenerate than the female. It is likely that the Iceland scallops

off Spitsbergen and Bear Island had spawned some time before or just before

the samples were taken and that the gonads could have been larger (heavier) both

earlier and later in the year. The relative size of the gonads can otherwise

given an indication of if the scallops had spawned or not. Skreslet and Brun

(1969) and Skreslet (1973) used the relationship.

çsonad weight x . 100 •

weight of (soft parts gonads)

as a gonad index. In Balsfjord near Tromsô the Iceland scallop usually spaWns

in the end of June, and the gonad index then goes from ca. 40 to 15-18 (Skreslet

1973).

From the experimental material described here, the relationship

' gonad weight (G)

muscle weight (M) gonad weight (G)

has been used.

Data from Andamsfjord (Wiborg 1970) and Balsfjord (Wiborg, unpublished)

14

x 100 (Table 1)

are also included in the table. The scallops tad probably not spawned in Andams-

fjOrd on June 16, 1972. In Balsfjord (see Fig.. 11) the index on May 26, the saine

56 46

26 t

31 . 22

27 29

27

15

year, was

measuring 80-85 nun. Larger scallops spawn earlier than smaller animals

according to Skreslet and Brun (1969). .

At Bear Island and Spitsbergen the index was low in August 1973, down to

half the values for Andamsfjord and Balsfjord (see gonads on Fig. 11). Even if

the conditions in-northern Norway cannot be compared to those further north

without reservations, it is likely that the Iceland scallops near.Spitsbergen

and Bear island had finished spawning in August 1973. Approximately the same

index was found at Bear Island in September 1969; for shell sizes 75, 80 e 85 -

and 90 mm, the indices were respectively 32, 25, 26 and 24. .The fact that

larger scallops have a lower indax.than the smaller ones could be due to factors

such as different condition or later'regeneration after spawning.

• . . . . I

G Tab* 1. Gclnadeindeks:

G x 100 hos haneskjell fra forskjclligellokaliteter.

+ M • . Gonad weight (G) . •

[Gonad index: X aoo • Gonad weight (G) + Muscle weight (M) I

' in :Iceland scallors from various .localities}.. 1 .

approximately just as high . as in.AndamsfjOT:d, except for scallops

Omràde Dato 60-70 mm

indeks

Skall4yde

min rideks

Nord-Norge Andamsfjord 16. juni 1962

Balsfjord 26. mai » 48 47, 30, 28 (75, 80, 85 mm)*

Spitsbergen Omràde A (Fig. 3)

• (Fig. 3) _ » C (Fig. 3) » D (Fig. 4) » F (Fig. 4)

10. august 1973 10.=-11.

7. .» » 17. » » 9. » »

23 20 22. ._ 21 18 17 25

Bjornoya

Orriràde It (Fig. 5) 22. » »

» J (Fig. 5) 23. » »

» K (Fig. 5) 25. » »

16

Commercial Utilization

The Iceland scallop beds at Bear Island are estimated to contain 2-5 x 109

individuals in the areas with the densest population (Anon.•-1974). The estimate

is possibly too low, since it was based on catches with a dredge that usually

takes only a few per cent.of available animals. On the other side, the stock

needs a long period of time, at least 10 years, to renèw itself so that the

yearly recruitment is hardly more than one tenth. Based on a muscle weight of

10 g, this would total-2000-5000 tons of edible muscle. In practice, it would,

however, be possible only to take a small part of this

No systematic mapping of the beds has been carried out in waters off

Spitsbergeri. The area fished to the north of Spitsbergen had an area of around

69 km2. The catches here were at times as high as off Bear Island. {9ith an_

estimated density of 10 scallops per m2, this totals 6.9 x 108 animals or 6900

tons of edible muscle. It is possible that the beds extend over a larger area

so that the stock could be of the same order of magnitude as near Bear Island.

The areas along the west side of Spitsbergen and around Forlandet seem to be of

lesser importance both quantitatively and qualitatively.

Some of the scallop samples from the catches taken by the "FEIEBAS" were

weighed whole, inclusive shell growths, in order to calculate net yield of muscle

(Table 2).

TabeI1 2. Ncttoutby.tte av muskcivek2 i prosent, og muskelvektav liancs'.cjeli over 65 mm; ved Spitsbergen og Bjornoya i august1973. [Nez yie:d o: meat (adductor muscle) in percent, and4Vt;ÿÎTi o'i :IàliScics ii-. g ïrviYi rce.ariQ scallops :aYS.:r tR.Tn GJ mm

at Spiwbcrgen and Bcar ïs:and in August 1973j.

0mrltc;e

Spilsbergen0mr:tclc A 2 (F ig. 3)

» A 3 (Fig. 3)

» A 4 (Fig. 3)

i) D I (Fig. '`-)

13jnrnoya

Qror:!dc I-i (F iti. 5)

Ii'roscnt Muskelvekt i g

Iutioytte1 - I Midcicl I Varir.sjon

11,0 7,7 6,3-11,610,0 9,6 6,2-12,410,7 8,6 7,8-14,89,0 3,6 3,4- 4,8

11,5 . 14,5 10,2-17,8

•

17

The net yield varied between 9% and 11.5% while the average muscle

weights showed larger variations; 14.5 g southeast of Bear Island, 8-10 g north

of Spitsbergen, but only 3.6 g on Mitragrunnen .

Outlook for a Commercial Fishery

During the experimental fishing cruise with - "FEIEBAS", up to 20 hauls

were made per day and catches as high as 2000 scallops were made in a 20 minute

haul. Daily catches were as high as 10,000 scallops (Hansen; Husa and Olsen

1974). With an average weight of 10 g per muscle, a catch of this magnitude

Would yield ca. 100 kg edible muscle, with a landed value of 2-3000 kroner

according to prices today (1 N.kr = za. 0.18 Can, $).

Before the Iceland scallop fishery could be profitable, many problems

must be solved. The catches could probably be increased both by extending the

number of hours fished and by using mure or'perhaps larger rakes. But the main

problem will be the processing. It is not realistic to sell the animals whole.

The edible part, i.e., the muscle and perhaps also the gonads must be separated

from the shell; Manual handling would be too costly and time consuming. Up to

100 scallops must be opened to yield one kg of edible muscle. On Iceland a

meChanical shucking machine mounted ashore has been taken in use. It costs

between 0.3 and 1 million kroner. - The best solution would be to have shucking

machines installed on board so that the catch could be processed continuously.

By .cooling the scallops, they can be kept fresh up to a week so.that a larger

load can be taken ashore for processing.

Freezing of whole scallops is - also a possibility, but would require

thawing before precessing, and no data are available on if the muscle could be

refrozen or if cooking or canning is necessary for further storage.

18

: LITTERATUR

ANoN. 1974. Matnyttige muslinger. Fisken og Havet, 1974

(Sternummer) : 95-98. BLINDIIEINI, J. and L.J0EN, R. 1972. On the hydrographie

conditions in the Spitsbergen current in relation to ice

distribution during the years 1956-1963. P. 33-41 in KARLSON, T. cd. Sea ice, Proceedings of an international

conference. National Research Council, Reykjavik.

DICKSON, R. R. and D0001NGTON, T. C. 1968. Hydrographie conditions off Spitsbergen in the summers of 1966 and

967. Amis biol. Copenh., 24: 24-29. - 1970. Hydrographic conditions off Spitsbergen in

the summers of 1968 and 1969. Ands biol. Copenh., 26:

26-32. HA_NsF.N, K., HusA, I. og OLSEN, H. E. 1974. Rapport fra

• forsoksfiske etter haneskjell ved Svalbard og Bjornoya i tiden 4;8. --25.8. 1973. Fiskeridirektoratet. Fiskeribedriftens

frrsoksfond. Rapp., 1974 (under trykning). JOHANNESSEN, O. H. 1973. Age determination. in Chlamys

islandica (O. F. Müller). ilstarte, 6: 15-20.

SKRESLET, S. 1973. Spawning in Chlamys islandica (O. F. Muller)

in relation to temperature variations catts.:d by vernal

meltwater discharge. Astarte, 6: 9-14.

— and BRUN, E. 1969.- On the reproduction of Chlamys

islandica (O. F. Müller) and its relation to depth and

temperature. Astarte, 2: 1-6. WIBORG, K. F. 1963. Some observations on the Iceland scallop

Chlamys islandica (Muller) in Norwegian waters. FiskDir.

Skr. Ser. HavUnders., 13 (6): 38-53. — 1970. Utbredelse av haneskjell . (Chlamys islandica Muller

pà Bjornoybankene. Fiskets Gang, 56: 782 —788.

Anon. 1974. Edible shellfish.' Fisken and - Havet, 1974 (Special issue): 95-98.

Hansen, K., Husa, I., and Olsen, H.E. - 1974. Report from experimental fishing

for Iceland scallop off Svalbard and Bear Island in the period 4/8-25/8,

•1973. Directorate of Fisheries, Fishing Industry Experiment Fund. Rep. 1974

(in press). - .

Wiborg, K.F. 1970. Distribution of Iceland scallop (Chiamys islandica Mulle -r)

on the.Bear Island banks. Fiskets Gang 56: 782-788.