Ægir - 01.07.1984, Síða 21

lQ^an Um ve'ð't,anu ar'ð 1982 og fram í nóvember
? Var samþykkt af öllum hlutaðeigandi aðilum.
n gagna um stærð loðnustofnsins fyrir 1978 er
11 að meta hvort hrun hans varð eingöngu vegna
e'ði. Sambærilegar tölur um fjölda loðnuseiða eru
' allt frá 1972. Því fer að vísu fjarri að slík gögn séu
serandi, en þau benda að sínu leyti til ríkulegrar
a' '^Unar þar til 1975/76 sem þá hafi farið ört minnk-
. 1 °§ verið léleg síðan. Pá má benda á rýrari loðnu
að við aldur hin síðari ár og kaldari sjó.
essi þróun fellur vitanlega saman við hina gífur-
su sóknaraukningu sem varð með tilkomu sumar-
haustveiðanna og þátttöku útlendinga í þeim.
haf ^ S1^ur verður að telja að hrun loðnustofnsins
• auk óumdeilanlegrar ofveiði, orsakast af slakri
týhðun
sem á rætur að rekja til óhagstæðra breytinga
1 fnhverfinu.
Urn em k£tur fer rett' íslenski loðnustofninn við svo
funaði á síðasta ári. Vonandi bera menn gæfu til
ss að leggja sítt af mörkum svo framhald geti orðið
a því.
l°^Um höfundur koma á framfœri þökkum
þáu^mar^ra starfsf^aSa’ íslenskra og norskra, sem
q J?^u 1 þeim rannsóknum sem þessi ritgerð byggir
v erslaklega ber að þakka Páli Reynissyni, eðlis-
u {rœðingi ágœtt samstarf til sjós og lands svo og
u -J°n °S kvörðun mælitœkja, en hann hefur ásamt
lmdi séð um hinn íslenska þátt bergmálsmæling-
unna.
^stract
Th ~ -----------------------—----------
Qr e/Celanc*'c caPe,in inhabit the area between Iceland,
0n anc* lan Mayen. Continuous systematic research
rea ■ st0ck has been carried out since 1966, gradually inc-
T‘ng 'n sc°pe and volume.
Wat C tce,andic capelin spawn when 3-4 years old in coastal
T)tee|rS’ ma'n,y off South and West Iceland in March-April.
ect,- 0/36 drift with the coastal current in a clockwise dir-
M-uon to tK
CaPel' ne west’ north and east of the country where the
'he f'n St)enct the first year of their life as 0-group. During
oCean- 'n® season juvenile and adult capelin have a more
tittg tQ'c h'stdbution, the oldest and largest fish even migra-
ents ° Waters north of Jan Mayen. These stock compon-
fr°maSlemble 'n ear‘y w'nter north and northwest of Iceland
Uary F erethespawningmigrationstartsinDecember/Jan-
r°m there the mature fish follow the edge of the shelf
to the east and south of Iceland. Growth is quite rapid during
the first 2-3 years. Average lengths and weights of I-, II- and
III-group fish after the feeding season were calculated for
the period 1966-1983. These show considerable changes,
both from year to year and also on a longer time scale, app-
arently in correlation with changes in temperature. Data on
the natural mortality coefficient have been obtained by com-
paring successive acoustic estimates of abundance, taking
into account the catch during the intervening period. The
results are near the level previously assumed for the matur-
ing stock in August-December, i.e. M=0.04/month. How-
ever, spawning mortality is very high and evidence is pres-
ented which suggests that the survival rate of spawners is
practically zero.
The fishery of the Icelandic capelin began in 1964 in the
coastal waters southwest of Iceland in winter. The fishery
was conducted only in winter until 1976, when a summer/
autumn fishery was started off North and Northwest Ice-
land. In the following two years catches increased from a-
round 500,000 tonnes to over 1,000,000 tonnes. The fishery
collapsed in 1981/82 and a complete fishing ban was impos-
ed, practically lasting from December 1981 to November
1983. The fishery was conducted by Icelanders only until in
1978, when they were joined by the Norwegians and two
years later by the Faroese as well as EEC countries.
Because of the short life of the capelin, fishery independ-
ent assessment of stock size has to be used. An 0-group index
of the size of each year class is available from 1972 onwards.
Tagging experiments have been successful in case of adult
capelin. The results, however, do not become available
early enough for management purposes. Acoustic estimates
of the abundance of the adult stock are available from 1978,
both from the autumn period and also from the early part of
the year. The results show a dramatic reduction in stock size
for 1978-1982, from over 2 million tonnes in the beginning of
the 1978 summer/autumn season to 300-400 thousand
tonnes in the summer of 1982. There was a considerable re-
covery in 1983. A high degree of accuracy of the acoustic
estimates of the abundance of adult Icelandic capelin has
been established. Nevertheless, these measurements have
been strongly contested by fishermen and authorities, and as
a result management has been inefficient and the stock
overfished. It is suggested that the effect of overfishing has
been accelerated by a prolonged period of unfavourable
environmental conditions.
This paper is based on a publication by the same author titled Bio-
logy, abundance estimates and management of the Icelandicstock of
capelin, appearing in Kit biskideildar (1983) 7, 3. A complete list of
references is contained therein.
ÆGIR-349