| dc.description.abstract | In 1980 most of the fishing effort was concentrated in the Breisund
and on the Buagrunn. Gill net was the main fishing gear. Both coastal
cod and mature Arctic cod (skrei) were caught.
From February to April a sampling programme was carried out. Data
on age, length, sex, maturity and stomach content were sampled.
The year classes 1970-1972 dominated in the skrei catches, but
throughout the season there seemed to be considerably more of the
1970 and 1971 year classes in the Breisund than on the Buagrunn.
The proportion of younger skrei (the 1972 and 1973 year classes)
increased from February to March on both fishing grounds. The older
skrei reach the spawning stage earlier in the year than the younger.
Therefore, the age distributions might indicate that while the
younger skrei were feeding on rich herring concentrations at the
Buagrunn during maturation, the older were spawning in the Breisund.
The age composition in the catches from the coast of Sør-Trøndelag
were similar to the Breisund ones.
The age distribution in the gill net catches from Lofoten were
dominated by 7 and 8 year old skrei, while the Breisund catches
mainly consisted of 9 and 10 year olds. An estimate of the age composition
of the mature stock based on VPA and a maturation curve
give an intermediate age distribution. Tagging experiments indicate
very limited exchange of spawning ground between skrei tagged in
Lofoten and on Møre. The most likely reason of the observed variation
of the age distributions in the two areas are suggested to be
a combination of the following:
-the part of the Arctic cod stock having the highest age
of maturation recruits to the Møre fishery.
-the recruitment to the two spawning areas is from different
nursery and feeding areas.
The coastal cod in catches with no skrei added, was dominated by 3
and 4 year old fish. In catches with excess of skrei, the coastal
cod was dominated by fish older than 4 years. | en |
