| Summary: | 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.
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