Preliminary reports of the Norwegian investigations on young cod and haddock in the Barents Sea during the winter 1984

Abstract

An acoustic survey and a bottom trawl survey for cod and haddock were carried out in the Barents Sea during the winter 1984. The two surveys gave different results, both in absolute terms and when changes from the 1983 surveys are considered. The acoustic survey showed an average 1982 year class and a strong 1983 yearclass of cod, which is in good agreement with previous estimates. The estimates of the year classes 1979-1981 were increased. For haddock, the acoustic survey confirmed that the year classes 1982 and 1983 are strong, and the estimates of the year classes 1980 and 1981 increased. In the bottom trawl survey, the index of year - old cod (1983 yearclass) is lower than in the acoustic survey. A decrease was observed in the indices of the 1979 year class of cod and the 1980 year class of haddock. Discrepancies with the 1983 survey results and the differences between the results from the acoustic and the bottom trawl surves are discussed. Variation in the availability of different site groups of fish for the bottom trawl is a major factor.