Preliminary report of the Norwegian investigations on young cod and haddock in the Barents Sea during the winter 1985

Abstract

An acoustic survey and a bottom trawl survey for cod and haddock were carried out in the Barents Sea during the winter 1985. The acoustic data and the biological data from trawl stations were combined in two different ways, giving two series of acoustic estimates of abundance which differed greatly. The first series which was based on the assumption that the catch compositions in the bottom trawl catches were representative for the whole water column, resulted in considerably higher figures for haddock than for cod. The second series which was based on the assumption that the catch compositions in midwater trawls were representative for the fish recorded in midwater and that the bottom trawl catches represented the fish recorded in the near-bottom layer, resulted in significantly more cod than haddock. However, both series of acoustic estimates as well as the bottom trawl indices supported previous findings showing that the recruitment of both cod and haddock in recent years had been substantially higher than in the period 1976-1981.