Estimates of stock size of northeast arctic cod and haddock, Sebastes mentella and Sebastes marinus from survey data, winter 1989

Abstract

The combined acoustic and bottom trawl survey in the Barents Sea in winter has been carried out since 1981. The target species are cod and haddock, but in recent years the redfish species Sebastes marinus and Sebastes mentella have also been included. Since 1982, an acoustic survey for spawning cod in the Lofoten area has been carried out immediately after the Barents Sea survey. For cod, the acoustic survey gives a total estimate in numbers which is about 10% lower than in 1988, whereas the bottom trawl survey gives a reduction of about 40%. The difference between the surveys probably to some extent reflects a change in the vertical distribution. Poor recruitment is confirmed by both surveys. A similar difference between the surveys is found for haddock, but the reduction in number is larger, about 30% and 60%, respectively, for the acoustic survey and the bottom trawl survey. Abundance indices for redfish indicate that the stock situation is stabilizing for Sebastes marinus and Sebastes mentella, although at a low level. The results of the Lofoten survey indicate that recruitment to the spawning population of cod is improving.