Relationship in distribution of blue whiting and hydrographic conditions in the Norwegian Sea during summer, 1980 -85

Abstract

During the summer period in the Norwegian Sea the stock of blue whiting was found to have decreased considerably from 1980 to 1983. Although the stock increased again, the adult part of it continued to decrease and in 1985 only 0.5 mill.tonnes of it were found. Particularly in the northern Norwegian Sea this was associated with an increasingly dispersed distribution and lack of fishable concentrations. Blue whiting was found to feed in water of temperatures from 0° to 8°C, with preference for 5-7°C, i.e., Atlantic water. The change in distribution and abundance of blue whiting in the Norwegian Sea observed in this period may therefore not only result from a general decrease in the stock, but also from environmental fluctuations. If the hydrographic conditions were important for these changes, they are not likely to be found in the Atlantic water. It is, however, more likely that the increasing extent of Artic water in the East Icelandic Current has been decisive.