Report of the joint Norwegian-Russian acoustic survey on blue whiting, spring 1993

Abstract

In spring 1993 the fourth joint Norwegian-Russian acoustic survey on the blue whiting spawning stock was carried out. The area to the west of The British Isles was covered by two vessels, one operating in the north-south direction and the other one in the south-north direction. The distribution could hence be confined to two periods and together with recordings in a third period thus gave illustration of a northward postspawning migration. The spawning stock size was estimated to 4.9 mill. tonnes; i.e. 0.6 mill. tonnes more than in 1992. This increase was mainly due to the numerous 1989-yearclass which contributed with more than 60% in numbers to the stock. The influence of the North Atlantic Current was found to be the same as in 1992.