Cannibalism as a factor regulating year class strength in the Norwegian spring-spawning herring stock

Abstract

The feeding area of the Norwegian spring-spawning herring stock is at present situated in the north-eastern parts of the Norwegian Sea. The eastern parts of the feeding area overlaps with the distribution of drifting larvae and 0-group of the same stock. This study presents preliminary results of a stomach sampling program on adult herring feeding off Vesterålen, confirming that cannibalism are taking place in the area. The size range of the cannibals was 24 to 36 cm, and the mean size of the 0-group eaten was 6 cm (range 4-8). The maximum number of 0-group found in one stomach was 7. These findings support the hypothesis that cannibalism may be a regulating factor for yearclass strength in Norwegian springspawning herring under the present migratory regime.