Size dependency in the migrations and distribution of Norwegian spring spawning herring

Abstract

The size at first spawning is comparatively larger in Norwegian spring spawning herring (Clupea harengus L.) than in other herring stocks in the Atlantic and Pacific oceans. This is probably an adaptation to a life with long seasonal migrations between wintering-, spawning- and feeding grounds. The present paper presents empirical data and model results suggesting that also historic long-term shifts and annual variations in migrations and distribution pattern may be attributed to size dependency.