A comparative study of the feeding habits of herring (Clupea harengus, Clupeidae, L) and Capelin (Mallotus villosus, Osmeridae, Muller) in the Barents Sea

Capelin (Mallotus villosus) and adolescent Norwegian spring spawning herring (Clupea harengus) co-occur in the southern Barents Sea during early summer. The diets of both species were dominated by calanoid copepods, and the overlap in diet was large. Both for herring and capelin the proportion of copepods in the diet decreased with increasing fish size, while euphausiids and appendicularians increased in importance. The ontogenetic shift in diet was thus similar for the two species. Herring showed an increasingly deeper distribution with increasing body size. Capelin were found deeper than herring in areas of spatial overlap. Based on the similarities in diet it is concluded that the two species are potential competitors for food in times of high abundance of planktivores or of low food availability in the Barents Sea.