On the food of capelin in the subarctic waters north of Iceland

The food of capelin, Mallorus villosus (MULLER), caught in July and November 1993 and in June-July 1994 in the waters north of Iceland was investigated. A total of 716 stomachs of capelin ranging in length from 2.1 to 20.0 cm were examined. Of these 575 or 80 % were found to contain food. Empty stomachs were most frequent amongst the smaller length classes arld more so in winter than summer. On average the stomach content was only ca 2 mg dry weight in November, while in June-July it was ca 78 mg dry weight. Copepods were numerically the most important identifiable food component in all length classes, constituting ca 92-99 % in July and ca 65-93 % in November. Calanus finmarchicus (GUNNERUS) was the most abundant copepod species, ranging in July from ca 14 to 65 % of identifiable copepods and in November from ca 19 to 85 % of the copepods. C. hyperboreus (KROYER) was the second most numerous copepod in the stomachs. When the food was considered in terms of weight copepods constituted 71-100 % of the weight of the food in July while euphausiids made up 0-23 %. In November the dry weight composition of the food was generally similar to that observed in July. In terms of dry weight the importance of copepods in the diet decreased with the size of the capelin while the opposite was true for euphausiids. The food of capelin was found to be largely similar to the composition of zooplankton in the sea indicating that limited food selection was taking place.