Harp seal (Phoca groenlandica) invasions in norwegian coastal waters: Age composition and feeding habits

Abstract

Since 1978 large numbers of harp seals (Phoca groenlandica) have invaded coastal areas of north Norway in winter and spring. In 1987 and 1988 dramatic increases occurred in both the magnitude and the geographic extent of these seal invasions. Sampling of stomach contents for food analyses and of teeth for age determinations was carried out on harp seals taken as by-catch in Norwegian gillnet fisheries in 1986 and 1988. It appears that the seal herds comprised both immature and mature animals, the latter being mainly males. The stomach analyses suggested that feeding was opportunistic, with a variety of fish (in particular the gadoid species cod, saithe, haddock, and Norway pout, and the pelagic shoaling species herring and capelin) being taken as prey. Prawns and squid were also consumed, but in considerably lower quantities than fish. © 1991 Conseil International pour l'Exploration de la Mer.