Journal of the Marine Biological Association of the United Kingdom

Research Article

The Diet of Sperm Whales (Physeter Macrocephalus) Captured Between Iceland and Greenland

A.R. Martina1 and M. R. Clarkea2

a1 Sea Mammal Research Unit, Natural Environment Research Council, c/o British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 OET

a2 The Laboratory, Marine Biological Association, Citadel Hill, Plymouth PL1 2PB

The stomach contents of 221 sperm whales were examined at the Icelandic whaling station between 1977 and 1981. Evidence of at least eight species of fish and 22 species of cephalopod was found, together with an assortment of foreign bodies including rock fragments and fishing nets. Fish remains were found in 87% and cephalopods in 68% of the sperm whale stomachs in this area, but quantification of dietary input is complicated by differential rates of digestion and variation in the retention of indigestible remains in the stomach. Prey species are benthic or pelagic in habit and are caught by the whale in waters from 400 m to at least 1200 m in depth. One fish, the lumpsucker Cyclopterus lumpus, forms a major part of the diet. Ninety-four per cent of cephalopods are oceanic and neutrally buoyant and 84 % of these are ammoniacal. Cranchiids contribute 57% by number and an estimated 25% of the weight, and histioteuthids 26% by number and 38 % of the weight of cephalopods eaten. Three species offish and two of cephalopod have not been previously recorded in sperm whale diets. Comparison with an earlier study shows that the diet is essentially stable over a 14-year period.