DIET COMPOSITION AND TROPHIC LEVELS OF MARINE MAMMALS

Standardized diet compositions were derived for 97 species of marine m ammals from published accounts of stomach contents as well as from mor phological, behavioural and other information. Diet was apportioned am ong eight categories of prey types (benthic invertebrates, large zoopl ankton, small squids, large squids, small pelagic fishes, mesopelagic fishes, miscellaneous fishes and higher invertebrates). Trophic levels were estimated for each species of marine mammals and compared with p ublished estimates derived using stable isotope ratios. Trophic levels ranged from 3.2-3.4 in baleen whales and sea otters, to 3.8-4.4 in mo st pinnipeds and odontocete whales, to 4.5-4.6 in killer whales. Such information can be used for ecosystem modelling and related studies. ( C) 1998 International Council for the Exploration of the Sea.