Diet of three commercially important shark species from Western Australian waters

Abstract

The diets of dusky (Carcharhinus obscurus), whiskery (Furgaleus macki) and gummy (Mustelus antarcticus) sharks from south-western Western Australia were examined by analysis of stomach contents. The majority of samples were obtained from catches of commercial gill-net fishers. Carcharhinus obscurus had a diverse diet dominated by pelagic teleosts and cephalopods. A wide range of demersal and benthic prey were also consumed, but represented only a small portion of the diet. As body size increased, importance of elasmobranchs in the diet of C. obscurus increased, while most other groups remained at similar levels. Furgaleus macki had a specialized diet, feeding almost exclusively on octopus and other cephalopods. The diet of M. antarcticus was dominated by benthic and epibenthic prey, including crabs, lobsters, tetraodontid fishes and octopus. As M. antarcticus increased in size there was an increase in the occurrence of rock lobster and a decrease in the occurrence of crabs in the diet. Differences in the diet were also noted between male and female M. antarcticus, but were confounded with differences between size classes.