Trawl discards in the diets of tropical seabirds of the northern Great Barrier Reef, Australia

Abstract

The diets of 12 species of tropical seabirds were investigated in two areas of the N Great Barrier Reef. The species whose diets included at least 20% discard taxa are Sterna bergii, S. dougallii and perhaps S. anaetheta; between 5 and 19% - Hydroprogne caspia, Anous stolidus, Sterna bengalensis, Sula leucogaster and Fregata ariel, less than 5% - Sterna sumatrana and none - Fregata minor, Sula dactylatra and S. sula. The provision of discards has not changed the size ranges of prey taken by any of the species. It may, however, have increased overlap in the diets of the various seabirds and changed some feeding strategies. There is little evidence that discards have directly affected breeding cycles or nesting periodicity. -from Authors