FEEDING-HABITS OF THE 2-BANDED SEA BREAM (DIPLODUS-VULGARIS) AND THE BLACK-SEA BREAM (SPONDYLIOSOMA-GANTHARUS) (SPARIDAE) FROM THE SOUTH-WEST COAST OF PORTUGAL

The stomach contents of Diplodus vulgaris and Spondyliosoma cantharus were: analysed using three simple methods (numeric, gravimetric and fr equency of occurrence) and a composite index (I.R.I - Index of Relativ e Importance). To compare the species, the Schoener index was used. Th e diet of D. vulgaris consisted mainly of ophiuroids, polychaetes, amp hipods and echinoids, while polychaetes, amphipods and hydrozoans domi nated in the case of S. cantharus. There were some size-related differ ences in S. cantharus feeding. Diet overlap was relatively slight, wit h significant differences in feeding between the two species, notably in terms of greater consumption of echinoderms by D. vulgaris and hydr ozoans by S. cantharus. As is the case for the majority of sea breams, D. vulgaris and S. cantharus are characterised by a diverse diet in t erms of prey reflecting available prey items in their environment.