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
Jms. Goncalves et K. Erzini, 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, Cybium, 22(3), 1998, pp. 245-254
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.