FEEDING HABITS OF DRUMS CILUS GILBERTI (ABBOTT, 1889) (PISCES: SCIAENIDAE) OFF TALCAHUANO COAST.

Abstract

The "drum" Cilus gilberti (Abbott, 1889), is a pelagic físh distributed in the South Eastem Pacific from Arica (18°20'S) to Chüoé (43°06'S) associated to soft bottom of Coastal areas. Despite the increasing interest on this species as a fishery resource, there is little Information on basic aspects of its biology. In this work we study the feeding habits of "drums", based on stomach contents of 827 specimens collected from fishing zones between Pingueral and Golfo de Arauco, during August (1994) and July (1995). The trophic habits were analyzed qualitatively and quantitatively by size class and by seasonal changes. Despite the high number of Ítems occasionally recorded in the stomach contents, the drums feed on a narrow trophic spectrum, preying preferentially on small crustaceans (mysidaceans and euphausids) and small fishes (anchovies and sardines). Our results show a possible ontogenetic dietary change, where the smallest specimens feed on small crustaceans whereas the biggest feed crustaceans and small fishes in
equal proportion. The seasonal variation was recorded exclusively during winter, where a specific change in the diet of specimens is observed.