Diet composition and feeding intensity of Mediterranean horse mackerel, Trachurus mediterraneus (Osteichthyes: Carangidae), in the central Adriatic Sea

Abstract

          Diet composition and feeding intensity of the Mediterranean horse mackerel, Trachurus mediterraneus, collected in the central Adriatic Sea were examined. Stomach contents of 1200 specimens, taken at monthly intervals (January–December, 1996) were analyzed. The stomach contents consisted of six major prey groups: Crustacea (Euphausiacea, Mysidacea, Decapoda), Cephalopoda, Polychaeta and Teleostei. Euphausiacea constituted the most important food resource by weight, number and frequency. Teleosts were the second most important food category, while Mysidacea, Decapoda, Cephalopoda and Polychaeta were occasional foods. Euphausicea were dominant during all seasons, and especially abundant in summer and autumn. Feeding intensity varied throughout the year. The lowest feeding intensity was recorded in winter at lower sea temperatures and during spawning (May, June). Feeding activity increased just prior to (April) and after (July, August) spawning. Feeding intensity also varied during the diurnal cycle. The highest feeding intensity was recorded at night and during early morning hours.