Feeding habits of the red scorpionfish, Scorpaena scrofa (Osteichthyes: Scorpaenidae) from the eastern central Adriatic Sea

The diet of the red scorpionfish, Scorpaena scrofa, from the central Adriatic Sea, was investigated with respect to fish size and seasons. Stomach contents of 684 specimens, 9.1 to 44.0 cm total length (TL), collected by trammel bottom nets from January 2006 to December 2008 were analysed. The prey species identified in the stomachs belonged to five major groups: Cephalopoda, Isopoda, Amphipoda, Decapoda (Natantia and Reptantia) and Teleostei. Teleosts were the most important ingested preys (IR1% = 80.4), especially in fish larger than 20 cm TL. Small preys like amphipods, isopods and natantia decapods constituted the main preys in the diet of fish smaller than 15 cm TL. Two teleosts, Chromis chromis and Spicara smaris were the most frequent preys. The mean weight of stomach contents increased significantly for fish larger than 25 cm TL, while the mean number of prey items did not differ significantly among length classes. Diet composition showed little seasonal variation; teleosts were the most important preys in all seasons especially during the winter. The percentage of empty stomachs showed seasonal variation, with maximal occurrence in winter (34.3%) and summer (21.5 %) and minimal in spring (6.9%). The lowest feeding frequency is probably related with lower sea temperature during the winter and with spawning period throughout the summer. The stomach contents of the red scorpionfish indicate that this species could be a generalist predator.