Feeding behavior of three common fishes at an artificial reef in the northern Adriatic Sea.

The trophic role played by the Senigallia artificial reef (northern Adriatic Sea) in the diet of three finfish (Sciaena umbra Linnaeus, 1758, Diplodus annularis Linnaeus, 1758, and Lithognathus mormyrus Linnaeus, 1758) was investigated seasonally from 1997 to 1999. The gut contents of each species were compared with the benthic communities on the manmade structures, in the surrounding soft bottom, inside and outside the reef, as well as at an open-sea control site. Due to low fish densities in winter and spring, only summer and fall data were considered. The vertical walls of the manmade structures were colonized by hard-substrate species, while the horizontal surfaces accumulated sediment and developed a community of soft-bottom organisms. The community inhabiting the soft seabed included primarily mollusks and polychaetes. All of the three fish species fed on hard/soft-bottom organisms and mostly preferred crustaceans (decapods), although L. mormyrus and D. annularis also fed on considerable quantities of mollusks and cnidarians, respectively. The artificial structures provided the main source of food for the three fishes and the link with the reef declined from S. umbra to D. annularis to L. mormyrus.