Food selectivity versus prey availability: a study using the marine fish Pomatoschistus microps

The food selection of the common goby, Pomatoschistus microps Krøyer, was studied in the field and in laboratory experiments on the Swedish west coast. The three most important prey organisms for P. microps in the study area were Corophium volutator, chironomid larvae and Nereis spp. Corophium was consumed more than any other prey, even when it was not the most abundant prey species in the bottom. One reason may be the higher activity of Corophium above the sediment surface, which may increase its visibility and consequently its vulnerability to visual predators. When P. microps was offered Corophium and chironomid larvae with similar exposure in laboratory experiments, it showed no preference for either of the prey items. It always took the closest mobile prey, regardless of species and size.