Visual cues determining prey selection by the turbot, Scophthalmus maximus L.

By presenting juvenile turbot, Scophthalmus maximus L., with models and natural prey, Crangon crangon, standardised for size, some of the visual characteristics that elicit a predatory response have been determined. By far the most important stimulus was overall body movement, but appendage movements of the crustacean and a ratio of vertical to horizontal dimensions lower than about 1:5 were also of significance. The body shape of a prey was not of great importance. Evidence was obtained for the heterogeneous summation of stimuli.