Ontogeny of prey selection by black surfperch Embiotoca jacksoni (Pisces: Embiotocidae): the roles of fish morphology, foraging behavior, and patch selection

Abstract

Proximate mechanisms leading to similarities and differences in diets of juvenile and adult black surfperch E. jacksoni in populations at Santa Catalina Island (USA) were explored. These fish are microcarnivorous, harvesting invertebrate prey primarily from benthic turf and foliose algae. Ontogenetic differences in prey size ultimately reflect age-specific differences in size of fish. Young juveniles are apparently gape limited and use a visual picking mode of foraging. Turf substrates are used extensively by older fish that employ winnowing behavior to separate prey from debris. The ability to winnow develops slowly during the first year of life and allows exploitation of turf, a prey-rich, extensive resource base.