Social mechanisms facilitating exploitation of spatially variable ephemeral food patches in a pelagic marine fish

Abstract

Juvenile walleye pollock, Theragra chalcogramma, are more successful at exploiting spatially variable ephemeral food patches when foraging in groups. This may be attributable to local enhancement and to social facilitation of feeding motivation. Feeding responses of individuals were not independent when fish foraged for spatially variable ephemeral food patches, indicating social cues displayed by successful foragers informed other fish of where food was located (local enhancement). Fish initiated feeding sooner when grouped (social facilitation) than when alone. These results indicate that local enhancement aids individuals in locating food patches, while social facilitation aids in rapid patch exploitation.