Risk of predation and foraging behaviour in shoaling banded killifish (Fundulus diaphanus)

Abstract

While foraging for patchily distributed benthic prey in the laboratory, solitary and shoaling banded killifish reduced their per capita rate of feeding attempts and shortened the duration of their feeding posture (when sampling outside the food patches) in the presence of a predatory brook charr. This presumably allowed more time for predator vigilance and avoidance. Individual feeding rate was independent of shoal size, in either the presence or absence of a predator. Solitary fish thus incurred only a slightly greater predator-mediated relative cost of lost foraging opportunities compared with shoaling fish. Killifish therefore altered their foraging behaviour to reduce risk of predation in the presence of a predator and appeared to trade off risk of mortality and energy gain.