Effects of Turbidity and Habitat Complexity on the Foraging Behavior of the Black Bullhead (Ameiurus melas)

Abstract

The role of vertebrate scavengers in nutrient flow of aquatic ecosystems has recently been emphasized. Evidence is accumulating that scavenging is an alternative tactic for certain predatory fish, but their foraging choices between scavenging and predation under varying environmental conditions have not been studied. In this experiment, we presented black bullheads, Ameiurus melas (Rafinesque, 1820), with both live and carcass prey of tubenose gobies, Proterorhinus semilunaris (Heckel, 1837), in aquaria with varying levels of turbidity and habitat complexity. Our findings revealed that black bullheads exhibit higher consumption of carcass prey in complex habitat and clear water condition. We also provide evidence of the active predatory behavior displayed by black bullheads, as a greater consumption of live prey was observed in simple habitat and turbid water. We did not find any relationship between individual exploratory behavior and the choice between carcass and live prey in black bullheads. Our results suggest that the choice between scavenging versus predatory foraging strategy under varying environmental conditions is influenced by the behavior of both consumer and prey. The ability of black bullheads to adapt their foraging strategy in different environments may contribute to their widespread success as an invasive species.