Chemically mediated avoidance behavior in wild brook trout, <i>Salvelinus fontinalis</i>: the response to familiar and unfamiliar predaceous fishes and the influence of fish diet

Abstract

Choice experiments were used to determine whether juvenile wild brook trout would avoid chemical traces of predaceous fishes found in their native stream; the fishes used were the red fin pickerel (Esox americanus) and American eel (Anguilla rostrata), and a predaceous fish with which the trout had no prior experience, the Atlantic salmon (Salmo salar). Juvenile trout avoided pickerel odors but did not avoid water conditioned by American eels. They also avoided water conditioned with Atlantic salmon. A second experiment using trout from two wild populations demonstrated that the brook trout's avoidance of Atlantic salmon was a response to the salmon's piscivorous diet. These results suggest that brook trout do not avoid odors of all predaceous fishes and are capable of altering their behavior patterns in response to a change in the diet of a predatory fish.