Living with failure: the prey capture success of young brook charr in streams

Abstract – We examined the prey capture success of recently emerged brook charr ( Salvelinus fontinalis ) foraging in shallow, clear, still-water pools along the edges of streams. Fewer than 42% of attacks ended with ingestion either because of difficulty distinguishing suitable prey from unsuitable items or because of difficulty capturing evasive prey. Probabilities of capture upon attack and ingestion upon capture depended upon where attacks were directed in the water column, the fish's level of activity at the time of attack and its fork length, and the sampling date. In general, success was higher for larger, sedentary fish attacking prey in the lower portion of the water column than for smaller, active fish attacking prey at the water surface. The frequency of items attacked was only a moderate predictor of the frequency of prey ingested. Poor capture success is an important aspect of the early life history of brook charr in particular and probably of young salmonines in general. ^NOTE