Abstract
We examined the effects of water velocity on prey detection and capture by drift-feeding juvenile coho salmon (Oncorhynchus kisutch) and steelhead (sea-run rainbow trout,Oncorhynchus mykiss irideus) in laboratory experiments. We used repeated-measures analysis of variance to test the effects of velocity, species, and the velocity x species interaction on prey capture probabiJity, prey detection distance, and swimming speeds during prey capture. We used 3D video analysis to assess the spatial and temporal characteristics of prey detection and capture. Coho and steelhead showed significant, velocity-dependent decreases in capture probability (-65% to 10%, with an increase of velocity from 0.29 to 0.61 m·s-1 ) and prey detection distance, with no effect of species and no velocity x species interaction. Neither velocity nor species affected prey interception speed; fish intercepted prey at their predicted maximum sustainable swimming speed (V max) at all velocities.
Keywords
Oncorhynchus kisutch,
steelhead,
coho salmon
Citation
Piccolo, John J.; Hughes, Nicholas F.; Bryant, Mason D. 2008. Water velocity influences prey detection and capture by drift-feeding juvenile coho salmon (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss irideus). Canadian Journal of Fisheries and Aquatic Sciences Vol. 65, 2008