BECK, J.L.*; TURINGAN, R.G.: The Effect of Prey Swimming Behavior on Prey-Capture Kinematics and Feeding Performance in Marine Fish Larvae

It is hypothesized that the strength of a recruiting class of marine teleosts is determined by the magnitude of mortality during the larval stage of ontogeny. This study investigates the possible influence of zooplankton prey swimming behavior on the feeding performance of marine fishes during this ‘critical period’ in their life history. Artemia franciscana (aged 1-9 days), Brachionus rotundiformis (rotifer sp.), and several species of copepods were cultured in the laboratory and filmed at 250 and 500 frames per second while swimming in a filming tank both with and without the presence of a larval fish predator. Zooplankters were sub-sampled to determine the swimming velocity (mm/second) of at least five individuals from each group. ANOVA and multiple pair-wise comparisons revealed significant differences in normal swimming and escape velocities between the various prey types. Slower-swimming zooplankters were preferred prey at first-feeding because they show little ability to escape from larval fish predators. Both the Artemia and copepod species exhibited a significant increase in swimming velocity when a larval fish predator was present. In addition, marine fish larvae showed variable feeding kinematics when fed prey of different swimming behaviors. Results of this study have profound implications for our understanding of the constraints imposed by the swimming behaviors of available zooplankton prey on the feeding performance of marine fish larvae.