Determination of factors influencing stomach content retention by striped bass captured using gillnets

Abstract

The influence of mode of capture, season of capture and total body length (LT) on the probability of regurgitation for striped bass Morone saxatilis captured using gillnets in Smith Mountain Lake, Virginia, was examined. Overall, the mean rate of regurgitation for striped bass which contained food contents in their stomach was 8·3%. Striped bass captured by wedging had a higher mean regurgitation rate (17%) than individuals that were either entangled (5%) or gilled (2%). Striped bass caught during the autumn had approximately the same frequency of regurgitation as individuals captured during the summer (10 v. 9%), but these regurgitation rates were higher than those observed for fish during the spring sampling periods (4%). Larger striped bass were more likely to regurgitate their stomach contents than smaller individuals, with the frequency of regurgitation increasing by 0·7% for every 50 mm increase in LT. The results of this study demonstrate the importance of identifying factors that influence regurgitation of stomach contents to minimize and account for biases associated with diet data collected from striped bass captured in gillnets. Using this information, sampling recommendations for food‐habit and feeding‐rate studies involving the collection of piscivorous fishes using gillnets are made.