ROLE OF DIET AND EXPERIENCE IN THE DEVELOPMENT OF FEEDING-BEHAVIOR IN LARGEMOUTH BASS, MICROPTERUS-SALMOIDES

Two groups of largemouth bass, Micropterus salmoides, were reared in the laboratory. One group was reared on an artificial, passive diet (frozen brine shrimp) whereas the second was reared on a natural, active diet (cultured zooplankton). Observations on the development of feeding behaviour indicated that the motor patterns and duration (number of weeks in the behavioural repertoire) of the feeding acts did not differ between fry reared on the two diets. While feeding on their respective diets, natural-diet fry performed significantly more orientations and bites, the two major early feeding acts, than did the artificial-diet fry. When tested with live fish prey, fish reared on the natural diet performed fewer orientations and strikes and captured more prey per fry than did the artificial-diet fry. Natural-diet fry had a significantly better net efficiency (captures minus strikes minus orientations) than did artificial-diet fry. Diet, experience, and length (T.L.) of fry affected their predator efficiency significantly. We argue that providing hatchery-reared bass fry with an opportunity to prey on live forage fish once or twice before their release would enhance their survival and eventual recruitment into natural populations.