We compared the ontogeny of feeding in two centrarchid species and hypothesised that the ontogeny of early feeding in the black crappie, Pomoxis nigromaculatus, would differ from that of the smallmouth bass, Micropterus dolomieui, and that the smaller black crappie fry would perform certain of the feeding MAPs (modal action patterns) at a higher frequency and for a longer period of time than the larger smallmouth bass fry. Under laboratory conditions crappie fry performed significantly more Fixates, Lunges, and Snaps than smallmouth fry. These three MAPS also remained in the feeding repertoire of the crappie two weeks longer than in the smallmouth repertoire. The size of the young fish at the onset of exogenous feeding influenced their early feeding behaviour.
The study took place at the Queen’s University Biological Field Station located on Lake Opinicon, Chaffey’s Locks, Ontario, Canada in summer, 1982. Fish were collected as eleutheroembryos from nests and immediately placed in separate wooden 90-1 glass-fronted tanks. Tanks were supplied with a continuous flow of lake water and a natural photoperiod was maintained. A 2 cm layer of gravel covered the bottom. Densities of fry in each observation tank were approximately 150 per tank initially and were reduced by natural mortality to approximately 50 per tank by the end of the study.