Phenotypic Variation of Young-of-Year Bluegills (Lepomis macrochirus) among Microhabitats

Young-of-year bluegills were collected in different microhabitats defined by depth and the presence or absence of vegetation within the littoral zone of a 20.9 ha lake. Analysis of covariance indicated that regressions of body depth, caudal peduncle depth, and head length on standard length were significantly different among fish from different microhabitats. Bluegills collected at depths 150 cm were more fusiform but increased in length and weight at a rate similar to fish collected from intermediate depths. The consistency in these relationships between two cohorts suggests that the differences are not due to chance. Numbers of lateral line scales were significantly different between fish collected at depths > 150 cm and those collected from shallower areas. Unlike morphometric and scale number characters, numbers of soft dorsal rays, anal-fin rays, and dorsal spines differed little among habitats. The observed phenotypic differences among microhabitats indicates that individual fish tended to specialize on one habitat.