Variation in Species Composition of the Larval Assemblage in Four Southwest Michigan Lakes: Using Allozyme Analysis to Identify Larval Sunfish

Abstract
Ecological studies of the early life history stages of many fishes are challenging in part because of the difficulty of identifying larval fish to the species level. I present an identification technique using cellulose acetate protein electrophoresis that is useful for distinguishing species of larval sunfish (Lepomis Centrarchidae). Using this technique in a survey of four Michigan lakes, I found that the species composition of larval Lepomis in the limnetic zone differed among lakes and through time. Larvae of bluegills L. macrochirus, pumpkinseeds L. gibbosus, and green sunfish L. cyanellus were all present in the limnetic zone of some lakes. Prior to this survey, the only larval Lepomis species identified as migrating to the limnetic zone was the bluegill.