Interactions Between Juvenile Bluegill and Yellow Perch for Prey and Habitat Resources in a Natural Lake

Examining interactions between species is important from ecological and management perspectives. Therefore, our objectives were to examine diet and habitat overlap between juvenile bluegill (Lepomis macrochirus) and yellow perch (Perca flavescens) in Pelican Lake, Nebraska while also examining bluegill and perch spatial alignment with prey resources (i.e., zooplankton and macroinvertebrates). Juvenile yellow perch and bluegill relative abundance and prey resources were determined in four different habitat patch types (i.e., Open water, Phragmites, Scirpus, Typha) during August, September, and October of 2009. Diets were also examined for each species within each habitat patch across each month. Diet overlap was relatively low between bluegill and yellow perch while habitat overlap was substantially higher. In addition, there was high overlap between bluegill abundance and available macroinvertebrate biomass and low overlap with available zooplankton biomass; however, yellow perch exhibited the opposite relation to their spatial alignment with prey resources (i.e., low macroinvertebrate overlap and high zooplankton overlap). These results indicate that despite using similar habitats during the juvenile life stage, these two species were consuming different prey types. Therefore, interaction for available habitat may be substantial or one species is being displaced by the other in relation to available prey resources (i.e., assuming one prey type such as macroinvertebrates or zooplankton is more profitable). Further examination is needed to elucidate which competing hypothesis is more supported.