Prey selection and diets of bluegill Lepomis macrochirus with differing population characteristics in two Nebraska natural lakes

Fisheries Management and Ecology (Impact Factor: 1.03). 01/2003; 10(1):31 - 40. DOI: 10.1046/j.1365-2400.2003.00323.x

ABSTRACT Abstract  Environmental prey samples and stomach contents of bluegill Lepomis macrochirus (Rafinesque) were collected in spring and summer 2000 from two Nebraska Sandhill lakes. Watts Lake contained a low-density bluegill population, whereas Cozad Lake contained a high-density bluegill population. Bluegill diets from both lakes were compared to determine if bluegill prey preference differed between the two populations. The highest median per cent (by calories) of zooplankton in the diet was 1.3%; the remainder was macroinvertebrates. Watts Lake bluegills preferred (based on Manly's alpha) amphipods in spring and chironomids in summer. Cozad Lake bluegills did not show a strong preference (compared with Watts Lake) for any macroinvertebrates, but still utilized amphipods and chironomids during both seasons. Larger bluegills in Watts Lake preferred chironomids in summer, but Cozad Lake bluegills did not exhibit this relationship. The higher density Cozad Lake bluegill population appeared to be more opportunistic than the lower density Watts Lake population, but both preferred macroinvertebrates.

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