Patterns of animal abundance in lakes : the role of competition in the fish-macroinvertebrate relationship

• Main Author: Hanson, John Mark, 1955-
• Format: Others
• Language: en
• Published: McGill University 1985
• Subjects: Fish populations > Mathematical models.; Competition (Biology); Predation (Biology); Freshwater animals.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71975

Data taken from the literature were used to develop and evaluate models predicting fish biomass and yield, crustacean zooplankton biomass, and profundal macrobenthos biomass in lakes. Total phosphorus concentration and macrobenthos biomass/mean depth were the best univariate predictors of fish biomass and yield. Phosphorus concentration was also the best predictor of zooplankton and macrobenthos biomass. In experiments testing for inter- and intraspecific competition, conducted in situ at densities based on measured natural fish densities, growth of yellow perch (Perca flavescens) and pumpkinseed (Lepomis gibbosus) reared alone was inversely related to density. Both species primarily ate macroinvertebrates when reared alone. When reared together: perch growth was significantly depressed compared to that of perch reared alone; pumpkinseed growth was equivalent to that of pumpkinseed reared alone; and the diet of perch changed to include food of inferior quality (microcrustaceans) in the presence of the superior competitor, pumpkinseed, whose diet did not change.