Macrobenthic Community Response to Carp (Cyprinus carpio L.) Foraging

Abstract

An examination of how fish predators (Cyprinus carpio L.) structure aquatic benthic macroinvertebrate communities was conducted. Three 225 meter² exclosures were stocked with varying densities of fish; three remained empty as controls. Every three weeks, replicate samples were taken from each exclosure for assessment of the benthos and sediment organic content. Sediment deposition rates were estimated for the last three week period. The data collected indicate that carp have an effect upon benthic community structure and dynamics as well as the physical environment in which these communities reside. Community diversity was lower in all test exclosures when compared to controls. Species patch distributions were different among treatments. Sediment deposition was inversely proportional to fish densities. Organic content within the sediment was not altered by treatment. We propose that both direct predation and predator mediated habitat modifications are major factors influencing soft-bottomed freshwater benthic community structure.