THE DIET OF SUNFISH FORAGING IN THE MILFOIL BEDS OF THE MENOMINEE RIVER WATERSHED, MICHIGAN
Sunfish (Lepomis macrochirus and L. gibbosus) were collected from beds of mixed Eurasian watermilfoil (Myriophyllum spicatum) and hybrid milfoil (M. spicatum x M. sibericum) from five reservoirs in the Menominee River watershed, MI, USA. The digestive tracts of the sunfish were preserved and contents identified. Chironomids were the dominant prey item in the diet of L. macrochirus whereas mollusks were the dominant prey item for L. gibbosus. Other major diet groups for L. macrochirus included plant material, beetles and mollusks. L. gibbosus also foraged heavily on chironomids and beetles. The milfoil beetle, Euhrychiopsis lecontei, which feeds on milfoil, was found in the digestive tracts of sunfish. However, based on the low percent of occurrence in the diet and on the low mean number of E. lecontei per sunfish, sunfish predation did not limit the milfoil weevil populations in this study. This appeared to be true even though resident populations of milfoil weevils were being augmented with milfoil weevil larvae and eggs. Terrestrial weevils from a root-feeding complex found in northern hardwood forests occurred in substantial numbers in the sunfish guts.
Mike Mendel (Primary Presenter/Author), Cedarville University, firstname.lastname@example.org;
Jeff Niehaus (Co-Presenter/Co-Author), EnviroScience, Inc., JNiehaus @ EnviroScienceInc.com;
Rhonda Mendel (Co-Presenter/Co-Author), EnviroScience Inc., email@example.com;
Jamie Krejsa (Co-Presenter/Co-Author), EnviroScience, Inc., JKrejsa @ EnviroScienceInc.com;