Oligochaete fauna of western Lake Erie 1961 and 1982: Signs of sediment quality recovery

The oligochaete fauna at 40 stations in western Lake Erie were collected in 1982 and compared to oligochaete fauna collected similarly in 1961. A total of 34 taxa, representing 18 Tubificidae and 16 Naididae, were identified. Changes in the proportions of low, moderate, and heavy polluted sediments, as determined by ranges of total numbers of oligochaetes, indicate that, in general, heavy pollution substantially decreased near shore and moderate pollution increased and low pollution decreased in open waters over the 21-year comparison. The most common taxon, the eutrophic species, Limnodrilus hoffmeisteri, decreased in abundance in open water, indicating decreased eutrophication, whereas the distribution and abundance of other indicator taxa, including the eutrophic species L. maumeensis, L. cervix, Quistadrilus multisetosus multisetosus, and mesotrophic species Ilyodrilus templetoni and three species ofAulodrilus indicate increased eutrophication in open water. In general, oligochaete trophic indices (based on tubificid species and abundances) in traditional area designations used in 1961, the nearshore designation (