Seasonal study of the fauna of bedrock substrates in the wave zones of lakes Huron and Erie

Abstract

Quantitative samples of the benthic macrofauna inhabiting bedrock substrates in the wave zone (0- to 2-m depth) at a site on Lake Huron and one on Lake Erie were collected in each season during 1975 and early 1976. The turnover of species between sampling visits was greatest in summer and at depths less than 0.5 m. The fauna at the Lake Huron site was dominated numerically by Hyalella azteca (Amphipoda) and larvae of Stenelmis spp. (Coleoptera: El-midae). The density of the fauna appeared to be greatest in winter. The fauna at the Lake Erie site was dominated by Gammarus fasciatus (Amphipoda), whose populations were largest in summer and smallest in winter, thus corresponding to the abundance of Cladophora in the wave zone. None of the common insect species underwent diapause as larvae at either site.