Detroit River-Western Lake Erie Basin Indicator Project
Figure 3. Incidence of mouthpart deformities in larvae of Procladius midges in western Lake Erie in 1982 (above) and 1993 (below). Data analysed by Doherty et al. (1998) from samples provided by D.W. Schloesser, Great Lakes Science Center, USGS. Shaded areas enclose sampling sites (points) from which 75 or more larvae could be examined for deformities. Dark grey areas - >6.0%; medium grey areas – 1.6-6.0%; light grey areas <1.6%. Across the entire Great Lakes, approximately 2.3% of Procladius larvae have deformed mouthparts (Burt et al. 2003).