Localized areas of Lake Huron and Georgian Bay have demonstrated a sensitivity to inputs of nutrients, evidenced by increased growths of Cladophora. Through the use of underwater photography a documentation of Cladophora growth was carried out in 1981. Two areas were investigated, one in the vicinity of the Bruce Nuclear Power Development in Lake Huron, and the second in southern Georgian Bay (Nottawasaga Bay) from Meaford to Collingwood. The latter area includes the Mary Ward Shoals which were similarly photographed in 1979 and 1980 by the Water Resources Branch of the Ministry, offering a basis for comparison. The 1981 work was completed in anticipation of an increasing demand on nearshore waters for nutrient dispersal, particularly through the use of extended outfalls. Bottom substrate was observed to the 10-metre contour and was generally free from growth, excepting areas under the influence of point sources of nutrients. The method proved to be an effective means of documenting the range of observed Cladophora growth and will serve as a valuable permanent record of present conditions.