ABSTRACT
The Great Lakes Water Quality Agreement of 1978 and subsequent revisions recognized the importance of reducing phosphorus loads to the Great Lakes as a mechanism of improving water quality. Bans on phosphorus use
in detergents and the regulation of phosphorus loading from wastewater treatment facilities have substantially reduced its impact in the western basin of Lake Erie (Munawar et al., 1999). In the central and eastern basins, mean concentrations have returned to historic levels (DePinto et al., 1986; Hartig and Gannon, 1986; Markarewicz and Bertram, 1991; Charlton, 1999). Numerous species level indicators were studied during the recovery. They showed declines and improvements that assisted in formulating targets and determining the success of management objectives (Wood, 1973; Robbins et al., 1989; Schloesser et al., 1995; Haag et al., 1993; Krieger et al., 1996; Ludsin et al., 2001).
