Lake Apopka near Orlando covers 38,000 acres and is one of Florida's largest freshwater lakes. It's also one of the state's most polluted. The reasons, says Tim Gross of the University of Florida in Gainesville, include a large chemical spill in 1980, pesticide pollution from the citrus industry, and chemical drainage from "muck farms," the marsh-rich farmland that is drained, farmed, and flooded two to four times a year.
The desire to understand this pollution's effects on lake animals steered Gross toward the largemouth bass. Earlier work by Gross and colleagues Franklin Percival and Louis Guillette suggested that pollution, particularly estrogenic pesticides, had caused Lake Apopka's alligator population to suffer reduced fertility and a surprising feminization of males (SN: 1/8/94, p.145).
The bass research, carried out by Gross, Percival, and William Johnson of the Florida Game and Freshwater Commission, began this April and ended in August. They collected 60 fish from each of three comparably sized lakes -- Lake Woodruff, pristine; Lake Griffin, mildly polluted; and Lake Apopka, heavily polluted. …