Use of Rotenone in Restoring Balance to Overcrowded Fish Populations in Alabama Lakes

Overcrowded sunfish populations have occurred in 5 of Alabamaˈs 18 State-owned public fishing lakes. They have resulted from a combination of factors, including presence of undesirable fish species, infestation with a branched alga, fish kills, loss of fish over the spillway, and heavy fishing. These overcrowded populations were usually balanced by three to seven marginal, or a combination of marginal and sectional, treatments with rotenone applied usually during September and October. The annual average catch by anglers was 193.4 pounds per acre during the years that the five lakes contained balanced fish populations, and 132.7 pounds per acre during the years that the lakes contained overcrowded forage fish populations. Although these lakes contained overcrowded forage fish populations for varying periods of time, an annual average of 156 fishermen per acre caught 174.5 pounds of fish during the 5 to 8 years that the lakes were open to continuous public fishing. This high sustained harvest was attributed to prompt correction of unbalanced fish populations by partial poisoning with rotenone.