THE ROLE OF BIOMANIPULATION IN FISHERIES MANAGEMENT

ABSTRACT Biomanipulation is a relatively new approach toward managing lakes. As a result, few data support its use, and many fisheries managers are reluctant to apply this technology. However, the results of biomanipulation and fisheries renovation programs are often the same: reduced populations of nuisance algae and improved water transparency. In this paper, the relative roles of rough fish elimination and restructuring the plankton–fish mix (biomanipulation) are compared as mechanisms in improving water transparency in lakes. Fisheries survey records from 13 renovated or winterkilled Indiana lakes are used to quantify these relationships. A statistically significant inverse relationship between Secchi disk transparency and percent of planktivorous fish exists for the lakes studied. Possible mechanisms for change are discussed, and recommendations for fisheries management are advanced.