Rotenone in Fisheries: Are the Rewards Worth the Risks?

2. Rotenone Neutralization Methods

Donald L. Archer

doi: https://doi.org/10.47886/9781888569339.ch2

Abstract.—Rotenone has been widely used to eradicate fish communities. Attempts to neutralize rotenone have been notoriously inconsistent and have occasionally resulted in tragic and highly publicized failures. Two major problems have been understanding the factors influencing the efficacy of the neutralizing agent and accurate projections of rotenone concentrations being neutralized. The chemical most commonly used to neutralize rotenone formulations is potassium permanganate (KMnO₄). Engstrom-Heg (1971, 1972) conducted some very definitive controlled experiments that demonstrate that dissolved electrolytes and organic matter have a major influence on the amount of KMnO₄ required to neutralize a given concentration of rotenone. This paper discusses application rates, field methods and equipment used to apply KMnO₄ effectively to neutralize field applications of rotenone.