Effect of Endrex on Aquatic Flora

Abstract

Endrex, a chlorinated hydrocarbon, has been used extensively as a piscicide by the Tropical Fish Culture Research Institute at Malacca, Malaysia to clear ponds of unwanted populations of fish; particularly Gambusia affinis (BAIR D & GIRARD), which has proved to be a serious pest, attacking and devouring broods of Tilapia, and in other ways constituting a danger to the experimental work (2). The Endrex is usually applied in aqueous suspension to the ponds after the water level has been lowered to within a few inches of the bottom. It has been estimatcd that a concentration of about 0.018 p. p. m. in the residua~ water is achieved during the treatment of the ponds. The lethal effect, however, decreases with time and after about three weeks the ponds may be restocked with fish.