The short-term effects of three molluscicides on the microflora and microfauna of small, biologically stable ponds in Southern Rhodesia.

Where large-scale molluscicide applications are anticipated, it is important to investigate the effects of the chemicals to be used on the freshwater microflora and fauna existing in the bodies of water to be treated. The food chains of which these organisms form basic parts are important in the general ecology leading up to fish and even to man. Some observations on the direct short-term effect of three molluscicides-copper sulfate, sodium pentachlorophenate and Bayer 73-on the populations of certain plankton organisms, carried out in biologically stable ponds in Southern Rhodesia, are reported on in this paper. It appears that copper sulfate has the most drastic and long-lasting effects on these organisms. The authors stress that snail control measures involving molluscicides should be so designed as to effect the minimum alteration to the ecological balance of the freshwater habitat.