Joseph P. McCraren

Information relative to control of problematical clam shrimp (EubranchiopodaConchostraca) with Masoten (Dylox) was accumulated over a 10. yr period at several Southwestern hatcheries. Laboratory and field studies showed that control could be achieved with single applications of Masoten as low as 0.01 mgl (active ingredient). No deleterious effects on fry, fingerlings, or adult fish of several species were noted. Decomposition of the chemical, as well as effects on plankton and bottom fauna, are discussed. The paper places on record the efficacy of Masoten against clam shrimp, a level of...

The effects of Masoten, an organophosphate parasiticide, on phytoplankton and zooplankton in earthen ponds were studied. In 2 separate trials, 3 ponds (0.04 hal received a single application of Masoten at a rate of 0.25 mg/l (active ingredient) and 3 ponds served as untreated controls. Net plankton samples were collected at pretreatment, and 5, 24 and 48 hI's following treatment. Toxic effects were based on quantitative.qualitative plankton analyses. Phytoplankton and rotifers were unaffected by treatment. The copepod Diaptomus sp. and nauplii were also unaffected. However, variability in...