Toxicity of rotenone to common carp and grass carp: Respiratory effects, oral toxicity, and evaluation of a poison bait

Rotenone was administered in a food bolus by gavage to common carp, Cyprinus carpio. The lethal dose of rotenone to 50% of the test animals (LD50) was 8.1 mg/kg with a 95% confidence interval of 7.7 to 8.5 mg/kg. The extrapolated lethal dose to 99% of the test animals was 11.6 mg/kg. Behavior of the fish receiving an oral dose of rotenone was similar to that of fish exposed to rotenone in water, and all deaths occurred within 16 h of gavage. Absorption of the oral dose of rotenone was via the intestine, rather than the gills, and was enhanced by including a surfactant in the formulation.;Common carp were exposed to a lethal concentration of rotenone (0.1 mg/l), and blood was sampled after 2, 7, and 21 min. Exposure times were selected to correspond with behavior changes: after 2 min fish started swimming to the surface, after 7 min equilibrium was lost, and after 21 min fish sank to the bottom. Blood oxygen partial pressure showed a 10-fold increase compared to control values after 21 min, while pH decreased and partial pressure of CO;A poison fish bait was evaluated as a fish management tool to kill grass carp, Ctenopharyngodon idella. Prentox...