Effects of cadmium and zinc on Procambarus clarkii: Simulation of the Aznalcóllar mining spill

Female red swamp crayfish, Procambarus clarkii, were exposed for 21 days in the laboratory to different dissolved concentrations of zinc (1000 µg L-1 and 3000 µg L-1) and cadmium (10 µg L-1 and 30 µg L-1), determined in the Guadiamar River after the Aznalcóllar mining spill (SW Spain). Female gonadosomatic and hepatosomatic indexes were analyzed at the end of the bioassay, and a general decrease in the gonadosomatic index and increase in the hepatosomatic index were observed in individuals at the same maturation stage, exposed to increasing heavy metal concentrations. Only the decrease in the gonadosomatic index values was significant at the highest zinc concentration. Decreases in gonadosomatic indexes were associated with reduced fecundity.