Effects of Cd, Cu and Zn on sperm motility indicators of the Caspian lamprey, Caspiomyzon wagneri

The present study investigated the effects of Cd, Cu and Zn on the sperm motility of Caspiomyzon wagneri. The sperm of the specimens were exposed to 0.01, 0.1, 1, 10, 100 and 1000 mg L-1 of the heavy metals, and the duration of sperm motility and percentage of motile sperms were measured using a compound microscope and digital camera. Based on the results, sperm motility parameters decreased with increasing the concentrations of heavy metals. A concentration of 1000 mg L-1 of heavy metals stopped completely the motile sperms. The present study indicated that heavy metals have detrimental effects on sperm motility and possibly decrease the fertilization and hatching rates of C. wagneri in the spawning ground, and thus a serious threat to the survival of this rare and native species.