The effect of inorganic and organic pollutants on sperm motility of some freshwater teleosts

Using four different sperm types from brown trout Salmo trutta fario (Salmonidae), chub Leuciscus cephalus (Cyprinidae), burbot Lota lota (Gadidae) and African catfish Clarias gariepinus (Clariidae) the effect of inorganic (cadmium, copper, mercury, lead, zinc and nitrite) and organic (cyclohexane and 2,4‐dichlorophenol) environmental pollutants on sperm motility was investigated. Spermatozoa were activated in double distilled water containing the different test substances and the motility was compared to controls of similar pH. From the investigated motility variables the sperm motility rate and swimming velocity reacted most to the environmental pollutants whereby the changes depended on the species and on the test substance. African catfish spermatozoa were the most resistant, chub and burbot spermatozoa showed medium resistance and brown trout spermatozoa were the most sensitive to the pollutants. With exception of 2,4‐dichlorophenol and zinc the effective concentrations of the tested pollutants exceeded the recommendation for surface waters 100–10·000‐fold and were in a range lethal for the fish themselves. Therefore, it was concluded that fish sperm motility is not a suitable marker for risk assessment of environmental pollutants.