Bioturbation by cyprinid fish affecting the food availability for predatory water mites.

Field observations suggested that benthivorous fish, causing bioturbation, are able to effect the food availability for predacious water mites feeding on bottom dwelling chironomid larvae. This hypothesis was tested in the laboratory. In an undisturbed situation the predation rate exercised by the water mites on the tube dwelling chironomid Cladotanytarsus mancus was very low. However, when the sediment was disturbed, the predation rate increased substantially. The relevance of this for the field situation is discussed.