The Effect of Copper on Behavioural Reactions of Noble Crayfish Astacus Astacus L.

A study was conducted with noble crayfish Astacus astacus L. A. astacus is the only native crayfish species in Lithuania and the most valuable of commercial crayfish species in Europe. During the recent years, the resources of noble crayfish have increased and pollution of water bodies decreased. Behavioural reactions are one of the most sensitive reactions of an organism to toxic materials. Heavy metals are among the most resistant pollutants in Lithuanian waters. The data of a 96-h lethal toxicity test conducted by us have shown that the median lethal concentration of one of the most toxic heavy metal, copper, to noble crayfish is 148.4 mg/l. Exposition to copper solution changes behavioural reactions, or frequency and duration of separate behavioural elements, of the crayfish. Because of these changes, the defence reactions of the crayfish become weak.