Copper-Induced Chemosensory Impairment is Reversed by a Short Depuration Period in Northern Clearwater Crayfish (Faxonius propinquus)

Abstract

Crayfish rely on their chemosensory system for many essential behaviours including finding food, finding mates, and to recognize individuals. Copper can impair chemosensation in crayfish at low concentrations; however, it is not clear if the effect is ameliorated once copper is removed. To better understand the effect of and recovery from copper exposure in crayfish, we exposed Northern clearwater crayfish (Faxonius propinquus) to 31.3 ${\upmu }\text{g}/\text{L}$ copper for 24 h and measured the response of the crayfish to a food cue. The crayfish were then placed into clean water to depurate for an 24 h. The results demonstrated that the crayfish did not respond to a food cue if they had been exposed to copper, but showed a full response after a 24 h recovery period without copper. Higher concentrations of copper have shown a much longer-term effect in rusty crayfish (Faxonius rustics), indicating there is a concentration where the copper is causing longer-term damage instead of just impairing chemosensation. These results highlight the fact that even though contaminants like copper can have profound effects at low concentrations, by removing the contaminants the effect can be ameliorated.