Red claw are probably susceptible to most diseases that affect native crayfish. In addition, red claw are susceptible to the “crawfish plague” which is a fungal pathogen. Native North American crayfish carry the plague but are usually not adversely affected by it. The fungus was not known to be a problem until North American crayfish were introduced to Europe over 100 years ago.
European crayfish had no resistance or immunity to the North American pathogen and many natural populations were devastated. Research has shown that the red claw are susceptible to this fungus. The fungus grows best at temperatures below 65oF and does not appear to be active or pathogenic above 70oF. Since red claw need temperatures above 70oF for good growth, careful attention to stocking and harvesting temperatures may reduce potential problems. There are no known methods of prevention and treatment of the plague.