A compendium of idiopathic lesions observed in redclaw freshwater crayfish, Cherax quadricarinatus (von Martens)

Idiopathic lesions observed in redclaw freshwater crayfish, Cherax quadrica rinatus (von Martens), from farms in northern Queensland, Australia, over a 4-year period are described. Various idiopathic lesions were observed in t he exoskeleton, antennal gland, mandibular organ, haemolymph vessel endothe lium and enteric tissues of C. quadricarinatus collected for histopathologi cal surveys, investigations of chronic mortalities or during other activiti es. The need for an increased use of histopathology in crayfish disease dia gnosis is highlighted.