Perkinus olseni is a protozoan parasite that has had a considerable impact on abalone populations in South Australia and New South Wales. The disease has led to mass mortality events but more typically causes losses due to lesions in the foot muscle that lead to rejection of catch by processors. The impact of Perkinsus on abalone fisheries has not been fully quantified and the factors driving prevalence and disease expression are unknown. This investment will consolidate current knowledge on Perkinsus, describe the impact and drivers of the disease in Australia, and determine whether shucking at sea is a high risk.