Drivers of long-term change in the Foveaux Strait oyster fishery (OYU 5) including the effects of disease and dredging essential oyster habitat are investigated. High densities of oysters are determined by recruitment and mortality from Bonamia exitiosa. Regular recruitment to the population shows productivity of the oyster fishery is high and is not likely to have changed. Oyster factors, co-infections with other pathogens, and climatic variables may affect oyster mortality and recruitment.