The Bonamia species that occurs in New Zealand is not B. ostreae . It was originally described as B. exitiosus , but that has now been changed to B. exitiosa. B. ostreae has never been reported in New Zealand. B. exitiosa occurs in commercial beds in Foveaux Strait, where it has a high prevalence and is associated with epizootic mortality in mid to late summer. It occurs intermittently around the South Island and in Wellington Harbour (North Island).