We evaluated the effects of temperature and salinity on in vitro trophozoite proliferation and zoosporangial development in Perkinsus olseni and P. honshuensis, infecting Manila clam. Trophozoite proliferation was highest at 28°C for both species and at 18-21‰ and 21-33‰ for P. olseni and P. honshuensis, respectively. Zoospore release rates, as the indicator of zoosporulation, were highest at 25-30°C and 25-35‰ for both species. However, these results seem not to explain the previously observed phenomena, i.e. lower infection prevalence in estuarine tidal flats (the two species not distinguished) and higher infection prevalence of P. olseni than P. honshuensis.
2013 The Japanese Society of Fish Pathology