To identify the pathogens and possible biological control agents for the introduced seastar Asterias amurensis, we examined seastars from source populations in central and northern Japan. In particular, we sought the scuticociliate Orchitophrya cf. stellarum. The ciliate was found in male A. amurensis from five sites. We also found the caprellid amphipod Caprella astericola on A. amurensis and Distolasterias nipon from Nemuro Bay. The copepod Scottomyzon gibberum was found on A. amurensis from Usujiri and polychaete scaleworms Arctonoe vittata were found on A. amurensis from Murohama and Nemuro Bay. Of these parasites and commensals, Orchitophrya cf. stellarum is the most likely agent for biological control of A. amurensis in Australian waters; however, its ability to regulate seastar populations is uncertain. |
