Use of parasites as biological tags for separating stocks of the starspotted dogfish Mustelus manazo in Japan and Taiwan

The parasite fauna of Mustelus manazo from seven localities in Japan and Taiwan was assessed for the feasibility of using parasites as biological tags for the identification of different host stocks. Examination of 1038 host specimens resulted in 13 parasite species recorded: one nematode, two myxosporeans, two copepods and eight cestodes. Although relatively low overall prevalence of the first five species at different localities showed some significant differences, the samples collected in Tokyo Bay bore the lowest similarity (19.2%). These results support previous studies, which suggested the existence of a unique host stock in Tokyo Bay. Accordingly, combinations of prevalence data may provide useful information on stock identification. Cestodes probably have the greatest potential for use as biological tags. Detailed examination of 25 specimens of M. manazo from Aomori and Tokyo Bay disclosed eight species of intestinal cestodes. A canonical discriminant analysis based on these species separated the two localities clearly.