Parasites in tarakihi (pisces: Cheilodactylidae) from three areas around New Zealand

Abstract

Abstract The parasite faunas of tarakihi Cheilodactylus macropterus (Bloch & Schneider) from East Cape, Tasman Bay, and the Chatham Islands were compared. A total of seven parasite species were found of which four were recorded in tarakihi for the first time: Nybelinea sp., Hepatoxylon trichiuri (Holten), Echinorhynchus sp. and Clavellodes sp. The last two of these were new records for New Zealand. The other parasites were: Contracaecum sp., Anisakis sp. and Aethon garricki Hewitt. The nematode Anisakis sp. and the copepods Aethon garricki Hewitt and Clavellodes sp. were the commonest parasites. Incidence and intensity of Anisakis sp. were high off the Chatham Islands, moderate off East Cape, and low in Tasman Bay. These differences in infestation were truly regional and were only partially caused by differences in age composition of the fish samples. Intensity of infestation with Anisakis sp. was related to age of fish off the Chatham Islands, but not in the other two areas, and this probably reflects regional differences in the diet of the tarakihi. Incidence of Clavellodes sp. was low in Tasman Bay. This parasite was absent from the other two areas, which either may indicate a true regional difference in the distribution of the parasite or may be caused by differences in the age composition of the samples. Incidence of Aethon garricki was moderate in Tasman Bay and off East Cape, but this parasite did not occur in the Chatham Islands tarakihi. Thus, tarakihi populations from three widely separated areas differed from each other in the incidence and intensity of at least one of the three commonest parasites.