Distribution of some parasites of freshwater eels in New Zealand

Abstract

Abstract Eight hundred and thirty nine short‐finned eels, Anguilla australis Richardson, 1848, and 459 long‐finned eels, A. dieffenbachii Gray, 1842, from the wild from 34 localities around New Zealand were examined for parasites. Thirty parasitic species were encountered, of which 26 were considered common and 4 accidental parasites of eels. Widespread and common were Myxidium zealandicum Hine, 1975, Myxobolus sp., Chloromyxum sp., Stegodex‐ amene anguillae Macfarlane, 1951, Telogaster opisthorchis Macfarlane, 1945, Phyllodistomum sp., Paracardicoloides yamagutii Martin, 1974, Cucullanus sp., Procamaflanus sp., and glochidia of Hyridella sp. Widespread but intermittent in distribution were Myxidium serum Hine, 1975, Myxidium acinum Hine, 1975, Paraquimperia sp., Hedruris spinigera Baylis, 1931, Eustrongy‐ lides sp., and Accmthocephalus galaxii Hine, 1977. Rarely encountred or limited in distribution were Thelohanellus sp., Henneguya sp., Coitocaecum anaspidis Hickman, 1934, Coito‐caecum zealandicum Hine, 1977. Anguillicola australiensis Johnston & Mawston, 1940, Ascaro‐phis sp., Paranisakis sp., Philometra sp., and Abergasilus amplexus Hewitt, 1978. No conclusions could be drawn on the occurrence or distribution of Trichodina sp. Deretrema minutum Manter, 1954, a hemiurid, a proteocephalid, and Neoechinorhynchus aldrichettae Edmonds, 1971 were rarely encountered and did not mature. Eels were considered to be unsuitable hosts for these parasites. Most parasite species were widespread in a variety of habitats, but Thelohanellus sp. was confined to streams on or near the coast in the southern North Island, Henneguya sp. to Lake Ellesmere, Hedruris spinigera, Acanthocephalus galaxii and Coitocaecum anaspidis to coastal areas, C. zealandicum to Wairarapa streams, and Abergasilus amplexus to Lake Ellesmere and one area of coastal rivers. Where possible distribution records were related to the need for and availability of intermediate hosts.