ENDOPARASITES OF THE CAPE FUR SEAL ARCTOCEPHALUS PUSILLUS PUSILLUS FROM THE EASTERN CAPE COAST OF SOUTH AFRICA

SUMMARY

A total of 53 Cape fur seals. Arctocephalus pusillus pusillus, collected along the Eastern Cape coast of South Africa between Plettenberg Bay (34° 03'S, 23° 24'E) and East London (33° 03'S, 27° 54'E) from 1992 to 1995, was examined for blubber and stomach parasites. Forty three of these seals (81%) harboured stomach parasites, and 13 (25%) harboured blubber parasites. Nine parasite taxa were identified. Helminth species included adult cestodes Diphyllobothrium sp., larval cestodes, Hepatoxylon trichiuri and Phyllobothrium delphini; nematodes, Anisakis physeteris, Anisakis simplex. Contracaecum ogmorhini, Contracaecum sp. and Hysterothylacium sp. and an acanthocephalan, Corynosoma sp. Three of these taxa, Hepatoxylon trichiuri, Anisakis physeteris, and Hysterothylacium sp., were accidental parasites. Scanning electron microscope examination confirmed the identity of Contracaecum ogmorhini and suggests that earlier studies may have incorrectly identified this nematode as Contracaecum osculatum. The prevalence and diversity of endoparasitism was higher in older seals. Intensity of infection was generally higher in stranded animals than in healthy animals incidentally captured in trawl nets. The endoparasites found in the present study did not appear to contribute to the mortality of Cape fur seals, at least in the population from which the examined specimens were taken. Although the anisakine nematodes, Contracaecum sp. and Anisakis sp., are potentially pathogenic, severe pathological changes were limited to small gastric lesions in the stomachs of three individuals.