Endoparasitic helminths of the whitespotted rabbitfish (Siganus sutor (Valenciennes,1835)) of the Kenyan coast: Distribution within the host population and microhabitat use

The parasitic fauna of the alimentary tract of adult whitespotted rabbitfish Siganus sutor, sampled in December 1990 at the Kenyan coast, was investigated. Five endoparasites were found: the digenean trematodes Opisthogonoporoides hanumanthai, Gyliauchen papillatus and Hexangium sigani, the acanthocephalan Sclerocollum rubrimaris and the nematode Procammalanus elatensis. No uninfected fish, nor single species infections occurred. Parasite population data showed very high prevalences for all endoparasites, ranging from 68.18\% to 100\%. G. papillatus occurred with the highest mean intensity, 201.68 +/- 12.54 parasites per infected fish. The parasites were overdispersed within their host's population and frequency distributions generally fitted the negative binomial function. The relationship between host size and parasite burden showed that smaller fish were more heavily infected. The infection with O. hanumanthai and H. sigani decreased significantly with total length of S. sutor. Study of the associations between parasites showed that the intensities of the three digenean species were significantly positively correlated. Possible transmission strategies. of the digenea and impact of the feeding habits of S. sutor are discussed. Microhabitat preferences of the five endoparasites indicated a selective site segregation of all species.