Masters Degrees (Zoology and Entomology)
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Browsing Masters Degrees (Zoology and Entomology) by Author "Botes, Heléne"
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Item Open Access Sessiline ciliophorans associated with Haliotis species (Mollusca: Archaeogastropoda) from the South Coast of South Afica(University of the Free State, 1999-06) Botes, Heléne; Basson, Linda; Van As, Liesl L.English: Abalone, locally known as perlemoen, are herbivorous marine gastropods with all species in one genus, Haliotis Linneaus, 1758. Abalone have been commercially exploited since ancient times. Along the southern African coast, the genus Haliotis comprises six endemic species. Surveys carried out from 1995 to 1999 at the De Hoop Nature Reserve along the south coast of South Africa, revealed the presence of scyphidiid peritrichs, of the genus Mantoscyphidia Jankowski, 1980, occurring in abundance on the gills of Haliotis spadicea Donovan, 1808 and H. midae Linnaeus, 1758. These were described as two new species, i.e. M spadiceae sp. nov. and M midae sp. nov. The mantoscyphidians in turn hosted ellobiophryids of the genus Caliperia Laird, 1953, which was also described as a new species, Caliperia perlemoenae sp. nov., occurring on both mantoscyphidian species. During the study a perlemoen aquaculture facility, Danger Point Abalone Farm, was also visited, specimens of H. midae were examined and found to harbour the same species of scyphidiid peritrich and caliperid than H. midae collected from the De Hoop Nature Reserve. In the present study, severe infections of redial, cercarial and metacercarial stages and a few adult specimens of a digenean trematode were also found in the digestive gland of Haliotis spadicea as well as on the gill filaments. In order to elucidate the symbiont/host associations field experiments and histopathological examinations were carried out. These led to the conclusions that the host/scyphidiid peritrich associations are most likely not parasitic. In the case of the mantoscyphidianlcaliperid association, no clear evidence was found that the caliperids are pathogenic to their mantoscyphidian hosts. On the other hand, the trematodes could be potential pathogens since they can cause tissue destruction and affect the reproductive organs in the host.