M.Sc. / At present large scale extensive cropping of fish populations of impoundments is being undertaken by the agricultural departments of the government of the Republic of Venda and selfgoverning states of Lebowa and Gazankulu. Parasitological surveys coinciding with the cropping program revealed that Clarias gariepinus (Burchell, 1822) and Oreochromis mossambicus (Peters, 1852) were infested by fish lice of the genus Dolops (Crustacea: Branchiura). A study was therefore initiated to examine the extent of these infestations and other impoundments in Transvaal were also included. A total of 14 localities in Transvaal extending from Bloemhof Dam in the Southwest to Luphephe and Nwanedzi Dams in the Northeast were surveyed during 1982 and 1983. At these localities fish were collected by means of gill nets, seining and electrofishing techniques. The collected fish were examined in a field laboratory at the collection localities for the presence of ectoparasitic Dolops. The fish were weighed and measured and the site of attachment of the parasites, if present, were recorded. The parasites were removed and fixed in either hot formalin or AFA. A number of parasites were transported alive to the laboratory in Johannesburg where they were kept in glass aquaria and their life cycle studied. A morphological description based on light microscopy as well as scanning electronmicroscopy of the eggs, larvae and adults were made, and comparative body dimensions of parasites from various localities recorded. It was found that only one species of Dolops that is D. ranarum (Stuhlmann, 1891) occurred in Transvaal. This parasite was found in only five of the 14 examined localities of which all were situated in Northern Transvaal, north of the watershed.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:3641 |
| Date | 05 February 2014 |
| Creators | Avenant, Annemarie |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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