M.Sc. (Zoology) / Please refer to full text to view abstract

D.Phil. (Zoology) / Fish parasites may cause disease and lead to commercial losses. In order to construct practical management systems to mitigate or manage potential adverse effects, information on basic biological variables is required. Compared to the number of internationally published papers on the subject, little is known about the monogenean parasite fauna of South African fishes. Monogeneans are largely ectoparasitic, thin, flattened, host- and site specific parasites with a simple life cycle involving a single host (often a fish). They range in size between 0.3 mm and 20 mm and are mostly bilaterally symmetrical with the body subdivided into a number of regions. Attachment organs are a necessary feature both anteriorly and posteriorly, with the morphology of the prominent posterior attachment organ (opisthaptor) highly variable between genera. It may contain suckers, clamps or large hooks (anchors) as well as marginal hooks. In some genera anchors (one to two pairs) are associated with spikes or accessory sclerites and are supported by a connecting bar. All these structures, together with the sclerotized male copulatory organ, are of taxonomic significance....

D.Phil. / Please refer to full text to view abstract

M.Sc. (Zoology) / Please refer to full text to view abstract

M.Sc. (Zoology) / The world’s ever increasing human population has lead to an almost unimaginable amount of waste being released in to the aquatic environment every day. Aquatic systems are faced with the greatest risk due to the fact that water is an indispensable resource required for industrial and agricultural processes. In recent years there has been a dire need for the monitoring and rehabilitation of aquatic systems. As a result many biological monitoring programmes were set into place in an attempt to manage this problem. The use of aquatic organisms as sentinels for biomonitoring studies has been wildly accepted with the majority of biomonitoring research focusing on the use of various fish and invertebrate species as aquatic sentinel organisms. However, the use of parasites as sentinel organisms is a relatively new field and as a result there has been little published work on the use of monogenean ectoparasites parasites as such sentinels. The bioaccumulation and subsequent biomagnification of metals by certain parasite species is well known, with bulk of the published work focusing on endoparasites (cestodes, acanthocephalans & nematodes), these published studies indicate that some species of endoparasites exhibit a remarkable ability to biomagnify metals in concentrations that far exceed that of their respective hosts as well as the ambient environment. Thus this project aims to assess the bioaccumulation and biomagnification of metals by the ectoparasitic diplozoon. The study site that was chosen for this project was the Vaal Dam; this site was deemed appropriate due to its near pristine condition and major economic importance. This meant that this particular site is ideal for the testing of a new biomonitoring system. All field sampling was performed around UJ Island (26°52.249’S; 20°10.249’E) from February 2011 to April 2011. A total of 29 Labeo umbratus (Smith, 1841) were collected with the aid of gill nets and three sediment samples were also taken using a grab sampler. Water quality data was obtained from the Rand Water Analytical Facility in Vereeniging as this organisation routinely monitors of the water quality parameters and the metal concentrations within the surface waters of the Vaal Dam, this information was obtained with the aid of data loggers situated in the dam...