Marliese Truter

PhD Candidate
Marliese Truter


The assessment of metazoan parasite diversity of native and extralimital Clarias gariepinus (Burchell, 1822) populations: a holistic approach.

Artificial introduction of alien freshwater fish species or the translocation of these species has been a common practice since the 18th century. These introductions and similarly, the introduction of parasites with these hosts are of concern for indigenous biodiversity in freshwater ecosystems. Upon introduction into a novel environment parasites can be co-introduced with their hosts and switch hosts or exert mechanisms of invasion such as parasite spillback, spill-over, dilution and enemy release, each with its own effects on the native biota in the introduced system. In addition, these co-introduced parasites often reach co-invader status and can outcompete native parasite fauna. The success of the parasitic communities in the novel environment can be dependent on the age of hosts, abiotic environmental factors, method of translocation and the region where they occurred to where they have been introduced to. The African sharptooth catfish, Clarias gariepinus (Burchell, 1822) will be used as the model species. It is a hardy and well-studied (in the fields of parasitology and ecotoxicology) species native species to Africa, including southern Africa, and a regional native in South Africa having invasive status in the Eastern and Western Cape provinces. Spread to extralimital regions occurred through manual transfers by anglers, escapes from aquaculture and inter-basin water transfer schemes. This project aims use an integrated approach of parasitology, ecotoxicology and literature to investigate the parasitic communities of C. gariepienus in native and extralimital distribution ranges, determine the invasion status of the parasite species and how host age and abiotic environmental factors link to parasitic infection.

Registered: North-West University, Unit for Environmental Sciences and Management, Water Research Group, North-West University

Supervisors: Prof Olaf Weyl, NRF/DST Research Chair in Inland Fisheries and Freshwater Ecology, South African Institute for Aquatic Biodiversity (NRF/SAIAB); Prof Nico J Smit, Unit for Environmental Sciences and Management, Water Research Group, North-West University