Dr Olaf Weyl

Principal Scientist
Dr Olaf Weyl
Tel : +27 46 603 5834
Fax : +27 46 622403
Cell : +27 (0)83 461 5434

View CV

Research Interests

Fish biology and ecology, particularly with reference to the impact of alien fishes and the influence of anthropogenic factors on aquatic ecosystems.

My current research focus at SAIAB is geared towards providing information with which to better manage Africa’s aquatic biodiversity. To this end my research group works on freshwater ecosystems in several African countries including Mozambique, Malawi, Namibia, Botswana, Zambia and South Africa. Current interests are fisheries, native fish conservation and alien fish invasions. As a result my research is multidisciplinary and includes not only research on natural systems and processes but also research on understanding how humans alter and benefit from aquatic systems.

Recent invasive fish related projects include assessing the impacts of recreational angling species such as carp and bass on native fish and invertebrate communities; parasitological and ecological research on eels; monitoring the recovery of stream ecosystems after alien fish removal using piscicides; impacts of hybridisation resulting from fish introductions; managing fish invasions in protected areas and assessing the role that alien fishes play in subsistence and recreational fisheries in South Africa.

I also provide policy support with regards to inland fisheries and legislation on alien fish management. I am also active in the development of decision making tools used by provincial nature conservation departments to assess invasion risks through fish introductions.

I am on the editorial board member of African Zoology, African Journal of Aquatic Science and Journal of Fish Biology and provide expert advice for several organisations including the Endangered Wildlife Trust and the World Wildlife Fund.

Current Students

University of Karlsruhe, Germany
Nelson Mandela Metropolitan University
South African National Parks
South African National Biodiversity Institute
Department of Ichthyology and Fisheries Science, Rhodes University, South Africa
Department of Aquaculture and Fisheries Science, Bunda College of Agriculture, Malawi
University of Namibia
Malawi Fisheries Research Institute, Department of Fisheries, Malawi

Recent Peer-Reviewed Publications

Google Scholar Profile


Alexander, M.E., Dick, J.T.A., Weyl, O.L.F., Robinson, T.B. & Richardson, D.M. 2014, Existing and emerging high impact invasive species are characterized by higher functional responses than natives, Biology Letters, vol. 10, no. 2.

Alexander, M.E., Kaiser, H., Weyl, O.L.F. & Dick, J.T.A. 2014, Habitat simplification increases the impact of a freshwater invasive fish, Environmental Biology of Fishes, .

Dick, J.T.A., Alexander, M.E., Jeschke, J.M., Ricciardi, A., MacIsaac, H.J., Robinson, T.B., Kumschick, S., Weyl, O.L.F., Dunn, A.M., Hatcher, M.J., Paterson, R.A., Farnsworth, K.D. & Richardson, D.M. 2014, Advancing impact prediction and hypothesis testing in invasion ecology using a comparative functional response approach, Biological Invasions, vol. 16, no. 4, pp. 735-753.

Ellender, B.R. & Weyl, O.L.F. 2014, A review of current knowledge, risk and ecological impacts associated with non-native freshwater fish introductions in South Africa, Aquatic Invasions, vol. 9, no. 2, pp. 117-132.

Ellender, B.R., Woodford, D.J. & Weyl, O.L.F. 2014, The invasibility of small headwater streams by an emerging invader, Clarias gariepinus, Biological Invasions, .

Lin, Y.-., Jessop, B.M., Weyl, O.L.F., Iizuka, Y., Lin, S.-. & Tzeng, W.-. 2014, Migratory history of African longfinned eel Anguilla mossambica from Maningory River, Madagascar: discovery of a unique pattern in otolith Sr:Ca ratios, Environmental Biology of Fishes, .

McHugh, K.J., Christison, K.W., Weyl, O.L.F. & Smit, N.J. 2014, Histological confirmation of Epizootic ulcerative syndrome in two cyprinid species from Lake Liambezi, Zambezi Region, Namibia, African Zoology, vol. 49, no. 2, pp. 311-316.

Taylor, G.C., Weyl, O.L.F., Cowley, P.D. & Allen, M.S. 2015, Dispersal and population-level mortality of Micropterus salmoides associated with catch and release tournament angling in a South African reservoir, Fisheries Research, vol. 162, pp. 37-42.

Weyl, O.L.F., Finlayson, B., Impson, N.D., Woodford, D.J. & Steinkjer, J. 2014, Threatened Endemic Fishes in South Africa's Cape Floristic Region: A New Beginning for the Rondegat River, Fisheries, vol. 39, no. 6, pp. 270-279.