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


Moravec, F., Weyl, O., Taraschewski, H. (2013). Redescription of Heliconema africanum (Linstow, 1899) n. comb. (Nematoda: Physalopteridae), a nematode parasite of freshwater eels (Anguilla spp.) in South Africa. Systematic Parasitology. 85(3): 263-269

Mäkinen T, Weyl OLF, van der Walt KA, Swartz ER. 2013. First record of an introduction of the giant pangasius, Pangasius sanitwongsei Smith 1931, into an African river. African Zoology (in press)

Weyl OLF, Ellender BR, Woodford DJ, Jordaan M (2013) Fish distributions in the Rondegat River, Cape Floristic Region, South Africa, and the immediate impact of rotenone treatment in an invaded reach. African Journal of Aquatic Science 2013, 38(2): xx–xx

Huchzermeyer CF, Weyl OLF, Cowley PD. (2013) Evaluation of acoustic transmitter implantation and determination of post-translocation behaviour of largemouth bass Micropterus salmoides in a South African impoundment. African Journal of Aquatic Science 2013, 38(2): xx–xx

McHugh KJ, Van Dyk JC, Weyl OLF, Smit NJ (2013) First report of nephrocalcinosis in a wild population of Mugil cephalus L. and Myxus capensis (Valenciennes). Journal of Fish Diseases. doi: 10.1111/jfd.12101

Jones RW, Weyl OLF, Swartz ER, Hill MP (2013). Using a unified invasion framework to characterize Africa’s first loricariid catfish invasion. Biological Invasions, 1-7  

Moravec, F., Weyl, O., Taraschewski, (2013). Redescription of Heliconema africanum (Linstow, 1899) n. comb. (Nematoda: Physalopteridae), a nematode parasite of freshwater eels (Anguilla spp.) in South Africa. Syst. Parasitol. (in press)

Taylor GC, Weyl O LF (2013), Validation of annulus formation in otoliths of largemouth bass Micropterus salmoides outside their native range. Journal of Applied Ichthyology. doi: 10.1111/jai.12150

 D. J. Woodford, C. Hui, D. M. Richardson and O. L. F. Weyl
The danger of inter-basin water transfer schemes in driving alien fish establishment
The poster was awarded the EIFAAC (European Inland Fisheries and Aquaculture Advisory Commision) award for best poster at the Freshwater Invasives - Networking for Strategy (FINS)  Conference, 9-11 April 2013, Galway, Ireland.


Wasserman RJ, Pereira-da-Conceicoa LL, Strydom NA, Weyl OLF. 2012. Diet of Anguilla mossambica (Teleostei, Anguillidae) elvers in the Sundays River, Eastern Cape, South Africa. African Journal of Aquatic Science. 37: 347-349.

Ellender BR, Taylor GC, Weyl OLF. 2012. Validation of growth zone deposition rate in otoliths and scales of flathead mullet Mugil cephalus and freshwater mullet Myxus capensis from fish of known age. African Journal of Marine Science 34: 455-458.

Lin Y-J, Jessop BM, Weyl OLF, Iizuka Y, Lin S-H, Tzeng WN, Sun CL. 2012. Regional variation in otolith Sr:Ca ratios of African longfinned eel Anguilla mossambica and mottled eel Anguilla marmorata: a challenge to the classic tool for reconstructing migratory histories of fishes. Journal of Fish Biology 81:427-441.

Ellender BR, Weyl OLF, Winker H. 2012. Age and growth and maturity of southern Africa’s largest cyprinid fish, the largemouth yellowfish Labeobarbus kimberleyensis. Journal of Fish Biology 81: 1271-1284.

Moravec F, Taraschewski H, Appelhoff D, Weyl OLF. 2012. A new species of Hysterothylacium (Nematoda: Anisakidae) from the giant mottled eel Anguilla marmorata in South Africa. Helminthologia, 49, 3: 174 – 180,.

Winker H, Weyl OLF, Booth AJ, Ellender BR. 2012. Life history strategy and population characteristics of an unexploited riverine cyprinid, Labeo capensis, in the largest impoundment in the Orange River Basin. African Zoology 47:85-99.

McCafferty JR, Weyl OLF, Ellender BR, Brtitz P. 2012. The use of water resources for inland fisheries in South Africa. Water SA 38:327-343.

Ellender BR, Becker A, Weyl OLF, Swartz ER. 2012. Underwater video analysis as a non-destructive alternative to electrofishing for sampling imperiled headwater stream fishes. Aquatic Conservation: Marine and Freshwater ecosystems. 22: 58-65.