Ryan Wasserman

Associate Professor of Zoology

Office: S16, Second Floor, Life Science Building
046 603 8168

Research interests

  • Global change biology
  • Trophic relationships in aquatic ecosystems
  • Aquatic invertebrate ecology

Post-graduate supervision

Current students


L. Mofu: Rhodes University, South Africa. Ichthyofaunal dynamics of the Sundays River irrigation impoundments.

D. Khosa: Rhodes University, South Africa. Invasion dynamics of Micropterus spp. in South Africa.

M. Buxton: BIUST, Botswana. Vector mosquito biology, ecology and eco-physiology in Central District, Botswana.


M. Tladi: BIUST, Botswana. The ecology of rockpond and pond branchiopod crustaceans in Central District, Botswana.

L. Makhuvha: University of Venda, South Africa. Organic matter dynamics in Nylsvlei wetland: Distribution and processes.

Past students 

P. Ndaleni: Rhodes University, South Africa. The biology and ecology of bluegill sunfish in the Kariega River system (2015-2016, awarded with distinction). Data chapter published in ISI accredited journal.

N. Mbandzi: Fort Hare University, South Africa. The relationship between river flow, plankton dynamics and the feeding ecology of two dominant zooplanktivorous fish species in the Kariega Estuary, South Africa (2015-2016, awarded with minor revisions). Data chapter published in ISI accredited journal.

C. Jooste: University of Johannesburg, South Africa. Genetic connectivity in Lovenula raynerae (Copepoda) from temporary aquatic ecosystems in the Eastern Cape of South Africa (2017-2018, awarded with distinction). Data chapter published in ISI accredited journal.

T. Muchekwa: University of Venda, South Africa. Invasive and indigenous leaf litter decomposition dynamics in agricultural water impoundments (2018-2019, awarded with distinction). Data Chapter published in ISI accredited journal.

R. Tshivhase: University of Venda, South Africa. An assessment of metal and nutrient dynamics in soils and macrophytes of the Nysvlei Wetland system (2018-2019). Data chapter published in ISI accredited journal.

Recent publications

Wasserman RJ, Whitfield AK, Deyzel SHP, James NC, Hugo S (2020). Seagrass (Zostera capensis) bed development as a predictor of size structured abundance for a ubiquitous estuary-dependent marine fish species. Estuarine, Coastal and Shelf Science 238, 106694.

Buxton M, Cuthbert RN, Dalu T, Nyamukondiwa C, Wasserman RJ (2020). Predator density modifies mosquito regulation in increasingly complex environments. Pest Management Science. DOI: 10.1002/ps.5746.

Buxton M, Cuthbert RN, Dalu T, Nyamukondiwa C, Wasserman RJ (2020). Cattle-induced eutrophication favours oviposition by multiple disease-vector mosquito species. Science of the Total Environment 715, 136952.

Buxton M, Cuthbert RN, Dalu T, Nyamukondiwa C, Dick JA, Wasserman RJ (2020). Temporary wetland predator diversity favours larval mosquito control. Biological Control 144, 104216.

Cuthbert R, Wasserman RJ, Dalu T, Kaiser H, Weyl OLF, Sentis A, McCoy M, Alexander M, (2020). Predator-prey interaction strengths are not conserved across size classes. Ecology & Evolution. ECE-2020-01-00026.R2.

Dickey JWE, Cuthbert RN, South Josie, Britton JR, Caffrey J, Chang X, Fadaei E, Farnsworth KD, Ismar S, Julius M, Laverty L, Lucy FE, McCard M, MacIsaac HJ, Reid N, Ricciardi A, Wasserman RJ, Weyl OLF, Dick JTA (2020). On the use of RIP: Using the Relative Impact Potential metric to assess and predict the ecological impacts of invasive alien species. Neobiota.

Sithagu R, Weyl OLF, Wasserman RJW, Dick JTA, Callaghan A, Froneman PW, Foord S, Dalu T (2020). Water volume differentially modifies copepod predatory strengths on two prey types. Limnologica 81, 125747.

Cuthbert R, Dalu T, Wasserman RJ, Weyl OLF, Froneman PW, Callaghan A, Dick JTA (2020). Shifting multiple predator effect strengths across intraspecific sex demographics. Basic and Applied Ecology

Cuthert RN, Dalu T, Wasserman RJ, Dick JTA, Callaghan A, Froneman PW, Weyl OLF. (2020). Lack of prey switching and strong preference for mosquito prey by a temporary pond specialist predator. Ecological Entomology 45, 369-372.

Lee JM, Wasserman RJ, Gan JY, Wilson RF, Raman S, Yek SH (2020). Human activities attract harmful mosquitoes in a tropical urban landscape. Ecohealth 17, 52-63.

Dalu T, Magoro ML, Naidoo LS, Wasserman RJ, Human L, Adams JB, Perissinotto R, Deyzel SHP, Wooldridge T, Whitfield AK (2020). Microphytobenthos diversity and community structure across different micro-estuaries and micro-outlets: Effects of environmental variables on community structure. Environmental Pollution 260, 114097.

Dalu T, Cuthbert R, Tiyisani C, Froneman PW, Wasserman RJ, (2020). Assessing sediment particle-size effects on benthic algal colonisation and total carbohydrate production. Science of the Total Environment 710, 136348.

Mbedzi R, Dalu T, Wasserman RJ, Murungweni F, Cuthbert RN (2020). Functional response quantifies microplastic uptake by a widespread African fish species. Science of the Total Environment 700, 134522.

Cuthert RN, Dalu T, Wasserman RJ, Weyl OLF, Froneman PW, Callaghan A, Dick JTA (2020). Alternative prey impedes impacts by mosquito natural enemies. Biological Control 141, 104146.

Cuthbert R, Wasserman RJ, Weyl OLF, Dick JTA, Froneman PW, Callaghan A, Dalu T (2020). Sex demographics alter the effect of habitat structure on interaction strengths in temporary pools. Hydrobiologia 847, 831-840.

Cuthbert R, Dalu T, Wasserman RJ, Monaco C, Callaghan A, Weyl OLF, Dick JTA (2020). Assessing multiple predator, diurnal and search area effects on predatory impacts by ephemeral wetland specialist copepods. Aquatic Ecology 95, 116-119.

Khosa D, South J, Cuthbert R, Wasserman RJ, Weyl OLF (2020). Temperature regime drives differential predatory performance in Largemouth Bass and Florida Bass. Environmental Biology of Fishes 103, 67-76.

Wasserman RJ, Dick JTA, Welch RJ, Dalu T, Magellan K (2019). Site and species selection for religious release of non-native fauna. Conservation Biology 33, 969-971.

Mokobela M, Wasserman RJ , Kerley GIH (2019). Botswana’s elephant hunting policy shift highlights the need for local experts. Nature (Letter to editor) 573, 346.

Wasserman RJ, Weston M, Weyl OLF, Froneman PW, Vink TJF, Welch RJ, Dalu T (2018). Sacrificial males: the role of copulation and predation in driving copepod sex skewed ratios in ephemeral pond ecosystems. Oikos 127, 970-980.

Wasserman RJ, Alexander M, Cuthbert R, Dalu T (2018). Shifting interaction strength between estuarine mysid species across a temperature gradient. Marine Environmental Research 140, 390-393.

See links below for comprehensive list:




Book Chapters

Weyl OLF, Ellender BR, Wasserman RJ, Truter M, Dalu T, Zengeya T, Smit N (2019). Alien Freshwater Fauna in South Africa. In Measy J, van Wilgen B (Eds) South African Biological Invasions and their Management.

Weyl OLF; Ellender BR; Ivey P, Jackson M; Tweddle D; Wasserman RJ, Woodford DJ, Zengeya T (2017) Africa: Brown Trout Introductions, Establishment, Current Status, Impacts and Conflicts. In Capitulo (Ed) Brown Trout: Biology, Ecology and Management. pp.623-639. DOI: 10.1002/9781119268352.ch24

Last Modified: Fri, 17 Apr 2020 09:38:20 SAST