The Importance of the Thukela River Estuary, East Coast of South Africa, for the Biology of the Near-Shore Environment and Associated Human Aspects: A Review

  • Ander M. De LeceaEmail author
  • Rachel Cooper
Part of the Estuaries of the World book series (EOTW)


The Thukela is the largest river on the KwaZulu-Natal (KZN) coastline, located at the South-Western edge of the Indian Ocean. This coast and the KZN Bight, where the Thukela meets the ocean, is considered meso-oligotrophic with distinct sources of nutrients entering the system. These sources are a series of oceanographic phenomena, including an upwelling cell, and several estuaries, the largest of which is the Thukela River estuary. The shallow Thukela Bank, formed as a sediment plume just off the Thukela estuary mouth, is the major site of several fisheries, notably the prawn trawl and line fisheries. Riverine influence has long been thought to be important for this fishery, but oceanographic research has, until recently, suggested that the main ecosystem driver was the upwelling cell. However, recent studies have shown that the biology of the Bight is primarily maintained by riverine organic matter and nutrients, mainly from the Thukela River. This input has helped support subsistence, recreational and commercial fisheries in one of South Africa’s most populated provinces. Despite the evidence of the Thukela’s ecological importance for the marine environment, the possibility of increasing water abstraction from the Thukela catchment to meet the needs of a growing population has been considered in water-stressed South Africa. Policy makers will increasingly have to face trade-offs between water demands for human consumption and marine ecological functioning, which are likely to be complicated by uncertainty surrounding future climate change effects on the river and its associated marine ecosystems. This review examines the role played by the Thukela estuary, amongst other estuaries in the Bight, and assesses their overall importance for the area from an ecological and human perspective.


Thukela River Estuary Fisheries Biology KwaZulu-Natal South Africa Western Indian Ocean 


  1. Adams JB (2014) A review of methods and frameworks used to determine the environmental water requirements of estuaries. Hydrol Sci J 59(3):1–15Google Scholar
  2. Ayers MJ, Scharler UM (2011) Use of sensitivity and comparative analyses in constructing plausible trophic mass-balance models of a data-limited marine ecosystem – The KwaZulu-Natal Bight, South Africa. J Mar Syst 88:298–311CrossRefGoogle Scholar
  3. Ayers MJ, Scharler UM, Fennessy ST (2013) Modelling ecosystem effects of reduced prawn recruitment on the Thukela Bank trawling grounds, South Africa, following nursery loss. Mar Ecol Prog Ser 479:143–161CrossRefGoogle Scholar
  4. Barlow R, Kyewalyanga M, Sessions H, van den Berg M, Morris T (2008) Phytoplankton pigments, functional types, and absorption properties in the Delagoa and Natal Bights of the Agulhas ecosystem. Estuar Coast Shelf Sci 80:201–211Google Scholar
  5. Barlow R, Lamont T, Britz K, Sessions H (2013) Mechanisms of phytoplankton adaptation to environmental variability in a shelf ecosystem. Estuar Coast Shelf Sci 133:45–57CrossRefGoogle Scholar
  6. Beckley LE, Alexander H, Skelton PH (2002) Synoptic overview of marine ichthyology in South Africa. Mar Freshw Res 53:99–105CrossRefGoogle Scholar
  7. Beckley LE, Fennessy ST, Everett BI (2008) Few fish but many fishers: a case study of shore-based recreational angling in a major South African estuarine port. Afr J Mar Sci 30:11–24CrossRefGoogle Scholar
  8. Begg G (1978) The estuaries of Natal, Report 41. Natal Town and Regional Planning Commission, PietermaritzburgGoogle Scholar
  9. Bosman C, Uken R, Leuci R et al (2007) Shelf sediments off the Thukela River mouth: complex interaction between fluvial and oceanographic processes. S Afr J Sci 103:490–492Google Scholar
  10. Branch GM, May J, Roberts B et al (2002) Case studies on the socio-economic characteristics and lifestyles of subsistence and informal fishers in South Africa. S Afr J Mar Sci 24:439–462CrossRefGoogle Scholar
  11. Bustamante RH, Branch GM, Eekhout S et al (1995) Gradients of intertidal primary productivity around the Coast of South Africa and their relationships with consumer biomass. Oecologia 102:189–201CrossRefGoogle Scholar
  12. Carter RA, d’Aubrey J (1988) Inorganic nutrients in Natal continental shelf waters. In: Schumann EH (ed) Coastal ocean studies off Natal, South Africa. Springer, Berlin, pp 131–151Google Scholar
  13. Carter RA, Schleyer MH (1988) Plankton distributions in Natal Coastal waters. In: Schumann EH (ed) Coastal ocean studies off Natal, South Africa. Springer, Berlin/Heidelberg, pp 152–177Google Scholar
  14. Clark BM (2006) Climate change: a looming challenge for fisheries management in southern Africa. Mar Policy 30:84–95CrossRefGoogle Scholar
  15. Clark BM, Hauck M, Harris JM et al (2002) Identification of subsistence fishers, fishing areas, resource use and activities along the South African coast. S Afr J Mar Sci 24:425–437CrossRefGoogle Scholar
  16. Cloern JE (2001) Our evolving conceptual model of the coastal eutrophication problem. Mar Ecol Prog Ser 210:223–253CrossRefGoogle Scholar
  17. Cooper JAG (2001) Geomorphological variability among microtidal estuaries from the wave-dominated South African coast. Geomorphology 40:99–122CrossRefGoogle Scholar
  18. Cooper A, Wright I, Mason T (1999) Geomorphology and sedimentology. Estuaries of South Africa. Cambridge University Press, Cambridge, pp 5–25CrossRefGoogle Scholar
  19. Costanza R, d’Arge R, de Groot R, Farber S, Grasso M, Hannon B, Naeem S, Limburg K, Paruelo J, O’Neill RV, Raskin R, Sutton P, van den Belt M (1997) The value of the world’s ecosystem services and natural capital. Nature 387:253–259CrossRefGoogle Scholar
  20. Cyrus DP, MacKay CF (2007) The environmental reserve and its role in retaining the diversity of birds at the Thukela Estuary. Ostrich J Afr Ornithol 78:621–631CrossRefGoogle Scholar
  21. Day JH (1981) Estuarine ecology, with particular reference to Southern Africa. A. A. Balkema, Cape Town Google Scholar
  22. DEA (Department of Environmental Affairs - South Africa) (2001) South African estuaries: Catchment landcover. Access – 2014
  23. De Lecea AM (2012) Isotopic ecosystem studies in the KwaZulu-Natal Bight. University of KwaZulu-Natal, Doctoral thesisGoogle Scholar
  24. De Lecea AM, Fennessy ST, Smit AJ (2013) Processes controlling the benthic food-web of a mesotrophic bight (KawZulu-Natal, South Africa) revealed by stable isotope analysis. Mar Ecol Prog Ser 484:97–114. doi: 10.3354/meps10311 CrossRefGoogle Scholar
  25. de Lecea AM, Cooper R, Smit AJ (2015) Identifying the drivers of the pelagic ecosystem of an Oligotrophic Bight (Kwazulu-Natal, South Africa) using stable isotopes (δ C, δ N) and C:N ratio analyses. Mar Freshw Res.
  26. De Lecea AM, Smit AJ, Fennessy ST (2016) Riverine dominance of a near-shore marine demersal food-web: evidence from stable isotope and C:N ratio analysis. Afr J Mar Sci 38(1), (in Press)Google Scholar
  27. De Ruijter WPM, van Leeuwen PJ, Lutjeharms JRE (1999) Generation and evolution of natal pulses: solitary meanders in the Agulhas Current. J Phys Oceanogr 29:3043–3056CrossRefGoogle Scholar
  28. Demetriades NT, Forbes AT (1993) Seasonal changes in the species composition of penaeid prawns on the Tugela Bank, Natal, South Africa. S Afr J Mar Sci 13:317–322CrossRefGoogle Scholar
  29. Dominy CS, Haynes RJ, Van Antwerpen R (2001) Long-term effects of sugarcane production on soil quality in the South Coast and Midlands areas of KwaZulu-Natal. Proc S Afr Sugar Technol Assoc 75:222–227Google Scholar
  30. Dunlop S, Mann B (2012) An assessment of participation, catch and effort in the KwaZulu-Natal shore-based marine linefishery, with comments on management effectiveness. Afr J Mar Sci 34:479–496CrossRefGoogle Scholar
  31. Dunlop S, Mann B (2013) An assessment of participation, catch and effort in the offshore boat-based linefishery in KwaZulu-Natal, South Africa. Afr J Mar Sci 35:79–97CrossRefGoogle Scholar
  32. DWAF (2004) Internal strategic perspective: Thukela water management area. Department of Water Affairs and Forestry; Report No. P WMA 07/000/00/0304, South AfricaGoogle Scholar
  33. DWS (2015) Implementation and maintenance of the water reconciliation strategy for the KwaZulu-Natal Coastal Metropolitan areas. In: Department water sanitation – online.
  34. Everett B (2014) Marine and estuarine fisheries along the KwaZulu-Natal coast: an inventory and brief description. No 11. South African Association for Marine Biological Research. Durban. ISBN: 978-0-620-64146-3Google Scholar
  35. Fairbanks DHK, Benn GA (2000) Identifying regional landscapes for conservation planning: a case study from KwaZulu-Natal, South Africa. Landsc Urban Plan 50:237–257CrossRefGoogle Scholar
  36. FAO (2014) The state of world fisheries and aquaculture 2014. Food and Agriculture Organisation, RomeGoogle Scholar
  37. Fennessy STT, Groeneveld JCC (1997) A review of the offshore trawl fishery for crustaceans on the east coast of South Africa. Fish Manage Ecol 4:135–147CrossRefGoogle Scholar
  38. Fennessy ST, Villacastin C, Field JG (1994) Distribution and seasonality of ichthyofauna associated with commercial prawn trawl catches on the Tugela Bank of Natal, South Africa. Fish Res 20:263–282CrossRefGoogle Scholar
  39. Gillanders B, Kingsford M (2003) Impact of changes in flow of freshwater on estuarine and open coastal habitats and the associated organisms. In: Gibson RN, Atkinson JA, Barnes M (eds) Oceanography and marine biology, an annual review, vol 40. Taylor and Francis, London, pp 233–309Google Scholar
  40. Graham LP, Andersson L, Horan M et al (2011) Using multiple climate projections for assessing hydrological response to climate change in the Thukela River Basin, South Africa. Phys Chem Earth Parts A/B/C 36:727–735CrossRefGoogle Scholar
  41. Griffiths CL, Robinson TB, Lange L, Mead A (2010) Marine biodiversity in South Africa: an evaluation of current states of knowledge. PLoS One 5:e12008CrossRefGoogle Scholar
  42. Harley CDG, Hughes AR, Hultgren KM et al (2006) The impacts of climate change in coastal marine systems. Ecol Lett 9:228–241CrossRefGoogle Scholar
  43. Hunter IT (1988) Climate and weather off Natal. In: Schumann EH (ed) Coastal ocean studies off Natal, South Africa. Springer, Berlin/Heidelberg, pp 178–208Google Scholar
  44. Hutchings L, Beckley LE, Griffiths MH et al (2002) Spawning on the edge: spawning grounds and nursery areas around the southern African coastline. Mar Freshw Res 53:307–318CrossRefGoogle Scholar
  45. Hutchings L, Morris T, van der Lingen CD et al (2010) Ecosystem considerations of the KwaZulu-Natal sardine run. Afr J Mar Sci 32:413–421CrossRefGoogle Scholar
  46. James NC, van Niekerk L, Whitfield AK et al (2013) Effects of climate change on South African estuaries and associated fish species. Clim Res 57:233–248CrossRefGoogle Scholar
  47. Lamberth SJ, Turpie JK (2003) The role of estuaries in South African fisheries: economic importance and management implications. Afr J Mar Sci 25:131–157CrossRefGoogle Scholar
  48. Lamberth SJ, Drapeau L, Branch GM (2009) The effects of altered freshwater inflows on catch rates of non-estuarine-dependent fish in a multispecies nearshore linefishery. Estuar Coast Shelf Sci 84:527–538CrossRefGoogle Scholar
  49. Lutjeharms JRE, de Ruijter WPM (1996) The influence of the Agulhas Current on the adjacent coastal ocean: possible impacts of climate change. J Mar Syst 7:321–336CrossRefGoogle Scholar
  50. Lutjeharms JRE, Valentine HR, Van Ballegooyen RC (2000) The hydrography and water masses of the Natal Bight, South Africa. Cont Shelf Res 20:1907–1939CrossRefGoogle Scholar
  51. Maslowski J (2003) Effects of trophic conditions on benthic macrofauna in the vicinity of the River Swina mouth (Pomeranian Bay; southern Baltic Sea). Oceanologia 45(1):41–52Google Scholar
  52. Meyer AA, Lutjeharms JRE, de Villiers S (2002) The nutrient characteristics of the Natal Bight, South Africa. J Mar Syst 35:11–37CrossRefGoogle Scholar
  53. Oliff WD (1973) Chemistry and productivity at Richards Bay. CSIR NPR: Oceanography Division Contract Report. Vol. CFIS 37B. DurbanGoogle Scholar
  54. Omarjee A (2012) Phytoplankton studies in the KwaZulu-Natal Bight by. University of KwaZulu-Natal, MSc thesisGoogle Scholar
  55. Polis GA, Hurd SD (1996) Linking marine and terrestrial food webs: allochthonous input from the ocean supports high secondary productivity on small islands and coastal land communities. Am Nat 147:396–423CrossRefGoogle Scholar
  56. Porter SN, Kaehler S, Branch GM, Sink KJ (2014) Riverine subsidies for inshore filter-feeder communities: potential influences on trophic patterns among bioregions. Mar Ecol Prog Ser 498:13–26CrossRefGoogle Scholar
  57. Pradervand P, Beckley LE, Mann BQ, Radebe PV (2003) Assessment of the linefishery in two urban estuarine systems in Kwazulu-natal, South Africa. Afr J Mar Sci 25:111–130CrossRefGoogle Scholar
  58. Reddering JSV, Rust IC (1990) Historical changes and sedimentary characteristics of southern African estuaries. S Afr J Sci 86:425–428Google Scholar
  59. Reid P, Vogel C (2006) Living and responding to multiple stressors in South Africa—Glimpses from KwaZulu-Natal. Glob Environ Chang 16:195–206CrossRefGoogle Scholar
  60. Rivers-Moore NA, Goodman PS, Nkosi MR (2007) An assessment of the freshwater natural capital in KwaZulu-Natal for conservation planning. Water SA 33:665–674Google Scholar
  61. Roberts MJ, van der Lingen CD, Whittle C, van den Berg M (2010) Shelf currents, lee-trapped and transient eddies on the inshore boundary of the Agulhas Current, South Africa: their relevance to the KwaZulu-Natal sardine run. Afr J Mar Sci 32:423–447CrossRefGoogle Scholar
  62. Schumann EH (1982) Inshore circulation of the Agulhas Current off Natal. J Mar Res 40:43–55Google Scholar
  63. Shipley AM, Zoutendyk P (1964) Hydrographic and plankton collected in the south west Indian Ocean during the SCOR international Indian Ocean Expedition 1962–1963. University of Cape Town Oceanography Department, vol 3. Cape TownGoogle Scholar
  64. Stryftombolas IC (2010) Ecotoxicological assessment of the impact of paper and pulp effluent on the lower Thukela River catchment, KwaZulu-Natal, South Africa and the toxicological assessment of similar effluent from two other mills. University of Johanesburg, MSc thesisGoogle Scholar
  65. Taylor V, Schulze RE, Jewitt GPW et al (2001) Practical issues of HELP: examples from the Thukela Basin in South Africa. In: Proceedings of the AWRA/University of Dundee international specialty conference on globalization and water management. http://www.awra/org
  66. Turpie JK, Lamberth SJ (2010) Characteristics and value of the Thukela Banks crustacean and linefish fisheries, and the potential impacts of changes in river flow. Afr J Mar Sci 32:613–624CrossRefGoogle Scholar
  67. Whitfield AK (2005) Fishes and freshwater in southern African estuaries – a review. Aquat Living Resour 18:275–289CrossRefGoogle Scholar
  68. Whitfield AK, Harrison TD (2003) River flow and fish abundance in a South African estuary. J Fish Biol 62:1467–1472CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Department for Biodiversity & Conservation BiologyUniversity of the Western CapeBelvilleSouth Africa
  2. 2.Marine Research Institute and Department of Biological SciencesUniversity of Cape TownRondeboschSouth Africa

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