South African kelp moving eastwards: the discovery of Ecklonia maxima (Osbeck) Papenfuss at De Hoop Nature Reserve on the south coast of South Africa

  • JJ Bolton
  • RJ Anderson
  • AJ Smit
  • MD Rothman

Abstract

Historical and recent evidence is documented to demonstrate that the eastern limit of the major kelp-bed forming seaweed Ecklonia maxima has moved c. 73 km eastward along the south coast of South Africa since 2006, after remaining unchanged for almost 70 years. A significant population has established at Koppie Alleen, De Hoop Nature Reserve, which has been monitored from 2008 to 2011. It is hypothesised that the eastward spread is limited by aspects of the inshore water temperature regime, and recent evidence suggests that gradual cooling along this coast may have caused the change in distribution. It seems likely that if a cooling trend continues along the South African south coast, kelp beds and their associated species will move farther eastward in future decades, affecting the ecology and livelihoods along this coast.

Keywords: biogeography, climate change, Laminariales, temperature

African Journal of Marine Science 2012, 34(1): 147–151

Author Biographies

JJ Bolton
Botany Department and Marine Research Institute, University of Cape Town, Rondebosch 7701, South Africa
RJ Anderson
Botany Department and Marine Research Institute, University of Cape Town, Rondebosch 7701, South Africa; Branch: Fisheries, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Rogge Bay 8012, South Africa
AJ Smit
School of Biological and Conservation Sciences, Faculty of Science, University of KwaZulu-Natal, Durban, South Africa
MD Rothman
Botany Department and Marine Research Institute, University of Cape Town, Rondebosch 7701, South Africa; Branch: Fisheries, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Rogge Bay 8012, South Africa
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X