Sightings of killer whales Orcinus orca from longline vessels in South African waters, and consideration of the regional conservation status

  • AJ Williams
  • SL Petersen
  • M Goren
  • BP Watkins


Killer whales Orcinus orca are seldom reported from South African nearshore waters but, allowing for the bias of vessel attraction, observations from longline vessels suggest there is a resident offshore population of fish-eating killer whales. We present reports of killer whales made by observers on pelagic longline vessels fishing for tuna Thunnus spp., swordfish Xiphias gladius and sharks off South Africa, and on demersal longline vessels fishing for Patagonian toothfish Dissostichus eleginoides off the Subantarctic Prince Edward Islands. Off South Africa, observers reported 689 occurrences of killer whales during the period January 2002 to  December 2006. Observations off South Africa peaked in January and were minimal in April–May. Most killer whale pods comprised 1–4 individuals and few were more than six. Observations were largely over the shelf edge between the Agulhas Bank and Port Elizabeth on the south-east coast of South Africa. In all, 1 843 line sets, using 3.8 million hooks, were monitored and killer whales occurred at an overall rate of 0.18 per 1 000 hooks. Killer whales depredated at an overall rate of 0.5% of the total catch. A small (maximum 12 individuals) population was recorded at longline vessels off the Prince Edward Islands, but observations were limited to August–September, October–November and May–June. We consider the conservation status of killer whales in southern African waters to be ‘vulnerable’, because the populations are very small and are subject to both short- and long-term impacts from the longline fisheries.

Keywords: conservation; killer whale; long-line fishery; Orcinus orca; Thunnus; Xiphias

African Journal of Marine Science 2009, 31(1): 81–86

Author Biographies

AJ Williams
Animal Demography Unit, Department of Zoology, University of Cape Town, Rondebosch 7701, South Africa
SL Petersen

WWF Responsible Fisheries Programme, WWF South Africa, PO Box 50035, Waterfront 8002, South Africa

M Goren
BirdLife Marine Programme, BirdLife South Africa, Unit 19, Foregate Square, Cape Town 8001, South Africa
BP Watkins

BirdLife Marine Programme, BirdLife South Africa, Unit 19, Foregate Square, Cape Town 8001, South Africa


Journal Identifiers

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