Short Communication

First documented southern transatlantic migration of a blue shark Prionace glauca tagged off South Africa

  • C da Silva
  • SE Kerwath
  • CG Wilke
  • M Meÿer
  • SJ Lamberth

Abstract

The first documented recapture of a South African-tagged juvenile blue shark Prionace glauca off Uruguay lends weight to the hypothesis of a single blue shark population in the South Atlantic. The presence of neonate blue sharks with umbilical scars and females with post-parturition scars, as well as the high  frequency of small juveniles in research longline catches, confirm the existence of a parturition and nursery area off South Africa. The final positions of three tagged sharks suggest that large-scale movement patterns in the South Atlantic  are a mirror image of movements in the North Atlantic, with sharks using the  north-westerly Benguela Drift to migrate into the tropics and ultimately across into South American waters. The confirmed existence of a parturition and nursery area off the south coast of South Africa and the movement of sharks into both adjacent ocean basins suggest that the southern African blue sharks  are part of a single stock that straddles the South Atlantic and Indian oceans, and possibly the entire Southern Hemisphere.

Keywords: blue shark, length frequency, migration, nursery area, Prionace glauca, South Atlantic

African Journal of Marine Science 2010, 32(3): 639–642

Author Biographies

C da Silva
Branch Fisheries, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Rogge Bay 8012, South Africa
SE Kerwath
Branch Fisheries, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Rogge Bay 8012, South Africa; Department of Zoology, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
CG Wilke
Branch Fisheries, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Rogge Bay 8012, South Africa
M Meÿer
Oceans and Coasts, Department of Environmental Affairs, Private Bag X2, Rogge Bay 8012, South Africa
SJ Lamberth
Branch Fisheries, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Rogge Bay 8012, South Africa; South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa
Section
Articles

Journal Identifiers


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