1. Marine Research (MA-RE) Institute and Department of Biological Sciences; University of Cape Town; Private Bag X3 Rondebosch 7701 South Africa
2. Department of Environmental Affairs; Oceans and Coasts; Private Bag X2 Rogge Bay 8012 South Africa
3. Institute of Aquatic Resources; Technical University of Denmark; North Sea Centre; PO Box 101 Hirtshals DK-9850 Denmark