Selected fishery and population parameters of eight shore-angling species in the Tsitsikamma National Park no-take marine reserve

  • A Götz Elwandle Node, South African Environmental Observation Network (SAEON), Private Bag 1015, Grahamstown 6140, South Africa
  • PD Cowley South African Institute for Aquatic Biodiversity (SAIAB), Private Bag 1015, Grahamstown 6140, South Africa
  • H Winker Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown 6140, South Africa

Abstract

An eight-year research angling dataset collected between February 1998 and December 2005 in the Tsitsikamma National Park marine protected area (MPA), along the south-eastern Cape coast of South Africa, was examined to provide estimates of important fishery and population parameters for eight important shore-angling species. Five different estimates of natural mortality (M), and the coefficients of variation (CVs) of catch per unit effort (CPUE) and size measurements were calculated. There was no consistency in estimates of M between methods, highlighting the difficulty in obtaining reliable estimates of this param eter for per-recruit assessments. The CVs of CPUE measurements were generally higher than those for size measurements. Estimates obtained for the most abundant species, blacktail Diplodus capensis, with a mean CPUE of 0.252 fish h–1, yielded the lowest CVs for CPUE (0.806) and size (0.130) measurements. Therefore, blacktail is considered the preferred indicator species for making comparisons with estimates obtained for shore-angling fish in exploited areas and other MPAs along the South African coastline. The large inter annual variations in mean CPUE and size for all species indicated that a minimum assessment period of four years is required to obtain reliable estimates.

Keywords: catch per unit effort; fisheries management; marine protected area; natural mortality; shore-angling fishery

African Journal of Marine Science 2008, 30(3): 519–532
Published
2008-12-17
Section
Articles

Journal Identifiers


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