Observations on the linefish resources of Namibia, 1990–2000, with special reference to West Coast steenbras and silver kob

Abstract

The Namibian linefishery is a multisector fishery, with recreational and commercial sectors argeting overlapping species. Prior to 1990, catch data were recorded for the boat sector, but little research was done on the population dynamics of any of the species. Hence, none of the stocks were assessed owing to the lack of parameter estimates for fisheries modelling. Current management regulations for the Namibian linefishery are therefore not based on scientific investigations but, for historical reasons, were adapted from South African legislation for similar species. From 1994, linefish research in Namibia focused on the life history and population dynamics of silver kob Argyrosomus inodorus and West Coast steenbras Lithognathus aureti, important species in both commercial and recreational sectors. A roving-roving creel survey was used to determine effort and catches of recreational shore-anglers. Both species were assessed using yield-per-recruit models. Based on the results, reduced daily bag limits and the implementation of size limits for the recreational sector were proposed. For the commercial sector, the introduction of a total allowable catch would seem to be the best option. Results from an economic survey indicated that the recreational sector earns six times more for the country annually than the commercial sector.

Keywords: creel survey, economics, genetics, migration, silver kob, West Coast steenbras, yield-per-recruit

African Journal of Marine Science 2001, 23: 135–144