Catch-and-effort estimates for the gillnet and beach-seine fisheries in the Western Cape, South Africa

Abstract

Total catch and effort for the inshore net-fisheries in the Western Cape, South Africa, were estimated by means of face-to-face questionnaire, telephone and access point surveys, analysis of factory records and compulsory catch returns. In most areas, gillnet fishing effort was confined to summer, with highest average catch per unit effort during months of low effort. Records of monofilament gillnet sales show that approximately 180 illegal nets are sold annually (20% of all sales). During the period 1994–1999, only 26 illegal mesh size nets were confiscated annually (14% of those sold) on average, indicating that few illegal fishers are apprehended. Beach-seine fishers appeared to operate opportunistically throughout the year along the West Coast, whereas South-West Coast permitholders concentrate their activity during summer. Sources of survey error in effort and catch-rate estimation are discussed. Approximately 25 000 gillnet days and 3 200 beach-seine hauls made annually land around 6 000 tons of fish, substantially more than the mean annual reported catch of 1 369 tons. Comparison of observed or documented catches with compulsory catch returns confirmed that as little as 21% of the actual effort and only 8% of the fish caught are reported. Despite the fact that catches are much greater than those reported, the lower catch rates, smaller average size of fish caught and historical and anecdotal evidence suggest that the harder Liza richardsonii stock is regionally overexploited in areas with high fishing effort. It is concluded that the inshore net fishery in the Western Cape is oversubscribed in most regions and a reduction in latent and “recreational” effort is therefore recommended. A suitable reduction in total effort may allow the L. richardsonii stock to recover, reduce the ecosystem effects of the fishery by reducing the amount of bycatch and improve catch rates for bona fide commercial fishers. It would also facilitate improved monitoring and policing of the fishery and hopefully improve compliance with regulations.

Keywords: beach-seine, catch-and-effort estimates, catch returns, gillnets, Liza richardsonii

African Journal of Marine Science 2002, 24: 205–225