The trouble with estuarine fisheries in temperate South Africa, illustrated by a case study on the Sundays Estuary
AbstractThis study provides empirical data on the exploitation of fishery resources on the Sundays Estuary on the south-east coast of South Africa. Total annual effort was estimated at 63 785 angler-hours, which accounted for an annual yield of 16 214 fish (8.0 t). Effort and mean catch per unit effort exhibited seasonal trends and were highest during summer. Dusky kob Argyrosomus japonicus and spotted grunter Pomadasys commersonnii were the most commonly targeted species and accounted for the bulk of the catch: 3.4 t (43% gravimetrically, 22% numerically) and 1.9 t (24% gravimetrically and numerically) respectively. The smaller-bodied Cape stumpnose Rhabdosargus holubi contributed only 0.2 t (0.03%); however, it accounted for 30.1% of the catch numerically and was important to the minority subsistence sector. Overall, the sustainability of the Sundays estuarine fishery is questionable due to high proportions of juvenile fish in angler catches, high retention rates of juveniles, and high targeting effort towards vulnerable species, such as A. japonicus, although success rates of the heavily targeted species were low. This is exacerbated by limited law enforcement, no fishery monitoring, ill-informed users and no public awareness campaigns. These threats to fishery resource sustainability are not unique to this system and a comparison of findings from similar studies suggests that the management of estuarine fisheries in South Africa is currently inadequate.
Keywords: catch composition, CPUE, estuarine fishery, fishing effort, management
African Journal of Marine Science 2013, 35(1): 117–128