Contribution of a large no-take zone to the management of vulnerable reef fishes in the South-West Indian Ocean

Abstract

A key element of an ecosystem-based approach to fisheries management is the use of marine protected areas (MPAs) as part of a holistic management strategy. This study, based in the South-West Indian Ocean, evaluated the benefits of area closure to vulnerable fishery species, which have been depleted by overfishing. A controlled fishing survey was conducted seasonally between 2006 and 2011 in the Pondoland MPA on the East Coast of South Africa. The MPA includes a 400km2 no-take zone where all forms of vessel-based exploitation are prohibited. Three endemic sparids (slinger Chrysoblephus puniceus, Scotsman Polysteganus praeorbitalis and poenskop Cymatoceps nasutus) and one widely distributed serranid (yellowbelly rockcod Epinephelus marginatus) were chosen as study species. These are slow growing, high trophic level species, which are prominent on rocky reefs in the Pondoland area and have been depleted by overfishing. Relative abundance was estimated using catch-per-unit-effort (CPUE) and length frequency distributions were used to determine the size structure of fish populations. The relative abundance and the mean length of all four species were significantly greater in the no-take zone. Over the 5-year study period, CPUE of C. puniceus and C. nasutus in the no-take zone increased as did the mean length of all species, except C. nasutus. This study presents clear evidence that the Pondoland MPA no-take zone is providing insurance against the depletion of vulnerable fishery stocks in fished areas, thereby establishing the basis for the enhancement of adjacent fisheries.