Trap modification opens new gates to achieve sustainable coral reef fisheries

Abstract

1. Innovative strategies are needed to escape the social-ecological poverty that so frequently emerges from persistent overfishing of coral reef resources. 2. This study focuses on fishing gear selectivity and its potential to increase ecosystem health and fisheries productivity without compromising the catch of profitable species. 3. An investigation into the effects of an escape gap (3 cm × 30 cm) modification to the traditional African basket trap on total catch biomass, catch composition and monetary value in two locations with different historical levels of fishing was undertaken. 4. Gated traps caught less low-value fish (juveniles and narrow-bodied coral reef species) while increasing the catch of high- and medium-value fish (wider-bodied commercially valuable species). The total monetary value of the gated trap catches was maintained in a heavily fished environment, while it increased in the less fisheries-depleted area. 5. For the most important local commercial species, the African white-spotted rabbitfish (Siganussutor), the gated traps significantly increased the mean length (by 12%) and weight (by 32%) of capture and decreased the proportion of catch under length at first maturity (Lmat) from 56% (traditional traps) to 25% (gated traps). 6. Escape gaps have shown the potential to affect the structure of the fishery and ecosystem by enhancing the number of mature individuals, increasing reef biodiversity and promoting functionally diverse reef fish communities without compromising fisher’s revenues.