Changes in a coral reef fishery along a gradient of fishing pressure in an Indonesian marine protected area

摘要

1. Human population growth, rising incomes, and increased commercialization of marine resources promote demand for reef fish, yet few studies in Indonesia have examined how artisanal fisheries are influenced by the socio-cultural conditions that contribute to their exploitation. This study examined artisanal fisheries of Karimunjawa National Park, Java, to understand how the condition of an artisanal fishery was related to socio-cultural factors, along a gradient in fishing pressure. 2. A total of 8674 fishes landed in Karimunjawa by fishers using four artisanal fishing gears were examined to understand how the condition of the artisanal fishery (standard and infinite fish length, trophic level and weight) related to fishing gear use, village fishing grounds, management, human population size, human population density and estimated fishing pressure. 3. Depletion in fish lengths and trophic structure were found at or above 46 fishing trips day(-1)km(-2), suggesting that fishing pressure is a key factor driving fishery catch structure. When catch characteristics were examined in relation to the fishing pressure estimates from each village, negative correlations were found between inshore fishing pressure (no. trips day(-1)km(-2)) and all four fish catch characteristics, but owing to small sample sizes (n=5), only the effects on trophic level were significant. 4. Fishery closures had limited impact on fish characteristics, and lack of any effect of spatial controls on fishing also supports the notion that fishing pressure and the types of fishing gears used, most likely driven by human population densities, are the greatest drivers of reef fish catch characteristics in the Karimunjawa fishery. 5. In the absence of support for fishery closures from local fishing communities or adequate enforcement of fishery closures, targeted gear or species management strategies that limit impacts on large-bodied fish and aim to conserve key species may be more effective in improving the size and trophic structure of fish populations