Spillover from marine reserves: the case of Naso vlamingii at Apo Island, the Philippines

The use of no-take marine reserves as fisheries management tools is controversial. A major expectation of marine reserves is that they will become net exporters of adult biomass (the 'spillover effect'), Herein, we show that the biomass of the surgeonfish Naso vlamingii tripled over 18 yr (1983 to 2001) in a reserve at Apo Island, Philippines. Over time, the biomass of N. vlamingii increased by a factor of 40 outside but close to the reserve boundaries (200 to 250 m) but not at greater distances (250 to 500 m). In 2000/2001 hook-and-line catch per unit effort (CPUE) for N. vlamingii was 45 times higher within 200 m of the reserve boundary than for all other fishing grounds combined, with 62.5% of the hook-and-line catch records being recorded within 200 m either side of the reserve, in just 11% of the reef fishing area. This comprises some of the best evidence that reserves can benefit fisheries by spillover.