Assessment of the effectiveness of two marine reserves in the Canary Islands (eastern Atlantic)

We assessed the effectiveness of two marine reserves (MRs) in the Canary Islands (eastern Atlantic), called "Punta La Restinga-Mar de Las Calmas" (El Hierro Island) and "Isla La Graciosa e islotes del norte de Lanzarote" (Chinijo Archipelago). Specifically, we evaluated the variability in the abundances and biomasses of four commercially-targeted fish species: the parrotfish (Sparisoma cretense), the island grouper (Mycteroperca fusca), the white sea-bream (Diplodus sargus cadenati) and the zebra sea-bream (Diplodus cervinus cervinus). Four fishing management categories were established within and around each MR: (1) a no-take or integral area (collection of all animals is not permitted), (2) a buffer area (fishing is permitted with traditional fishing gears), (3) a neighbouring fishing area (<20 km), and (4) a fishing area off a neighbouring island. Two randomly selected sites were sampled within each management category and MR in October and March 2004. Univariate tests provided evidence of a moderate "reserve effect" for both MRs consistent through time. Differences in abundances and biomasses of each species among management categories were clearly species-specific and inconsistent between both MRs. Species of the genus Diplodus showed greater abundances and biomasses within protected locations compared to unprotected locations at El Hierro Island. Moreover, the four selected species showed greater abundances and biomasses in the locations surveyed at El Hierro Island compared to unprotected locations at the neighbouring island. In contrast, S. cretense appeared to be the only species that benefited from protection in the Chinijo MR. Differences in the sizes of the MRs, the fishing effort around the MRs and the effectiveness of the enforcement within each MR, appeared to be possible explanations for the patterns observed.