Marine reserves (areas closed to fishing) have been advocated for the management of many species, including the rock scallop Spondylus calcifer in the northern Gulf of California (NGC), Mexico. We developed an explicit coupled biological-oceanographic model (CBOM) to assess connectivity among fished subpopulations of S. calcifer. We focused on the Puerto Peñasco corridor, located in the northeastern portion of the NGC. We validated CBOM's outputs through 2 different techniques: population genetics with 9 microsatellite loci and measurements of spat abundance on artificial collectors. We found strong demographic connectivity between the corridor and southern sources. Sampled localities showed low levels of genetic structure; however, we identified 2 subtly differentiated genetic clusters. On average, the spatial scale of demographic and genetic connectivity is in agreement, suggesting that connectivity decreases when the spatial scale is >100 km. We observed a gradient of higher values of both predicted particles and observed densities of settled spat for the northern and southern sites and lower values for the central sites. Larval recruitment within the corridor could be linked to a large spatial scale of larval inputs, including local sources and subpopulations further south. The absence of a strong barrier to migration suggests that the siting of marine reserves along upstream sites would likely benefit downstream subpopulations. The spatial scale of connectivity (~100 km) could be used as a reference for the strategic siting of marine reserves in the study area. CBOMs and population genetics are powerful complementary tools to assess the relative strength of connectivity among sites.
KEY WORDS: Spondylus calcifer · Larval dispersal · Genetic structure · Marine reserves · Gulf of California
Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 463: [159][160][161][162][163][164][165][166][167][168][169][170][171][172][173][174][175] 2012 grounds (Gell & Roberts 2003, Beukers-Stewart et al. 2005, Pelc et al. 2009).Benthic bivalve species are structured in metapopulations in which separate subpopulations of sessile juveniles and adults are connected through larval dispersal (Lipcius et al. 2005, Orensanz et al. 2006. The extent to which these subpopulations are linked by the exchange of larvae is termed connectivity and can have multiple and different patterns (Palumbi 2003, Orensanz et al. 2006. Thus, effective design and implementation of marine reserves requires knowledge about the spatial and temporal dynamics of biological connectivity between subpopulations, particularly those that are sources of larvae that can populate other habitats (Fogarty & Botsford 2007, Pelc et al. 2010.Depending on how connectivity is measured it can have different meanings and implications (e.g. for fisheries management, conservation of species and their evolutionary potential) (Lowe & Allendorf 2010). Demographic connectivity is the degree to which the subpopulation growth ...