Dynamic connectivity patterns from an insular marine protected area in the Gulf of California

Abstract

We studied connectivity patterns from a small and isolated island in the Gulf of California (San Pedro Mártir Island Biosphere Reserve), as a source of propagules to surrounding Marine Protected Areas and fishing sites. We used a particle-tracking scheme based on the outputs of a three-dimensional numerical hydrodynamic model to assess the spatial domain to which the island exports larvae as well as larvae retention. We modeled the release of passive particles from locations around the island during the four release dates (May 15 and 31, and June 14 and 30), matching the lunar phases and the peak of the reproductive season for several commercial invertebrates and fish, at the time when currents in the Gulf typically reverse. For each simulation we analyzed the data at 15, 20 and 30 days after the release to represent different planktonic propagule durations. Particle dispersion was highly dynamic and spread over ~ 600 km along the coast over the study period. Overall, we observed potential ecological connectivity with a few key distant fishing sites that changed trough time, and potential genetic connectivity towards many near and distant sites, including all neighboring Marine Protected Areas, although not simultaneously. The percentages of particles remaining within the boundaries of the island tended to decline from May to June, and decreased with delayed planktonic propagule duration. The design of effective Marine Protected Areas should acknowledge the dynamic nature of connectivity patterns, for instance, by establishing adaptive network reserves to respond to changing ocean features that match reproductive patterns of target species and fisheries behavior.

We studied connectivity patterns from a small and isolated island in the Gulf of California (San Pedro Mártir Island Biosphere Reserve), as a source of propagules to surrounding Marine Protected Areas and fishing sites. We used a particle-tracking scheme based on the outputs of a three-dimensional numerical hydrodynamic model to assess the spatial domain to which the island exports larvae as well as larvae retention. We modeled the release of passive particles from locations around the island during the four release dates (May 15 and 31, and June 14 and 30), matching the lunar phases and the peak of the reproductive season for several commercial invertebrates and fish, at the time when currents in the Gulf typically reverse. For each simulation we analyzed the data at 15, 20 and 30 days after the release to represent different planktonic propagule durations. Particle dispersion was highly dynamic and spread over ~ 600 km along the coast over the study period. Overall, we observed potential ecological connectivity with a few key distant fishing sites that changed trough time, and potential genetic connectivity towards many near and distant sites, including all neighboring Marine Protected Areas, although not simultaneously. The percentages of particles remaining within the boundaries of the island tended to decline from May to June, and decreased with delayed planktonic propagule duration. The design of effective Marine Protected Areas should acknowledge the dynamic nature of connectivity patterns, for instance, by establishing adaptive network reserves to respond to changing ocean features that match reproductive patterns of target species and fisheries behavior.