Collection of Bivalve Post-larvae to Test an “Order zero” Connectivity Model in the Northeastern Gulf of California, Mexico

GASPAR SORIA; IVAN MARTÍNEZ; MARINONE GUIDO; WILLIAM SHAW

Sarasota, Florida, USA

Simposio; 7th W. R. and L. Mote International Symposium. The Spatial Dimensions of Fisheries: Putting It All in Place; 2008

The Gulf of California harbors industrial and small-scale fisheries. These fisheries are socially and economically relevant for the region, but sustainability of marine resources is gaining more attention from managers, scholars and fishermen themselves. The diminishing supply of shellfish stocks led fishermen from Puerto Peñasco (PP), a fishing town located in the Northeastern side of the Gulf, to collectively establish, monitor, and enforce a network of “no take” areas in an effort to recover the declining stocks. An “order zero” model of particles’ transport for larvae dispersal resulting from advection by currents and turbulent diffusion was developed for the Northern Gulf. The model represents different hypothetical scenarios for passive larvae dispersion. For the area of PP, the model forecast that throughout the summer the connectivity is always cyclonic, while it is basically null in the opposite direction. If larvae abundance/distribution is driven by currents, a gradient of spat abundance matching the cyclonic circulations must be expected. To test this gradient we deployed bivalve larvae collectors in 6 sites throughout the fishing area of PP. Collectors were retrieved and replaced every 2 months, throughout 14 months. Seven commercial bivalve species were found. Each species showed a particular gradient of relative abundance among sites, and depths. Preliminary results on these gradients are presented and discussed.  For establishing management and conservation guidelines, the analysis of other sources of information (biophysical and fishery data) is critical to fully understand the connectivity among sites in the area of PP.