Numerical Study of Surface Connectivity in the Eastern Mexican Pacific

Abstract:

East boundary ecosystems are the most productive regions in the world and they sustain a large percentage of world fisheries. Understand and describe the connectivity and exchange between different regions of the ocean is very important for larvae dispersion study and other tracers like pollutants. In this work we use an offline numerical model to simulate Lagrangian particle trajectories in the Eastern Mexican Pacific (between 120-94 W and 12-34 N). Particles are advected whit velocity fields generated with the model ROMS (Regional Ocean Modeling System) in the period 1980-2006. We define connectivity indexes in order to classify different zones by their capacity of exporting, receiving and retaining particles. We aim to identify the most transited pathways, quantify connectivity between different regions of EMP through connectivity matrix and describe their seasonal variability. It has been identified zones of high isolation and retention (Vizcaino Bay, Northern of Gulf of California), high retention and importation (between Ensenada and Point Conception) and high exportation and importation (Cabo Corrientes). Connectivity has clear equatoward preference in the California Peninsula region dominated by the influence of California Current with an increase in winter and spring, and also equatoward in the south region of Mexico (from Cabo Corrientes to Tehuantepec Gulf), dominated by the anticyclonic circulation of Tehuantepec Dome. It is observed a complete disconnection between the Baja California Peninsula and Cabo Corrientes zone and further south. Results suggest that the scales of connectivity does not significantly change for simulations over 3 months.