Abstract

Ocean currents, driven by climatological processes and moderated by topography, are principal determinants of larval dispersal and are, in part, responsible for regional differences in Red Snapper distributions observed in the Gulf of Mexico. Current data from the HYCOM model are used to track simulated transport of Red Snapper larvae spawned at 26 locations spread across Campeche Bank for the years 2003, 2005, 2008 and 2010. A simple Lagrangian stochastic model is applied at each time step to ten water parcels launched simultaneously from each of the 26 locations, simulating the spread of spawned larvae. The end points of the planktonic larval drift (ready for settlement in shallow water as juveniles) were eval-uated to determine if Campeche Bank serves as a major source for other regions. The Yucatan Current, flowing along the eastern side of the Bank, provides a mechanism for supply of larvae to the Florida continental shelf and to the Atlantic; however, most of the spawn remains on the bank. Natal retention ranges from 67 to 73% of launched particles with less than 2% entering the Straits of Florida. For particles transported off Campeche Bank, ~ 28% are lost to the deep basin. Suc-cessful basin crossing (ended pelagic drift in < 200 m water depth), as percentage of total particles launched for the com-bined years, was ~ 0.33% with the southwest Florida shelf receiving the majority. Larvae from the Bank may contribute to homogenization of the gene pool, but are insufficient to restore depleted regional populations.

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