Red Snapper Larval Transport in the Northern Gulf of Mexico

This study examines the advection of red snapper Lutjanus campechanus larvae in the northern Gulf of Mexico. The potential for repopulating the eastern Gulf stock through larval transport from the more populous western stock is addressed. Transport pathways across topographic features that inhibit alongshelf flow (e.g., the Mississippi River delta. DeSoto Canyon, and the Apalachicola peninsula) and interregional larval transport are considered. An advective field of currents is developed front a large database of drifter and moored Currents. augmented by an operational model to fill gaps. The starting points for larval transport are the locations and day of the year of larval captures from the Southeast Area Monitoring and Assessment program ichthyoplankton surveys. Because the Field Of Currents is derived front near-surface observations and the depth distribution of larvae is uncertain. findings are expressed in terms of maximal transport pathways. Transport pathways were principally vectored toward the west during September. October, and May under the influence of relatively strong climatological westward wind stress. Eastward pathways Occurred in June. July. and August under the influence of weaker shoreward wind stress. Westward transport pathways past the Mississippi delta were found near the delta. whereas eastward transport pathways were found in deeper waters beyond the continental shelf break, away front typical juvenile settlement habitat. Water movement front east to west across the Apalachicola peninsula occurred in the fall. suggesting the potential for genetic exchange front the eastern to the western Gulf. Eastward water movement across the Apalachicola peninsula occurred in July. but only along the outer shelf.