Abstract

In this study, we examine larval transport by continental shelf circulation across the northern Gulf of Mexico (nGOM). Life histories of many marine species contain a planktotrophic larval stage where seasonally consistent circulation patterns play a major role in dispersion and subsequent recruitment. Continental shelves in the nGOM are relatively broad and flat. Alongshelf flow can be interrupted, however, by topographic impediments such as the Mississippi River Delta, the DeSoto Canyon and the Apalachicola Peninsula. This has a tendency to separate the northern shelf into basins with the potential to geographically isolate stocks, especially for those species with sedentary adult stages. In this study, we take advantage of a large data base of drifter and moored current meter records to compile a field of currents for tracking propagules. Because wind stress occurs from east to west for most of the year, westward intra-basin flux of propagules readily occurs on drift scales of several weeks. Eastward intra-basin flux of propagules occurs during July when the climatological wind stress has an eastward component. In addition, eastward flux past topographic impediments generally occurs in deeper waters along the continental slope where mortality is expected to be higher for shelf species. Knowledge of basin wide dispersion patterns during planktonic stages provides data critical to the understanding of recruitment dynamics and is important for fishery management.

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