Larval transport on the Atlantic continental shelf of North America: a review

This review considers transport of larval fish and crustaceans on the conti nental shelf. Previous reviews have contained only limited treatments of th e physical processes involved. The present paper provides a physical backgr ound that is considerably more comprehensive. It includes a discussion of t hree principal forcing agents: (I) wind stress; (2) tides propagating from the deep ocean; and (3) differences in density associated with the buoyant outflow of estuaries, surface heat flux, or the interaction of coastal and oceanic water masses at the seaward margin of the shelf The authors discuss the effects of these forcing agents on transport of larvae in the Middle A tlantic and South Atlantic Eights along the east coast of North America. Th e discussion concentrates on three species (blue crab, menhaden, bluefish) that have been the subject of a very recent multi-disciplinary study. Taken as a whole, the reproductive activities of these three species span the en tire year and utilize the entire shelf, from the most seaward margin to the estuarine nursery. The blue crab is representative of species affected by physical processes occurring during summer and early autumn on the inner an d mid-shelf Menhaden are impacted by processes occurring in winter on the o uter and mid-shelf. Bluefish are influenced primarily by processes occurrin g during early spring at the outer shelf margin near the western boundary c urrent. The authors conclude that alongshore wind stress and density differ ences, i.e. buoyancy-driven flow, are the primary agents of larval transpor t in the region. Circulation associated with the western boundary current i s only important at the shelf margin and tidally driven processes are gener ally inconsequential. (C) 2001 Academic Press.