Transport mechanisms of larval and pelagic juvenile bluefish (Pomatomus saltatrix) from South Atlantic Bight spawning grounds to Middle Atlantic Bight nursery habitats

In this study we examined the mechanisms by which Pomatomus saltatrix (Pisces: Pomatomidae) larvae and pelagic juveniles are transported from South Atlantic Bight spawning grounds to Middle Atlantic Bight estuarine nursery habitats. Data on larval and pelagic juvenile distributions, estuarine juvenile recruitment, hydrography, wind speed and direction and satellite- derived, sea surface temperature were used to examine potential larval transport mechanisms. On the basis of these analyses, a scenario for northward transport of P. saltatrix was developed. Gulf Stream-associated flow moves P. saltatrix larvae northeastward from their South Atlantic Bight spawning grounds. Larval transport from the Gulf Stream to the Middle Atlantic Bight shelf edge occurs in warm-core ring streamers, but some more developed individuals may swim across. Finally, P. saltatrix pelagic juveniles actively swim across the Middle Atlantic Bight shelf, a behavior initiated when the surface shelf-slope temperature front dissipates in late spring. This scenario predicts that the number of South Atlantic Bight- spawned P. saltatrix juveniles entering estuaries (i.e. recruitment) is determined in part by warm-core ring streamer activity. The timing of recruitment, however, is determined almost entirely by the timing of the dissipation of the surface shelf-slope temperature front.