|Reyns, N.B., D.B. Eggleston, and R.A. Luettich, Jr. , Dispersal dynamics of postlarval blue crabs, Callinectes sapidus, within a wind-driven estuary, Fisheries Oceanography, in press|
We examined how postlarval blue crab (Callinectes sapidus) dispersal occurs within Pamlico Sound, North Carolina, USA, a predominately wind-driven system. We sampled during multiple 24-hr periods over two years (2000-2001) to relate the spatial distribution of postlarvae in the water column with circulation patterns. A hydrodynamic model of the region was used to recreate dispersal trajectories and to assess potential transport mechanisms and pathways that link near-inlet and across-Sound nursery habitats. Most postlarval blue crabs were collected in surface waters at night, and were consistently distributed within the northwestern region of Pamlico Sound. Particle-tracking simulations suggested that dispersal from the inlets to across-Sound nursery habitats only resulted from the combination of tidal and wind-driven currents. Our simulation results further indicated that the northern-most inlet (Oregon Inlet) was the primary supplier of postlarval blue crabs throughout the northern basin of Pamlico Sound, as crabs ingressing through Hatteras Inlet to the south were not retained within our study area. A dispersal pathway connecting Oregon Inlet and across-Sound settlement habitats was evident from field observations. Collectively, our results indicate how multiple forcing agents, coupled with postlarval vertical positioning within the water column, drive estuarine dispersal and connect spatially-separated nursery habitats.