For many species such as the blue crab, Callinectes sapidus, successful estuarine recruitment to juvenile nursery habitats is dependent on the biophysical processes experienced during dispersal of the early life stages. The goal of this study was to determine how blue crab primary (postlarval) and secondary (early juvenile) dispersal occurs within a predominately wind-driven estuary, Pamlico Sound, North Carolina, USA. We (1) characterized circulation patterns in Pamlico Sound during the fall blue crab recruitment months over two consecutive years using current meters (2) sampled during multiple 24 h periods to relate spatiotemporal water column distributions of postlarval and early juveniles blue crabs with circulation patterns, and used a hydrodynamic model to recreate dispersal trajectories from eastern (inlet) to western sound nursery habitats and (3) examined the environmental (wind, diel cycle, tidal phase) and biological (ontogenetic, density-dependent) factors that contribute to early juvenile blue crab secondary dispersal from near-inlet nursery habitats. During our study, surface currents responded synchronously to wind-forcing by generally flowing in the same direction as the wind. Particle-tracking simulations suggested that dispersal from Oregon and Hatteras Inlets to across-sound nursery habitats resulted from the combined use of tidal and wind-driven currents. Simulation results and observed crab distributions further indicated that Oregon Inlet was the primary supplier of postlarval blue crabs (dispersing in surface waters at night) throughout Pamlico Sound, as postlarvae ingressing through Hatteras Inlet were not retained within our study area. Furthermore, Oregon Inlet supplied early juvenile blue crabs (dispersing in bottom waters at night) to northwestern sound habitats, while crabs from Hatteras Inlet dispersed to mid- and eastern-sound regions. Results from our study in near-inlet settlement habitats confirmed the importance of tides to mediating dispersal partway into Pamlico Sound, as early juvenile blue crabs responded to increasing conspecific density in settlement habitats by using flood-tide transport near the inlets to rapidly leave these habitats. Based on our findings, we make recommendations regarding the prioritization of nursery habitats for conservation and fisheries management.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-10312004-143755 |
| Date | 29 November 2004 |
| Creators | Reyns, Nathalie Brigitte |
| Contributors | Lian Xie, Thomas S. Hopkins, Daniel Kamykowski, Richard B. Forward, Jr., David B. Eggleston |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-10312004-143755/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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