@article{bell_eggleston_2023, title={Timing and route of migration of mature female blue crabs in a large, wind-driven estuary}, volume={152}, ISSN={["1548-8659"]}, DOI={10.1002/tafs.10391}, abstractNote={AbstractObjectiveQuantify the timing of mature female blue crab Callinectes sapidus migration and the routes they take in the Croatan, Albemarle, and Pamlico Estuarine System (CAPES) in North Carolina, USA.MethodsMark–recapture data collected by commercial crabbers in northeastern North Carolina during 2008 and 2009 identified the timing, rate, and route of movement for 1049 postcopulatory female blue crabs out of 8400 tagged (17.5% recapture).ResultMature female blue crabs consistently moved from their original, up‐estuary release sites towards the Oregon Inlet spawning sanctuary in early summer. Although crabs averaged 2 km/d and covered distances in excess of 50 km during the tagging season, no recaptures were reported from inside or within 10 km of inlet spawning sanctuaries connecting the CAPES to the Atlantic Ocean. The vast majority of recaptures were concentrated within the area where Albemarle, Currituck, and Croatan sounds merge, which is likely due to a combination of high fishing effort and the narrowing of the waterways that concentrate mature females as they migrate south towards spawning sanctuaries.ConclusionThe high concentration of blue crab recaptures in this region suggests that extending no‐take, inlet sanctuary boundaries into these waters may protect mature females as they migrate to the inlet spawning grounds.}, number={2}, journal={TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY}, author={Bell, Geoffrey W. and Eggleston, David B.}, year={2023}, month={Mar}, pages={253–269} }
 @article{eggleston_bell_searcy_2009, title={Do Blue Crab Spawning Sanctuaries in North Carolina Protect the Spawning Stock?}, volume={138}, ISSN={["1548-8659"]}, DOI={10.1577/T08-070.1}, abstractNote={AbstractSpawning sanctuaries located at the five major inlets to Pamlico Sound, North Carolina, as well as various harvest controls, have not been adequate to protect the spawning stock of the blue crab Callinectes sapidus. We conducted an extensive trawl survey within Pamlico and Croatan sounds as well as five inlet spawning sanctuaries during 2002 to quantify the spatiotemporal use of spawning sanctuaries by mature female blue crabs and to identify potential migration corridors to spawning grounds. The abundance of mature females was highest along the northwestern portion of Pamlico Sound, suggesting this is an important staging area for females before their seaward migration; however, there was no clear evidence of specific migration corridors. Mature female abundance was no different inside inlet sanctuary boundaries versus 1‐2 km outside sanctuary boundaries, and sanctuaries only protect 44.9% and 0.7% of the current local inlet and Pamlico Sound‐wide spawning populations, respectively, of mature female blue crabs. In general, the abundance of mature female blue crabs was higher at inlets located to the extreme north or south in Pamlico Sound than at inlets located in the central portion of the sound. The results from this study suggest that the particular geometry and placement of inlet spawning sanctuaries are not adequate to protect the North Carolina blue crab spawning stock, and other management options should be considered, such as (1) a double sanctuary and migration corridor system located in northern and southern portions of Croatan and Pamlico sounds coupled with either (2) reduction of fishery effort on females or (3) seasonal closures.}, number={3}, journal={TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY}, author={Eggleston, David B. and Bell, Geoffrey W. and Searcy, Steven P.}, year={2009}, month={May}, pages={581–592} }
 @article{bell_eggleston_noga_2009, title={Environmental and Physiological Controls of Blue Crab Avoidance Behavior During Exposure to Hypoxia}, volume={217}, ISSN={["1939-8697"]}, DOI={10.1086/bblv217n2p161}, abstractNote={Generalizing the impacts of hypoxia on aquatic animal populations is difficult due to differences in behavioral and physiological responses among individuals as well as varying hydrodynamics of hypoxic events. Information on which environmental cues animals use to avoid hypoxia and how abiotic covariates and physiology influence avoidance behavior is lacking. Our laboratory flume studies quantified the interacting effects of hydrography (dissolved oxygen [DO], temperature, and salinity), hydrodynamics (rate of DO decline and current speed), and physiological state on avoidance behaviors of blue crabs (Callinectes sapidus). Changes in DO stimulated increased rates of movement, regardless of whether the change resulted in hypoxia. Increased rates of DO decline stimulated faster movement rates under hypoxic conditions because crabs spent less time in hypoxia compared to crabs under conditions of slow rate of DO decline. Blue crabs that had hemocyanin structures with a high affinity for O2 (hypoxia-tolerant) were less active under hypoxic conditions than conspecifics with hemocyanins with a low O2 affinity, suggesting that physiological state influences behavioral responses to stressors. These results provide a mechanistic understanding of how physiological acclimation and hypoxia hydrodynamics may influence population dynamics.}, number={2}, journal={BIOLOGICAL BULLETIN}, author={Bell, Geoffrey W. and Eggleston, David B. and Noga, Edward J.}, year={2009}, month={Oct}, pages={161–172} }
 @article{eggleston_bell_amavisca_2005, title={Interactive effects of episodic hypoxia and cannibalism on juvenile blue crab mortality}, volume={325}, ISSN={["0022-0981"]}, DOI={10.1016/j.jembe.2005.04.023}, abstractNote={We hypothesized that as the spatial extent of hypoxic bottom water increased, (1) adult blue crab predator densities would increase in shallow habitats as they avoided hypoxia, and that (2) juvenile blue crabs, which use shallow unvegetated habitat as a predation refuge from adult conspecifics, would experience increased mortality rates during crowding by cannibalistic adult blue crabs. These hypotheses were tested along a depth gradient of sandy-mud shoreline in the Neuse River Estuary (NRE), North Carolina, USA using a combination of (1) hydrographic measurements to characterize the spatial extent of hypoxia, (2) beach seines to quantify the density of adult blue crab predators in relatively shallow water as a function of 1, and (3) tethering experiments to quantify relative rates of predation on juvenile blue crabs as a function of 1 and 2. During our seven tethering experiments, the NRE study site experienced a range of DO scenarios including normoxia, chronic hypoxia, and hypoxic upwelling. No known predators of juvenile blue crabs, other than adult conspecifics, were collected in any of our shallow-water seines. During the transition from normoxia to chronic hypoxia, blue crab predator densities in shallow refuge habitats increased 4-fold, and relative mortality rates of juvenile blue crabs in shallow habitats increased exponentially with the density of adult conspecifics. Conversely, during hypoxic upwelling events, the density of adult blue crabs in shallow water declined, which may explain why the relative mortality of juvenile crabs did not increase significantly with the increasing spatial extent of hypoxia. Thus, juvenile blue crabs may be relatively safe from adult conspecifics during hypoxic upwelling events, but not during chronic hypoxia. These experimental results highlight the need to consider the effects of dynamic water quality on mobile consumers emigrating from degraded habitats when considering indirect trophic impacts beyond the immediate area of impact.}, number={1}, journal={JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY}, author={Eggleston, DB and Bell, GW and Amavisca, AD}, year={2005}, month={Nov}, pages={18–26} }
 @article{bell_eggleston_2005, title={Species-specific avoidance responses by blue crabs and fish to chronic and episodic hypoxia}, volume={146}, ISSN={["0025-3162"]}, DOI={10.1007/s00227-004-1483-7}, number={4}, journal={MARINE BIOLOGY}, author={Bell, GW and Eggleston, DB}, year={2005}, month={Mar}, pages={761–770} }
 @article{bell_eggleston_wolcott_2003, title={Behavioral responses of free-ranging blue crabs to episodic hypoxia. I. Movement}, volume={259}, ISSN={["0171-8630"]}, DOI={10.3354/meps259215}, abstractNote={Episodic hypoxic events in estuaries can alter the trophic dynamics of important benthic predators. During hypoxic upwelling events mobile predators may reduce their feeding activity as they migrate to relatively shallower, oxygenated water, and may reinvade deep-water habitats dur- ing relaxation of hypoxia to exploit vulnerable infaunal prey (e.g. clams and polychaete worms) that have reduced their burial depth in response to hypoxia. We used biotelemetry techniques with con- current measurements of dissolved oxygen (DO) to monitor the feeding and movement responses of free-ranging blue crabs Callinectes sapidus to episodic hypoxic upwelling and subsequent relaxation events within the Neuse River Estuary (NRE), North Carolina, USA. Although telemetered crabs fed in hypoxic water with DO concentrations as low as 1.01 mg l -1 , percent feeding occurrence declined slightly when crabs were exposed to mild (DO = 2 - 4 mg l -1 ) and severe hypoxia (DO 4 mg l -1 ). Crabs reduced the proportion of time spent feed- ing during hypoxic upwelling conditions except for the most severe events when DO dropped rapidly from normoxia to severe hypoxia. The proportion of time crabs spent feeding did not increase and crabs did not reinvade deeper water habitats during relaxation events, as was hypothesized. These results are somewhat inconsistent with previous studies and we suggest that crabs may have fed on prey other than benthic infauna, or that upwelling events may not have lasted long enough to cause infauna to migrate close enough to the sediment surface to be vulnerable to predation by blue crabs. Our study highlights the importance of examining the complex interaction between the hydrody- namics of episodic events and various behaviors (e.g. feeding and movement) when trying to under- stand the impact of these events on estuarine trophic dynamics.}, number={2003}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Bell, GW and Eggleston, DB and Wolcott, TG}, year={2003}, pages={215–225} }
 @article{bell_eggleston_wolcott_2003, title={Behavioral responses of free-ranging blue crabs to episodic hypoxia. II. Feeding}, volume={259}, DOI={10.3354/meps259227}, abstractNote={Episodic hypoxic events in estuaries can alter the trophic dynamics of important benthic predators. During hypoxic upwelling events mobile predators may reduce their feeding activity as they migrate to relatively shallower, oxygenated water, and may reinvade deep-water habitats during relaxation of hypoxia to exploit vulnerable infaunal prey (e.g. clams and polychaete worms) that have reduced their burial depth in response to hypoxia. We used biotelemetry techniques with concurrent measurements of dissolved oxygen (DO) to monitor the feeding and movement responses of free-ranging blue crabs Callinectes sapidus to episodic hypoxic upwelling and subsequent relaxation events within the Neuse River Estuary (NRE), North Carolina, USA. Although telemetered crabs fed in hypoxic water with DO concentrations as low as 1.01 mg l–1, percent feeding occurrence declined slightly when crabs were exposed to mild (DO = 2 – 4 mg l–1) and severe hypoxia (DO <2 mg l–1), relative to normoxic concentrations (DO > 4 mg l–1). Crabs reduced the proportion of time spent feeding during hypoxic upwelling conditions except for the most severe events when DO dropped rapidly from normoxia to severe hypoxia. The proportion of time crabs spent feeding did not increase and crabs did not reinvade deeper water habitats during relaxation events, as was hypothesized. These results are somewhat inconsistent with previous studies and we suggest that crabs may have fed on prey other than benthic infauna, or that upwelling events may not have lasted long enough to cause infauna to migrate close enough to the sediment surface to be vulnerable to predation by blue crabs. Our study highlights the importance of examining the complex interaction between the hydrodynamics of episodic events and various behaviors (e.g. feeding and movement) when trying to understand the impact of these events on estuarine trophic dynamics.}, number={2003}, journal={Marine Ecology Progress Series}, author={Bell, G. W. and Eggleston, David and Wolcott, T. G.}, year={2003}, pages={227–235} }