Author: Chesapeake Biological LaboratoryPublisher:
ISBN:
Category : Blue crab
Languages : en
Pages : 30
Book Description
A Field Study of the Population Dynamics of the Blue Crab, Callinectes Sapidus, in the Chesapeake Bay
Author: Chesapeake Biological LaboratoryPublisher:
ISBN:
Category : Blue crab
Languages : en
Pages : 30
Book Description
A Field Study of the Population Dynamics of the Blue Crab, Callinectes Sapidus Rathbun, in the Chesapeake Bay
Author: Marcel M. MontanePublisher:
ISBN:
Category : Callinectes
Languages : en
Pages :
Book Description
A Field Study of the Population Dynamics of the Blue Crab, Callinectes Sapidus Rathbun, Chesapeake Bay
Author: 1997 Chesapeake Bay Blue Crab Fishery Management Plan
Author: The Effects of Harvesting and Habitat Fragmentation on Blue Crab (Callinectes Sapidus) Population Dynamics in Chesapeake Bay
Author: Toni L. MizerekPopulation Dynamics and Stock Assessment of the Blue Crab in North Carolina
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The blue crab (Callinectes sapidus) is an ecologically important estuarine predator and represents North Carolina's most important commercial fishery. Recent fishery-dependent and --independent data suggest the population is declining. The goal of this study was to increase our understanding of the status and population dynamics of the blue crab in NC by addressing the following objectives: (1) estimate population demographics of blue crabs in salt marsh creeks, (2) construct a discontinuous model of blue crab growth in NC using growth rates estimated from free-ranging blue crabs, and (3) provide a comprehensive stock assessment for the blue crab in NC. A series of complimentary laboratory and field studies assessed the nursery role of salt marsh habitats for the blue crab (Callinectes sapidus). Population demographics and movement patterns of juvenile and adult blue crabs were quantified in two tidal salt marsh creeks near Beaufort, North Carolina, USA during June -- October 2001. While there are many studies that report estimates of population density, mortality rates, or movement rates for blue crabs, this study represents one of the first attempts to estimate all quantities concurrently. Juvenile crabs were mobile within the interstices of the vegetated marsh surface during flood tide, and were equally distributed buried in intertidal marsh and adjacent mud areas during ebb tide. Juvenile crabs may experience a spatial refuge from cannibalism in the marsh surface since adult conspecifics are physically impeded by dense vegetation and rarely move far into marsh habitats. This spatial refuge in the vegetated marsh surface may be significant, since cannibalism represents a large source of mortality for this species. The relatively high use of the marsh surface by juvenile blue crabs, combined with a general lack of sampling these complex habitats, suggest that crab densities may be even higher in salt marsh systems than previously thought. Growth models c.
Juvenile Blue Crab Survival in Nursery Habitats
Author: Amanda Marie BromilowPublisher:
ISBN:
Category : Blue crab
Languages : en
Pages : 86
Book Description
Predator populations can have significant impacts on prey recruitment success and prey population dynamics through consumption. Young, inexperienced prey are often most vulnerable to predation due to their small size and limited evasion capabilities. To reduce the risk of predation, new recruits and young juveniles typically settle in structured nursery habitats, such as seagrass beds, which promote higher survival by acting as refuges from predators. Thus, successful recruitment to the adult portion of the population is often dependent on the availability of suitable nursery habitat. In this thesis, I used field tethering experiments and gut content analyses to assess the role of habitat, body size, finfish predation, and cannibalism on the survival of one of the most ecologically and economically important species in Chesapeake Bay: the blue crab Callinectes sapidus. In field tethering experiments, survival probability of juvenile blue crabs in York River nursery habitats (i.e. seagrass beds, sand flats) increased significantly and additively with crab size and SAV cover. Images of predation events during tethering experiments revealed cannibalism by adult blue crabs to be a major source of juvenile mortality. Gut content analyses from three field studies identified seven predators of juvenile blue crabs in lower Chesapeake Bay nursery habitats: adult blue crabs, striped bass Morone saxatilis, red drum Sciaenops ocellatus, silver perch Bairdiella chrysoura, weakfish Cynoscion regalis, Atlantic croaker Micropogonias undulatus, and oyster toadfish Opsanus tau. Using frequency of consumption and diet proportion metrics, I determined striped bass, red drum, and silver perch to be the most impactful finfish predators on juvenile mortality, in addition to cannibalism. Atlantic croaker and oyster toadfish play minor roles in juvenile mortality in Chesapeake Bay nursery habitats. The probability of juvenile crabs being present in a predator’s gut was also significantly higher in seagrass beds than in unvegetated sand flats. Food web dynamics are an important aspect of ecosystem-based fisheries management. Understanding the ecological interactions between populations, and their environment, can provide insight into natural population fluctuations of valuable fishery species such as the blue crab. This thesis demonstrated the positive effects of body size and SAV cover on juvenile crab survival, indicating the importance of seagrass nursery habitat for blue crab population dynamics in Chesapeake Bay. However, despite the predator refuge offered by SAV, high densities of predators and prey in seagrass beds resulted in greater consumption of juveniles in those habitats. Key predators of juvenile blue crabs were also identified and their relative impacts were estimated. The predator-prey relationships revealed in this thesis were integrated into a revised food web for blue crabs in Chesapeake Bay, in the hopes of informing future ecosystem-based management efforts.
A Model of the Population Dynamics of the Blue Crab in Chesapeake Bay
Author: Betty Springer HesterPublisher:
ISBN:
Category : Callinectes
Languages : en
Pages : 234
Book Description
Synopsis of Biological Data on the Blue Crab, Callinectes Sapidus Rathbun
Author: Mark R. MillikinPublisher:
ISBN:
Category : Blue crab
Languages : en
Pages : 324
Book Description
Author: