Journal of Shellfish Research 17:451–458.įischler, K. Conservation and management of the blue crab fishery in Georgia. Plant and Animal Populations: Methods in Demography. Transactions of the American Fisheries Society 128:1085–1105.Įbert, T. Catch and bycatch: The qualitative effects of fisheries on population vital rates of Atlantic croaker. Ecological Applications 4:437–445.ĭiamond, S. ![]() Predicting the impact of Turtle Excluder Devices on loggerhead sea turtle populations. A stage-based population model for loggerhead sea turtles and implications for conservation. American Fisheries Society Symposium 23:115–136.Ĭrouse, D. A stochastic stage-based population model of the sandbar shark in the western North Atlantic. Matrix Population Models: Construction, Analysis and Interpretation. Journal of Shellfish Research 17:487–491.Ĭaswell, H. New York's blue crab ( Callinectes sapidus) fisheries through the years. Management of the sandbar shark ( Carcharhinus plumbeus): Implications of a stage-based model. Pod-specific demography of killer whales ( Orcinus orca). When are there “two few” newborns in a small population of marine mammals? American Fisheries Society Symposium 23:107–114.īrault, S. The seasonal dynamics of the Chesapeake Bay ecosystem. Northwest Atlantic fisheries Organization, Serial Document SCR 82/VI/64. The Calculation of F 0.1: A Plea for Standardization. Reductions in other sectors of the fishery are also required to ensure sustainability.Īnthony, V. The model indicated that reductions in the winter dredge fishery would have a substantial role in ensuring the long-term sustainability of the population. The egg production realized by large adults was also shown to be an important regulatory process. Transitions to and from small age-1 crabs were shown to be important in regulating the overall dynamics of the population. This value is less than the current estimate of exploitation in Chesapeake Bay (0.9–1.1) indicating that the level of exploitation in this system needs to be reduced to avoid overfishing. If the natural mortality rate is estimated for a maximum life expectancy of 8 yr, this translates to moderate levels of exploitation (F<0.32). ![]() I developed a stage-based matrix model of the blue crab population to address three key questions: What is the ability of blue crab populations to support sustainable exploitations? What stages of the life cycle are most important in regulating the dynamics of the populations? And specific of the Chesapeake Bay, what is the importance of a winter dredge fishery in determining long-term sustainability of the crab population? The model indicated that with the current pattern of exploitation blue crab populations are able to sustain a total instantaneous mortality rate (Z)∼0.7. It supports a large commercial fishery in the United States with approximately one third of the landings taken from Chesapeake Bay. “That could be one potential benefit of having blue crabs.Blue crab ( Callinectes sapidus) plays an important ecological and economic role in estuaries from South America to New England. “We’re wondering if the blue crab can become a new predator or competitor of the green crab, helping to tamp down their population,” she said. He is just starting research on how crabs will affect prey populations and how the crabs might adapt to fit their new ecosystem.Ĭrane is especially interested in how blue crabs will interact with the European Green Crab, a problematic invasive species. They will fight you over an old boot,” Johnson said. No one knows yet what a permanent blue crab population in the Gulf of Maine would mean for the people and animals who currently live there. “That would be a strong indicator that the crabs are reproducing in the system,” she said. ![]() Yet, a “missing puzzle piece” for Crane is the lack of egg-bearing female crabs in their surveys. Surveys at the Wells Reserve have recorded blue crab larvae since 2016. How the crabs are actually getting into the Gulf is uncertain, although both Crane and Johnson mentioned that ocean currents are likely moving larvae around Cape Cod. “It’s not that the whole population has shifted northward, it’s just that they’ve expanded to more places,” David Johnson, associate professor at the Virginia Institute of Marine Science (VIMS), said. More crabs in Maine doesn’t mean fewer crabs elsewhere, though. “If we’re finding blue crabs for five or ten years in the same locations, that starts to be a more compelling argument that this is a permanent population.” ![]() “We don’t want to make claims yet that this is a permanent population,” Crane said. South of Portland, Maine, at the Wells National Estuarine Research Reserve, Research Associate Laura Crane and her colleagues have been trapping adult blue crabs for three years to monitor local population numbers, catching almost 100 crabs.
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