Maryland Sea Grant: Blue Crab Workshop - Research Recommendations

Research Recommendations

Following overview presentations, participants identified important research areas that over the short-term and long-term could improve blue crab production in Chesapeake Bay and better inform sustainable management of a species that is of such economic and ecological importance. These research needs are presented in the following lists without priority. Further refinement of these research areas should be considered within the context of a formal program development and proposal review process.

Reproductive Biology

Hormonal regulation of key aspects of crab reproduction, particularly basic aspects of endocrinology and the mechanisms regulating reproduction.
Maturation processes (e.g., timing, cues) with an emphasis on improved understanding of the regulation of the terminal molt.
Implications and impacts of smaller males and concurrent sperm limitation, and determine the biological consequences of increasing the minimum male harvest size.

Physiology, Molecular Biology and Behavior

Cues, timing and regulation of molting, both in terms of natural populations as well as crab shedding applications.
More refined condition indices for crabs at various life history stages to enable a more sophisticated understanding of environmental regulation of growth and development.
Basis of aggression in crabs, which may provide important clues to the behavior of local populations.
The molecular basis of molting to optimize production of soft shell and improve traditional crab shedding operations, including both flow-through and recirculating systems.

Habitat

Minimum habitat needs and distributions for viable populations throughout the Bay. Assessing how alterations to habitat differentially impact crab life history stages.
Importance of a mosaic of habitat types and new methodologies for accurately mapping and defining the relevant spatial and temporal scales that structure habitats that support viable populations. Linking these data to the development of spatially explicit models.
Ecological implications of the loss of seagrass beds, in particular determining if small crabs are using alternate habitats (i.e., marshes and creeks) and their suitability with regard to issues such as size and predation pressure.
If the decline in Bay grasses becomes a permanent element of the Bay ecosystem, will alternate natural habitats gain a greater role? What are the implications of sea level rise and the concurrent loss of marshes to crab populations?

Population Dynamics

Estimates of natural mortality rate based upon marked recapture experiments or by catch curve analysis.
Estimates of lifetime fecundity and recruitment.
Quantify distributional patterns in Chesapeake Bay.

Anthropogenic Influences

Given the importance of olfactory cues, assess potential impacts of anthropogenic influences (i.e., contaminants and toxic chemicals) on crab behavior.
Impact of endocrine disruptors, as well as other toxic chemicals on reproduction, molting, and other physiological processes.
Given the changing habitat of the Bay region, evaluate the role that alternate structures (rip rap, piers, debris) are playing for crabs at different life cycle stages. What are the impacts and potential benefits of ongoing habitat restoration efforts (particularly with regard to oyster reefs) to crab populations?