Chesapeake Bay blue crabs (Callinectes sapidus) support hundreds of livelihoods in Maryland and Virginia. During the period 1991-2000, mean annual landing (hard / soft crabs and peelers) was 35 thousand metric tons, which represented 32% of world harvests for this species (Secor et al. 2002). Maryland ex-vessel value in 1999 was $63.3 million dollars, comprising 60% of Maryland watermen's income (MD Sea Grant 2001). But there are threats to this resource due to declining recruitment and spawning stock (Abbe 2002; Lipcius and Stockhausen 2002) and competition with imported crab products (Petrocci and Lipton 1994; MD Sea Grant 2001). Past declines in Chesapeake Bay blue crab landings, and evidence for past declines in recruitment and spawning stock, have prompted increased regulation of harvest, increased habitat management and restoration, and calls for improved scientific understanding on factors that control blue crab production (CBSAC 2001; MD Sea Grant 2001).
Management targets and thresholds for Chesapeake Bay blue crabs are based upon age-based stock assessments, yet there was (until recently) no means to directly age blue crabs. The goal of our research was to use lipofuscin-based ageing methods to test critical underlying assumptions on survival, growth and seasonal recruitment rates that control monthly yields of blue crab fisheries in the Chesapeake Bay. In particular, we sought to develop a juvenile growth model, which will permit prediction of seasonal recruitments of juvenile crabs to peeler and hard crab fisheries (Puckett et al. 2008).
Beyond harvest regulations, some experts have suggested that
hatchery-based supplementation of blue crab stocks may have merit. PI Secor
led a team of scientists to Japan to evaluate whether hatchery-based
enhancement was effective in enhancing swimming crab stocks there, and -
based upon salient features of the Japanese Sea Farming Program -
evaluated the feasibility of using hatcheries to enhance Chesapeake Bay
blue crabs. His conclusion, while differing from my co-authors, was a
definite NO on the feasibility of subsidizing the Chesapeake Bay blue
crab stock. Alternatively, the team did concur that hatchery
capabilities in support of research aimed at better fisheries
regulations and habitat management would be quite valuable. Such
capabilities have been developed at the Center of Marine Biotechnology, providing a fantastic source of experimental crabs.
Ariyama, H., and D.H. Secor. 2010. Effect of environmental factors, especially hypoxia and typhoons, on recruitment of gazami crab Portunus trituberculatus in Osaka Bay, Japan. Fisheries Science 76: 315-324.
Harvey, H.R., D.H. Secor, and S-J. Ju. 2008. The use of extractable lipofuscin for age determinations of crustaceans: Reply to Sheehy (2008). Mar. Ecol. Progr. Ser. 353: 307-311.
Puckett, B.P., S-J. Ju, and D.H. Secor. 2008. Validation and application of lipofuscin-based age determination for Chesapeake Bay blue crabs. Trans. Am. Fish. Soc. 137: 1637-1649.
Ju, S-J, D.H. Secor, and H.R. Harvey. 2003. Demographic assessment of the blue crab in Chesapeake Bay using extractable lipofuscin as age markers. Fisheries Bulletin. 101: 312-320.
Ju, S-J, D.H. Secor and H.R. Harvey. 2001. Growth rate variability and lipofuscin accumulation rates in the blue crab, Callinectes sapidus. Mar. Ecol. Progr. Ser. 224: 197-205.
Ju, S-J, D.H. Secor and H.R. Harvey. 1999. The use of extractable lipofuscin for age determination of the blue crab, Callinectes sapidus. Mar. Ecol. Progr. Ser. 185: 171-179.
Secor, D.H., E.J. Niklitschek, J.T. Stevenson, T.E. Gunderson, S.P. Minkkinen, B. Richardson, B. Florence, M. Mangold, J. Skjeveland and A. Henderson-Arzapalo. 2000. Dispersal and growth of yearling Atlantic sturgeon, Acipenser oxyrinchus, released into Chesapeake Bay. Fish. Bull. 98: 800-810.
Secor, D.H., V. Arefjev, A. Nikolaev and A. Sharov. 2000. Restoration of sturgeons: Lessons from the Caspian Sea Sturgeon Ranching Programme. Fish and Fisheries 1: 215-230.
Secor, D.H. and E.D. Houde. 1998. Use of larval stocking in restoration of Chesapeake Bay striped bass. ICES J. Mar. Sci. 55: 228-239.
Secor, D.H. and E.D. Houde. 1995. Larval mark-release experiments: Potential for research on dynamics and recruitment in fish stocks. pp. 423-445, In: Secor, D.H., S.E. Campana and J.M. Dean [Eds.], Recent Developments in Fish Otolith Research. Belle W. Baruch Library in Marine Sciences Number 19. University of South Carolina Press, Columbia, S.C. 735 pp.
Secor, D.H., J.M. Dean, T.A. Curtis and F.W. Sessions. 1992. Effect of female size and propagation methods on larval production at a South Carolina striped bass hatchery. Can. J. Fish. Aquat. Sci. 49: 1778-1787.
Secor, D.H., M.G. White and J.M. Dean. 1991. Immersion mass marking of hatchery-produced larval and juvenile striped bass with oxytetracycline. Trans. Am. Fish. Soc. 120(2): 261-266.