Chesapeake Bay blue crabs (Callinectes sapidus), despite their current depleted status, 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 recent 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). Recent declines in Chesapeake Bay blue crab landings, and evidence for 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 is (until recently) no means to directly age blue crabs. The goal of our research is 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 seek to develop a juvenile growth model, which will permit prediction of seasonal recruitments of juvenile crabs to peeler and hard crab fisheries.

Beyond harvest regulations, some experts have suggested that hatchery-based supplementation of blue crab stocks may have merit. I 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. My 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 are now being developed at the Center of Marine Biotechnology by Dr. Al Place.

	David H. Secor, Anson H. Hines and Allen R. Place. 2002. Japanese Hatchery-based Stock Enhancement: Lessons for the Chesapeake Bay Blue Crab [will open in a new window]

Ju, S-J, D.H. Secor and H.R. Harvey. In press. Demographic assessment of the blue crab in Chesapeake Bay using extractable lipofuscin as age markers. Fisheries Bulletin.

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.