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Blue Crab Winter Dredge Survey Shows Stable Adult Abundance
ANNAPOLIS — The Maryland Department of Natural Resources (DNR) Fisheries Service and the Virginia Institute of Marine Science (VIMS) today presented the results of the 2007 blue crab winter dredge survey, which indicates the total number of crabs estimated to be overwintering in the Chesapeake Bay in 2007 remained stable, similar to the number observed in 2006.
The abundance of female crabs that will spawn during 2007 remained unchanged from 2006. Female spawning abundance has remained steady since 2003, but is below historic levels. The abundance of young of the year crabs (less than two inches across the carapace) declined significantly in 2007, and is among the lowest levels observed in the survey. It is important to note that fluctuations from year to year in the juvenile blue crab index are unpredictable and not uncommon. As in 2006, total abundance remained below the 17-year survey average.
“Once water temperatures warm, early season blue crab harvests should be similar to last year, but lower numbers of young crabs could present some problems later in the season,” said Howard King, Director of the Maryland DNR Fisheries Service. “We also remain concerned that the low abundance of young crabs could put the stock in greater risk, especially if we do not see a rebound in the next one or two years. For the time being the regulations in place will hold, and we will remain vigilant in monitoring our populations and fishing pressure.”
Overall, the survey indicates that the blue crab population remains steady at a low level of abundance. Based on the historical relationship between dredge estimates and subsequent harvests, DNR and VIMS expect that the 2007 harvest for the Chesapeake Bay will be comparable to the 2006 harvest, which preliminary estimates place at 51.8 million pounds.
The Bay-wide blue crab winter dredge survey is a cooperative effort between DNR and VIMS, and is the primary survey used to assess the condition of the Chesapeake Bay blue crab population. Since 1990, the survey has employed crab dredges to sample blue crabs at 1,500 sites throughout the Chesapeake Bay from December through March. By sampling during winter when blue crabs are buried in the mud and stationary, scientists can develop, with good precision, estimates of the number of crabs present in the Bay. Estimates of abundance are developed separately for young of the year crabs, mature female crabs and adult male crabs. Together these groups of crabs will support the 2007 fishery and produce the next generation of crabs.
The winter dredge survey is the primary survey used to assess the condition of the Chesapeake Bay blue crab population. During 2007, the National Oceanic & Atmospheric Administration (NOAA) Chesapeake Bay Stock Assessment Committee (CBSAC) will analyze the winter dredge survey as well as supporting data from three additional surveys - the Maryland trawl, Virginia trawl and Calvert Cliffs pot study. Based on the results of the CBSAC analysis, the NOAA Chesapeake Bay Office will issue a 2007 Blue Crab Advisory Report in the fall of 2007.
April 23, 2007
The Maryland Department of Natural Resources (DNR) is the state agency responsible for providing natural and living resource-related services to citizens and visitors. DNR manages more than 449,000 acres of public lands and 17,000 miles of waterways, along with Maryland's forests, fisheries and wildlife for maximum environmental, economic and quality of life benefits. A national leader in land conservation, DNR-managed parks and natural, historic and cultural resources attract 12 million visitors annually. DNR is the lead agency in Maryland's effort to restore the Chesapeake Bay, the state's number one environmental priority. Learn more at www.dnr.maryland.gov