2004 Winter Dredge Crab Survey Shows Little Change Over 2003
ANNAPOLIS, MD — The Maryland Department of Natural Resources Fisheries Service and the Virginia Marine Resource Commission today announced results of the 2004 winter dredge crab survey.
Estimates of total blue crab abundance did not change significantly in 2004, and have remained stable since 1998. Likewise, the estimated number of mature females in the population did not differ significantly from last year's (2002-2003) survey, although mature female abundance in the most recent two years has been significantly higher than during the 2000-2001, and 2001-2002 surveys. The estimate of the number of juveniles did not differ in 2004 and has remained at low but stable levels since 1998.
Biologists have not yet fully assessed the effects of 2003-2004 over-winter mortality. Large crabs are most sensitive to winter cold, so any effects will be seen early in the 2004 crabbing season, both in terms of size and quantity of crabs harvested. Based on the historical relationship between dredge estimates and subsequent harvest, DNR expects a 2004 harvest of 20-25 million lbs in the Maryland Bay.
The winter dredge survey is one of four surveys used to assess the condition of the Chesapeake Bay blue crab population. During the spring of 2004 the NOAA Chesapeake Bay Stock Assessment Committee (CBSAC) will complete analysis of the winter dredge survey and the remaining three surveys - the Maryland trawl, Virginia trawl and Calvert Cliffs pot study. Based on the results of the CBSAC analysis, a 2004 blue crab advisory the NOAA Chesapeake Bay Office will issue a report in late June or early July this year.
The Bay-wide winter crab dredge survey is a cooperative effort between the DNR and the Virginia Institute of Marine Science (VIMS). Since 1990, the survey has employed crab dredges to sample for blue crabs at 1,500 sites throughout the Chesapeake Bay from December through March. By sampling during winter when blue crabs are burrowed 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 for juvenile crabs entering their first year, mature female crabs, and adult male crabs. Together, these groups of crabs will support the following year’s fishery and produce the next generation of crabs.
For more information on the survey log on to: www.dnr.state.md.us/fisheries/crab/winter_dredge.html
Posted April 13, 2004