Extreme cold temperatures this winter are being blamed for a 31 percent drop in the number of blue crabs in the Chesapeake Bay, officials said Tuesday.
Warmer than normal weather heading into winter and then a rapid cold spell in early December and below average temperatures until the beginning of February left the population at 460 million crabs - down from more than 650 million crabs last year, according to the results of the 2011 Blue Crab Winter Dredge Survey.
“Quite clearly, this year presented a perfect storm,” said Tom Miller, professor of fisheries at the University of Maryland Center for Environmental Science. “Any one of these would have caused increased mortality, but in combination, they were exactly what we didn’t need.”
Steven G. Bowman, commissioner of the Virginia Marine Resources Commission, said the number of crabs that died as a result of the cold weather this winter was “the worst we’ve seen since 1996.”
But officials were also quick to point out good news in the results, noting that even with the decline the crab population was at its second highest level since 1997 - nearly double the record low of 249 crabs million recorded in 2007.
In 2008, Maryland, Virginia and the Potomac River Fisheries Commission began a coordinated effort to protect the crab population, instituting management measures that included daily catch limits and closed periods.
The unusually high number of crabs last year led to a harvest of more than 89 million pounds - the highest since 1993.
Maryland Gov. Martin O’Malley said officials are realizing “the benefits of the very tough decisions we made three years ago - decisions that are bringing us closer to our ultimate goal: a self-sustaining fishery that will support our industry and recreational fisheries over the long term.”
The governor also pledged not to allow “the removal of 60 to 75 percent of our population, which ultimately resulted in the fishery’s decline.”
The survey reported that 254 million adult crabs survived the unusually cold winter in the Chesapeake, above population targets for the third straight year. It marked the first time since the early 1990s that the Bay has seen three consecutive years where the adult population was above the target level of 200 million crabs and the combined harvest was below the target of 46 percent.
The assessment of the bay’s blue crab population is conducted annually by Maryland’s Department of Natural Resources and the Virginia Institute of Marine Science. Since 1990, the survey has employed crab dredges to sample blue crabs at 1,500 sites throughout the Chesapeake Bay from December through March.
Scientists sample during winter when blue crabs are buried in the mud and stationary, developing estimates of the number of crabs in the Bay.