The annual winter survey of Maryland and Virginia waters tallied 300 million crabs, the Department of Natural Resources reported. That's down nearly two-thirds from the number seen last year, when Gov. Martin O'Malley held a press conference at a crab house in Annapolis to declare crabs had rebounded from near-collapse in 2008 and were more plentiful than they’d been in nearly two decades.
This year, Natural Resources Secretary John R. Griffin presided over the announcement and acknowledged in a statement that the crab numbers were "by no means ideal." But he expressed confidence that with cooperation from Virginia, steps could be taken to sustain the population, and the seafood industry that depends on it.
Though the number of mature female crabs increased and remains well above the threshold scientists say is needed to sustain the population, the survey found the crop of juvenile crabs has fallen by 80 percent since last year.
"The bay's blue crab population varies naturally," explained Tom O'Connell, DNR's fisheries director. "Weather conditions, an increase in predators or other natural occurrences can affect the crab stock."
Officials said overharvesting didn't appear to be the problem. Instead, they said an influx of crab-eating fish into the bay or possibly an uptick in cannibalism among crabs themselves had contributed to the mysterious disappearance of the record number of young crabs seen in last year’s survey.
While state officials had predicted a bountiful harvest last year, the catch declined to an estimated 56 million pounds baywide, according to preliminary estimates, down from 67 million pounds in 2011.
With the harvest off overall, Maryland and Virginia watermen apparently did not take more female crabs last year than scientists consider advisable. But officials said they would seek to reduce the female catch by 10 percent this year as a precaution, given the poor reproduction last year and loss of so many juveniles. Limits on how many female crabs Maryland watermen can catch in a day likely will be reduced in May, said Lynn Fegley, deputy fisheries director. Comparable cutbacks are expected in Virginia and on the Potomac River, officials said.
Maryland and Virginia curtailed the catch drastically five years ago amid warnings from scientists that the bay's crab population, especially the females needed to produce young, had fallen to dangerous levels. The crabbing season was cut short in the fall, and daily catch limits and harvest times were cranked down to reduce the harvest of females by a third.
The population rebounded after that, and though it took another dip in 2010, last year's survey found the highest number since 1997. The one sour note was a precipitous decline in females seen, though officials maintained there were still enough to sustain the population.
"We had all those babies last year, we thought it’s going to be a banner fall," said Fegley. "And those crabs just did not materialize in the harvest later in the year."
Scientists believe an unusual influx of red drum, a large, reddish fish that visits the lower bay from spring through autumn, may be behind the disappearance. Drum feed on young crabs, and state officials say according to federal records, Virginia's recreational anglers caught 2.5 million of the fish last year -- 40 times the number reported in 2011.
Drum aren't common in Maryland waters, but state officials estimate 300,000 of them were harvested last year, more than 100 times the number reportedly caught in each of the previous two years.
Anson C. "Tuck" Hines, a crab biologist and director of the Smithsonian Environmental Research Center in Edgewater, said the drop in juvenile crabs this year should come as no surprise, since the number of females to spawn young last year had fallen by more than half — almost back, he noted, to levels that had triggered the crisis in 2008.
Hines expressed skepticism, however, that the loss of so many juvenile crabs before they could reach adulthood last year could be laid to red drum or any other fish.
"This is the same old story that we heard about there's too many striped bass [that] are eating all the baby blue crabs," he said, "when really it was about fishing." In Maryland waters, at least, Hines said his research has shown that cannibalism among crabs, which increases when they're crowded together, is the leading cause of death among juveniles.
Still, Russell Dize, first vice president of the Maryland Watermen’s Association, said fisheries officials need to take into account the impact of other species on the bay's crabs.
"You've got an overabundance of rockfish, an overabundance of puppy drum, and an overabundance of cownose rays, which all eat crabs," Dize said. "We probably had as many small crabs last year in July and August as we’ve ever seen, but they never materialized. We think they got eaten up."
Whatever got them, the Chesapeake Bay Foundation’s senior fisheries scientist, Bill Goldsborough, suggested that another factor in the demise of so many juvenile crabs was "degraded habitat." Earlier this week, scientists reported a 21 percent decline last year in the bay’s underwater grasses, which provide vital shelter for growing young crabs, especially when they shed their old shells to form a new, larger one.
Goldsborough said last year’s poor reproduction apparently stemmed from unfavorable weather in the crab spawning waters near the bay's mouth, which he noted "we can't control, and low numbers of females, which we can."
Though fisheries officials have said in years past that the winter dredge survey is a good indicator of how many crabs will be available for harvest, Fegley said after last year's results she wouldn't dare predict how abundant they’ll be for steaming at Maryland crab houses or backyard feasts.