Results of latest blue crab survey spurs call for action

By Karl Blankenship

Scientists have notched upward their concern about the Chesapeake Bay's blue crab population, warning that states need to begin crafting plans to rebuild the bay's most valuable fishery.

A report from the Chesapeake Bay Stock Assessment Committee, which includes scientists and fishery managers from around the bay, said the crab population remains low and that the 2007 catch will almost certainly exceed the committee's overfishing threshold, further elevating worries.

"One year of bouncing above that line does not a catastrophe make," said Lynn Fegley, a fisheries scientist with the Maryland Department of Natural Resources and chair of the stock assessment committee. But if crab abundance does not start to increase, she added, "then we're compounding the problem."

The committee's report predicted that when 2007 harvest data is compiled, it will show that about 63 percent of the Bay's legal size crabs were harvested. The overfishing threshold -- the percentage of adults that can be sustainably taken -- is 53 percent. About 50 percent were harvested in 2006.

The jump is not caused by an unusually high catch. Scientists expect the 2007 harvest to be about 48.7 million pounds, roughly the same as the 48.9 million pounds landed in 2006.

The problem is that last year's reproduction, as measured in the annual winter dredge survey conducted across the bay, was the second lowest since the survey began in 1989. The same level of fishing on a smaller population likely pushed the harvest above the overfishing line.

Blue crabs have tremendous reproductive capability; a single female can produce up to 8 million eggs. That creates the possibility that this winter's dredge survey could find an upward tick in reproduction, in which case the 2008 harvest could fall below the overfishing threshold.

But scientists are worried because the blue crab stock has showed no real sign of rebounding. After a precipitous crab population drop in the late 1990s, states imposed regulations to reduce fishing pressure. Those actions are credited with halting the population drop, but instead of increasing, crab abundance stabilized at a level well below the long-term average.

No one is sure why crabs have not bounced back. Some say predation on blue crabs may have increased over time, perhaps as a result of the robust striped bass population. Other possibilities include changes in local ocean currents, which influence the survival of larval crabs, or the decline of underwater grasses in the lower bay, which juvenile crabs use as shelter.

"There is a good reason we are scratching our heads a little bit," said Tom Miller, a fisheries scientist with the University of Maryland Center for Environmental Science and a member of the stock assessment committee. "We simply don't know what that answer is."

Whatever the cause, scientists have long warned that a low stock size makes it particularly vulnerable to natural fluctuations, such as last year's poor reproduction.

As a result, the committee's annual advisory report for the first time recommends that agencies begin working with groups such as watermen to make plans for the next steps in management including "specific management actions for rebuilding a depressed stock."

Committee members said the plan should outline management actions to be taken if, for example, overfishing continues to take place, or if crabs fall below a certain level of abundance. The idea, they say, is to have actions ready to go if those thresholds are reached.

Larry Simns, president of the Maryland Watermen's Association, said that's a good idea. In the past, he said watermen felt regulations were rushed through that were unduly harmful.

"We need to start ahead of time and think of what we might need to do," he said. "Right now, we're not in a position that we need to do anything. But if it gets any worse, we need to have something ready so we know what we're going to do. We want it to be worthwhile and not disastrous to the watermen."

Some preliminary efforts are already under way. The Virginia Marine Resources Commission this year convened a panel of experts, to review all of its blue crab fishing regulations.

The idea is to identify the regulations that overlap, are ineffective, or need to be modified to achieve desired results, and then to recommend possible changes and get input, said Robert O'Reilly, the VMRC's deputy chief of fisheries management and a member of the stock assessment committee.

"In the past, it was almost after the fact that the stakeholders and the industry was provided the opportunity to provide input," O'Reilly said. "Here's an opportunity to have that same kind of input from various concerns, and in the beginning stages."

Karl Blankenship is editor of the Bay Journal.