Blue crab management has less margin for error in the Chesapeake than previously thought, according to a new review of the Bay’s most economically valuable species.

While Virginia and Maryland officials say there is no immediate need for new regulations to control blue crab harvests, they say further action may be needed if current trends continue.

“We’re going to keep a close eye on this fishery for the next few years to see what goes on,” said Phil Jones of the Maryland Department of Natural Resources.

In a review released earlier this year, the blue crab stock was considered “fully exploited” by the Chesapeake Bay Stock Assessment Committee, an advisory panel coordinated by the National Oceanic and Atmospheric Administration’s Chesapeake Bay Office.

Only two years ago, a review of the stock said that crabs were near — but not at — the full exploitation mark, which is considered the maximum harvest level at which the reproductive capacity of the species can be safely protected.

The new review found that the number of young crabs entering the population has been steady in recent years, while a larger portion of the adult crabs has been harvested.

Managers said hitting the threshold was not a cause for immediate action because both Maryland and Virginia have imposed numerous new crabbing regulations in recent years, the effect of which have not been fully felt.

“We’re still in the early parts of realizing some of the management gains,” said Rob O’Reilly of the Virginia Marine Resources Commission.

A key element of those actions was limiting the number of commercial crabbers licensed to participate in the fishery. “That’s pretty unprecedented,” O’Reilly said. “For probably 80–90 years, it has been a laissez-faire approach.”

Still, there are concerns that harvest pressure could increase. For example, the Chesapeake Bay Blue Crab Fisheries Management Plan approved last year indicated that even with the new restrictions, there was the potential for added pressure because many licensed crabbers were not fishing to the maximum limit allowed.

“I’m not sure that the management measures we have in place will effect a complete cap on effort without further action,” said Bill Goldsborough, senior scientist with the Chesapeake Bay Foundation. “I think there are still ways for effort to expand.

“I don’t think we need to rush out right now and take some emergency action based on that,” he added. “But I think that it does indicate that we are not all the way there, and we have to continue to closely watch the management of the fishery.”

Goldsborough said the data continue to suggest that the total effort is still too high in the fishery, leading to too many crabs being caught when they are small, and that the value of the fishery — and the health of the stock — would be improved if regulations were adjusted to reduce effort and allow more crabs to reach larger sizes.

Of four Bay crab surveys used in the assessment update, one showed that the fishing mortality exceeded the threshold, two were at the threshold, and one was below.

While concerned, managers note that many assumptions used in establishing the threshold are based on conservative estimates. For example, it is assumed that crabs can live to be 8 years old — something that is widely questioned.

If crabs actually have a shorter life span, which many suggest, the formula used to calculate the “safe” harvest level would show that more crabs could be harvested without putting the stock at risk.

Research is under way to answer that question. In addition, efforts to better track the recreational catch of crabs will begin next year — something that could help to improve estimates of the stock’s overall health in the future.

“It would be very preliminary to even think about what type of further management you need, but you definitely need to keep up the process that we’re doing,” O’Reilly said. “And this has to be done regularly.”

He noted that the next blue crab stock assessment update will be out in August 1999.