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Hatchery spawns hope for crab stock enhancement
Panel recommends limit for crab harvests
They Check In and They Don't Check Out
The number of blue crabs in the Bay, especially adult females, increased dramatically last year, which officials say is an early indication that strict new catch limits are showing results.
Figures from the annual winter dredge survey show that the total number of crabs in the Bay increased by nearly 50 percent, from about 280 million last year to 418 million in this winter's survey.
Almost all of the increase was among adult crabs, where the number of males increased by about 50 percent, while the population of adult females nearly doubled, according to figures from the annual survey conducted by the Maryland Department of Natural Resources and the Virginia Institute of Marine Science.
This winter's survey estimated the adult crab population at 243 million-the first time since 1994 that their number surpassed an interim Baywide goal of 200 million adults. Last year, the survey found about 120 million adults.
"This is clearly a direct result of our management, because it is the adult females that increased, which is where we placed our conservation measures," said Lynn Fegley, assistant director of the Maryland DNR Fisheries Service.
Last spring, Maryland Gov. Martin O'Malley and Virginia Gov. Tim Kaine jointly announced that the two states would adopt regulations aimed at reducing the harvest of female crabs by 34 percent to help rebuild a crab population that had remained at near record-low levels for most of the last decade.
Officials from both Maryland and Virginia warned that the recovery of the crab population is far from over, and both states plan to maintain strict harvest restrictions, although there will be some adjustments from last year.
"It's a great first step in terms of rebuilding this crab population, but just the first step, not the last," said John Griffin, Maryland secretary of natural resources. "The real issue is to build this population back up and sustain it over time so that it is providing the economic opportunities for the industry, as well as the recreational opportunities for working families in both states."
Preston Bryant, Virginia secretary of natural resources, agreed that the survey results were good news, but cautioned, "let's remember the broader context. The crab population is one third what it was 15 years ago. We didn't get into this situation overnight. We are not going to get out of it overnight."
The survey did have some cautionary signs. The number of juveniles barely changed, edging up from about 160 million last year to 175 million, remaining far below average.
In part, that reflects the fact that females protected by last year's restrictions will not spawn until this year.
Those females, which hibernated in the mud over much of the Bay during the winter, will still be vulnerable to fishing pressure as they resume their migration to the mouth of the Bay, where they will begin spawning this summer.
"Some fraction of those will still be harvested," said Rom Lipcius, a VIMS researcher who oversees the Virginia portion of the survey.
Scientists hope a large number of those female crabs will successfully spawn, which could lead to an increase in the number of juvenile crabs in next year's survey.
That isn't guaranteed. Crab larvae spend the first several months of their lives outside the Bay. Environmental conditions during that time are a major factor in determining how many ultimately re-enter the Chesapeake.
"With crabs, it often is not a one-to-one relationship between adults and babies," Fegley said. "You also need a lot of environmental things to line up."
But a large number of females provides the opportunity to sharply increase crab numbers, if they align with favorable off-shore conditions, she said.
Even if there is a surge in the number of juveniles next year, scientists said they would like to see several years of good reproduction before they feel confident that the population is recovering from years of near-historic low numbers.
"We really need to be careful about what we're doing," Lipcius said. "We definitely are not out of the woods yet.
Another concern is that last year's harvest rate was still 50 percent of the crab population.
That's below the 53 percent threshold, above which the sustainability of the stock is threatened. But it is still above the target of 46 percent for the population, a figure which would create a margin of safety and allow the stock to grow over time.
Scientists believe the crab population plunged after the crab harvest exceeded 53 percent-and once surpassed 70 percent-over a five-year period starting in 1998.
"We will continue to manage our fishery for that 46 percent target removal rate," said Tom O'Connell, Maryland DNR director of fisheries.
Although the exact details of this year's harvest restrictions won't be set until May, fishery managers in both states said strict measures will likely stay in place until the stock is clearly rebounding, although they said some easing of the restrictions on females might be possible.
Another concern is the large number of "latent" licenses that exist in both states-valid licenses that have not been used in years. Should those licenses become active, the percent of the population caught could increase.
"We need to look at the potential of those inactive licenses coming back into the fishery this year given the national economy and the recognition that the population has increased," O'Connell said.
Nonetheless, because the overall crab population is higher, this year's catch is also likely to be up. "If you are harvesting at 46 percent, 46 percent of a bigger number is a bigger number," Fegley said.
The preliminary catch estimate for last year is estimated at 48.6 million pounds, a slight increase from 44 million pounds in 2007.
The blue crab winter dredge survey began in 1990 and samples blue crabs at 1,500 sites throughout the Bay from December through March. By sampling during the winter when blue crabs are buried in the mud and stationary, scientists can develop highly accurate estimates of crab numbers in the Chesapeake.
