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Blue crab abundance holds steady in the Chesapeake Bay, a year after rebounding from historic low

Christine Condon, Baltimore Sun on

Published in Outdoors

BALTIMORE — After a rebound last year from a rock bottom count the year before, the number of blue crabs estimated in the Chesapeake Bay held fairly steady, according to this year’s winter survey.

For the survey, released last Wednesday, state officials dredge the bay bottom to find the crustaceans resting beneath the mud for warmth, then approximate the species’ total abundance. This year, they estimate there are 317 million blue crabs in the bay and its tributaries, compared to 323 million last year.

For the fifth straight year, the count is below the historical average, which is above 400 million crabs. But this year’s tally is an improvement relative to 2022, when surveyors recorded 229 million crabs, the lowest figure since the winter dredge began in 1990.

The roughly 2% decline from last year is hardly significant, and the department doesn’t expect to make any major changes to harvest restrictions come July, when the rules are reevaluated, said Michael Luisi, associate director of Fishing and Boating Services at the Maryland Department of Natural Resources.

“We feel pretty confident that the measures that we have currently in place are doing their job, with the abundance that we have — and given that the abundance hasn’t changed very much since last year,” Luisi said.

That means bushel limits for male crabs, set for the first time in 2022, are likely to remain in place. Historically, the state only placed commercial limits on the harvest of spawning-age female crabs, called sooks, to ensure ample reproduction from year to year.

But Maryland fisheries managers became concerned that too many male crabs were being removed from the population, Luisi said, prompting the limits.

Despite those restrictions, the number of adult male crabs in the Chesapeake declined slightly in this year’s survey, conducted by DNR and the Virginia Institute of Marine Science from December through March.

“The population still hasn’t shown any signs of abundance surging,” Luisi said. “So, we feel like at this point, we’re just going to maintain the male limits as well as the female limits for this coming year.”

The male bushel limits were a disappointing development, said Robert T. Brown, president of the Maryland Watermen’s Association, but continued strong market demand for crabs softened the blow for crabbers.

“We don’t like them,” Brown said of the limits. “But that’s just the way it is with the science and stuff — You have got to protect our industry.”

Perhaps the most worrisome development from this year’s survey, though, is the continued low numbers of juvenile crabs in the bay, Luisi said. This year’s data showed a slight improvement, but remained below average for the fourth straight year.

 

Blue crabs grow quickly, reaching maturity in 12 to 18 months, so low numbers of juveniles quickly impact the overall population. The crustaceans generally live 3 to 4 years.

Plenty of ecosystem threats could account for the low numbers, including poor water quality and the corresponding loss of underwater grasses — critical habitat for growing crabs. Invasive blue catfish, known for their indiscriminate appetites, also could be playing a role. Studies have shown that the cherished crustaceans are on the menu for blue catfish, along with a host of other bay species.

That being said, it’s unclear precisely which factors are causing the continued low “recruitment” numbers of baby blue crabs, Luisi said, which is also tied to the quantity of spawning females.

“I believe that we definitely have enough females in the population to produce a strong year class,” Luisi said, “but we just haven’t had one in a few years.”

The number of female crabs in the bay — 133 million — is above a ground floor threshold of 72.5 million, but below the department’s target of 196 million.

“There remains a significant need to continue to protect adult females and critical nursery habitats, like underwater grasses, in order to help ensure better numbers in the future,” said Chris Moore, Virginia executive director of the nonprofit Chesapeake Bay Foundation, in a news release last week.

The Bay Foundation urged state governments to “proceed with caution” when it comes to setting harvest limits for the year, and to avoid any measures that would increase removals.

“The results of this year’s survey are less than hoped for given the importance of blue crabs in the Chesapeake Bay region,” Moore wrote in a statement.

Findings in recent years have triggered a new stock assessment for the species, a process that hasn’t been completed since 2011. That assessment doesn’t involve new surveys of the bay’s crab population, but rather a reevaluation of statistical modeling, which could provide new clues about the population, said Mandy Bromilow, DNR’s blue crab program manager. The new assessment, expected to be released in 2026, could help explain — for instance — why the numbers of juvenile crabs have remained low, Bromilow said.

With more than a decade of new data to pull in, the task is work-intensive, Luisi said. Fisheries managers have been eager to initiate a new assessment for years, Luisi said, but had to find the budget and resources in Maryland and Virginia.

“It’s been something that we’ve wanted to do,” Luisi said. “I’m very happy at this point right now, it’s underway — the wheels are turning.”


©2024 Baltimore Sun. Visit baltimoresun.com. Distributed by Tribune Content Agency, LLC.

 

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