The estimated population number for the iconic Chesapeake Bay blue crab has fallen compared to last year, causing concern among state officials and alarm among advocates.

The latest winter dredge survey estimates 238 million crabs in the Bay — the second-lowest count since the survey began in 1990.

It’s a sharp drop from last year’s 317 million and far below what scientists want to see. The lowest record was in 2022, when the estimated population fell to 226 million.

Maryland officials say cold snaps over the winter probably drove up crab mortality.

The blue crab population has been below-average since before 2020. Experts are conducting a large-scale stock assessment to better understand the decline.

The Chesapeake Bay Foundation called the results of the dredge survey “distressing.”

“The red flags are flying for blue crabs,” said foundation Maryland Executive Director Allison Colden in a statement. “With more than five years of below-average crab numbers, it is clear that changing conditions in the Bay are undermining the current management of this important species.”

Researchers are in the middle of large-scale blue crab stock assessment to evaluate and understand factors that influence the crustacean’s survival and reproduction in the Chesapeake Bay.

The ongoing assessment is the first since 2011. There are an estimated 103 million juvenile crabs this year, compared to 138 million last year. State officials said they hope it will help scientists understand why the number of juvenile crabs has been so low for consecutive years.

According to Mandy Bromilow, Maryland Department of Natural Resources (DNR) blue crab program manager, the stock assessment will help officials understand how to support the bay’s crabs.

“Until then, we need to maintain caution in our management approach for blue crabs,” Bromilow said in a statement.

The winter dredge survey does not reveal immediate concern about the number of female crabs, although the number remains lower than what officials would like to see. The estimated number of female crabs this year is 108 million, down from 133 million last year. That’s above the threshold number of 72.5 million that would trigger more concern and regulatory action from the state.

However, it’s also below the target number of adult female crabs in the Bay: 196 million.

Crab reproduction is “naturally variable,” Maryland DNR officials said, and the blue crab harvest tends to follow a boom-and-bust cycle.

Fisheries managers in Virginia were not surprised by the low numbers this year, according to a statement from the Virginia Marine Resources Commission, because of the colder-than-average temperatures over the winter.

Officials from the Virginia commission said the stability in the adult female crab population “supports cautious optimism.”

Half of the blue crab harvest in the United States comes from the Chesapeake Bay, according to state data. The seafood industry, including crabbing, contributes nearly $600 million to the state economy.

Detailed results of the winter dredge survey can be found on the DNR website.