Blue crab population rebounds but remains below targets

The Chesapeake Bay blue crab population has shown signs of improvement after last year’s historic lows, but there’s still cause for concern, according to the 2023 Blue Crab Winter Dredge Survey published Thursday.

The overall population rebounded to 323 million this year, a 42% increase, which means more juveniles survived the winter, said Chris Moore, a senior regional ecosystem scientist with the Chesapeake Bay Foundation. The survey, conducted by the Virginia Institute of Marine Science and the Maryland Department of Natural Resources, found 116 million juvenile crabs, up from an all-time low of 86 million in 2021. Researchers are cautiously optimistic, but say juvenile numbers are still too low.

Virginia’s crab industry generates $22 to $38 million each year, according to the foundation. In addition to posing a risk to the ecosystem, decreases in crab numbers pose a risk to the livelihood of thousands. Measures taken to counteract the drop, such as fishing limits, also affect the industry.

But it isn’t easy to determine exactly what will help the crabs.

“We tend to look mostly at the total number of blue crabs, the number of juveniles and the number of adult females,” Moore said. “Very seldom are we in a situation where all three of those numbers are pointing in the same direction.”

Last year’s survey counted only 227 million blue crabs — the lowest total in its 33-year history. The Virginia Marine Resources Commission, which makes recommendations for managing the crab population, responded in part by lowering the number of crabs people could catch each day by as much as 43%.

Over the past few years, Moore said, experts have begun to pay more attention to the adult male population, and worries grow that there are too few male crabs to fertilize the females’ eggs. Juvenile, adult female and adult male crab population segments impact how scientists and policy managers evaluate the success of human interventions.

This year, male adults doubled and female adults increased by over 50%. But the survey counted 116 million juvenile crabs, only about a 14% increase.

Factors such as a warm winter can help crabs survive to adulthood — but can also increase their predators, including blue catfish and red drum fish. Efforts to increase the grass beds that provide crab habitats or to improve water oxygen levels can help population growth. And while hurricanes can disrupt the ecosystem, they can also help increase crabs by pushing larvae into the bay.

The VMRC will hold a public meeting Wednesday with the Crab Management Advisory Committee to discuss the survey results and any potential management responses.

Katrina Dix, 757-222-5155, katrina.dix@virginiamedia.com