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Study: Warmer winters will mean more Chesapeake Bay blue crabs, but that could have unpredictable domino effects

New research suggests that Chesapeake Bay blue crabs will be more plentiful amid milder winters in the coming decades, but scientists say that’s not a reason to welcome global warming.

They predict that more of the crustaceans will survive the winter in the future, given forecasts of less frequent and intense cold. Winter cold can kill off significant numbers of crabs, who spend the season burrowed in mud for warmth.

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“In 100 years, we would expect winter for crabs in Solomons to look more like winter currently looks in southern North Carolina,” said Hillary Lane Glandon, who conducted the research at the University of Maryland Center for Environmental Science and is now a post doctoral research associate at the University of North Carolina in Wilmington. “No winter for the crabs.”

In a study published Monday, UMCES researchers suggest that could have unpredictable domino effects in the larger Chesapeake ecosystem and could create new issues for regulators managing the commercial crab harvest.

Tom Miller, a professor and director of the institution’s Chesapeake Biological Laboratory in Solomons, said a reduction in cold conditions could lead to pressure to allow wintertime harvesting of crabs. That is currently prohibited in Maryland, but is allowed on a limited basis in warmer states.

And if crabs spend less of the year in hibernation and more time feeding, it could have effects down the food chain.

“If crabs start moving and feeding year-round, they represent an added predation pressure on the bay’s ecosystem, and we don’t know how the ecosystem will respond,” Miller said.

The research predicts that crabs could spend about half as much time hibernating in 2100 as they do now. In waters near Solomons, in Southern Maryland, it could decrease from about 117 days, on average, to about 56 days, the study suggests.

That could mean virtually all crabs survive the winter, an increase of about 20% in the species’ survival rate in the Chesapeake.

The scientists noted that it is difficult to predict how blue crabs will fare simply based on rising temperatures. The bay’s creatures are also expected to endure increasingly acidic and salty waters, and those changes are expected to have mixed effects on crabs.

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