Who eats the most Maryland blue crabs every year? Spoiler: it’s not people.

Smithsonian researchers discovered who ate the youngest blue crabs in the Chesapeake Bay; these aren’t humans, or even fish, but larger blue crabs with a surprising cannibalistic appetite.

And you thought your uncle Danny, deep in the ocean, held the record.

They knew cannibalism was a common threat to young crabs, said Anson “Tuck” Hines, lead author and a former scientist at the Smithsonian Environmental Research Center in Edgewater. he told Scientific American.

“The surprising thing was that we found no fishing here; not a single instance of fishing,” he said. “All the predation was due to cannibalism by other crabs.”

The center has spent 37 years tracking who eats young blue crabs. They found that where and how deep the youngsters hid made a big difference. In the main brackish part of the Gulf, between the fresh water of the Susquehanna River and the salty Atlantic, its top predators were old crabs. Invasive blue catfish prefer freshwater upstream, and predatory saltwater fish stay near the mouth of the bay.

The crabs are the dominant predator on the bottom of the bay, Smithsonian researchers wrote, and they often feed by pushing their claws into mud or sand where young crabs tend to hide. Juveniles were better able to hide in shallow water weeds, but once they reached adulthood, or around 4.7 inches wide, the researchers found they could fend for themselves.

People may be second to none in their cravings for Maryland’s state crab. Watermen hauled an estimated 20 million crabs from the bay in 2024, valued at $41 million. According to the Maryland Department of Agriculture. Population estimate for that year Published by Chesapeake Bay Foundation There were 238 million crabs in total; this was the second lowest number of sweeps since the surveys began in 1990. This comes three years after an all-time low of 226 million crabs counted in 2022.

They tied young crabs to poles at different depths and at different times of the year and checked their condition the next day. Since fish eat whole prey, they expected to find a fish on the hook if they took the bait. Instead, almost all of the bait crabs were found in shell fragments or injured upon check-in. Because crabs eat by breaking hard shells with their powerful pincers, injured crabs with partial bodies or missing limbs were attributed to crab hunting.

“Cannibalism by large adult crabs accounted for more than 97% of predation by juvenile crabs; predation by fish was not observed; and deaths from physiological stress were rare (less than 1%),” the article states.

They published their work in the journal March 16 Proceedings of the National Academy of Sciences.

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