Second alien crab identified in waterways

August 08, 2006|By TOM PELTON | TOM PELTON,SUN REPORTER

Scientists identified yesterday a mysterious crab found more than a year ago in Baltimore's Patapsco River as a Chinese mitten crab, suggesting that the exotic species from Asia could be breeding.

The identification comes three days after the state Department of Natural Resources issued an alert for the possible invasive species, saying a Pasadena waterman reported catching a mitten crab in the same river.

Researchers want to know if the hairy-clawed, spider-legged creatures will multiply in the Chesapeake Bay and become pests, said Gregory Ruiz, a biologist with the Smithsonian Environmental Research Center in Edgewater.

The Asian natives have invaded San Francisco, Germany and England in recent years, ripping fishing nets, digging holes in earthen dams and clogging water intake pipes.

"This suggests there might be other ones out there," said Ruiz of the second mitten crab found in Maryland. "We still don't know if the population is established here. We are very keen to hear of any other sightings of the crab."

On Saturday, Steve Takos, a volunteer park ranger at North Point State Park in Edgemere, saw a photograph of the crab in The Sun and recognized it as the same kind he had in his freezer.

"It was exactly the same thing. The same mittens and everything, but bigger than the one in the paper," said Takos, 83, a former waterman. "I'm sure there are others out there."

Takos, who runs a nature exhibit for children at the park, said another waterman had given him the unusual-looking crab about two or three years ago. Takos said he originally mistook the crab for a variety of spider crab that lives in the Atlantic Ocean, and put it into one of the park's fish tanks, where it was on display for months.

After the crab died, Takos said he froze it and stored it in an icebox at the park in Baltimore County because he knew it was an unusual specimen.

When Takos saw the photo of the Chinese mitten crab Saturday, he immediately called state wildlife officials. They contacted fellow researchers with the Smithsonian research center, who picked up the frozen crab yesterday. They showed it to a visiting crab expert from China, Dr. Yongxu Cheng, and concluded it was a mitten crab, said Ruiz.

State biologist Lynn Fegley said yesterday it is still unclear whether mitten crabs are living and breeding in the Patapsco.

The most likely scenario, Fegley said, is that two different ships unintentionally carried the crabs in their ballast into Baltimore Harbor, and released them when dumping the water.

"Or we could have [mitten] crabs living here at very low populations, so they are not often detected," Fegley said. "That's the lesser of the possibilities, but it can't be ruled out."

Scientists said they are discussing the possibility of conducting DNA tests on the two crabs - both males - to see whether they likely came on the same ships. If one mitten crab came from Europe, and the other from California, they would have different DNA.

Researchers are also discussing the possibility of searching river banks along the Patapsco River for mitten crab burrows, and perhaps casting nets to try to catch more of them.

Meanwhile, officials are asking anyone who has seen a mitten crab to send an e-mail to lfegley@dnr.state.md.us. The Chinese species is about the size of a dinner plate, with spindly legs, white claws and tufts of hair or "mittens" around the claws.

The crabs are not sold in local Chinese restaurants, although they are considered a delicacy in Asia. The eggs are thought to be an aphrodisiac. Ruiz said it's unlikely that the mitten crabs would outcompete fierce Chesapeake blue crabs. But the Chinese crabs could multiply and change river ecosystems in unexpected ways, researchers said.

Takos said he got the second crab from waterman Jim Foltz, 39, of Fort Howard. Foltz's recollection of the timing was different, saying he was "95 percent certain" he caught the crab in May 2005 - not two or three years ago - while checking his crab pots in the Patapsco River.

"I was pretty surprised when I saw what I had - it had that fur on its claws," said Foltz. "It was one of the strangest things I've caught."

As owner of Captain Jimmy's Crab House in Edgemere, Foltz said, he's well-attuned to the tastes of his customers. He said it's unlikely that the mitten crabs - if they start reproducing in the Chesapeake Bay - would be marketable to Maryland residents, despite the Asian appetite for them.

"I don't think so," Foltz said. "It's kinda ugly, looking very much like a spider."

tom.pelton@baltsun.com

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