Unlocking secrets of bay's blue crab

Scientists raise crustaceans in UM hatchery, then release them to observe how they live

May 07, 2007|By Rona Kobell | Rona Kobell,Sun reporter

In a basement laboratory tucked amid the tourist attractions of Baltimore's Inner Harbor, two Israeli-born scientists are unlocking the mysteries of the Chesapeake Bay blue crab.

Over the past five years, Yonathan Zohar and Odi Zmora have spent most of their waking hours poring over tanks filled with the snapping crustaceans and their tiny offspring at a University of Maryland lab on Pratt Street. They feed the crabs homemade algae tailored to their life stage. The researchers control the water temperature, light and salinity, and document the crustaceans' every move as they shed their shells, mate and reproduce.

And once the young crabs are strong enough, the scientists pack them on boats and release them in secluded coves near the Chesapeake Bay.

Zohar and Zmora are leading a team of researchers from the University of Maryland Biotechnology Institute and four other institutions around the country in an effort to do what no one thought could be done -- raise crabs in a hatchery, then put them in the bay and watch how they live.

The goal is eventually to increase the population of crabs reproducing in the Chesapeake Bay -- a feat that scientists say has not been accomplished in any body of water anywhere in the world.

Some doubt that it will work. Not only would the hatchery have to produce many millions of crabs to make a difference in the bay, but past attempts to restock the world's waterways with hatchery-raised fish have been expensive disasters.

"If we think of it in the whole big picture of things, we're attempting to do something that history has shown has produced failure after failure," said Donald F. Boesch, president of the University of Maryland Center for Environmental Sciences, a sister institution. He questions whether it is wise to pour so much federal money into the gamble. The project has received $12 million over the past five years at the request of Sen. Barbara A. Mikulski, a Maryland Democrat.

The director of the biotechnology institute's Center for Marine Biotechnology is undaunted. With the future of the blue crab at stake, Zohar said, the biggest failure would be not to try.

"I keep telling people, one reason I came here was because of the crabs," he said. "In light of what's going on in the bay, this is one stone that should not remain unturned. Even if it is not going to work, we're going to learn ... a tremendous amount about the biology of the blue crab."

Since he began the Blue Crab Advanced Research Consortium, Zohar has recruited some of the nation's top experts to answer key questions about the blue crab, Callinectes sapidus, including where it migrates, how fast it grows, and whether it would be a good species for aquaculture. His work is influencing regulations, including a new rule to create a 94-square-mile sanctuary in Virginia for pregnant females.

"They have done things in the lab that nobody thought could be done," said Eric Schwaab, deputy secretary of the Maryland Department of Natural Resources. "They really have learned a lot in a very short period of time that has all kinds of implications for our management efforts."

Even though the blue crab has been a staple of the seafood economy for centuries, biologists and watermen didn't know a lot about it. Unlike the bay's oysters, which have been in trouble for decades, there wasn't much urgency in studying the blue crab. Crabs were not dying of diseases the way the oysters were. And the fishery did not appear to be in trouble -- harvests in Maryland alone are measured in the tens of millions of pounds, according to the Department of Natural Resources, and provide income for more than a thousand watermen.

But several years ago, studies in Virginia and Maryland began to indicate a steady decline in the number of juvenile crabs in the bay. Both states put in fishing restrictions in hopes of reducing harvest pressure and protecting the spawning stocks. Some scientists talked of going a step further -- if they could figure out why the stocks were declining, they might be able to bring them back.

Zohar, a Jerusalem-born, Paris-educated endocrinologist, seemed an unlikely choice to lead the effort. He'd never even seen a blue crab until he was in his 30s, and he'd spent most of his career studying fish. But in 2000, when Zohar was testifying before the Maryland General Assembly about stock enhancement techniques for fin fish, then-Del. C. Richard D'Amato of Annapolis asked him if he could do the same thing to shore up crabs.

Zohar replied that he thought it was possible. D'Amato helped him get $100,000 to try. Phillips Foods, the Baltimore-based seafood company, kicked in $300,000.

Zohar began assembling an all-star team of researchers. He persuaded Zmora, a fish nutrition expert, to leave his post at an Israeli lab in the Red Sea resort of Eilat and move to Baltimore to set up the algae kitchen. Until he walked into the Columbus Center, Zmora had never seen a live blue crab.

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