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Two threatened species targeted Experiment: Once-abundant Atlantic sturgeon and trumpeter swans show signs of making a comeback in the Chesapeake.

THE BALTIMORE SUN

IT'S A FINE spring day a few decades in the future, and near your boat something swirls massively, a 10-foot dinosaur of a fish.

Virtually extinct in Chesapeake Bay waters for a century, sturgeon have begun to prosper since they were restocked in the Nanticoke River back in 1996.

And from overhead comes a loud calling, as piercing as a Klaxon horn, absent from Chesapeake skies for about 200 years.

Trumpeter swans, the world's largest flying waterfowl, are heading north, their ranks swelled to thousands from the little flock reintroduced to Dorchester County in the autumn of 1997.

Such a scenario is only slightly fanciful. Both species once were abundant here, and scientists think there is evidence both could thrive again.

Atlantic sturgeon, which can reach 15 feet and 800 pounds, filled bay rivers on their spring-summer spawning runs from the ocean nearly to Harrisburg on the Susquehanna and as far up as Georgetown on the Potomac. (One leaping fish landed on a Revolutionary War officer in his rowboat, breaking his thigh.)

They supported commercial caviar operations on the James and Potomac rivers until around the turn of the century, when pollution, dams and overfishing sent them into virtual extinction in the bay. (The Hudson River still has a run of sturgeon.)

Last summer, Maryland scientists released about 3,700 baby sturgeon from a federal hatchery into the Nanticoke River near where U.S. 50 crosses it at Vienna. Each was tagged for identification.

No one was sure whether the modern-day bay could support this return of the natives; but as of recent months "the results are very encouraging," according to Jill Stevenson, one of the researchers.

Around 150 of the released sturgeon have been caught by commercial fishermen (primarily in gill nets set for rockfish), and returned to researchers.

"They have grown like wildfire, to 12 inches [from 4 to 5 inches] in a few months; and their guts were full of worms and amphipods [little, bottom-dwelling crustaceans], which you'd expect them to be eating," Stevenson says.

Most surprising was how far the little sturgeon quickly ranged from the Nanticoke. Returns came from near Baltimore Harbor to North Carolina.

The sturgeon recovery effort in the Chesapeake is still very much in the experimental stage. Enough hatchery stock is not yet available for serious restocking.

And there is more to learn, such as how they will tolerate summers when the bay's bottom waters lose oxygen to pollution (last summer was a good one for oxygen).

Since female sturgeon don't become sexually mature for a couple of decades, any full recovery will be the work of a half-century or so.

Still, when Washington tourists someday flock to the Potomac shore in Georgetown to see the giant, leaping fish -- remember, you read it here first.

Of trumpeter swans, you will likely hear more by autumn. William J. L. Sladen and his environmental studies team from the Airlie Sanctuary in Virginia plan to lead a small flock behind ultralight planes to Dorchester County.

Sladen, a retired Johns Hopkins University professor, was a consultant for the recent film "Fly Away Home," based on the true story of a Canadian who taught Canada geese to migrate between Ontario and North Carolina.

Migration in geese and swans appears to be learned, rather than instinctual. Normally, it is the birds' parents who first teach the annual route to their young.

But the trumpeters lost their way to the Chesapeake nearly two centuries ago. Hunted heavily for their eggs, meat, feathers and skins from Colonial times, their Atlantic Coast populations went from an estimated 100,000 to none, according to Sladen.

During the peak of the trade in trumpeters in the 19th century, the Hudson's Bay Co. sold 108,000 of their skins. Only in Alaska did significant numbers remain.

Lacking parents to teach them to migrate, the trumpeters in Virginia will be "imprinted" at birth this summer to regard an ultralight aircraft and its pilot as their parents. (They attach to the first large, moving objects they encounter.)

After "flight training," they will follow the ultralight, or perhaps a remote-controlled model plane, about 100 air miles to Crapo in southern Dorchester County this fall.

They will be led to a 255-acre farm there owned by Robert Ferris, a wildlife expert with Defenders of Wildlife, a national group helping to raise $750,000 to finance the three-year project.

The waters of the Honga River and marshes of nearby Blackwater National Wildlife Refuge should provide ample habitat for the 10 to 12 swans scheduled to make the historic return to the bay.

It should be quite a sight. Trumpeters weigh up to 40 pounds and are a third larger than the big tundra swans that now migrate to the bay from as far away as Alaska. The trumpeters' call is one of nature's more unforgettable sounds.

Sladen says trumpeters and tundra swans, having evolved together for thousands of years, should get along fine on the Chesapeake.

A third swan, the nonmigratory mute, was introduced from Europe decades ago and has become a problem, munching all summer on the underwater grasses that are a critical bay habitat, and interfering with other summer-nesting birds.

Like the sturgeon, the trumpeters are still very much in the experimental stage. It must be proved over the next few years that they can learn to migrate back to Airlie on their own.

Eventually a long-term summer nesting ground must be chosen, perhaps in New York, and the swans taught to move between there and the bay.

"I can't think of another species that's been gone so long that has such potential to come back," says Ferris, who has worked in the West in reintroducing wolves.

Pub Date: 6/27/97

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