At a lonely bend on Wisconsin's Wolf River, Jane and Lloyd Merkel balance on some rocks and peer down into the tea-brown water.
"Look, Lloyd!" Mrs. Merkel says. "Isn't she a beauty?" A gray fish as long as a fence post swims past, its big tail making slow undulations. There are dozens and perhaps scores of the big fish in the river. They appear and disappear, rising out of the deep to nuzzle and splash in the shallows. They have spiky backs, barbed snouts, and mouths like vacuum cleaners. They are like nothing else the Merkels have ever seen.
Sturgeons are struggling to survive the world over, from the Caspian Sea in Central Asia to Chesapeake Bay and the Missouri River. Dams, pollution, and the appetite for caviar - raw sturgeon eggs - have made life difficult for a fish that has endured since the Cretaceous period, the age of dinosaurs.
But lately there have been growing efforts to protect sturgeons and, in some places, to restore them to waters where they had vanished. More people like the Merkels will start to see these striking fish for the first time.
Next month, for example, biologists from the Tennessee Aquarium in Chattanooga plan to release several hundred young lake sturgeon into the French Broad River upstream of Knoxville as part of a long-term effort to restore the fish to the Tennessee River system.
In May, when it last released sturgeons in the French Broad, a crowd of officials and journalists gathered to watch, a measure of the attention that sturgeons are receiving in some places.
"It was quite a big event," says Chris Coco, an Aquarium biologist. "It's an example of a fish that was gone and now it's back."
Eastern Wisconsin is one of the few places where sturgeons thrive, thanks in part to the enthusiasm of ordinary people like the Merkels. Each spring, hundreds of "sturgeon guards" volunteer to spend a 12-hour shift watching over spawning areas to discourage poachers.
To aficionados, sturgeons have many charms. They have an ancient pedigree, a bizarre appearance, and immense size.
The lake sturgeon, which lives in the Mississippi River system and the Great Lakes region, is only a middling sturgeon, but it can grow to more than six feet and over 100 pounds.
Sturgeons are also long lived. In 1953, a 6-1/2-foot lake sturgeon caught in the Lake of the Woods, in Ontario, was determined to be 152 years old. It had been a fingerling during the first Jefferson administration.
Sturgeons are survivors. They live a largely hidden life, snuffling along the bottom of lakes and rivers and eating almost anything they bump into. As Fred Binkowski, a scientist at the Great Lakes Water Institute, says, "Whatever killed the dinosaurs didn't kill sturgeons."
And yet sturgeons have declined almost everywhere. The recent collapse of the Caspian Sea sturgeon, the source of most of the world's caviar, is only the best-known example. Until the 19th century, sturgeons abounded in North America, too. Native Americans depended upon them for food in the spring. Later, European Americans fed them to pigs, plowed them under as fertilizer, and burned their dried, oily carcasses as fuel in steamboats. Nineteenth-century fishermen harvested them in large numbers, and by the mid-20th century, overfishing, pollution, and dam construction had decimated sturgeons in many places.
Eight species of sturgeon live in American waters today. Four are endangered and another is threatened; all are watched closely by scientists and conservationists. Unlike most other fish, sturgeon mature late and reproduce slowly. They cannot easily be brought back from the brink. Ron Bruch, a sturgeon expert with the Wisconsin Department of Natural Resources, says that sturgeons survive in the Great Lakes only in scattered remnants, even though large-scale commercial fishing for them ended a century ago.
"Populations are just now being to increase to where we can catch a fish now and then," he says. "It's taken that long."
Efforts to revive sturgeon populations reflect not just a new respect for a once disdained fish, but also dramatic improvements in water quality. Just last month, biologists released thousands of lake sturgeon fry in Wisconsin's Milwaukee and Manitowoc rivers, which empty into Lake Michigan, after concluding that cleaner water and the removal of dams might allow sturgeons to flourish once again.
But such efforts raise questions about how far the nation's waters might be returned to nature. Atlantic and shortnose sturgeons once abounded in Chesapeake Bay. Today, they are rare. David Secor, a sturgeon expert at the Chesapeake Biological Laboratory, doubts they will ever return in significant numbers because farming in the surrounding countryside has so altered the bay.
"We can't go back to water quality as it was in the 19th century," Mr. Secor says. "I think it's reasonable to strive for, but I don't think we're going to get there."
On the Missouri, the pallid sturgeon, a federally endangered species, is in trouble largely because the river has been transformed since Lewis and Clark ascended it in 1804. Much of it has been damned and dredged for flood control and barges, eliminating backwaters and shallows fish need for spawning. Dams and reservoirs have muted seasonal flows, so that the river runs neither as high in the spring nor as low in the summer as it once did. Earlier this month, a federal judge ordered the Army Corps of Engineers to lower water levels to help save sturgeon and two endangered bird species.
"Nobody wants the big floods to come back," says Jim Milligan, a project leader for the US Fish and Wildlife Service. "But we think it can be tweaked so that the spring rise is a little higher and the summer lows a little lower."
A more recent threat to North American sturgeons is the demand for caviar. With less caviar coming from the Caspian Sea, the industry has turned increasingly to America, especially to the shovelnose sturgeon, which lives in the Mississippi. In the past half decade commercial fishermen have netted the shovelnose in unprecedented numbers, and the population has plummeted.
In a few places, though, sturgeons have been nursed back to abundance. Shortnose sturgeon are thriving again in the upper Hudson River, thanks to a cleaner river. In eastern Wisconsin, the number of lake sturgeon has increased five-fold since the 1950s. Tougher game laws have helped, but so has a transformation in public attitude. Only a few decades ago, the people of Shiocton were notorious as poachers. Today, local sturgeons attract admirers.
"It's kind of an honor, to help preserve them for future kids," says Mrs. Merkel, as sturgeons thrash at her feet.