As an industry, ecotourism takes in $20 billion a year. The World Tourist Organization says nature travel accounts for 20 percent of all international travel and is increasing every year. But there are also growing concerns about the ability of the industry to help people learn about wildlife without harming it.

On a raft on the Skagit River, where it flows out of the Cascade Mountains of Washington state, a group of ecotourists is on the lookout for the area's prime attraction, the majestic bald eagle. Not just one?but hundreds. So many, in fact, that Dave Button - who runs a company called Pacific Northwest Float Trips - jokes with his customers. "All we charge you guys is a dollar an eagle," he says with a laugh. "So make sure you keep a good count."

The six passengers in the raft are on the river to admire a creature that was once on the verge of extinction because of the now-banned pesticide DDT. Today, bald eagles are back. Mr. Button counts them off for the tourists. "1, 2, 3, 4, 5, 6, 7, 8?look at 'em ahead, " he says. "It's like a beehive in here, look at 'em taking off."

The area is one of the largest winter feeding grounds for bald eagles. They gorge on dead chum salmon before returning to Canada and Alaska in the spring. "I'm just mesmerized by the eagle," says tourist Barbie DeCarlo. "In a lot of traditions, the eagle represents illumination and it represents being aligned with creator energy. In a lot of mythical stories, the eagle was the one who could get closest to God?you know, that high."

But there are questions about whether people are getting too close to the eagles. That is why U.S. government officials imposed limits on commercial raft operators like Dave Button. "Federal agencies did a lot of studies and they found the eagles are most vulnerable when they are feeding," says Mr. Button. That would be early in the morning. "So the big enforcement on the river," he explains, "is we don't start until 11 o'clock when the eagles generally aren't feeding."

Mr. Button accepts the regulations in large part because the eagles are his livelihood. But in other parts of the world, tour operators are not so benign. "Tourism is an industry just like any other industry and there are many people out there who are in it simply to make a profit," says Eileen Gutierrez, ecotourism manager for the nonprofit organization Conservation International, based in Washington, D.C.

"We've got projects that are out there that are damaging reefs," says Ms. Gutierrez. "In rainforest areas, you can see some of the worst manipulations of wildlife: feeding and having sort of little petting zoos and animals in cages, and the inappropriate clearing of forest in order to build facilities that just don't harmonize with the environment."

She says the solution is a combination of government regulation and industry guidelines that guarantee that ecotourism operators respect wildlife and improve the well being of local communities. Ms. Gutierrez supports efforts by the International Ecotourism Society and the World Tourism Organization to create an accreditation program for the industry.

Back along the banks of the Skagit River, a strong grassroots effort is helping to minimize ecotourism's impact on the bald eagles. The North Cascades Institute, for example, has organized the Eagle Watchers Program, where volunteers set up telescopes on the riverbank to give tourists a close-up view of the birds without disturbing them. As volunteer Todd Burley peeks through a viewfinder, he provides a running commentary on the activities of one particular bird. "It just flew down from a tree where it was perched at," he tells visitors, "and is tearing apart a horribly disgusting salmon that's fallen apart."

Tourists not only take advantage of the Eagle Watchers who talk to visitors on the shore and the raft operators like Dave Button who take them down the river. The area also boasts an interpretive center and an annual Bald Eagle Festival. Todd Burley says this mosaic of educational adventures provides the basis for ecotourism and the foundation for building respect for nature. "You see this with children when they get into the outdoor setting?[they scream] 'oh, wow!'" he says. "They just come into a new element. And being able to be out there and actually seeing what they're learning about and experiencing really brings that wonder to light. And that wonder is what gets people to take a personal stake in what they're learning about.

In this case, ecotourists of all ages seem to be learning about the eagles, the salmon, and the importance of conserving both of them.