When Brandy Pounds swam in central Florida's Crystal River earlier this month, she came so close to an endangered manatee that she could feel the sea cow's breath tickling her toes.

"And then I turned around and we were face-to-face," said the 41-year-old therapist from Texas.

"We made eye contact. It was pretty cool."

Languid, whiskered and weighing as much as 1,200 pounds (545 kilograms), the bulbous Florida manatees -- a subspecies of the West Indian manatees -- were among the first creatures to be named by the United States as a federally endangered species in 1967, alongside the iconic bald eagle and American alligator.

For decades, manatees have been celebrated and protected by environmentalists and celebrities alike, earning the title of the official state marine mammal of Florida and the admiration of celebrities like singer Jimmy Buffett, who co-founded the popular non-profit Save the Manatee Club in 1981.

But times may be changing for these slow-moving seagrass eaters.

A controversial proposal by the US Fish and Wildlife Service calls for downgrading them from "endangered" to "threatened," based on their ballooning population size.

In Florida alone, the agency said the manatee population has grown to a record 6,350 as of February.

Early estimates of their population are hard to come by, but the first aerial surveys flown over Florida in 1991 counted 1,267 manatees.

A final decision, expected sometime in 2017, would apply to all West Indian manatees in the region, from Florida to the Caribbean and northern South America.

"I believe this is just a first step of celebrating a success story," Ivan Vicente, visitor services specialist at the Fish and Wildlife Service Crystal River National Wildlife Refuge Complex, told AFP.

"It's only a very minor difference," he said of the change in terminology.

"It just means that the species is not as vulnerable to extinction as it once was, but still vulnerable. So the level of protection does not change."

- Threats remain -

Opponents say a host of threats remain, including disease, loss of habitat, cold stress and collisions with watercraft.

"We really think it is premature," said the Save the Manatee Club's director of science and conservation, Katie Tripp.

She said the change could amount to less money for manatee protection, and doesn't take account of future risks the manatees will face.

Among them, the expected loss of winter refuge they get from clustering around power plants that discharge warm water.

As those plants are gradually made more environmentally friendly, as many as 4,000 manatees -- which are creatures of habit -- could die from the cold, she said.

For Tripp, it doesn't matter that five times more manatees exist today than 25 years ago.

"We are not at all focused on a number and we don't want the agency focused on a number either. It is just about the habitat," she said.

- Idle speed for manatees -

In the winter, hundreds of Florida manatees converge in the natural warm water springs near Crystal River, where boat captain and Mike Dunn, co-owner of Manatees in Paradise, says manatees have shaped the local way of life.

Dunn leads small tours of six tourists at a time into Three Sisters Springs and the surrounding canals. Snorkelers must watch a video first that explains how to avoid harassing manatees -- no chasing, no poking, no hugging allowed.

Killing a manatee is also forbidden. Violators of federal protections may face fines of up to $100,000 and a year in prison.

Dunn drives his boat slowly, moving at idle speed according to local regulations to reduce the risk of striking a manatee.

He waves his arms and chastises other boaters whenever he sees them going faster than they should.

"It's all about respect," according to Dunn, who said he views as "absurd" any effort to downgrade the manatees' status.

"I cannot believe anybody that's actually making money on manatees wants to downlist them," he said.

"Without the manatees, we don't need the restaurants, we don't need the hotels. Manatees are the main source of income here."

But boating groups have led the charge -- along with a group called Save Crystal River which petitioned the government in 2012 -- to reclassify the manatee as "threatened," based on Fish and Wildlife's own findings in 2007.

The push to downlist manatees began in 1999 with Wade Hopping, a powerful boating industry lobbyist who argued that manatee protection would limit the number of docks, marina and boats, according to the Tampa Bay Times' environment reporter Craig Pittman, who authored the book, "Manatee Insanity."

David Ray of the Marine Industry Association of Central Florida insisted that cautious boating practices will not change if the manatee is downgraded.

"The rules that have been put in place to protect the manatee have done an extremely good job," Ray told AFP.

"If you have slow speed limits in some areas where manatees are very prolific, then those speed limits will remain in place and the manatees will be protected."

- Boat strikes -

More than 1,100 comments -- many in favor of keeping the manatees listed as endangered -- have already been posted on the Fish and Wildlife Service's website.

The public comment period ends April 7.

Fish and Wildlife spokesman Chuck Underwood said if a change is announced, "the public would see no differences in our conservation and protection efforts."

More protections could even be added if needed, he said.

"I understand this will beg the obvious question -- why do this?

"Simple. Based on the best data and information at the time of our review, our biologists determined the species no longer meets the definition of endangered -- in imminent threat of extinction."

For tourists like Pounds, the idea of letting go of the manatees' endangered status is hard to fathom, especially after she witnessed the apparent effect of an old boat strike on one of the creatures.

"One of the ones that I came contact with today had some scars and scratches on its back, and pretty deep ones, so that's just a sign of someone being irresponsible," she said.

"I think you've got to use the word 'endangered,'" she added.

"You call them 'threatened' and people are going to get out there with their boats and cut them up."