Florida's most famous endangered species, the manatee, no longer deserves to be called endangered, say federal wildlife officials.

They announced Thursday that they are dropping manatees from the endangered list and reclassifying them as merely threatened.

The U.S. Fish and Wildlife Service took this momentous step the day after celebrating "Manatee Appreciation Day" on its social media accounts.

The change was made despite a record number of manatees killed in Florida by boaters in 2016. For the first time ever, more than 100 manatees died after being run over by boaters.

"While it is not out of the woods, we believe the manatee is no longer on the brink of extinction," said Larry Williams, head of the agency's Vero Beach office, at a news conference. "This is truly a success story."

The decision goes against the recommendations of manatee biologists concerned about the continuing loss of manatee habitat to waterfront development. Instead of science, the agency's decision "seems to be based on hope," said biologist James "Buddy" Powell, who has studied manatees for more than 40 years.

Nearly 87,000 comments and petition signatures opposing the change were submitted during the 90-day public comment process. Only 72 people said they were in favor.

Federal officials acknowledged their decision was spurred by a lawsuit filed by a libertarian group called the Pacific Legal Foundation. And it's likely to lead to a lawsuit by the Save the Manatee Club to overturn it. One Florida congressman has already promised to ask new Secretary of the Interior Ryan Zinke to reconsider.

"The decision to weaken protections under the Endangered Species Act threatens the survival of the manatee, one of Florida's most beloved animals," said U.S. Rep. Vern Buchanan, R-Longboat Key. "It needs to be reversed."

Because the state's own endangered list copies the federal one, this means manatees will be automatically knocked down a notch on the state list too, said Florida Fish and Wildlife Conservation Commission executive director Nick Wiley.

Although federal officials promised changing the manatees' classification won't weaken their protections, Pat Rose of the Save the Manatee Club predicted this will be followed by a concerted effort to roll back habitat protection and other measures.

The Pacific Legal Foundation represents a group from Citrus County — where manatee-related tourism has been a mainstay of the economy — that dislikes some recent manatee protection regulations there. Its goal has been to prevent any more.

The manatee, a plump and whiskery mammal that breathes air, is an unlikely figure to spark so much controversy. As big as a couch and shaped like a yam with flippers, it's a placid vegetarian with no natural enemies except humans.

Fossils show manatees have existed in Florida for centuries. The first written account of someone seeing a manatee comes from the log of Christopher Columbus, who noted that mermaids were not as attractive as he had been led to believe.

Ever since Jacques Cousteau featured them in a 1972 television documentary called Forgotten Mermaids, the manatee has become a popular symbol of Florida's natural bounty, not to mention the centerpiece of several tourist attractions and a mascot for many schools.

Manatees have been classified as endangered since the first federal endangered species list was issued in 1967. They were included on that list not because of their numbers, which were unknown, but because of the threats they faced from being clobbered by speeding boats or having their habitats destroyed by waterfront development.

"The threats that landed them on the list have been reduced," Jay Harrington, who heads up the federal agency's Jacksonville office, said Thursday.

However, 104 manatees were run over and killed by boaters last year, the first time that number has topped 100 since the state began tracking it in the 1970s. Widespread dieoffs caused by cold weather and toxic algae blooms have also taken a toll.

Meanwhile, a controversial lawsuit filed in 2000 by a coalition of environmental groups against state and federal wildlife agencies led to settlements requiring new boat speed zones and manatee sanctuaries. Biologists have credited those measures with spurring an increase in the population. More than 6,000 manatees were counted in the most recent statewide aerial surveys.

Florida's boating and building interests have been trying for 18 years to knock manatees off the endangered list, in hopes of blocking further restrictions on boating speeds and development. No one succeeded until the PLF suit.

The PLF was founded in the 1970s in California to counter groups like the Sierra Club and the Environmental Defense Fund and challenge regulations. It filed the manatee lawsuit in 2014.

"I am glad to hear that the federal government is finally formally acknowledging … the manatee is on the mend and no longer in danger of extinction," PLF attorney Christina Martin said. "This is a victory for everyone who believes that the government must follow the requirements of the law."

But the latest fight over the manatees is just getting started. Rose said the Save the Manatee Club is "looking very, very closely at how this decision comports with the law and whether it relies on the best available science, and upon first review, it does not."

That means, he said, "we need to hold their feet to the fire."

Contact Craig Pittman at craig@tampabay.com. Follow @craigtimes.