By Letitia Stein

TAMPA Fla. (Reuters) - The manatee could be downgraded from an endangered species to merely threatened as federal wildlife officials, under pressure from boating activists and libertarians, reconsider the status of Florida's popular "sea cow."

The U.S. Fish and Wildlife Service said on Tuesday it would review the latest science and seek public input on the West Indian manatee, even as conservationists note the animals suffered a record number of deaths in Florida last year.

The move follows a lawsuit filed in April on behalf of Save Crystal River Inc, an organization advocating for boaters' rights in west-central Florida waters that are known for frequent manatee sightings.

"We want the government to acknowledge that it’s improved," said Christina Martin, an attorney for the Pacific Legal Foundation, which is representing the group. "A threatened species is still protected."

The organizations petitioned to re-evaluate the manatee's status in late 2012 but the agency has not acted on their request.

In recent years, manatee numbers in Florida and Puerto Rico have met the benchmark for reclassification set in a 1997 federal wildlife recovery plan, officials acknowledged in announcing their review. But averages fall short of the 10,000 nesting pairs identified in the current plan.

"The population is undeniably going backwards," said Patrick Rose, an aquatic biologist and executive director for the Save the Manatee Club, citing deaths in recent years and erosion of manatee habitat.

"This is a really bad time because there is too much uncertainty, too much at risk, going forward," he said.

The whiskered and wrinkled sea cow, a beloved state symbol in Florida, has a large tubular body, flippers and paddle-shaped tail. It is related the African and Amazon species and to the dugong of Australia. It grows to be about 10 feet long (3 meters) and more than 1,000 pounds (450 kg).

(Reporting by Letitia Stein; Editing by Edith Honan and Bill Trott)