Biologists tallied a record number of manatees this winter, counting more than 6,000 of them scattered around the state, according to numbers released Monday.

During the February aerial survey, a team of 20 observers from 11 organizations counted 3,333 manatees on Florida's east coast and 2,730 on the west coast, for a total of 6,063. That's nearly 1,000 more than the previous record, set in 2010.

Every winter, biologists coordinated by the Florida Fish and Wildlife Research Institute in St. Petersburg take to the skies over the state to fly around power plants and springs looking for manatees huddled together in warm water.

The numbers in the counts are notoriously unreliable, with one biologist comparing it to "counting popcorn while it pops." But the overall trend since the official statewide counting began in 1991 has shown a steady climb from about 1,200.

About 1,000 of the manatees counted in February were found in the warm spring waters of Citrus County. In Citrus they are a popular sightseeing subject for swimmers, snorkelers, kayakers and ecotour boats — so popular, in fact, that an environmental group is threatening to sue to stop people from swimming with them to protect them from harassment.

The largest single herd of manatees, about 1,100 were found at the warm water outfall for Florida Power & Light's Cape Canaveral plant.

State officials credited the growth to boating regulations and other measures put in place after a 2001 lawsuit settlement with the Save the Manatee Club and a coalition of other environmental groups.

The high population count "shows that our long-term conservation efforts are working," said Florida Fish and Wildlife Conservation Commission chairman Richard Corbett of Tampa.

Conditions were nearly ideal for this year's count, which contributed to the high numbers, state officials said.

"In many of the regions surveyed, warm, sunny weather caused manatees to rest at the water's surface, which facilitated our efforts to count them in these areas," state biologist Holly Edwards said.

Biologists were particularly relieved about the high count after seeing a record number of manatees killed by cold and by Red Tide toxins in recent years — not to mention the mysterious deaths of more than 100 manatees in polluted Indian River Lagoon. The statewide manatee death toll in 2013 topped 800 for the first time ever.

"Obviously it's very good news, but it needs to be kept in context," said Pat Rose, executive director of the Save the Manatee Club. "It doesn't mean we've got 1,000 more than we had in 2010."

Manatees — once confused by lonely sailors for mermaids — have been found in Florida for thousands of years. Ever since Jacques Cousteau featured them in a 1972 television documentary, they have become an extremely popular symbol of the state's natural bounty and a key part of several tourist attractions. The manatee's homely image is depicted on everything from license plates (which pay for state manatee research) to barbecue sauce labels and liquor bottle holders.

In the past, such big jumps in the population counts have touched off discussions about whether manatees should still be included on the endangered species list.

Manatees have been on the federal list since the first one was drawn up in 1967. Records show they were placed on the list not because of their numbers — which were unknown at the time — but because of the threats they faced from speeding boats, pollution and the loss of habitat to waterfront development.

The Pacific Legal Foundation has urged the U.S. Fish and Wildlife Service to lower manatees a notch to merely "threatened" status. The libertarian foundation is working on behalf of Save Crystal River Inc., which opposes new federal rules requiring boats in Kings Bay to slow down during the summer as well as winter. The agency agreed last year to consider the step.

Asked if the highest manatee count of all time might become a factor in the agency's decision, foundation attorney Christina Martin said, "Probably."

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