Legend has it that centuries ago, manatees used to be mistaken for mermaids, so a sight last week at one Florida state park would have put ancient sailors in shock.

Blue Spring State Park is home to one of the largest winter gathering sites for manatees in Florida, and recently, the park reached a new record when the number of manatees spotted in one group was nearly 1,000.

"Record-breaking morning at Blue Spring State Park," read a Facebook post from Friends of Blue Spring State Park. The volunteer group, which helps support the park, said the previous record of manatees gathering was 736 on New Year's Day of this year.

Manatees typically flock to the park during the winter months, but several factors have caused their numbers to increase over the years.

According to a Facebook post from the non-profit Save the Manatee Club, Jan. 21 was one of the coldest mornings of the Florida winter season so far. The temperature of the St. Johns River, which Blue Spring sits on, was recorded at 58.8 Fahrenheit.

"In Florida, over the past couple of weeks, we've had more frequent cold fronts that have been closer together," says Monica Ross, director of manatee research and conservation at Clearwater Marine Aquarium's Research Institute. "That drops the ambient water temperature down and that's when you're going to have more animals showing up at one time."

To survive the cold winter weather, manatees will seek out water that is typically warmer than 68 degrees. This is because despite their thick looking bodies, the blubbery animal affectionately known as the sea cow only has "about an inch of fat and a very slow metabolism, meaning they cannot easily stay warm," says the state park.

Since their spring water remains at a constant 72-degrees, and is protected from human recreational activity, Blue Spring makes the perfect manatee refuge during the colder months.

What's more, "many manatees rely on artificial warm water sources from power plants, and these might be going offline in the near future. So having some of these manatees come to these natural warm water sites and finding them is really encouraging," says Cora Berchem, a research associate and the director of multimedia at Save the Manatee Club.

What's driving the increase?

According to the Florida Fish and Wildlife Conservation Commission, there are anywhere between about 7,000 to 11,000 manatees in Florida, which represents a large increase over the past 25 years.

At Blue Spring State Park, the number has grown from about 36 animals since research began in the 1970's to over 700 animals, according to the park.

That growth is attributed in part to higher reproductive rates, but also because "you've got more animals that are shifting their habitat and shifting how they're wintering," said Ross. She continued that there's been an increase throughout other springs along the St. Johns River as well.

The higher numbers at Blue Spring are encouraging, as there are many threats that exist towards these aquatic creatures — including habitat loss, pollution and collision with watercraft. They have also been losing access to a primary source of food, seagrass, due to algal blooms that are inhibiting its growth.

The reliable food availability at these warm spring sites could be another driving factor for manatees to come, says Ross.

Experts caution that the increasing count at Blue Spring is not necessarily representative of the greater condition of manatees statewide.

"We do have to keep in mind that [the numbers at Blue Spring are] really only a small subset of the entire manatee population in Florida," says Berchem.

The Florida Fish and Wildlife Conservation Commission and the U.S. Fish and Wildlife Service have in partnership been tracking an unusually high level of manatee deaths along the Atlantic Coast of Florida, including in 2021, when more than 1,000 manatees are estimated to have died in Florida largely due to starvation.

More than 500 manatees died in 2023, according to preliminary numbers from the state's Fish and Wildlife Conservation Commission.

In 2017, the U.S. Fish and Wildlife Service lowered the status of the West Indian manatee (of which, the Florida manatee is a subspecies of) from "endangered" to "threatened". The move caused outcry at the time.

In October 2023, two petitions to reclassify the species back to "endangered" were introduced.

"The fact that [manatees] are choosing to be at Blue Springs shows how important of a site it is and what a manatee is really looking for, for survival," said Ross.

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