Manatees moving into Lee’s waters

Water temps drop, boaters beware

By Kevin Lollar

Originally posted on December 08, 2007

Boaters be wary: Local waters haven’t reached the critical manatee low-temperature threshold, but large numbers of the endangered marine mammals are gathering in Lee County.

Manatees are extremely cold sensitive — they can die from what scientists call “cold stress” — and when water temperatures drop to 68 degrees, they move to warm-water refuges such as the canals of Matlacha Isles and the discharge from the Florida Power & Light plant on the Orange River.

Although water temperatures are still in the mid-70s, Mote Marine Laboratory scientists conducting an aerial survey this week counted 497 manatees in county waters — Mote has a contract with Lee County to perform aerial manatee surveys twice a month.

“The weather’s still warm, and there are hardly any manatees in the river,” Mote senior biologist Kerri Scolardi said. “Most are outside the mouth of the Caloosahatchee, feeding outside their winter refuges, moving into position.

“Some of them came down from Sarasota County, where the water temperatures are below 70. Animals that spend the summer and fall farther north move to Fort Myers for the winter.”

As water temperatures continue to drop, manatees will move toward warm water, which means they’ll be cruising through the same areas traveled by the county’s thousands of power boats — Lee County’s seasonal manatee speed zones are in effect until March 31.

About 25 percent of all manatee deaths are caused by watercraft, and over the past 10 years, boats have killed 136 manatees in Lee County —more than in any other county in the state.

A combination of statistics is behind the county’s high boat-related manatee body count: A large population of manatees spend all or part of the year in county waters, and almost 51,000 boats are registered here.

“It’s something we think about all the time: We have so many manatees and so many boats,” said Justin McBride, a county senior environmental specialist.

“I don’t know of another county that’s as heavily regulated or where enforcement and compliance are better. I don’t know what the solution is, but I don’t think more speed zones is the answer.”

Another factor at this time of year is that local waters are more crowded with vacationers and winter residents.

“Anybody who’s been in Lee County for two or three years is aware of the manatee issue, unless they’ve been living under a rock,” McBride said. “But people will come down for a month and rent a boat, or move here during the season, so our education efforts really increase in November and December, but there’s still a learning curve.”

During manatee season, the Lee County Marine Task Force — personnel from the Coast Guard, U.S. Fish and Wildlife Service, Florida Fish and Wildlife Conservation Commission, Lee County Sheriffs Office, and the Sanibel, Cape Coral and Fort Myers police departments — monitors manatee movements.

“The supervisors say, ‘Hey, this is where they are this week; let’s target enforcement in that area,’” said Joanne Adams, spokeswoman for the FWC.

“People need to be alert, keep a good eye out, look for the manatee footprint: That swirl in the water. But sometimes there’s nothing you can do. A manatee doesn’t know he’s out of his zone.”