Thursday, February 11, 2010

Focus on Mote Marine Lab Manatee Research

Manatees huddle in Florida cold

Counts in warm waters indicate population growth

by Kevin Lollar (

February 10, 2010

(NOTE from CSS: Click on the title above to view an awesome interview with Dr. Joel Ortega-Ortiz of the Florida Fish and Wildlife Conservation Commission. The associated story below was published in The News-Press, Fort Myers, Florida and can be accessed online at Photo (c) Valerie Roche/

1:10 A.M. — An aerial survey conducted Monday shows that cold weather is keeping manatees bunched up at warm-water refuges. Meanwhile, a researcher says manatee behavior might be an indication of climate change.

Flying over six Florida Power & Light plants and two other sites across the state, John Reynolds, director of Mote Marine Laboratory's Manatee Research Program, counted 929 manatees, including 527 in the FPL warm-water discharge area on the Orange River.

"I saw more than I expected at Fort Myers," Reynolds said. "Very few places get more than 500. When it's that cold for so long, animals that ordinarily don't go to warm-water sites are compelled to go, or they don't survive."

Manatees are cold-sensitive, so they move to warm-water refuges when water temperatures drop below 68.

Last month, when water temperatures hit the low to mid-40s, a record 77 manatees statewide died from cold stress.

Reynolds wasn't the only researcher counting manatees during the recent cold weather.

During the week of Jan. 11, 21 observers from 10 organizations counted a record 5,076 manatees during the state's synoptic survey - 877 manatees were documented in Lee County waters, which included the FPL plant, the Caloosahatchee River, Pine Island Sound, Matlacha Pass and Estero Bay.

The previous record, set last year, was 3,802.

"Part of the reason for this year's high count is this was an exceptionally cold year," said Holly Edwards, a Florida Fish and Wildlife Conservation Commission biologist. "We've always admitted that we miss animals on surveys. This illustrates the magnitude of what we missed: This year's count was 33 percent higher than last year."

FWC's survey gives a minimum number of manatees in the state, not the manatee population: It's the number of manatees observers saw that day.

"We're working on improving our methods to come up with something more robust statistically than a minimum number," Edwards said. "Even as a minimum number, we get errors. Looking at a pile of manatees is like trying to count a jar of jelly beans."

Reynolds' manatee surveys of FPL plants are much smaller than the state's, but the program is older: The state started counting manatees in 1991; the FPL project started in 1977, with Pat Rose, now executive director of the Save the Manatee Club, as the original observer.

"The initial idea was to determine what impact FPL warm-water effluents were having on manatees," Rose said. "Initially, we looked at FPL and non-FPL

plants to ascertain whether or not manatees are using them. In the first year, we flew in the summer, too, to demonstrate they weren't using the plants in warmer weather."

Rose's work led to the Manatee Sanctuary Act of 1978, which authorizes the state to adopt boating regulations to protect manatees.

With 33 years of data from the FPL plants, esearchers can draw some conclusions about manatee populations and, possibly, about climate change, said Reynolds, who took over the project in 1982.

"Of late, the counts are much higher than back in the 1990s," he said. "In the past five years, we've had huge counts, and it's not all an increase in population.

"We've had some incredible prolonged cold periods. A lot of people feel global warming is going to result in increasing warmer times. But another outcome might be increasing extreme weather, such as more hurricanes and perhaps these long cold periods."

Although the state's surveys aren't intended to determine the manatee population, they do show promising trends, Edwards said.

"My guess is that the population has been growing the last 15 or 20 years," she said. "We're finally getting enough animals in the population to recognize that things are getting better. It's showing that our conservation methods are having a positive effect on the population."

No comments: