Cold weather deals blow to warm-blooded manatees

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The warm-blooded manatees are unable to adjust their body temperatures and suffer quickly and, often fatally, from cold water. Winter cold snaps in 2018 have proven deadly for Florida manatees. Islander Photo: Courtesy Sea to Shore Alliance
Manatees huddle Jan. 21, warming their backs in the sun at the bayfront outflow for the TECO power plant. Islander Photo: Sandy Ambrogi

It was the Ides of March, and while “normal high temperatures” around Anna Maria Island should have been about 76 degrees, at 10 a.m. the thermometer barely pushed up from an overnight low in the 40s.

A late winter cold snap, sent down by the jet stream, was putting area manatees at risk — again.

Hundreds of manatees routinely seek refuge at the Tampa Electric Company discharge basin in Apollo Beach, and also at Homosassa Springs, Three Sisters Springs and Kings Bay, which are fed by warm water springs. Some also journey south, seeking warm water.

Cold temperatures in January were responsible for manatee deaths statewide — 38 from cold stress and 20 undetermined deaths, which, in the winter can be attributed to cold, according to Michelle Kerr, public information specialist with the Florida Fish and Wildlife Conservation Commission’s Research Institute.

Three of the 120 January deaths were manatees found in Manatee County waters.

Then came February. Mother Nature stepped in with record high temperatures and a string of hot sunny days. The manatees left their refuges and journeyed into open waters, which had returned to more than 70 degrees, even in the Gulf of Mexico, according to the National Weather Service.

Two sudden cold snaps lowered the water temperatures in March, and manatees were again suffering. Twice in March, FWC pulled deceased manatees from Palma Sola Bay, attributing at least one of the deaths to cold stress and labeling the other undetermined.

Through March 23, when the most recent statistics were tallied, 218 manatees had died in Florida this year.

“This is higher than the latest five-year average,” Kerr said.

Caught miles away from their refuges, area manatees huddled in basins, coves and protected inlets, warming their backs in the sun by day and conserving energy. Despite their bulbous appearance, manatees have little fat to insulate them in frigid waters.

Cold-stressed manatees can be identified by white lesions and spots on their bodies — more white means a higher level of danger for manatees. Water temperatures below 68 degrees threaten manatees and the longer the cold exposure, the worse the condition becomes.

By mid-March, 35 rescues had taken place in the state, with assistance from several agencies and organizations.

On March 22, a cold-stress rescue took place in Tampa Bay, where a manatee was found severely underweight and suffering from lesions. The animal was captured by Sea to Shore Alliance and transported for rehab to Sea World in Orlando. On the state’s east coast, rescues were occurring almost daily.

Kerr said the majority of Tampa Bay area manatees sought refuge at TECO in Apollo Beach when the water temperature dropped again.

It is estimated the entire population of West Indian manatees stands at more than 6,300, having doubled in the past 20 years with conservation efforts. In 1991, only 1,267 manatees were located in the first-ever aerial survey of state waters.

Pat Rose, an aquatic biologist and executive director of Save the Manatees, said in an email to The Islander, “The increases of the past 40 plus years won’t be enough to maintain the population in the face of shrinking food reserves, increases in red tide and watercraft mortality unless more is done to control and reduce these threats.”

Rose said severe fluctuations in weather patterns can severely affect populations. In 2010, more than 300 manatees died from cold stress.

“It becomes clear that the potential for manatees to recover from future catastrophic losses is going to be very low,” Rose said.

Rose also noted an early trend in 2018 — death rates are on track to break the third highest record for total deaths from all causes for manatees.

For now, the weather is warming and manatees will be on the move.

From April 1 through Nov. 15, seasonal manatee zones require boaters to slow down in certain areas. The FWC asks boaters to be on the lookout for manatees as they move through local waters.

The FWC requests that any sightings of tagged, distressed or dead manatees be reported to its 24-hour hotline at 888-404-3922 or *FWC on a cellphone.

 

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