Imagine not being able to escape the cold, day after day, night after night, ultimately succumbing to weariness and disease.That's what happened to Florida's iconic manatees during the winter; the lovable "sea cows" have perished in record numbers and carcasses are still being recovered.
Through last Friday the official death toll had reached 448, the majority of victims having died from what are referred to as cold-stress-related ailments, caused by prolonged exposure.
It might take months or even years to determine what affect the die-off might have on the long-term health of the endangered mammals, which are a famous attraction for boaters, scuba divers and general tourists.
The animals typically migrate to inland canal systems and spring outflow areas in winter months. Or they seek shallower and typically warmer areas such as the Everglades. But during January and February, when air temperatures dipped below freezing and water temperatures plummeted, these secondary areas were too cold to sustain some of the manatees.
The cold spell was caused by high pressure in the North Atlantic, which allowed winter storms to track much lower across the U.S. and into the Southeast. Manatees thrive in water 68 degrees or higher but were forced to endure temperatures in the 40s and 50s, or even lower in some areas.
Martine DeWit, a veterinarian for the Florida Fish & Wildlife Conservation Commission, said prolonged exposure to cold weakens the animals' immune systems. They begin to develop lesions and secondary infections. They become lethargic and stop eating, and may develop pneumonia and other diseases.
"And what we're seeing now are the delayed affects of the cold," DeWit said, in reference to the continued trickle of deaths. "It has not completely slowed down because a lot of animals are still sick and it will take a while for them to recover."
The state agency does not have a reliable population estimate but counted 5,076 manatees during a synoptic survey in early January. That was a much higher count than expected but it was because so many animals were congregated near power-plant discharge areas or springs, where water temperatures were slightly warmer.
Ken Kurtis, who owns Reef Seekers Dive Company in Beverly Hills, Calif., led a trip to Florida's Crystal River in early February, and his group dove near a spring outflow, at which about 250 manatees had gathered to try to find warmth. They had visited the same area in 2008 and counted only 50 manatees.
While the divers enjoyed spectacular viewing it was a bittersweet experience because the divers knew the animals were suffering. "Manatees are quite cute and they've certainly been embraced by humans," Kurtis said. "But knowing, especially after one swims over to you and rolls over for a belly-rub, that's there's nothing you can really do to help them... is quite a helpless and powerless feeling."
-- Pete Thomas
Photos courtesy of Ken Kurtis/Reef Seekers