More manatees have died in 2013 than in any year on record, Florida’s Save the Manatees Club is reporting. With two months to go in the year, 769 manatee deaths have bee recorded in Florida waters, breaking the previous record of 766 set in 2010. Deaths are blamed mostly on a red tide bloom that started in southwest Florida in September 2012 and that only recently dissipated.
At least 272 manatees in southwest Florida died from exposure to red tide in 2013, with an additional 33 manatee deaths from the tide in 2012. The total deaths represent a staggering 15 percent of the state’s manatee population, set earlier this year at around 5,000. The deaths may delay or reverse attempts by some groups, such as the conservative Sacramento, Calif.-based Pacific Legal Foundation, to remove manatees from the endangered species list and list them as threatened instead. (See the county-by-county breakdown of manatee deaths so far this year.)
Manatee deaths from boats have declined, in part because there are fewer manatees in the waters, but also because of the Florida Fish and Wildlife Conservation’s speed zones: so far this year 62 manatees have been killed by boats, compared with 72 by this time last year. The five-year average is 75. Four manatee deaths have been recorded in Flagler so far this year, but none related to boats. Flagler recently instituted limited speed zones on the Intracoastal, after boaters successfully diluted a more aggressive plan by Fish and Wildlife. Two of the manatee deaths in Flagler were perinatal, one was due to cold weather, and one was undetermined.
So far this year, Lee County (with 269) and Borward (224) had the most manatee deaths.
“And to those who would argue that ‘we have more manatees, so we have more deaths,’ let me stop you right there,” Katie Tripp, director of science and conservation for the Save the Manatees Club, wrote in an OpEd issued today. “The deaths we are seeing have nothing to do with the size of the manatee population. These deaths are not natural controls on a growing population. They are a loud and clear signal that our waterways are in trouble.” Tripp added: “There’s little question that human mistreatment of the Indian River Lagoon had a hand to play in the disastrous cascade that began in 2010. On the southwest coast, during the peak of the red tide, manatees were dying so fast that scientists didn’t have the time or resources to conduct post-mortem exams on all of them before committing them to mass graves. Red tide is another one of those natural events to which our species adds fuel to the proverbial fire with our coastal nutrient runoff.”
Red tide acts as a neurotoxin in manatees, giving them seizures that can result in drowning, absent human intervention. If manatees exposed to red tide can be moved out of the affected area by trained biologists and stabilized at a critical care facility, their prognosis is vastly improved. Signs that a manatee is affected by red tide include a lack of coordination and stability in the water, muscle twitches or seizures and difficulty lifting its head to breathe.
Numerous manatees were helped away from the red tide and back to health through the intervention of several groups, including Fish and Wildlife, Lowry Park Zoo’s Manatee Hospital, Lee County Manatee Park, Ellie Schiller Homosassa Springs Wildlife State Park, Save the Manatees Club and other rescue and rehabilitation partners and volunteers who put in countless hours during the red tide crisis.
Because of their help, Save the Manatees reported, many manatees were rescued in southwest Florida who otherwise would have perished. The manatees were found alive and were successfully rescued and transported to a critical care facility. Fifteen manatees were released between June 13 and July 17.
Another threat is still claiming manatee lives on the state’s east coast in Brevard. Since 2012, at least 111 manatees have died of unknown but presumed natural causes, possibly from a different toxin or toxic syndrome. With vast amounts of Brevard’s seagrass wiped out from a huge die off, it is still not known if manatees may be accessing other food sources or contaminants that are making them sick and killing them. One theory is that since the seagrass is not available, manatees have switched to a different food source — a macroalgae called Gracilaria — that is getting into their digestive tract and killing them. Another theory is that the toxins are found on seaweed that manatees eat.
Veterinarians and scientists at the University of Florida are currently testing genes and proteins expressed when manatees are exposed to toxins. The study is funded in part by Save the Manatee Club and is designed to see if differences between affected and healthy animals carry the biological signature of an immune system responding to toxin exposure — a signature they can then test for in the Indian River Lagoon manatees.
“If you haven’t seen and felt the effects of red tide or the algal blooms in the Indian River Lagoon,” Tripp wrote, referring to her OpEd, “then this article might not mean very much to you. Our species has a keen ability to ignore that which we don’t see ourselves. Unfortunately, until we all, each and every one of us, accept that we’re part of the problem, and even more importantly, an integral part of the solution, there’s little hope for our canaries in the coal mines: our manatees and their imperiled habitat.”