Environmental degradation over the long term has resulted in the mass dying of manatees (Trichechus manatus) in Florida this year. As of the end of May, 749 manatees have died in 2021. Manatees are considered to be a sentinel of environmental health. Florida is the third most populous state, around 21.4 million, and is still growing. Development impacts are accumulating, causing degradation of water quality, killing fish and the marine mammals that rely on them. Florida is becoming known for its red tide algae infestation as much as for its white sand beaches.
Conservationists think about a thousand manatees could die this year. With a population of only 7500 in the wild, only a few years remain for the species survival after staging a remarkable comeback from near extinction in the 1970s. Their legal protection was downgraded from endangered to threatened in 2017, a decision that has proved controversial since the threats to their survival are growing. Algae blooms encouraged by pollution prevent sea grasses from growing. Sea grasses are the manatees' favorite food source; sea grasses that survive the malevolent blooms are then overgrazed by manatees whose sources of food have shrunk, so the plants can't quickly regrow and continue to feed them. They consume about one hundred pounds of grass a day, giving rise to their common name, "sea cows". If they cannot consume this amount daily they begin to loose weight, eventually starving.
Manatees have learned to rely on warm water outflows from power plants on both Florida coasts. Since they do not have enough blubber to survive in waters below 68℉, periods of severe cold temperatures are fatal. The last mass mortality event occurred in 2010 when historic cold weather killed 760 manatees. About two-thirds of the state's population flock to warm water outlets in winter. If Florida transitions to more sustainable energy sources, those havens will disappear, leaving a threatened species more vulnerable.
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| Manatees swim unharmed in Crystal River, FL |
An example of what has gone wrong with manatee recovery is Indian Creek Lagoon, which stretches 150 miles along the east coast. Once an ecologically rich area, it provides habitat for one third of the state's manatees. Water pollution is responsible for a 58% reduction in sea grasses and some areas are full of microplastics according to the state water district. A 2018 study found crabs and oysters with high levels of plastic contamination.
Dead manatees now float in the lagoon; washed ashore their bones are picked clean by vultures. Manatee deaths are simply a "symptom of a system that is under stress and near collapse," says one marine biologist. Restoration requires funding. Local activists have struggled, sometimes successfully as in the case of the Crystal River, to turn the tide in favor of manatee survival. [photo credit: Discover Crystal River] The heavily Republican state government led by Gov. Ron DeSantis has appealed for more federal funding of water quality projects. Rotting manatee corpses are hardly consistent with Florida's self-image as a tropical Shangri-la