A toxic red algae bloom is killing off Florida’s endangered manatees in record numbers, according to state officials and wildlife experts.
The algae appear annually off the west coast of the state. However, this year the bloom has been particularly severe, long and deadly. Already, 241 of the roughly 5,000 manatees have died and the toll continues to rise, according to the state Fish and Wildlife Rescue Institute. The number far exceeds the previous annual record of 151 deaths.
The annual red tide affects numerous aquatic animals, including dolphins and manatees. The algae contain a nerve poison called brevetoxin that seeps into the water and also blows into the air when waves break open the algae’s outer casing. Animals die when they accidently eat the algae or small organisms that cling to sea grass and soak up the poison while filtering seawater. Because manatees eat up to 100 pounds of sea grass daily, they are susceptible to the toxin.
The algae can also cause health problems in residents and tourists who can inhale brevetoxins while walking on beaches near red tides or who may eat oysters and clams that absorbed the toxins.
Experts are unsure why this year’s algae bloom has been so long and toxic. While some believe it’s due to phosphorus runoff from fertilized farms (algae thrive on a phosphorus diet), others believe it could be an issue of weather and timing. A mild, fairly windless winter helped algae thrive in the ocean.
The deaths from the red tide are another hard blow to the manatee population this year. At least 463 manatees have already died in 2013 from a range of causes. This is more deaths than in any previous comparable period.