The ongoing unusual mortality event is prompting the U.S. Fish and Wildlife Service to consider reclassifying Florida’s state marine mammal as an endangered species.
Over 1,000 Florida manatees died in 2021. That number is the peak in the current unusual mortality event.
This is a human-made issue, said Molly Lippincott, the senior curator of Florida and Marine Life at Zoo Tampa at Lowry Park.
“Their biggest problem is people,” Lippincott said.
The mortality event primarily focuses on the east coast of Florida, near the Indian River Lagoon. Iske Larkin, who has a doctorate in philosophy in physiological sciences, said poor water quality in the lagoon is a primary cause of manatee mortality.
Nutrient buildup from runoff, increased development and septic systems have led to harmful algal blooms. These algal blooms then decimate the seagrass, which is the manatee’s food source.
Larkin, a senior lecturer and education coordinator at the University of Florida’s College of Veterinary Medicine, noted that water quality should be a key focus of the issue.
“Some of the efforts … should be focused on water quality and not necessarily on the manatees,” Larkin said, adding that manatee mortality is a consequence of poor water quality.
Several other factors contribute to manatee mortality, including collisions with watercraft, entanglements and cold stress, which is when the water is too cold during winter.
Experts have different opinions regarding a solution to this problem.
Larkin said initiatives that decrease runoff and increase natural barriers between human development and the shoreline would be beneficial. Research also shows that reintroducing shellfish is linked to increased seagrass.
Todd Osborne and the Indian River Clam Restoration Project repatriated clams from Mosquito Lagoon on the east coast of Florida to the Indian River Lagoon.
As clams filter feed, they reduce algae and detritus, or dead particulate organic material. In turn, the water turbidity decreases, meaning it’s less cloudy. Sunlight can then reach the bottom where seagrass grows.
Osborne did not respond to a request for comment.
Others would like to see manatees return to the endangered species list.
“It adds more protection and more funding available for us to continue to protect the species,” Lippincott said.
The West Indian manatee, native to the coastal waters of the southern Atlantic Ocean, was downlisted from endangered to threatened by the FWS in 2017. Cora Berchem, director of multimedia and manatee research associate for Save the Manatee Club, said she believes that decision was premature.
Species listed as endangered receive special protection under the Endangered Species Act. Berchem said one of those protections for manatees makes it harder for people to build along Florida’s waterways.
Building along a waterway requires a permit from the Florida Department of Environmental Protection. The permit is more difficult to obtain if the desired location is near an endangered species.
Berchem and Save the Manatee Club want manatees to be listed as endangered so they can receive this and other protections.
“We think they deserve the highest protection they can get, which means they should be listed as an endangered species,” Berchem said.
She added that everyone should care about helping manatees because they provide several services.
Manatees eat a lot of vegetation, which keeps the waterways clear for boaters. They also help ecosystems by cropping the seagrass, helping it grow back better.
The economy even gets a boost from manatees. When people travel to Florida to see manatees, they spend money at hotels, restaurants and on other services, all feeding back into the economy.
Lippincott summed it up in one sentence.
“If you care about animals, you should care about manatees,” Lippincott said.
