Are Manatees Endangered? Status and Threats in Florida

What is the manatee’s conservation status?

Two systems are used. The IUCN Red List is the global scientific assessment of extinction risk, while the U.S. Endangered Species Act (ESA) is the law that protects species inside the United States. The West Indian manatee has two subspecies, and their status differs:

The IUCN estimates that there are about 8,200–11,300 mature West Indian manatees in total. Most of them are Florida manatees, about 6,100–7,200 adults, while the Antillean subspecies has only around 2,100 mature animals and is declining. The IUCN also expects the species as a whole to keep losing numbers over the coming decades, because each generation of manatees lasts about 20 years and losses take a long time to make up.

From endangered to threatened: the 2017 downlisting

The Florida manatee was among the first animals listed as endangered in the United States, in 1967, and the Antillean manatee was added in 1970. At that time, only several hundred manatees were thought to remain in Florida, although no reliable counts existed, and boat traffic and coastal development were growing quickly.

Decades of protection followed. Florida created slow-speed boating zones and manatee sanctuaries and protected important warm-water sites. Counts rose: a statewide aerial survey in 2017 found 6,620 manatees, the highest number since the surveys began in 1991, and a 2015–2016 estimate put the population at about 8,800.

In 2017, citing that recovery, the U.S. Fish and Wildlife Service reclassified the species as threatened. The decision was controversial. Conservation groups argued it ignored the large die-offs of 2010 and 2013, record boat deaths and the manatees’ growing dependence on power plants for winter warmth. The agency stressed that all existing federal protections stayed in place.

The 2021 die-off and the loss of seagrass

Within a few years the critics’ worries seemed justified. In late 2020 manatees on Florida’s Atlantic coast began dying in unusual numbers, and in 2021 about 1,100 Florida manatees were reported dead, nearly double the average and the highest toll ever recorded.

Most of them starved. Years of algal blooms, fed by nutrient pollution from septic systems, fertilizer, stormwater and wastewater, had clouded the water of the Indian River Lagoon and killed much of its seagrass, the manatees’ main food in a lagoon where hundreds spend the winter. In an unprecedented step, wildlife agencies trialed feeding lettuce to manatees at a power plant outflow in the winters of 2021–2022 and 2022–2023, while warning the public never to feed manatees themselves.

Deaths fell to about 800 in 2022 and to around 555 in 2023 and 565 in 2024, and seagrass in parts of the lagoon began to recover. In March 2025, Florida wildlife officials announced that this unusual mortality event had officially ended.

What are the main threats to manatees?

• Boat strikes: Collisions with boats are the leading known human cause of death in Florida, killing a then-record 137 manatees in 2019. Manatees can hear boats but are slow and often have nowhere to escape in shallow water.
• Seagrass loss and pollution: Algal blooms and murky water kill the seagrass meadows manatees depend on, as the 2021 die-off showed.
• Red tide: Blooms of the toxic alga Karenia brevis poison manatees through the water, the air and the plants they eat. Red tide killed a record 276 manatees in 2013.
• Cold stress: Manatees cannot survive long in water below about 20 °C (68 °F). A severe cold spell in 2010 killed about 280 of them.
• Loss of warm-water refuges: Natural springs are losing flow because of groundwater pumping, and many manatees now depend on power plants that may close or change, as described in Where do manatees go in winter?
• Entanglement and debris: Fishing line, crab trap ropes and swallowed plastic injure and kill manatees every year, and flood gates and canal locks can trap them.
• Hunting and fishing nets: Outside the United States, Antillean manatees are still poached for meat in some areas and drown in gillnets. Their small, scattered populations also have low genetic diversity, which makes them more vulnerable.

How many manatees are left?

A statewide study for 2021–2022, carried out by the Florida Fish and Wildlife Conservation Commission and the U.S. Geological Survey, estimated about 9,800 Florida manatees, within a likely range of 8,350–11,730. That is more than in 2015–2016, but it was measured just as the die-off began, so scientists warn against reading too much into a single estimate.

Antillean manatees are much harder to count because they live in murky water across more than a dozen countries. Many local populations number only in the dozens or low hundreds, and manatees have already vanished from most of the Lesser Antilles.

What is being done to protect manatees?

In the United States, manatees are protected by the Endangered Species Act, the Marine Mammal Protection Act of 1972 and the Florida Manatee Sanctuary Act of 1978. Florida has many slow-speed and no-entry zones for boats, and the Crystal River National Wildlife Refuge was created in 1983 specifically to protect manatees in winter. In September 2024 the U.S. Fish and Wildlife Service proposed expanding the manatee’s critical habitat in Florida to nearly 2 million acres and adding new critical habitat in Puerto Rico.

A network of zoos, aquariums and state agencies rescues sick, injured and orphaned manatees, treats them and returns them to the wild. Florida is also funding seagrass restoration and projects to cut nutrient pollution in the Indian River Lagoon and other waters.

Visitors can help by obeying boating speed zones, wearing polarized sunglasses to spot manatees, keeping fishing line and trash out of the water, and never feeding, touching or giving water to manatees. In Florida, injured, orphaned or dead manatees should be reported to the Florida Fish and Wildlife Conservation Commission’s Wildlife Alert Hotline at 888-404-3922. Florida’s other marine wildlife faces similar pressures, as explained in What is happening to Florida’s coral reefs?