The manatee, often nicknamed the “sea cow,” is a large, slow-moving aquatic mammal primarily found in the warm freshwater and brackish environments of the southeastern United States, particularly Florida. Recent, unprecedented mortality events have raised serious questions about the long-term survival of this species.
Current Conservation Status
The West Indian manatee’s federal status was changed from endangered to “Threatened” in 2017 under the U.S. Endangered Species Act (ESA). This downlisting was based on evidence of significant population growth and improved habitat conditions. A threatened designation means the species is no longer considered in immediate danger of extinction, but is likely to become so in the foreseeable future without continued protection.
Florida also provides state-level protection through the Florida Manatee Sanctuary Act, which regulates watercraft speed and prohibits harassment. However, the recent increase in deaths has led to calls for re-evaluating this status.
Primary Causes of Decline and Mortality
One long-standing danger to manatees is collision with watercraft, which remains the leading cause of human-related manatee deaths. Manatees are slow-moving and spend time just below the surface, making them susceptible to strikes from boat hulls and propellers in shallow coastal waters. Despite regulatory measures like slow-speed zones, these injuries often lead to severe internal trauma or fatal cuts.
A much more recent threat has been the widespread loss of their primary food source, seagrass, causing mass starvation. Since late 2020, an Unusual Mortality Event (UME) has been declared, centered in the Indian River Lagoon, where over a thousand manatees died in 2021 alone. This crisis resulted from nutrient pollution, such as nitrogen and phosphorus runoff, fueling harmful algal blooms. These intense blooms cloud the water, blocking sunlight and causing a catastrophic die-off of seagrass beds.
Manatees relying on these areas became severely emaciated. The lack of food also compounds the risk of cold stress, which occurs when water temperatures drop below 68°F (20°C).
Habitat Protection and Recovery Efforts
Regulatory efforts focus on managing human activity in manatee habitats, primarily through the enforcement of manatee protection zones. These zones mandate specific boat speeds, such as idle or slow speeds, in areas known for high manatee congregation.
A significant portion of recovery efforts is now directed toward habitat restoration and water quality improvement. The state has committed funding toward projects aimed at reducing the nutrient pollution that decimated the Indian River Lagoon. These efforts include upgrading wastewater treatment facilities and converting septic systems to sewer lines to limit nutrient runoff into sensitive waterways.
Active intervention has also become a temporary necessity in response to the starvation crisis. Wildlife agencies conducted a supplemental feeding trial during the winters of 2021-2023, providing lettuce to starving manatees at a warm-water power plant discharge site. While this temporary action helped reduce immediate mortalities, long-term success relies on the restoration of natural seagrass meadows. Ongoing rescue and rehabilitation programs continue to be expanded to treat and release emaciated or injured manatees.