Manatees, often called “sea cows,” are large, slow-moving aquatic mammals primarily found in the shallow, warm waters of Florida and the southeastern United States. The Florida manatee is a subspecies of the West Indian manatee. While the species is no longer classified as Endangered, the U.S. Fish and Wildlife Service (USFWS) currently lists the West Indian manatee as Threatened, meaning it remains under federal protection. This designation reflects a complex recovery story where a growing population faces increasingly severe modern threats.
Historical Listing and Downlisting
The manatee population was once in severe decline, leading to its original protection under the Endangered Species Act (ESA) in 1973. At the time of the initial listing, estimates suggested there were only around 800 to 1,000 Florida manatees remaining.
The USFWS officially downlisted the West Indian manatee from Endangered to Threatened in 2017. This decision was based on a significant increase in the population, which had grown to over 6,000 individuals in Florida at the time. The agency determined that the species had met the established recovery criteria laid out in its recovery plan.
Defining the Current Conservation Status
Under the ESA, the distinction between Endangered and Threatened carries a specific legal meaning. An Endangered species is defined as one that is currently in danger of extinction throughout all or a significant portion of its range. In contrast, a Threatened species is one that is likely to become an Endangered species in the foreseeable future.
The manatee’s current designation as Threatened confirms that the species is still vulnerable and requires continued federal protection and monitoring. While the immediate threat of extinction has lessened, the population remains susceptible to future declines without ongoing intervention. The USFWS has recently proposed to replace the current single listing by listing the Florida manatee specifically as Threatened and the Antillean manatee subspecies as Endangered.
Persistent Dangers to Manatee Survival
Despite the population recovery that led to the downlisting, manatees face multiple ongoing threats that prevent a full recovery or delisting. Watercraft collisions are consistently the leading cause of human-related manatee deaths in Florida. Manatees are slow-moving and often feed in shallow coastal areas, making them susceptible to fatal strikes or propeller wounds from boats.
Manatees rely on warm-water habitats during the winter months because they cannot survive prolonged exposure to water colder than about 68 degrees Fahrenheit. Historically, manatees congregated near natural springs. They have also adapted to gathering in the discharge canals of power plants, which provide artificial warm-water refuges. The eventual closure of these aging power plants poses a threat, as it eliminates a significant portion of their winter survival habitat.
Environmental hazards also contribute to population vulnerability, including harmful algal blooms like red tide, which can poison manatees upon ingestion or inhalation. Large-scale Unusual Mortality Events have occurred, such as the event beginning in 2020-2021. During this event, record numbers of manatees died primarily from starvation due to the widespread loss of seagrass. Nutrient pollution from human development fuels this loss, reducing the manatees’ primary food source and leading to chronic malnutrition.
Conservation Measures and Future Outlook
Conservation efforts focus on mitigating human-related mortality and protecting habitat to ensure the manatee’s long-term future. Agencies enforce boating speed zones, particularly in areas known for manatee congregation or travel, to reduce the frequency of fatal watercraft collisions.
Several measures are employed to support the manatee population:
- Agencies enforce boating speed zones to reduce fatal watercraft collisions.
- Habitat restoration projects improve water quality and actively plant seagrass to restore their food source.
- Rescue and rehabilitation programs retrieve injured, sick, or cold-stressed manatees for veterinary care before release.
- Ongoing population monitoring tracks manatee numbers and mortality causes to inform management decisions.
The outlook for the manatee depends on the continuation of these proactive measures, especially the restoration of their natural warm-water refuges and food supply, for the species to move toward eventual delisting.