Manatees are permanent residents of the Gulf of Mexico, with their population centered overwhelmingly along the coast of Florida. These large, gentle marine mammals inhabit the shallow, warm coastal waters, estuaries, and rivers of the Gulf year-round. While the majority remains near the Florida peninsula, some individuals undertake seasonal migrations. These migrations extend their range occasionally into the northern and western Gulf states during the warmest months.
Identifying the Gulf Manatee Population
The manatees found in the Gulf of Mexico are the Florida manatee, a distinct population segment of the West Indian manatee (Trichechus manatus). This subspecies (Trichechus manatus latirostris) is native to the southeastern United States. They are aquatic herbivores, typically growing to about 10 feet in length and weighing around 1,000 pounds, though some individuals can exceed 13 feet and 3,500 pounds.
Their body shape is torpedo-like, ending in a large, paddle-shaped tail used for propulsion, and they possess two fore-limb flippers. As the only herbivorous marine mammals in the U.S., they spend a large portion of their day grazing on submerged aquatic vegetation. This Gulf population is genetically distinct from the Antillean manatee, the other subspecies found further south in the Caribbean.
Geographic Range and Key Habitats
The primary habitat for the Gulf manatee population is the West Coast of the Florida peninsula, extending from the Panhandle down to the Everglades. Manatees thrive in diverse environments, including shallow coastal bays, brackish estuaries, and freshwater rivers, moving freely between salt and fresh water. Their preferred foraging habitats are areas with extensive beds of seagrass and other aquatic plants.
During the warmer summer and early fall months, the manatees’ range expands considerably. Sightings have occurred in peripheral Gulf states, including Alabama, Mississippi, Louisiana, and Texas. These sightings are almost always of seasonal migrants that follow warm currents and are not indicative of established, resident populations outside of Florida. These individuals typically begin their return migration to Florida waters in October as temperatures start to cool.
The Critical Role of Warm Water Refuges
Manatee distribution is dictated by their low metabolic rate and sensitivity to cold water. Manatees are cold-intolerant and cannot survive prolonged exposure to temperatures below 68°F (20°C). When Gulf water temperatures drop, manatees must seek thermal refuges to avoid cold stress, which can be fatal.
These warm water sites are found almost exclusively in Florida and fall into two categories: natural springs and artificial discharges. Natural freshwater springs, such as those feeding Crystal River or Kings Bay, maintain a constant temperature of around 72°F year-round, serving as historical winter havens. The other major source is warm water effluent discharged from coastal power plants, created as a byproduct of cooling equipment.
An estimated 60% to 75% of the population relies on these power plant outfalls for winter survival. As power plants are retired, the loss of these artificial sites could lead to significant cold-related mortalities due to the manatees’ ingrained site-fidelity patterns. Managers are working to secure a reliable network of thermal refuges, including restoring natural springs, to mitigate the impact of these industrial closures.
Conservation Concerns in Gulf Waters
Manatees face multiple threats, with recreational and commercial boat traffic being the most immediate danger. Manatees are slow-moving and often swim just below the surface, making them highly susceptible to collisions with fast-moving watercraft. Research indicates that nearly 96% of adult Florida manatees bear scars from boat strikes, which can lead to severe injury, infection, or death.
Habitat degradation is another threat, specifically the loss of seagrass meadows, the manatee’s primary food source. Runoff and pollution contribute to poor water quality, causing massive seagrass die-offs and leading to starvation-related Unusual Mortality Events. The Gulf is also prone to harmful algal blooms, such as Red Tide (Karenia brevis), which produces a neurotoxin. Manatees can ingest this toxin by consuming contaminated seagrass, causing them to suffer seizures and potentially drown.
While the West Indian manatee’s conservation status was recently downlisted to Threatened, ongoing human-related impacts continue to pose a risk to the health of the Gulf population.