ManaTeach
Manatees have a lot to teach us! These gentle creatures are curious and peaceful, but their health depends on a critical balance of safe, temperate waterways and plentiful food sources. The lives of manatees in Florida and beyond are in danger from human and environmental threats that we are working to improve through education and advocacy.
Why do wild manatees come to Moore's Creek in the Indian River Lagoon?
The manatee, a marine mammal, needs warmth when surrounding water temperatures drop below 68° Fahrenheit. Despite their blubbery-looking bodies, the manatee, or sea cow, has only an inch or so of body fat and a slow metabolism, making it hard for them to stay warm.
At one time, the Henry D. King power plant, run by the Fort Pierce Utilities Authority, was just across the street from the Center here on Moore’s Creek. The plant used water from the Indian River Lagoon to cool its pipes. The water leaving the plant was 7 degrees warmer than the surrounding water, so manatees stayed close to the Center to enjoy the warmer temperature. As the weather warmed, manatees still traveled in and out of Moore’s Creek for its fresh waters, making the creek part of the manatees’ migration pattern.
Although the power plant and its warm water source is gone, manatees still visit the creek, a passive thermal basin and secluded resting spot. Manatees drink the fresh water found in Moore’s Creek. Just like us, they must drink fresh water to survive. Manatees arrive here to rest, drink water, and “park” their babies. The creek serves as a little manatee nursery where babies stay while the mother manatees run their errands of drinking water and eating grass further up the creek.
The restorative waters of Moore’s Creek also serve as a release site for rehabilitated manatees ready to return to the wild, so it’s especially important to keep our creek and lagoon waters healthy.
Manatee Watching
Did you know Manatee Center volunteers spot hundreds manatees a year?
If you spot one on a visit, be sure to let a member of the Manatee Center team know, or if after hours, email your sighting to us.
27 Years of Manatees in Moore’s Creek
The Manatee Center has collected weekly data on the number of manatees visiting our creek spanning 27 years. We record a weekly number count based on sightings and collect related data on water conditions.
View historical and current manatee count numbers annually and monthly.
Get to Know Your Manatees
Common Name: Florida Manatee
Scientific Name: Trichechus manatus latirostris
Population Status: Endangered, but increasing with effort
Estimated Population: The Florida Fish and Wildlife Conservation Commission states there are between 7,000 to 11,000 manatees in Florida as of 2024
Range: Rivers, springs, and shallow coastal waters of Florida and adjacent states
Florida Manatees are a subspecies of the West Indian Manatee (Trichechus Manatus). The Florida manatee lives in brackish, salt, and freshwater coastal areas around Florida. It is a plant-eating mammal (herbivore) that comes to the surface to breathe air every three to five minutes while grazing. While resting (sometimes up to 12 hours), manatees can hold their breath much longer, but must resurface for air every 20 minutes.
Mature Manatees
The adult manatee weighs around 1,000 pounds and grows to about 10 feet long. Like all mammals, it has hair on its body, nurses its young, and is warm-blooded. Manatees can live to be about 50 to 60 years old.
Young Manatees
Manatees reach sexual maturity at 4–7 years, with females giving birth every two to three years. The gestation period is 13 months, and usually one calf is born, although twin births are known to occur. Newborn calves weigh between 60 to 80 pounds and stay with their mothers for up to two and a half years.
Manatees in the Indian River Lagoon
The Indian River Lagoon stretches for 156 miles along Florida’s east central coast, supporting more than 4,400 species of plants and animals found in the lagoon watershed. Recent algae blooms, caused by excess nitrogen and phosphorus in the water, are blamed for a 90 percent seagrass loss and the death of more than 1,100 manatees (12 percent of our local population) since 2021. Avoiding nutrient pollution and restoring the sea grass biomass is a priority to protect further loss of manatees and other species.
Threats to Manatees
Manatees have no natural predators outside of careless humans. However, the manatee’s low reproductive rate, combined with loss of habitat and high death rates, threaten their survival. Manatee and human interactions have increased in recent years as our activities take place in and around manatee habitats.
Human impacts have diminished the extent and quality of the manatee’s once pristine habitat and continue to do so at an alarming rate:
- Extensive development of coastal lands for housing, agricultural, and commercial purposes which affect important manatee feeding sites
- Irresponsible recreational and commercial boating practices
- Poor water quality from civic, commercial, industrial, or agricultural run-off
- Alteration of wetlands, rivers, streams, and other changes to fresh-water flow
A Critical Cycle: Manatees, Seagrass, and Habitat Health
Manatees are considered a keystone species, meaning they are good indicators of the health of our aquatic ecosystems. When manatees are healthy, the ecosystem is healthy, and when they are unhealthy, it may indicate an environmental issue.
Manatees may affect habitats they feed in, especially seagrass beds. Studies find that manatees normally feed on the edges of sparse seagrass beds and return to formerly grazed areas to feed from year to year. Manatees’ role in the health and regeneration of seagrass beds in the Indian River Lagoon is complex. While manatees feed on seagrass and can consume large quantities, their impact depends on the health of the ecosystem.
Positive Contributions of Manatees to their Habitat:
Grazing Control: As manatees graze, they trim seagrasses, keeping it healthy for continuous new growth and life. Manatees also spread seeds along the lagoon, helping to build up underwater plant life. They can also prevent certain seagrass species from becoming overly dominant, promoting biodiversity within seagrass beds. This can create a more balanced and resilient ecosystem, benefiting the overall health of the lagoon.
Negative Impacts of Manatees on their Habitat:
Overgrazing: In areas where seagrass beds are already stressed or limited, overgrazing by manatees can hinder seagrass regeneration. The Indian River Lagoon has been experiencing significant seagrass loss due to water quality issues like nutrient pollution and algal blooms, so intense grazing pressure by manatees could potentially exacerbate the issue.
Currently the biggest threats to seagrass health in the Indian River Lagoon come from water quality issues, not directly from manatees. Balancing manatee populations and improving lagoon water quality are both critical for seagrass recovery.
Learn more about Florida's Amazing Manatees!
Produced in 2013 with John Nelson of Florida’s Wild Outdoors, this video highlights the Manatee Center’s origin, made possible by the Henry King Power Plant. It shares the ongoing story of how manatees are drawn to the warm waters of Moore’s Creek, where our Center continues to inspire education and conservation efforts.