Manatees, often called “sea cows,” are gentle, slow-moving marine mammals that live in warm coastal waters and rivers. Known for their calm nature and friendly curiosity, manatees play a vital role in aquatic ecosystems by grazing on seagrasses and other aquatic plants. However, despite their peaceful existence, manatees are facing increasing threats that are putting their survival at risk.
In this article, we will explore the main reasons why manatee populations are under threat, the challenges they face in the wild, and what can be done to protect these iconic creatures.
Who Are the Manatees?
There are three species of manatees:
- West Indian Manatee (Trichechus manatus) – found in the Caribbean, Gulf of Mexico, and southeastern United States (especially Florida).
- Amazonian Manatee (Trichechus inunguis) – lives in freshwater rivers in the Amazon Basin.
- West African Manatee (Trichechus senegalensis) – found along the western coast of Africa.
All three species are considered vulnerable or threatened, with certain populations experiencing significant declines. The West Indian manatee, particularly the Florida subspecies, has received the most conservation attention due to heavy human interaction in Florida’s waterways.
1. Boat Strikes: A Leading Cause of Death
One of the most well-known and deadly threats to manatees is collisions with boats. Manatees often swim near the surface of the water, making them vulnerable to fast-moving watercraft. Because they are slow swimmers and frequently rest just below the surface, they often don’t have time to move out of the way.
Propellers and hulls can cause:
- Deep cuts and gashes
- Broken bones and internal injuries
- Fatal wounds that lead to death
Many living manatees show scars from past encounters with boats, and some are permanently injured or disabled. In areas like Florida, where boating is common, this has become a major source of mortality.
2. Loss of Habitat
Manatees rely heavily on warm, shallow coastal waters, rivers, and estuaries. They need access to both freshwater and saltwater habitats, as well as plenty of aquatic vegetation to eat. Unfortunately, these habitats are disappearing due to human development.
Key habitat threats include:
- Coastal development: construction of homes, hotels, and marinas destroys seagrass beds and displaces manatees.
- Water pollution: runoff from agriculture, industry, and cities leads to poor water quality and algal blooms.
- Wetland drainage: many freshwater wetlands that manatees depend on have been altered or eliminated.
Habitat loss means manatees have fewer places to feed, rest, and reproduce. As suitable environments shrink, they are pushed into riskier or more crowded areas.
3. Pollution and Red Tides
Water pollution doesn’t just affect the land—it also poses a serious threat to marine animals like manatees. Agricultural fertilizers, sewage, and chemicals can flow into rivers and oceans, encouraging harmful algae to grow.
One of the most dangerous results is red tide, a type of toxic algal bloom caused by a microorganism called Karenia brevis. Red tide can:
- Poison the water manatees breathe
- Kill the seagrasses they eat
- Directly cause manatee deaths through inhalation of toxins
Florida has experienced increasingly frequent and severe red tide outbreaks. During especially bad years, hundreds of manatees have died from these toxic blooms.
4. Cold Stress Syndrome
Manatees are tropical animals. They cannot survive in cold water for long periods. When water temperatures drop below 68°F (20°C), manatees may develop cold stress syndrome, which causes:
- Skin lesions
- Immune system problems
- Fatigue
- Infections
Cold stress can be fatal if the manatee doesn’t find warm water soon. Natural warm springs used to offer shelter during cold months, but many have been altered or closed off by development.
Today, manatees often rely on warm-water outflows from power plants, which are not natural and may not always be available in the future. If these artificial sources are removed, many manatees could struggle to survive winter.
5. Starvation and Seagrass Loss
In recent years, a new and serious threat has emerged: manatee starvation. This is especially true in Florida’s Indian River Lagoon, where massive losses of seagrass beds have occurred.
Seagrasses are the manatee’s primary food source. Pollution and algal blooms block sunlight from reaching underwater grasses, killing them off. Without enough seagrass to eat, manatees become malnourished and weak. In some regions, the food shortage has led to record-breaking numbers of manatee deaths.
In 2021 and 2022, more than 1,100 manatees died in Florida alone, many from starvation. This crisis continues today, with emergency feeding programs set up by wildlife officials to try to save starving animals.
6. Fishing Gear and Plastic Waste
Another threat to manatees is entanglement in fishing gear and other debris. Manatees can become caught in:
- Fishing lines and nets
- Crab trap ropes
- Plastic bands and bags
Entanglement can cause wounds, restrict movement, and sometimes drown manatees if they can’t reach the surface to breathe. Ingested plastic can also block their digestive systems, leading to death.
As plastic pollution continues to rise, more manatees are being harmed by garbage left in the water.
7. Climate Change
Like many animals, manatees are affected by the changing climate. Rising sea levels, stronger storms, and temperature changes all impact their habitat. As oceans warm and weather becomes more unpredictable, food sources like seagrasses are also affected.
Climate change also increases the frequency of red tides and makes cold snaps more dangerous. Since manatees are already struggling, climate change may worsen every other threat they face.
8. Human Disturbance and Harassment
Even well-meaning people can unintentionally harm manatees. In places where manatees are common, some tourists try to touch, chase, or ride them. These activities can cause stress and injury to manatees and disturb their natural behavior.
Crowded boating areas or tourism hotspots can make it hard for manatees to rest, feed, or care for their young. While regulations exist in places like Florida to protect manatees from harassment, enforcement can be difficult.
Are Manatees Endangered?
Manatees are not all classified the same way:
- The West Indian manatee (including Florida’s manatees) is currently listed as Threatened under the U.S. Endangered Species Act.
- The Amazonian and West African manatees are listed as Vulnerable by the International Union for Conservation of Nature (IUCN).
Some conservationists argue that Florida manatees should be re-listed as endangered, especially in light of recent starvation events and habitat collapse.
What Is Being Done to Help?
Several efforts are in place to protect manatees and support population recovery:
- Speed zones and boating laws reduce the risk of boat strikes.
- Protected areas help conserve manatee habitats.
- Rescue and rehabilitation programs treat sick or injured manatees and release them back into the wild.
- Public education campaigns encourage people to avoid disturbing or harming manatees.
- Feeding programs have been used in emergencies to help starving manatees survive.
Long-term solutions involve restoring habitats, improving water quality, and reducing pollution and climate impacts.
How You Can Help
You can also take action to help manatees:
- Respect speed limits when boating in manatee zones.
- Avoid disturbing manatees in the wild. Never touch or feed them.
- Reduce plastic use to cut down on ocean waste.
- Support conservation groups working to protect marine life.
- Report injured or distressed manatees to local wildlife authorities.
By taking small steps, you can make a big difference in ensuring that these gentle animals have a future.
Manatees are strong survivors, but they cannot fight these threats alone. With human help and global awareness, we can protect manatees and the waters they call home.