Why Do Manatees Like Warm Water?

Posted on · Posted in Blog
Posted by
Manatees like warm water because they require refuges to survive the cold of winter. Despite a weight of 1,000 pounds or more, manatees lack a continuous layer of blubber (like whales have) to keep them warm. The animals have relatively low body fat and a lower metabolic rate compared to other aquatic animals and cannot tolerate cold for an extended period of time. When the water temperature reaches 68 degrees Fahrenheit (20oC) or below, manatees usually seek out warm waters and are often huddled together in warm-water springs and power plant outflows.

How are manatees affected by cold water?

When subjected to cold for a longer period of time, manatees are not able to produce enough metabolic heat to compensate for the heat they lose to the environment. As a result, manatee mortality increases during unusually cold winter months due to cold stress syndrome. The cold stress syndrome is characterized by a number of physiological issues and disorders instigated by cold water and extremely low temperatures. For instance, metabolism slows down in manatees, resulting in diminished appetite, digestion problems and weight loss. That is why manatees exposed to cold water show signs of starvation, such as a generally sunken appearance and a thinned blubber layer. When exposed to cold for a long period of time, the immunity of the animals also drops significantly, making them susceptible to environmental toxins and a variety of diseases, including intestinal infections and pneumonia.

Warm-water options for manatees

In the past, the sea cows relied on warm water springs to survive the cold of winter. But a number of such springs have been altered by construction, blocked by dams, used intensively for recreation, degraded by overuse or face declining flows due to increased underground water pumping for agricultural and human consumption. Therefore, manatees are always seeking alternatives to the natural warm-water springs and continue to find the mechanically heated waters of private and municipal power plants necessary for surviving the winters.

The power plants continuously pump out warm water to the surrounding ponds or canals. Presently, about two-thirds of all Florida manatees rely on power plant outflows to survive tough winter days. But since the projected life of the majority of the power plants they currently rely on is only 35-40 years, it is unclear whether the natural warm-water springs will be adequate for the current numbers of manatees. And since manatees usually return to the same warm-water spots every winter and could return to inactive power plants in the future, only to die of cold in the unheated waters, there is a lot of risk associated with power plants going offline. So alternative refuges that are independent of power plants are necessary for the survival of manatees.

Warm-Water Gathering Areas

In winter, Florida manatees usually gather around natural springs, including Homosassa and Crystal Rivers on the west coast of Florida and Blue Spring on Florida’s east coast. These springs maintain a constant water temperature — averaging 72 degrees Fahrenheit — throughout the year. So when the water in surrounding waterways becomes colder, manatees tend to move into these springs to escape the cold. The U.S. Fish & Wildlife Service closes off access to springs such as the Three Sisters Springs during winter because of the hundreds of manatees that flock to the serene 72-degree waters there.

Cold stress is fatal for the animals and even those that find refuge in the springs can lose a lot of weight in winter. So because these springs are popular destinations for canoeists, kayakers and snorkelers who want to swim or boat with these gentle animals, it is necessary to close them off during the winter to protect the manatees. But as the warm-water refuges face the risk of disappearing — with spring flows diminishing due to increased usage by Florida’s burgeoning population and aging power plants going offline — there is a need to improve spring flows and create warm-water alternatives for manatees. Want more information on manatees and manatee tours, visit the “Captain Mike’s Swimming With The Manatees” site.

Swimming with the Manatees boasts the best water adventure in Crystal River, Florida with lots of things to do for you and your family. For more information, contact us online, or call us at (352) 571-1888.

You might also like to read about