Big Bend Power Station in Apollo Beach delivered reliable electricity to the community for 16 years before the commercial operation of Big Bend Unit 4 in 1986. That year, people started seeing manatees in large numbers in the power station's discharge canal, where saltwater – taken from Tampa Bay to cool Unit 4 – flowed, clean and warm, back to the bay. When Tampa Bay reached 68 degrees or colder, the mammals would seek out this new refuge. The Manatee Viewing Center was soon born. Today, Big Bend's discharge canal is a state and federally designated manatee sanctuary that provides critical protection from the cold for these unique, gentle animals.
Inside the MVC's environmental education building, colorful displays immerse you in the world of the manatee and its habitat. Others show how Big Bend Power Station generates electricity for the community in an environmentally responsible way. See some of the power station's beneficially reusable byproducts. Inspect actual manatee bones and piece together puzzles. And before feeling the blast of a hurricane in the center's simulator, find out more about hurricanes and how Tampa Electric prepares for and responds to major storms.
Outside, stroll among award-winning butterfly gardens and Florida-friendly landscaping and see solar panels – the largest installation among Tampa Electric's photovoltaic arrays in the community. Track real-time output from the array inside the education building. You also can see a variety of native and coastal plant life as you stroll along the center's tidal walk. Catch a glimpse of animals in the wild that make the center's habitat their home.
At the southwest corner of the MVC's parking lot, across from the entrance for vehicles, your journey into nature continues through three habitats on a 0.8-mile trail, which features a wide variety of vibrant plant life that you can see up close. The trail is part of a larger plan underway to transform a former palm tree farm south of the MVC into a new conservation and technology park, a partnership between the Florida Aquarium, the Florida Fish and Wildlife Conservation Commission and Tampa Electric that will become a showcase of environmental stewardship. When completed, visitors will have another free environmental resource to explore, one that will feature an energy technology center, a center for conservation, a fish hatchery, an educational facility, catch and release fishing programs, waterways for kayaking and more.
All about manatees
The West Indian manatee (Trichechus manatus) is believed to have evolved from a four-footed, plant-eating land mammal more than 60 million years ago. Its closest modern land relative is the elephant, hyrax and aardvark. The West Indian manatee belongs to the order Sirenia, which also includes the West African manatee, Amazonian manatee, the Pacific located dugong and the extinct Steller's sea cow. The Florida manatee (Trichechus manatus latirostris) is a subspecies of the West Indian manatee.
Fossils of the present day manatee, as old as two-million years, and fossil ancestors of the dugong, as old as 45-million years, are found in Florida. These fossils are often found on dry land, in areas that were once shallow bays and estuaries, when sea levels were higher.
Manatee: mammal or myth?
Legend has it that sailors who caught the first glimpse of the manatee mistook it for the Greek mythical "siren," a temptress who lured sailors to deadly reefs, rocks and treacherous waters. Christopher Columbus provided us with the first reference to the manatee in his logbooks from 1493.
Florida's waters host a variety of aquatic life. Perhaps one of the most mysterious is the Florida manatee. The Florida manatee is a large, plant-eating, warm-blooded marine animal found in Florida's shallow coastal waters, rivers and springs. At first glance, the behavior of the manatee appears simple and unstructured, but the behavior is specifically adapted to Florida's sub-tropical climate.
The average adult manatee, or "sea cow," is about 10 feet long and weighs approximately 1,200 pounds. It has a large, seal-like body that tapers to a large, spatula-shaped flat tail known as the "fluke." The two forelimbs or flippers of the manatee are paddle-shaped with up to four nails at the tip of each flipper.
The finely wrinkled skin of the adult manatee is gray or gray-brown. The hair is thin and far apart, except for the stiff, brush-like facial whiskers, which help the manatee forage for food.
Sight & sound
The manatee's eyes are small and are protected by inner membranes, which can be drawn across the eyeballs. Research indicates that the manatee can differentiate colors, but that its depth perception is limited. The manatee can hear well, even though its ears contain no external lobes. Its nostrils, located on the snout, are tightly closed by flaps of skin when the manatee is underwater and opened when it surfaces to breath.
Manatees are known as generalist herbivores. They will eat anything green! They can eat up to 15 percent of the body weight in aquatic vegetation each day. Manatees eat submerged and floating vegetation.
The manatee is generally a slow moving creature and is content to simply glide along, moving forward by using its tail and steering by using both its tail and flippers. Manatees can, however, swim up to 20 mph. Manatees use their flippers to help them swim and to hold vegetation while feeding. For its large size, the manatee is quite nimble, performing such underwater feats as upside-down swimming, head and tail stands and barrel rolls.
The manatee rests from two to 12 hours per day. It remains motionless with its eyes closed, either lying on the bottom or suspended near the surface. Air compression in the lungs allows the manatee to sink without exhaling or using its tail or flippers. While resting, the manatee may rise to the surface to breathe every seven to 20 minutes. When active, they breathe every three to five minutes.
Manatees reach sexual maturity in two to five years. Even though female manatees form very strong bonds with their calves, they do not form permanent associations with males after mating. After a gestation period of approximately 13 months, female manatees, called cows, bear one calf. Twins are a rare occurrence. During the first two years of its life, a calf remains very close to its mother's side for nourishment and protection. Cows give birth every two-and-a-half years, so it is quite possible to see a mother with a larger, older calf and a new, smaller calf at the same time.
At birth, calves are almost black in color, three feet long and weigh between 60 and 80 pounds. The calf nurses from its mother's teats, located at the base of each flipper. During feeding, the mother can sometimes be seen rolling on her side or back to help the calf suckle. While calves are sometimes seen mouthing vegetation soon after birth, their long weaning period of up to two years allows time for the digestive tract to fully develop. This is important for animals who eat vegetation containing cellulose, so they may fully absorb nutrients.
Population and distribution
Manatees are commonly found in coastal rivers, estuaries and canals. They move freely within salt, brackish and fresh water habitats, often in water less than six-feet deep, where underwater vegetation is most abundant. Manatees are a migratory species and Tampa Bay is home to more than 600 manatees, and scientists estimate there are 5,000 in Florida's waters.
The tidal walk
A featured part of the Great Florida Birding Trail, the Manatee Viewing Center's tidal walk offers more than just vibrant birdlife. On this 900-foot, ADA-compliant walkway from the center to the Tampa Bay Estuary, you can identify a wide selection of native coastal plants and trees as well as a wide variety of animal life. At the end of the walkway, you can view manatees in Big Bend Power Station's clean, warm water discharge canal. For illustrations of more life along the tidal walk, download and print the Tidal Walkway Nature Trail guide.
Nickerbean (Caesalpinia bonduc): Notice the densely prickled brown seed pods on this aggressive, sprawling shrub-like vine. Nickerbean pods open to reveal lustrous gray seeds. You must handle the leaves, stems and seed pods with care because of the many spines and sharp edges! Enjoy the lustrous shine of the seeds of the Nickerbean, a thorny tropical plant that some cultures believe holds various healing powers. Found in coastal areas, the plant often grows quickly, sometimes reaching lengths of up to 20 feet!
Cabbage palm (Sabal palmetto): Located on the opposite side of the walkway, the cabbage palm is the state tree of Florida. Its trunk, which remains fairly constant in diameter throughout its life, can be partially or fully covered with old leaf bases, called boots. These boots will eventually drop off, leaving a smooth gray trunk. Many parts of this tree were eaten or used in other ways by Native Americans and early settlers; the heart and berries were eaten both raw and cooked, the boots were used as boot jacks to remove shoes, and the leaves were woven into baskets and mats. Also known by its Latin name, Sabal palmetto, this tree's flowers are a nectar source for bees and other insects, its berries providing food for a variety of wildlife. Dead cabbage palms provide homes for woodpeckers and other cavity-nesting birds.
Buttonwood (Conocarpus erectus): Considered the fourth mangrove by some, this native tree grows to heights of 30 feet or more and was used extensively in the days of old to manufacture charcoal. It is still used for smoking fish and other meats. Note that there are two species of the buttonwood along the tidal walk – the more prominent Green buttonwood and the Silver buttonwood. These slow-growing trees can withstand salt, wind and drought, which make them invaluable coastal plants. Note the small cones resembling buttons that give the tree its name. Buttonwood trees make excellent landscape trees for your Florida-friendly yard.
Marsh elder (Iva frutescens): Found in coastal regions from Canada to Florida, this shrub does well in moist, salty soil (as long as the salt content is low). Marsh elder seeds are an excellent food source for many birds and small mammals.
As you continue down the Tidal Walk, you'll notice one plant that dominates – you have moved into the mangrove forest. Mangroves are one of Florida's true natives, and are critical to the health of the Tampa Bay estuary. There are three types of mangroves in the Tampa Bay estuary: white, black and red mangroves. You will see all three species along the Tidal Walk.
You are most likely to see mangroves in any coastal community from Tampa Bay south.
Mangroves are very important to the ecosystem because they are the base of the food chain, provide valuable habitat, prevent erosion, filter out pollution, and are important nursery areas for shellfish, crustaceans and juvenile fish. The nonpoisonous mangrove water snake is a subspecies of the Gulf salt marsh snake. Coloration varies, but may include some reddish or orange pigmentation.
Mangroves can live in both freshwater and saltwater; the mangroves along this Tidal Walk are thriving where fresh water meets salt water. This fascinating plant obtains fresh water from salt water. The White and Black Mangroves excrete excess salt through their leaves, while the Red Mangrove blocks absorption of salt at their roots. Nature is an amazing thing! Even though they are not endangered, red, white and black mangroves are protected plants, which means that state and local regulations have been enacted to protect Florida's mangroves. Mangroves cannot be removed, pruned, or disturbed on either state or private land without a permit from local or state agencies. Be sure to check with officials in your area before taking action!
White mangrove (Laguncularia racemosa): Identify a white mangrove by its leaves. They are light yellow green, oval-shaped and have a notched tip. Additionally, the leaves have two distinguishing glands at the base of the leaf blade where the stem starts. The two glands pump out the salt and sugar that the plant produces. You may see ants or other insects enjoying the sugar. The white mangrove usually grows in the highest elevations farther upland than either the red or black mangroves. The white mangrove has no visible aerial root systems like the black or red mangroves.
Black mangrove (Avicennia germinans): At high tides, the water will cover the roots of the Black mangrove. This is the largest of the mangroves and can grow up to 50 feet tall. It has numerous breathing tubes, called pneumatophores, which grow vertically up from the mud and provide air to the roots. The leaves are slender and pointed with a silvery gray backing. As you walk, notice the difference between the white and black mangrove leaves. You can see that the black mangrove leaves are lighter in color than the white mangrove! The leaves are often coated with salt crystals which were eliminated from the tree. It was thought that early Native Americans used the leaves when cooking to add a salty taste to their food. The seeds are lima bean-shaped and actually germinate while still on the tree. The seeds float in the water until they wash up on a shoreline and find a sandy spot to settle into.
This area of sandy, high ground is called a coastal berm. This is a ridge of sand, shell and debris created by storm tides. Coastal berms are common along the southwest Florida coast. In mangrove areas like one, storm winds and waves are not powerful enough to build up sand dunes. Coastal berms support a variety of vegetation types because the materials that create them can be so varied. Notice the sea grapes growing on the berm.
Coin vine (Dalbergia ecastophyllum): A trailing or climbing shrub or vine with stems to 25 feet in length, the plant grows in marshes behind the sand dunes, in mangrove swamps and wherever the tides carry the seed. The fruit are one-seeded pods, one-half to one inch in diameter. They are flat, round and copper-colored at maturity accounting for the common name, "coin vine." Chemical compounds in these plants cause fish to become stupefied when roots or bark are crushed and placed in the water, a technique commonly used by coastal native Americans years ago.
Sea grape (Coccoloba uvifera): These native trees are useful to bees (for honey) and produce an edible fruit that is often made into jelly or a wine-like beverage. Birds and animals feed freely on the abundant grape-like fruits. This plant is widely used in central to south Florida landscapes because of its tolerance to salty soils. It is very sensitive to cool temperatures; its leaves will turn orange and red when cold stressed, and look quite beautiful!
Plants and animals living along the shoreline have had to adapt to several environmental stresses. Low soil oxygen levels, tidal fluctuations, and drought conditions brought on by a salty environment make life here a challenge. Since this is an area sometimes covered with water and sometimes exposed, a host of animals, both terrestrial (land-based) and marine, make use of it.
At low tide, look on the mud flat for the footprints of raccoons, ibis, egrets, herons and others who have come to feed on crabs, worms, mollusks and other tasty critters. The low tide also provides an excellent opportunity for wading birds to feast on fish trapped in tide pools or swimming in the shallow water.
The small holes you see in the mud belong to marine worms that live below the surface (in the benthos). The holes provide a way to obtain both oxygen and food, as well as a way to discharge waste. This shoreline community plays a vital role in the estuarine food web – providing food and shelter for terrestrial and marine organisms of all shapes and sizes. The smell at low tide is proof that the system is working. As organisms rot and decay they form detritus, the slimy, foul-smelling muck that is the basic food of the entire system.
Red mangrove (Rhizophoramangle): Usually found along the waters edge, this tree is easily identified by the tall, arching roots called prop roots. These roots add stability to the tree. The leaves are dark green and waxy. The torpedo-shaped seeds are called "pencils" and can remain alive for up to 12 months while floating in the water.
Tampa Bay Estuary
Now you have reached the Tampa Bay estuary. An estuary is a semi-enclosed body of water where salt water from the sea mixes with fresh water from rivers and streams. This mixture is known as brackish water. There are many types of fish such as spotted sea trout, snook and tarpon that can be seen in the water. The easiest one to see and identify, however, is the mullet. This fish is frequently seen in large schools, and jumps out of the water.
Watch for large diving birds, like the Brown Pelican, feeding on schools of fish. Also notice the large black-colored birds perched on the pilings with their wings spread apart. This is the Double-crested Cormorant drying its wings in the sunshine. Unlike most water birds, this bird does not have oil in its feathers, so it must periodically dry its wings out in order to fly.
Keep an eye out as well for the leaping spotted eagle ray, which can jump completely out of the water. The southern stingray and the cow-nosed ray will glide along in the shallow waters on either side of the tidal walk.
The Manatee Viewing Center's docents (volunteer educators) help educate thousands of center visitors each season about the Florida manatee, coastal vegetation and bird and fish habitats. The docent's primary responsibility is to greet and interact with visitors and school groups on behalf of Tampa Electric to promote environmental stewardship.
Docents are teachers, leading guided tours to our visitors. At the Manatee Viewing Center, there are opportunities to share with visitors information about the endangered manatee as well as the diverse plant life and amazing wildlife that inhabit Florida's coastal habitats and Tampa Bay waters. Many of our docents have volunteered for over 10 years, returning season after season. Volunteering for the Manatee Viewing Center is truly a rewarding experience for you and for the visitors!
If you are age 18 or older and would like to volunteer as a docent, the Manatee Viewing Center will provide you with training materials you need to answer questions such as:
- How much does a manatee weigh?
- What is that large fish I see in the water?
- What does a manatee eat?
- What type of butterfly is that?
- What are those trees with the funny-looking roots?
- What is the name of that pink bird?
We ask that docents commit at least one day a week for three hours for the duration of the center's open season, from November 1 through April 15. During that time, the Manatee Viewing Center is open seven days a week, from 10 a.m. to 5 p.m. Note: the center is closed Thanksgiving, at 3 p.m. on Christmas Eve, Christmas Day and Easter.
If you are interested in volunteering and becoming a docent, send us an email from our contact us page (be sure to select Manatee Viewing Center in the pull-down box).
If talking to the public does not interest you, there are other volunteer opportunities available. We need volunteers to assist in caring for and maintaining the center's butterfly gardens and our Florida-friendly demonstration gardens. We have beautiful gardens just waiting for you!