Posted by: Doc Bruce | July 27, 2010

A week of Manatees

Don’t Have a (Sea) Cow, Man!

By:  Kate Pozeznik

Did you know that Florida has the largest population of manatees in the United States?  In fact, Lee County is a haven for manatees because of our bays and estuaries, and river habitats that stay relatively warm all year.  Last week at the Sanibel Sea School, enthusiastic campers explored what makes manatees so unique.

Early in the week, we visited a seagrass bed near a shipwreck.  Well, in actuality, it was a small sailboat that ran aground this past winter, but its location on a shallow grass flat made for a great story collectively told by our boat’s “crew” speculating the cause of the sailboats mysterious demise.  With masks and snorkels, we carefully entered the shallow water in order to get a close-up view of this choice manatee habitat – a seagrass bed.  Manatees are herbivores, preferring a diet of sea grass and other marine plants.  We discovered that sea grass is delicate and is easily damaged or destroyed by boat propellers and heavy footsteps.  To reduce our impacts, we stepped gingerly in the shallow water and allowed the buoyancy of salt water to float above the manatees’ food source.  Sea grass is important to many marine animals, as we discovered during our snorkel.  Many juvenile fish rely on the cover of sea grass to avoid larger predators, and it also provides a home for many crustaceans and mollusks.

We learned that poor water quality can negatively impact manatees.  This can be caused by pollutants and the destruction of sea grass and mangrove habitats which collectively assist in purifying and filtering the water.  To help keep manatees healthy, we made our own biodegradable soap that is more marine friendly than traditional soaps, which often contain chemicals that can contaminate water sources.  Shells, small treasures, and even coins were inlaid in many of the bar- and shell-molded soaps creating a menagerie of brightly colored and essential oil-scented instruments to cleanliness.

We created beads with modeling clay to represent manatee otoliths.  We learned that otoliths are ear bones that feature concentric rings that allow us to ascertain the approximate age of a manatee and can indicate high growth periods during the life of a manatee.  Manatees grow slower in the winter when water is cooler and they are less active.  In warmer months, when food is abundant and manatees are active, they grow more rapidly.  In fact, female manatees can grow up to 1,200 pounds and give birth to baby manatees that weigh up to 70 pounds.  Male manatees do not grow as large as females, but can weigh as much as 800 pounds.  Due to their size, manatees are often referred to as sea cows; despite their large mass, manatees have only about one inch of fat covering their bodies.

On Wednesday, an obstacle course was set up on the beach in order to mimic the dangers that manatees face.  One part of the course included throwing soft foam shapes at dodging campers to represent manatees avoiding boat propellers.  Manatees cannot hear high-pitched noises generated by boats well, making them susceptible to boat propeller injuries.  Campers ran a jump rope gauntlet that represented manatees avoiding cold water to seek warm water during the winter months.  After all that running around on the beach, we needed a cold treat and we cooled off by getting ice cream at Dairy Queen.  It was refreshing after a day in the sun!

We emulated manatees in the summer by spending the day at Bowman’s Beach.  During the winter months when the water is cool, manatees spend much of their time in the rivers where the water is shallow and warmer.  Many of us were surprised to learn that manatees rely on fresh water for survival.  During the summer months when the water is warmer, they may venture out into the Gulf of Mexico.

At the end of the week, we decided to showcase our knowledge of manatees by creating posters that feature facts about manatees, the dangers they face, and how we can help keep our local manatee population healthy.  We will display our manatee awareness posters at Bailey’s Grocery Store and other local merchants.  Although we were not fortunate enough to glimpse a manatee in their natural environment, it may have been the best week yet at the Sanibel Sea School.

It takes a village to raise a child, and a community to produce Sanibel Sea School’s Summer Camp.  We are grateful to the Sanibel-Captiva Kiwanis Club who helps support students through scholarships.  Dan Hahn Custom Builder supports our summer program.  Bailey’s General Store quenches our thirst on these hot days with lots of ice.  The Sanibel Community House hosts our Friday afternoon milk and cookies.  Billy’s Bikes keeps us in cardboard from which we build life size models to really understand how big our marine neighbors are.  To all these folks and the countless others, we are grateful.

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