Adults only reproduce once every two years, with the calf remaining with the mother for about 18 months after birth. They are herbivores, cruising shallow waters to feed on many species of aquatic plants. Manatees are very susceptible to drops in water temperature. In colder weather, they congregate around the warm water outlets of coastal power pants, or in the rivers fed by warm water springs. They cannot survive in water temperatures under 60 degrees F. Down to only a few hundred individuals in the 1970's, on their way to extinction. They have made a huge comeback due to efforts to protect them. There are now an estimated 6,000+ Manatees in Florida. Their only significant enemy is man.
Historically, they were captured and slaughtered for their meat. Cowpens Key in the Florida Keys refers to the aquatic corrals that were created there to hold these "sea cows" for later consumption. Recognizing the Manatees' perilous state, in 1981, Jimmy Buffet and then Governor Bob Graham founded the Save The Manatee Club, of which I am proud to be a life member. The club's staff lobbied tirelessly for the federal and Florida governments to enact laws to protect them, with great results. Hunting them has long been illegal; however, their greatest threat continues to be strikes from boats. Most adult Manatees have several healed propeller wounds, and over 100 of them are killed by boats each year. No wake "Manatee Zones" have been established in channels adjacent to shallow areas, which help to reduce the number of strikes. Some boaters constantly complain about, and try to repeal these laws, out of pure selfishness. I just can't understand why it's such a big deal to slow down and protect the Manatees in these areas. They are very slow moving, and incapable of hearing the frequency of propeller vibrations; however, they can avoid slow moving boats in time. What's the hurry??
Observing Manatees is fascinating. In a smaller, shallow draft boat, one can usually spot them feeding or traveling, especially in rivers, and particularly in the Florida Keys. You are prohibited from approaching too closely or harassing them in any way. This does not mean that they will not approach you, whether you are idling along in your boat, or swimming in the water, and they often do. Before it was prohibited years ago, Manatees would happily swim over and drink fresh water from a hose, when offered to them. While drinking, they would also enjoy a head or belly scratch from a delighted human friend. I totally understand why such actions are now illegal, possibly leading Manatees into a dangerous complacency around humans. The rules are like those of whale watching from a boat, where federal law prohibits one from approaching closer than 500 feet, at idle speed, at which time the engines must be taken out of gear. Like Manatees, whales will often approach your boat. While whale watching about 30 miles at sea from Boston Harbor in my 30-foot boat, at Stellwagen Bank, we came upon two Humpback Whales. After stopping the boat, one whale- at least 80 feet long- came alongside, no more than ten feet from us. This magnificent creature then turned a bit, so he/she could look right up at us with that very intelligent eye. We were totally in awe. After a few minutes, the great whale slowly swam off, whacking the water with its tail, as if to say goodbye. Humpbacks and other whales can also be regularly spotted in offshore Florida waters, when migrating north or south.
No, you can't expect to see these "nature shows" every time you go out on the water, but the more time you spend there, the better your chances are. For example, during the hundreds of days I have spent fishing and cruising offshore Florida, only once did I observe the spectacle of a Giant Manta Ray (up to 30-foot wingspan, weighing 6000+ pounds!) leaping fully out of the water, and landing with a huge splash. No one knows for sure why they do this, but scientists speculate that it may be to dislodge parasites, or maybe just for a bit of fun! Seeing such things is yet another boating pleasure, with no better place to enjoy it than Florida.