The West Indian manatee (Trichechus manatus), or sea cow is a large, plant-eating aquatic mammal which is commonly found in shallow coastal waters, rivers, canals and springs of Florida. They range in color from gray to brown, and are seal-shaped in appearance, with flat, rounded tails. Adult manatees average 10 feet in length and weigh over 1000 pounds!
Manatees are most common in Lake Worth Lagoon during winter months, when many migrate to the warm water discharge at the Florida Power and Light Riviera Beach Power Plant. This area, noted on the boater's guide map, is recognized as one of the most important warm water manatee refuges on the east coast of Florida. They are often observed swimming, resting or feeding near submerged seagrass beds.
Seagrass appears as beige or dark green patches against white colored sand. In dark colored water, manatees are more difficult to see, but may be identified by their dark, round snouts which break the surface of the water to breathe. Large, circular swirls in the water may also indicate the presence of manatees. High mortality, primarily associated with human activity, as well as a low reproductive rate and loss of habitat continue to keep the number of manatees low and threaten the future of the species.

Some Manatee Facts

  • Manatees and their closest relative, the dugong, are in the Order Sirenia; their ancestors evolved from four-footed land mammals over 60 million years ago.
  • Manatees are more distantly related to elephants and hyraxes; the latter are small mammals native to Asia and Africa.
  • They range in color from gray to brown, and the average adult is about 10 feet long and weighs between 1,500 and 2,200 pounds. Life expectancy is about 60 years.
  • Female manatees typically start to reproduce at 4 to 5 years of age.
  • The gestation period is 11 to 13 months; twin births occur occasionally.
  • Newborns range in size from 4 to 4.5 feet, and weigh about 60 pounds.
  • Calves are dependent on their mother for up to 2 years; nursing takes place underwater.
Manatee Deaths in Florida
The Florida Fish and Wildlife Conservation Commission reports that 325 manatees died in state waters last year. 81 of those deaths are a result of watercraft-related injuries.
In 2000, manatee deaths totaled 273. Watercraft-related injuries accounted for 78 of those deaths.

In 1999, 269 manatees died in Florida waters. Of those, 82 animals died from injuries sustained in watercraft-related incidents.

Causes of Manatee Deaths in Florida
Manatee fatalities and injuries occur on Florida's waterways. Approximately 25-30% of manatee deaths statewide are attributed to watercraft injuries. Injuries from blunt trauma are nearly equal in number to those injuries caused by propeller. The faster a boat goes, the more force is applied to a "strike." For instance, the difference between the force of a strike at 30 miles an hour is exactly twice that of a strike at 15 miles an hour, all other factors being equal.

If the watercraft happens to strike a manatee in the head as it is taking a breath, acute trauma may result and the animal may die immediately. A mid-body strike can even be fatal if ribs are broken or disarticulated. Their internal injuries can result in death from internal bleeding or infection.
It is difficult to differentiate between the blunt trauma caused by different sized vessels after an animal dies. The only thing that can be determined from fresh carcasses struck by boats is whether or not a propeller was involved, where on the carcass a strike occurred, and the size of the vessel on a macro-scale (if the carcass was chopped into large pieces, then it was a vessel with a big propeller, i.e. tanker or cargo vessel).

What Can You Do?
When Boating or Jet Skiing
Abide by the posted speed zone signs while in areas known to have manatees present or when observations indicate manatees might be present. What to look for when trying to see manatees: Observations may include a swirl on the surface caused by the manatee when diving; seeing the animals back, snout, tail, or flipper break the surface of the water; or hearing it when it surfaces to breathe.

Wear polarized sunglasses to reduce glare on the surface of the water. this will enable you to see manatees more easily.
Try to stay in deep-water channels. Manatees can be found in shallow, slow-moving rivers, estuaries, lagoons, and coastal areas. Avoid boating over seagrass beds and shallow areas.
Remain at least 50 feet away from a manatee when operating a powerboat. Don't operate a boat over large concentrations of manatees.

If you like to water ski, please choose areas that manatees do not use, or cannot enter, such as land-locked lakes.
Please don't discard monofilament line, hooks, or any other litter into the water. Manatees may ingest or become entangled in this debris and can become injured or even die. Note: discarding monofilament fishing line into the waters of Florida is unlawful.
If you do hit a manatee while boating, it is important that you obtain immediate help for the animal*

*Note the animal's location and contact the Florida Marine Enforcement (1-888-404-FWCC or *FWC on your cellular phone). The sooner the animal is located and its condition is assessed, the better its chance for survival. Please be responsible for your actions while on the waterways and take immediate action if something does occur.

Boating Safety Legislation passed in 1996
The state of Florida passed boating safety legislation in 1996 with the approval of the boater education bill. This bill requires persons under the age of 16* to successfully complete a boating education course, or an equivalency exam, prior to operating a marine vessel with 10 or more horsepower. (*The applicable age will rise one year for five years so that by the year 2001 anyone under the age of 21 would need to comply.) Florida now joins 18 other states that require mandatory boating education courses.

Boating Accidents in Florida
Florida leads the nation in boating fatalities, injuries and accidents. A significant number of these accidents occurred because the boat operators were either unaware of or chose to ignore the rules of safe boating operation. (See FWC Florida Marine Enforcement Boating Accident Statistical Report)

What Are Manatee Protection Rules?
Manatee protection rules are rules that are established by FWC to restrict the speed and operation of vessels where necessary to protect manatees from harmful collisions with vessels and from harassment. In areas that are especially important to manatees, the rules can prohibit or limit entry into an area as well as restrict what activities can be performed in the area. FWC is authorized to adopt these rules by the Manatee Sanctuary Act (370.12(2), Florida Statutes). The rules appear in Chapter 68C-22 of the Florida Administrative Code (FAC).

Local governments can also establish manatee protection zones through the adoption of a local ordinance. These zones must be approved by FWC before they can take effect, as required by 370.12(2)(o)FS. The only other limitation on a local government's ability to establish manatee protection zones is that local zones cannot include waters within the main marked channel of the Florida Intracoastal Waterway or waters within 100 feet thereof.

For more information go to:

Used by permission from the Environmental Resource Management site.