The West Indian Manatee (Trichechus manatus) is a manatee, and the largest surviving member of the aquatic mammal order Sirenia (which also includes the Dugong and the extinct Steller's Sea Cow).The West Indian Manatee, Trichechus manatus, is a species distinct from the Amazonian Manatee, T. inunguis, and the West African Manatee, T. senegalensis. Based on genetic and morphological studies, the West Indian Manatee is divided into two sub-species, the Florida Manatee (T. m. latirostris) and the Antillean Manatee or Caribbean Manatee (T. m. manatus). However, recent genetic (mtDNA) research suggests that the West Indian manatee actually falls out into 3 groups, which are more or less geographically distributed as: (1) Florida and the Greater Antilles; (2) Central and Northern South America; and (3) Northeastern South America
The Florida manatee, (Trichechus manatus latirostris) a subspecies of the West Indian manatee, is the largest of all sirenians. Florida manatees inhabit the most northern limit of sirenian habitat. Over three decades of research by universities, governmental agencies, and NGOs, have contributed to our understanding of Florida manatee ecology and behavior, which is more than we know about any other species. They are found in fresh water rivers, in estuaries, and in the coastal waters of the Gulf of Mexico and the Atlantic Ocean. Females usually have their first calf when they are about 4 years old. Normally they only have one calf every 2-5 years, but there are rare occurrences of twins. The family unit consists of mother and calf, which remain together for up to 2 years. Males aggregate in mating herds around a female when she is ready to conceive, but contribute no parental care to the calf. Florida manatees may live to be greater than 60 years old in the wild. The biggest single threat to Florida manatees is death from collisions with recreational watercraft.
The other subspecies of the West Indian manatee is sometimes referred to as a Caribbean manatee (Trichechus manatus manatus). Antillean manatees are sparsely distributed throughout the Caribbean and the NW Atlantic Ocean, from Mexico, east to the Antilles, and south to Brazil. They are found in French Guiana, Surinam, Guyana, Trinidad, Venezuela, Colombia, Panama, Costa Rica, Nicaragua, Honduras, Guatemala, Belize, Mexico, Cuba, Haiti, Dominican Republic, Jamaica, and Puerto Rico. Historically Antillean manatees were hunted by local natives and sold to European explorers for food. Today they are threatened by loss of habitat, poaching, entanglement with fishing gear, and increased boating activity. Several of Sirenian International's scientists study Antillean manatees in Belize, which may be the last stronghold for the subspecies. Funds for research, education, and conservation projects are desperately needed in other Central American nations.
The West Indian Manatee is an opportunistic feeder, with large adults feasting on nearly 9 to 30 kg(20 to 65 pounds) of sea grasses and plant leaves daily. Because manatees feed on abrasive plants, their molars are often worn down and are continually replaced throughout life. They are also known to eat invertebrates and fish.
Due to their low reproductive rates, a decline in manatee population may be hard to overcome. They enjoy protection from the U.S. Endangered Species Act of 1973, and the U.S. Marine Mammal Protection Act of 1972. However, in April 2007, the U.S. Fish and Wildlife Service announced that the West Indian manatee population of Florida had rebounded. It advised that the species be reclassified as "threatened" rather than "endangered".
Federal wildlife officials had to ignore scientific criteria they put in place in 2001 and assume the threats facing manatees will not increase.
A computer model produced for the federal study shows a 50 percent chance that the current statewide manatee population of about 3,300 could dwindle over the next 50 years to just 500 on either coast.
Contrary to what the USFWS has recommended, the Florida manatee subspecies (Trichechus manatus latirostris) has recently (October 2007) been listed as Endangered by the IUCN on the basis of a population size of less than 2,500 mature individuals and a population that is estimated to be in decline by at least 20% over the next two generations (estimated at ~40 years) due to anticipated future changes in warm-water habitat and threats from increasing watercraft traffic over the next several decades.
U.S. FISH & WILDLIFE SERVICE ANNOUNCES AVAILABILITY OF WEST INDIAN MANATEE FIVE-YEAR REVIEW, STAFF RECOMMENDATION TO RECLASSIFY SPECIES
Apr 09, 2007; The U.S. Department of the Interior's U.S. Fish & Wildlife Service issued the following press release: The U.S. Fish and Wildlife...
Fish and Wildlife Service Issues Notice about Availability of Draft Revised Stock Assessment Reports for Two Stocks of West Indian Manatee
Mar 31, 2013; WASHINGTON, March 31 -- Fish and Wildlife Service has issued a notice called: Marine Mammal Protection Act; Draft Revised Stock...
DOCUMENTATION OF WEST INDIAN MANATEE TRICHECUS MANATUS (MAMMALIA: SIRENIA) FROM SAN JOSE ISLAND, ARANSAS COUNTY, TEXAS.(Brief Article)
Aug 01, 2001; George D. Baumgardner The West Indian manatee (Trichechus manatus Linnaeus) occurs only rarely along the Texas Gulf coast...