The West Indian manatee (Trichechus manatus) — sometimes called the sea cow—is found along the coast of Florida and in the Caribbean. Most adult manatees are about 10 feet long and weigh 800 to 1,200 pounds, although some larger than 12 feet and weighing as much as 3,500 pounds have been recorded. These “gentle giants” have tough, wrinkled brown-to-gray skin that is continuously being sloughed off. Hair is distributed sparsely over the body. With stiff whiskers around its mouth, the manatee’s face looks like a walrus without tusks.

Christopher Columbus was the first European to report seeing a manatee in the New World. To Columbus, and other sailors who had been at sea for a long time, manatees were reminiscent of mermaids—the mythical half-fish, half-woman creatures of the ocean. Manatees are not fish, however, but marine mammals.

The manatee maneuvers through the water moving its paddle-like tail up and down and steering with its flippers. It is very agile for such a large animal, sometimes somersaulting and doing barrel rolls in the water.

The manatee often rests suspended just below the water’s surface with only the snout above water. It feeds underwater, but must surface periodically to breathe. Although the manatee can remain underwater for as long as 12 minutes, the average time is 4-1/2 minutes.

Manatees are herbivores, a term that means they eat only plants. They consume 4 to 9 percent of their body weight each day—that’s 32 pounds of plants for an 800-pound animal! To do this, manatees spend 5 to 8 hours a day eating—typically non-native water hyacinths and hydrilla, along with native aquatic plants such as Vallisneria or eelgrass.

Manatees move between fresh- water, brackish, and saltwater environments. They prefer large, slow-moving rivers, river mouths, and shallow coastal areas such as coves and bays. The animals may travel great distances as they migrate between winter and summer grounds. During the winter, manatees congregate around warm springs and around power plants that discharge warm water. During summer months, they have occasionally been seen as far north as Virginia and Maryland.

Manatees reach breeding maturity between 3 and 10 years of age. The gestation period is approximately

13 months. Calves may be born at any time during the year. Usually a single calf is born, but twins do occur. An adult manatee will usually give birth to a calf every 2 to 5 years. The low reproductive rate makes the species less capable of rebounding from threats to its survival. Newborn calves weigh 60 to 70 pounds and are 4 to 4-1/2 feet long. They nurse underwater for about three minutes at a time from a nipple located behind their mother’s forelimb. Born with teeth, calves begin eating plants within a few weeks but remain

with their mother for up to 2 years. Manatees may live for several decades.

Manatees communicate with each other by emitting underwater sounds that are audible to humans. The vocalizations, which sound like squeaks and squeals, are especially important for maintaining contact between mother and calf. One field report described a mother and her calf, separated by a flood gate, calling to each other for three hours without interruption until they were reunited.

Manatees face many threats to their survival throughout their range. Historically, they were hunted for their flesh, bones, and hide. Manatee fat was used for lamp oil, bones were used for medicinal purposes, and hides were used for leather. Hunting is thought to be largely responsible for the initial decline of the species; however, hunting is no longer allowed in countries where manatees are protected.

Today, the greatest threats to manatee survival are collisions with boats and, in Florida, loss of warm water habitat.

The West Indian manatee or sea cow (Trichechus manatus) is commonly found in shallow coastal areas, but can also be found in shallow rivers, estuaries, and canals. In the United States this species is concentrated around Florida in the winter months and migrates as far north as Virginia and as far west as Louisiana in summer months. The range of this species extends through the Caribbean, along the eastern coast of Central America and the northern coast of South America as far as northeastern Brazil.

Biogeographic Regions: nearctic (Native ); neotropical (Native ); antarctica (Native ); atlantic ocean (Native )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) Range encompasses rivers, estuaries, and coastal areas of subtropical and tropical areas of northern South America, West Indies/Caribbean region (but apparently never very abundant in the Greater Antilles, except perhaps Cuba, Lefebvre 1989), Gulf of Mexico (now mainly western and southwestern portions), and southeastern North America (mainly Florida).

Present range limits are similar to those known historically, but the distribution is fragmented due to areas of local extirpation (O'Shea and Ludlow 1992). Area of occupancy and abundance are apparently greatly reduced in Central and South America compared to the historical situation. Small numbers exist in the Greater Antilles but the species has not been documented in the Lesser Antilles south of the Virgin Islands since the 1700s. Sightings are rare in the Bahamas. Manatees remain relatively abundant in Belize (compared to elsewhere in Central America) and in Guyana, and they are still reasonably abundant in some areas of Mexico and on both coasts of Florida (Lefebvre et al. 1989). In Puerto Rico, manatees are most often observed in coastal areas from San Juan eastward to the east coast, (and including Vieques Island) and then south and west, past Jobos Bay, to the west coast, and about as far to the northwest as Rincon; they are concentrated in several areas, including Ceiba, Vieques Island, Jobos Bay, and Boquerón Bay, and are less abundant along the north coast, between Rincón and Dorado (USFWS 2007). Manatees are very rare (transient) in the U.S. Virgin Islands (USFWS 2007). See Fairbairn and Haynes (1982) and Hurst (1986) for information on status and distribution in Jamaica. See Lefebvre et al. (1989) for a fairly detailed overview of country by country status.

U.S. populations occur primarily in Florida (e.g., see Van Meter 1987), where they are effectively isolated from other populations by the cooler waters of the northern Gulf of Mexico and the deeper waters of the Straits of Florida (Domning and Hayek 1986). In the southeastern United States, manatees are more or less retricted to the vicinity of warm-water sites in peninsular Florida during the winter, although a few may remain year-round in Cumberland Sound, southeastern Georgia, where factory warm-water outfalls allow survival of colder winter months (Reeves et al. 1992). Occasional manatees occur in summer from Texas to North Carolina (e.g., see Schwartz 1995, Brimleyana 22:53-60, for North Carolina records). Those in Texas may be wanderers from Mexican population, but DNA analysis of an individual captured linked it to the Florida population (T. Ettel, pers. comm.). Manatees range along most of the Gulf coast of Florida but infrequently occur north of the Suwannee River and between the Chassahowitzka River and Tampa Bay. They inhabit the Atlantic coast of Florida from the Georgia coast to Biscayne Bay and the Florida Keys, including the St. Johns River, the Indian River lagoon system, and various other waterways (O'Shea and Ludlow 1992). In Florida, the most well-used wintering areas are at Crystal River, Homosassa River, Tampa Bay, Ft. Myers, Port Everglades, Riviera Beach, near Titusville, and Blue Spring (O'Shea and Ludlow 1992).

The average body length of an adult West Indian manatee is approximately 3 meters but some individuals can reach a length of 4.5 meters including the tail. The average weight of these manatees ranges between 200 and 600 kg, however the largest individuals can weigh up to 1,500 kg. These upper figures are unusual in manatees and females generally reach greater lengths and weights than the males of the species. Newborns measure between 1.2 and 1.4 meters and weigh approximately 30 kg. The adults are grey or brown whereas newborns are darker, a coloration they lose at about one month.

Manatees are somewhat seal-shaped with forelimbs (flippers) adapted for a completely aquatic life and no hind limbs. Lungs extend the length of the animal's body, which is important in controlling position in the water column. Hair is distributed sparsely over the body and the surface layer of skin is continually sloughing off. This is believed to reduce the build-up of algae on their skin.

(FPL 1989, Rathbun 1990)

Range mass: 200 to 1500 kg.

Average mass: 400 kg.

Range length: 4.5 (high) m.

Average length: 3 m.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: female larger

Average basal metabolic rate: 70.0056 W.

Length: 350 cm

Weight: 400000 grams

Trichechus manatus differs from T. inunguis of the Amazon Basin in larger size (maximum total length of inunguis is about 280 cm), less slender proportions, wrinkled skin rather than smooth skin, less elongate flippers, and presence of nails on the flippers (nails usually are lacking in inunguis) (Nowak 1991).

• Freshwater
• Marine

West Indian manatees are capable of withstanding large changes in salinity and move freely between freshwater and marine habitats. They can be found in shallow rivers, canals, saltwater bays, estuaries and coastal areas. Because of their extremely low metabolic rate and absence of a thick layer of insulating body fat, they are restricted to tropical and subtropical waters.

This species may inhabit clear or muddy waters. Because of their large size, manatees prefer water reaching at least 1 to 2 meters in depth. These animals are most commonly found travelling in waters 3 to 5 meters deep and waters over 6 meters are generally avoided.

If the water is deep enough and the currents are not too strong (under 5 kilometers per hour), manatees are capable of travelling large distances upstream on inland rivers. In St. John's river, manatees live up to 200 km away from the ocean. Manatees found in the Gulf of Mexico are rarely more than a kilometer from the mouth of a river.

(FPL 1989, Rathbun 1990)

Aquatic Biomes: rivers and streams; coastal

Habitat Type: Marine

Comments: Habitat includes shallow coastal waters, estuaries, bays, rivers, and lakes; throughout most of the range, manatees appear to prefer rivers and estuaries over marine habitats (Lefebvre et al. 1989). Manatees are not averse to traveling through dredged canals or using quiet marinas. They apparently are not able to tolerate prolonged exposure to water colder than 20 C. In the north during October-April, manatees congregate in warmer water bodies (spring-fed rivers, outfalls from power plants). They prefer waters at least 1-2 meters in depth; along the coast manatees often are in water 3-5 meters deep, usually in areas lacking strong current. Except in the Greater Antilles, manatees are consistently associated with freshwater sources (Lefebvre et al. 1989). In Brevard County, Florida, the cul-de-sac shelter type was the most ecologically valuable of all shelter types (Burke 1994).

In Florida, manatees occur in freshwater, brackish, and marine environments; typical coastal and inland habitats include coastal tidal rivers and streams, mangrove swamps, salt marshes, freshwater springs, and vegetated bottoms; where feeding often occurs in shallow grass beds, with ready access to deep channels (Smith 1993). In coastal Georgia and northeastern Florida, manatees feed on smooth cordgrass (Spartina alterniflora) in salt marshes at high tide (Baugh et al. 1989, Zoodsma 1991). Manatees drink from springs and freshwater runoff sites, mating, calving, and care of young often occur in secluded canals, creeks, embayments, and lagoons (Marine Mammal Commission 1986, 1988; O'Shea and Ludlow 1992; Gannon et al. 2007).

In Puerto Rico, manatees are primarily marine but appear to depend on access to fresh water, and seagrass beds provide the primary foraging habitat (USFWS 2007).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

n North America north of Florida, this species is mainly a migrant or irregular visitor. In Florida, manatees may migrate southward for winter; seasonal migrations of at least 530 miles (850 kilometers) to wintering areas have been documented, and migrations of 125-190 miles (200-300 kilometers) are usual along the Atlantic coast (O'Shea and Ludlow 1992).

Home range varies widely throughout the year. In summer, males may move over areas extending up to a couple hundred kilometers and tend to travel more widely than do females.

The snout of West Indian manatees is bent further down than other species in this family. This may be related to the food habits of this species. West Indian manatees feed mainly on sea grasses growing on the sea floor and the orientation of the mouth aids in grasping these plants. One of the unique characteristics of manatees is their flexible split upper lip which is used to pass food to the mouth. Manatees are opportunistic feeders, eating the leaves of most plants that can be manipulated by the upper lip. Manatees may also use their flippers to dig up the roots of these plants. This variable diet is most likely necessary to meet their nutritional demands. Some manatees may also eat invertebrates and will eat fish both in captivity and in the wild.

Because of the low nutritional value of the plants consumed, manatees must graze for 6 to 8 hours a day. Each day they consume 5-10 percent of their body weight, which can be over 100 kg in a large individual. This low-nutient diet also has also contributed to the the development of low metabolic rates. Manatees can survive on 25% percent less energy than a typical mammal of similar size.

Manatees feed on abrasive plants and, as a result, their molars are continually replaced throughout life as they wear down. Hind-gut fermentation is another adaptation to the herbivorous diet of the manatee, aiding in breaking down the cellulose of the plants eaten.

(FPL 1989, Nowak 1999, Rathbun 1990)

Comments: The manatee's diet is mainly submergent, emergent, and floating vegetation, but the diet varies with plant availability and opportunistically may include other foods (e.g., acorns in early winter in Florida, fishes caught in gill nets in Jamaica). In Florida, the diet is not restricted to native plant species (O'Shea and Ludlow 1992).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 6 - 20

Comments: The precise number of distinct occurrences (subpopulations) is unknown. MtDNA data suggest the existence of three main lineages, which could be regarded as occurrences from the broad perspective but may be too large for most practical conservation purposes.

In Florida, where manatee distribution is well known, manatees exist as four major units that in the past have been referred to as subpopulations but today are recognized as management units rather than as discrete subpopulations, due to the high level of gene flow among the four units (USFWS 2007).

USFWS (2001) identified 26 winter aggregation sites in Florida, not counting many lesser known minor aggregation sites used as temporary thermal refuges. These do not necessarily represent distinct occurrences from the perspective of population biology, but they do help identify some of the important focal areas for manatee conservation in the northern portion of the range.

2500 - 10,000 individuals

Comments: Total adult population size is unknown but is at least a few thousand and probably is less than 10,000.

The best, current, minimum population estimate of the statewide Florida manatee population is approximately 3,300 animals, based on a single statewide count at warm-water refuges and adjacent areas in January 2001 (USFWS 2007); although surveys have been conducted more recently than 2001, the weather conditions for that particular survey were ideal and, as a result, the count from that year still provides the best minimum population estimate (USFWS 2007). However, the 2001 count is now several years old, and given ongoing mortality (see threats) the current manatee population in Florida may no longer be 3,300.

A January 2005 helicopter survey of the entire Puerto Rico coast yielded a count of 121 manatees, including 20 calves (Mignucci-Giannoni 2005). Mignucci-Giannoni (2005) speculated that the relative abundance of manatees in Puerto Rico may be between 150 and 360 individuals.

Numbers are undocumented elsewhere.

In the north, manatees congregate in winter (largest groups may exceed 300); otherwise they are not highly social (except close mother/calf bond and temporary aggregations of several males around an estrous female).

Die-offs associated with red tides and with unusually cold weather have occurred in Florida (Van Meter 1987).

Maximum potential rate of population increase has been estimated at 2-7% per year and is most sensitive to changes in adult survival (secondarily, subadult survival) (see O'Shea and Ludlow 1992).

Comments: Manatees may be intermittently active day or night. In Honduras, where hunted, they were mainly nocturnal (Reeves et al. 1992).

Average lifespan

Status: captivity: 28.0 years.

Average lifespan

Status: wild: 30.0 years.

Average lifespan

Status: captivity: 30.0 years.

Although individuals of this species are largely solitary, mating herds form when a female is in estrus. These groups are made up of bulls pursuing the sexually receptive female. Courting bulls establish a dominance hierarchy for mating rights while the female attempts to avoid these males during most of her estrus cycle.

Females may attract up to 20 males, which pursue her for one week to one month.

Males reach full reproductive maturity between the ages of 9 and 10, but they are capable of mating as early as 2. Females are capable of reproduction at 4 to 5 years of age. Young females lack the skills necessary to raise calves and are less successful breeders. Most females breed successfully between the ages of 7 and 9. Gestation periods for West Indian manatees range from 12 to 14 months and calves are dependent on their mothers for about 2 years. One calf is produced at a time, however twins have been occasionally recorded. The inter-birth interval is 3 to 5 years, but this period may be shortened in the event of the early death of a calf. Calves nurse underwater from teats near the forelimbs. Calves are born with both molars and premolars and can begin consuming plants soon after birth, usually within the first 3 weeks.

The mother-young pair is the only stable, long-term association within the species. It has been suggested that the mother and her young can recognize each other after weaning and the association continues, to a certain extent, through the subadult years of the young. This long period of parental care might aid in the transfer of information about migration routes and other learned information.

(FPL 1989, Nowak 1999, Rathbun 1990)

Average birth mass: 32000 g.

Average gestation period: 335 days.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)

Sex: male: 913 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 1278 days.

This species exhibits a promiscuous mating system. Gestation lasts about 12-14 months. One young (rarely 2) is born in spring/early summer (usually). Young are weaned in 1-2 years. The interval between successive births for an individual female is 3-5 years (though 2 years if the calf is lost early). Females are sexually mature at a minimum age of 4-5 years, though newly mature individuals often do not successfully rear young; most females breed successfully by 7-9 years. Males may be 9-10 years old before they breed, though they may attain physical maturity a few years earlier. Maximum longevity is several decades. See O'Shea and Ludlow (1992) for further details.

While manatees have no natural predators, their numbers are threatened by human activities. Because of their low reproductive rate, it is difficult for the species to rebound from a decline in numbers. Although the population in Florida has historically been hunted by Native Americans and, later, by the European inhabitants, it was never the victim of commercial hunting. In other parts of their range West Indian manatees have been exploited commercially and, in some cases, this continues. Although protection laws exist in countries such as Costa Rica and Venezuela, illegal poaching still occurs.

One of the main causes of manatee mortality is collisions with motorboats. Manatees are also killed in canal locks and found entangled in fishing nets. They are also threatened by the loss of (or damage to) sea beds due to agricultural and industrial runoff. These same pollutants have been shown to accumulate in the tissues of manatees and some could be toxic to the animals.

Manatee conservation efforts were initiated as early as the eighteenth century, when the English established Florida as a marine sanctuary for the species. In 1893 a state law was established to protect manatees. At the start of the twentieth century fines were established for the killing of a manatee. Manatees are now protected by the U.S. Marine Mammal Act (1972), the U.S. Endangered Species Act (1973), and the Florida Manatee Sanctuary Act (1978).

(Marsh 1994, Oshea 1998, Reynolds 1995, FPL 1989)

US Federal List: endangered

IUCN Red List of Threatened Species: vulnerable

United States

Rounded National Status Rank: N2 - Imperiled

Rounded Global Status Rank: G2 - Imperiled

Reasons: Small range in coastal areas from the southeastern U.S. to northeastern South America; population size probably not much larger than a few thousand adults; high mortality rate, often a result of boat collisions (Florida, Puerto Rico) and hunting (elsewhere); threat from boat collisions is increasing despite improved regulations; low reproductive rate; population stable or possibly increasing in Florida and Puerto Rico, but a good estimate of the population in Florida is now several years old, status and trend poorly known elsewhere.

Intrinsic Vulnerability: Highly vulnerable

Comments: Reproductive rate is very low; a healthy adult female produces just one calf every three years.

Other Considerations: This species benefits from some human disturbances, such as thermal pollution.

Global Short Term Trend: Increase of 10-25% to decline of 30%

Comments: Current information suggests that the Florida manatee population (subspecies latirostris) is growing (USFWS 2007), but the latest good population estimate is from 2001. The Antillean manatee population (subspecies manatus) in Puerto Rico, while not as well studied as the Florida manatee, is also thought to have increased over the past 40 years and is now stable or slowly increasing (USFWS 2007). Little is known about trends in areas outside U.S. jurisdiction (USFWS 2007).

Based on status and trend information primarily from Florida and secondarily from Puerto Rico, USFWS (2007) concluded that the West Indian manatee no longer meets the definition of an endangered species. However, because of the threats of potential habitat loss and watercraft collisions and the concerns regarding the adequacy of regulatory mechanisms associated with those threats, USFWS (2007) stated that the West Indian manatee should be classified as threatened.

Global Long Term Trend: Decline of 30-50%

Comments: Over the long term, extent of occurrence has not changed much, but population size and habitat quality presumably have declined to a large but undetermined degree.

In Florida, the overall range has not changed over the long term, but the winter range has shifted from one based solely on natural warm waters to one based primarily on warm-water outlets of power plants (almost two-thirds of population) (USFWS 2007).

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: OVERVIEW: Threats include habitat loss and degradation, and mortality from boat collisions, hunting, fishing, red tide poisoning, entrapment in water control structures, entanglement in fishing gear, and exposure to cold temperatures. Manatees are vulnerable to catastrophic mortality when gathered in large numbers at winter aggregation sites in Florida. In Florida, primary human-related threats include mortality and injury from collisions with watercraft, entrapment and/or crushing in water control structures, and entanglement in fishing gear (USFWS 2007). Natural threats include exposure to cold (loss of warm-water winter refuges) and red tide (brevitoxicosis) (USFWS 2007). The most significant threats to Florida manatees are collisions with boats and potential loss of warm water habitat throughout the state (USFWS 2007). In Belize, watercraft-related mortality was reported as the major threat, followed by illegal hunting and entanglement in fishing gear, whereas in northeastern Brazil the stranding of live-orphaned calves was identified as the main recent threat (Parente et al. 2004, cited by Deutsch et al. 2008).

FURTHER INFORMATION:

In many areas this species is threatened by high mortality often associated with human activity (especially collisions with boats in Florida), in conjunction with low reproductive rate and habitat loss. In Florida, mortality from boat collisions is increasing (69-95 deaths per year during 2000-2007; data from Florida Wildlife Research Institute). Mortality from collisions with boats is believed to be the primary threat to the small manatee population in Puerto Rico (USFWS 2007).

A significant threat to manatee habitat is the potential loss of natural and man-made warm-water refugia (USFWS 2007). Natural springs are vulnerable to reductions in water quality and flow(resulting in part from human consumption of groundwater) and are threatened by factors that affect manatee access and use of the springs, whereas power plants are not permanent reliable sources of warm water, and many power plants upon which manatees now depend are expected to terminate operations within the next couple of decades (USFWS 2007).

In Florida, habitat loss caused by residential and commercial development of coastal land remains a problem.

In Florida in 1996, about 160 died apparently as a result of the toxic effects of the "red tide" alga Gymnodinium breve (Turner 1996).

Fisheries result in low numbers of deaths and nonlethal injuries in Florida but may be significant elsewhere in the range.

Hunting is responsible for the decline throughout much of the range. Illegal hunting is still a problem in much of the range in Mexico, the West Indies, and Central and South America. Opportunistic taking by fishermen is a major source of mortality in the Greater Antilles.

Manatees have low tolerance of human disturbance in calving areas, but are moderately tolerant of swimmers in wintering sites. There are no data at this time to indicate that harassment is limiting the recovery of the Florida manatee (USFWS 2007).

Management Requirements: .

Biological Research Needs: See USFWS (2007).

Global Protection: Many (13-40) occurrences appropriately protected and managed

Comments: This species receives limited protection in several managed areas within the United States, but no entire occurrence is adequately protected. U.S. Fish and Wildlife Service listed the following national wildlife refuges in which this species is known to occur: Ace basin, Blackbeard Island, Chassahowitzka, Crystal River, Harris Neck, Island Bay, J. N. 'Ding' Darling. Lake Woodruff, Lower Suwannee, Matlacha Pass, Merritt Island, Pelican Island, Pine Island, Pinellas, Savannah-Pinckney, St. Marks, Ten Thousand Islands, Vieques, and Wolf Island.

In Florida, all primary warm-water refuge sites, except the Weeki Wachee/Mud Creek/Jenkins Creek complex, have been protected (USFWS 2007). Secondary sites are variously protected, with some sites continuing to go unprotected and others fully protected. Ten of the 47 total warm-water sites either need protection or are in need of additional protection (USFWS 2007). While all important warm-water refuge sites within the network in Florida have been identified, the Manatee Habitat Working Group has not yet identified nor characterized feeding sites associated with these refuges (USFWS 2007). The Manatee Habitat Working Group also is in the process of identifying a network of migratory corridors and other use areas to ensure protection of feeding, calving and nursing areas throughout the state (USFWS 2007). Many of these sites are already known in the various counties and are variously protected under the Florida Manatee Sanctuary Act and/or the Federal Endangered Species Act/ Marine Mammal Protection Act.

In Florida, USFWS has designated sanctuaries at warm-water sites, patrols these areas, and uses its permitting authorities to minimize harassment of manatees (USFWS 2007). Outreach and education programs are also in place to minimize harassment in these areas.

The Florida Manatee Sanctuary Act of 1978 established Florida as a refuge and sanctuary for manatees. The Act protects manatees from injury, disturbance, harassment, or harm in the waters of Florida and allows for enforcement of boat speeds and operations in areas where manatees are concentrated.

Subsequent to the 2001 Florida Manatee Recovery Plan (USFWS 2001), there have been numerous additions and improvements to federal, state, and local manatee protection zones throughout peninsular Florida, as well as a number of ongoing studies to assess the effectiveness of these protection zones (USFWS 2007). To reduce unauthorized "take" associated with boat facility construction and the boats that use them, USFWS, state, and permitting authorities have developed permitting guidance to minimize the effects of these activities on manatees (USFWS 2007). In addition, the state of Florida recently drafted a management plan in conjunction with their decision to reclassify the state status of the manatee from "endangered" to "threatened." In addition, numerous counties have adopted manatee protection plans and other manatee protection measures (USFWS 2007).

Needs: Efforts should be made to reduce poaching in areas outside the United States. In Florida, reduction is needed in the level of mortality resulting from boat collisions.

In Florida, warm-water winter refuges are in great need of protection. USFWS and the state of Florida are working together and coordinating with other agencies and industry to address possible warm water loss from a variety of angles, including seeking alternative sources of warm water in the short term, and restoring major springs to provide access to natural sources of warm water for the long term (USFWS 2007). Failure to protect existing sources of warm water in winter or to provide secure surrogate habitats for the long-term could lead to a future decline in the Florida manatee population, reduced long-term carrying capacity, and an elevated risk of extirpation on either coast of Florida (USFWS 2007).

N/A

For centuries West Indian manatees have been hunted for their meat, hide, and bones. This hunting continues in many South and Central American countries. The domestication of manatees has been suggested. Their status as an endangered species makes this an unlikely option. It has also been suggested that manatees be used as a method of aquatic weed control within their range. However, it has been shown that the amount of plant material consumed by these animals is not large enough to make this a viable option.

As the state's official marine mammal, the Florida manatee (a subspecies of Trichechus manatus) is of particular interest to tourists visiting the area.

(FPL 1989)

Comments: This species has been hunted for meat, bone, hides, and fat (subsistence harvest mainly, some commercial harvest formerly in South America). Some subsistence hunting still occurs in parts of Central and South America. Some people believe that certain parts of the body have medicinal value.

Manatee populations may not eat enough to be an effective control on undesirable aquatic plants (Van Meter 1987), though Reeves et al. (1992) gave two examples of apparently successful weed control by manatees in South America.

Stewardship Overview: For the Florida manateee, USFWS (2001) summarized recovery efforts as follows: "The near and long term threats from human-related activities are the reasons for which the Florida manatee currently necessitates protection under the Endangered Species Act. The focus of recovery is not on how many manatees exist, but instead the focus is on implementing, monitoring and addressing the effectiveness of conservation measures to reduce or remove threats which will lead to a healthy and self-sustaining population."

Actions needed in Florida include the following: minimize causes of manatee disturbance, harassment, injury, and mortality; determine and monitor the status of the manatee population; protect, identify, evaluate, and monitor manatee habitats; facilitate manatee recovery through public awareness and education (USFWS 2001).

Comments: One of only four living species in the order Sirenia; the two other manatee species occur along the coast of West Africa (T. senegalensis) and in rivers of northeastern South America (T. inunguis). The other living sirenian, Dugong dugong, occurs in tropical bays and estuaries of the Indian and western Pacific oceans.

García-Rodríguez et al. (1998) examined range-wide phylogeography based on mtDNA variation in eight locations from Florida south to coastal Brazil. They detected three distinctive mtDNA lineages, corresponding approximately to: (1) Florida and the West Indies (Puerto Rico, Hispaniola); (2) Gulf of Mexico to the Caribbean rivers of South America (Mexico, Colombia, Venezuela); and (3) northeast Atlantic coast of South America (Guyana, Brazil). These lineages, which exhibit strong but incomplete geographical partitioning, are not concordant with previously recognized subspecies designations.