**Number range CHAPTERWEST INDIAN MANATEE**

**RESPONSE PLAN**

[**WEST INDIAN MANATEE** **RESPONSE PLAN**]{.underline}

The West Indian manatee, *Trichechus manatus*, is a large aquatic mammal
with flat broad forelimbs, no visible hind limbs, and a flat rounded
tail fluke. Adults range in color from gray to brown, can reach a length
of 13 feet (4 meters) and can weigh up to 3,500 pounds (1,500
kilograms). The average manatee is about 10 feet (3 meters) long and
weighs about 790-1,200 pounds (1,500 kilometers). Manatees are long
lived but no adequate method of determining age has yet been developed.
There are however, records of one captive manatee living for almost 50
years (Marmontel 1992).

The skin of manatees is finely wrinkled and the surface layer is
continually sloughing off. A layer of blubber occurs under the skin.
Hair is distributed sparsely over the body with stiff whiskers growing
around the face. The wide-set eyes have inner membranes that can be
drawn across the eyeballs for protection. Nostrils are located at the
upper end of the snout, while ear openings are located just behind the
eyes.

Manatees are tropical mammals highly susceptible to cold. Their low
metabolic rate and poor insulation limit the manatee\'s ability to
tolerate cool water temperatures. Field and laboratory observations
indicate that they are not energetically well adapted to water
temperatures less than about 70°F (20°C) (Irving 1983, Shane 1983).
Their slow healing rate appears due to their low metabolic rate as well.

Manatees spend approximately 5 hours a day feeding and in that time
consume 4-9 % of their body weight in vegetation (Van Meter 1989). They
are known to be opportunistic feeders, eating many different kinds of
plants, by grazing on aquatic vegetation or digging into the sediment
with their forelimbs to eat the roots and rhizomes. Submerged, emergent,
and floating vegetation, in that order, appear to be their preferred
foods. Manatees often choose protection from wind and currents in their
feeding grounds. Manatees also incidentally eat invertebrates and in
captivity will accept fish (Best 1981). Manatees rest from 2 to 12 hours
a day either suspended near the surface or lying on the bottom.

Manatees are not territorial or aggressive, nor does one individual
dominate a group. Groups seem to form casually without regard to age or
sex, except for the bond of mother and calf (Hartman 1979) and some
bachelor groups during breeding. Social interaction includes; nuzzling
bumping, chasing, and frequent vocalizations (Bengtson 1985).

Female manatees usually reproduce successfully by 7 to 9 years of age
producing a single calf per pregnancy. Most calves are born during warm
weather after a gestation period of about 13 months. The interval
between births is probably 3 to 5 years. Newborn calves range in length
from 4 to 4.5 feet (1.2 to 1.4 meters) and weigh about 65 pounds (30
kilograms). Calves remain dependent on their mothers for up to two years
usually nursing for one to one and a half years. Calves are born with
premollars and molars and begin nibbling on plants within a few weeks of
birth.

Manatees are protected in U.S. waters by the Marine Mammal Protection
Act (1972) and the Endangered Species Act (1973). The State of Florida
enacted the Florida Manatee Sanctuary Act (1978) and recognized the
manatee as the official State Marine Mammal and established the entire
state as a \"refuge and sanctuary for the manatees\". The Florida
Department of Environmental Protection (FDEP) has been designated as the
agency responsible for the manatee\'s protection. The Florida Manatee
Recovery Plan (1989) mandates specific strategies for the recovery of
the species by coordinating all agencies involved in manatee research,
management and recovery (USFWS 1989).

The impact of discharged oil on adult manatees\' thermoregulatory
abilities are probably not affected by direct contact with oil because
they use blubber for insulation. Also, they exhibit no grooming behavior
that would contribute to ingestion. Concern has been expressed with
regard to manatees inhaling vapors from light petroleum fractions
(Hansen 1992) during periods of inhalation at the surface. It is very
likely that exposure to petroleum would irritate eyes and sensitive
mucous membranes (St. Aubin and Lounsbury 1990). Nursing pups may be at
risk due to ingestion of oil from contaminated teats. There may be long
term chronic effects as a result of migration through oil contaminated
waters, and there is a substantial possibility of consuming contaminated
plant material and other incidental organisms. Manatees may not be
severely affected by the oil spill through direct contact but they are
sensitive to habitat disturbances and injury, such as collisions with
boats and barges and propeller strikes, as well as the presence of
various debris (Beck and Barros 1991) due to response actions.

**Distribution**

The U.S. manatee population centers around peninsular Florida, with some
movement into nearby states in the spring and summer. Populations are
also found throughout the Carribean. Although migration patterns are
more complex and extensive than previously thought, there appears to be
little interchange between the Atlantic and Gulf coast populations.
Manatees are frequent visitors to Georgia, with frequency diminishing
northward along the Atlantic coast to Cape Hatteras, rarely as far as
Virginia (Rathbun et al 1982). On the Gulf coast, they occasionally
wander as far west as Louisiana (Powell and Rathbun 1984). Strays from
the Mexican population are sometimes sighted in Texas waters. From April
to November, manatees range widely between suitable habitats,
particularly on the east coast within the protected waterways (Smith
1993, Reid et al 1991, O\'Shea 1988).

> **Florida winter aggregations\*:**
>
> Sixteen are natural aggregations at warm water springs, nineteen are
> at anthropogenic warm water refuges (Smith 1993, Hartman 1974).

**East coast\*:**

> Manatees are found largely in the Intracoastal Waterway and lagoons of
> Nassau, Broward, Palm Beach, Martin, St. Lucie, Indian River, Brevard,
> Volusia and Duval Counties. They have been observed in Blue Lagoon
> Lake near Miami and Florida Bay (Dade County). Significant wintering
> sites within this coastal region include Blue Spring (Volusia County),
> Florida Power & Light Company\'s (FPL) Cape Canaveral Power Plant, OUC
> Indian River Power Plant and Banana River (Brevard County), Indian
> River (Indian River County), FPL Riviera Beach Power Plant (Palm Beach
> County), and FPL Port Everglades Power Plant, FPL Fort Lauderdale
> Power Plant (Palm Beach County) and St. Johns River (Duval County).
> Manatees have been found to winter as far north as Glynn and Camden
> Counties in Georgia at artificial warm water refuges.

**Carribean**

> Puerto Rico

**West coast\*:**

> Manatees are found in inlets along the coastal Everglades in Collier
> County as well as in Citrus, Pinellas, Lee, Monroe, and Hillsboro
> Counties. Wintering populations are found in the Caloosahatchee River,
> Charlotte Harbor, and at the FPL Ft. Myers plant near the junction of
> the Orange and Caloosahatchee Rivers (Collier & Monroe Counties).
> Significant wintering sites in this coastal region include Crystal and
> Homosassa Rivers with their natural warm water springs (Citrus
> County), FPC Bartow Power Plant (Pinellas County), TECO Port Sutton
> Power Plant and TECO Big Bend Power Plant at the Big Bend River where
> gatherings of 20-60 manatees of various ages regularly occur
> (Hillsboro County), and Fort Myers Power Plant (Lee County).

\* (Perry 1994, Smith 1993, Geraci and Lounsbury 1993, Van Meter 1989)

**Primary Response**

Primary response strategies should be emphasized for the West Indian
Manatee.

**o Mechanical cleanup**

> Oil should be prevented from entering protected waterways, natural
> warm-water springs, and anthropogenic sources of warm-water where
> manatees are known to inhabit.

**o Protective boom and sorbent boom technology**

> If mechanical cleanup is not feasible, booms may be used for cleanup
> or they can augment the mechanical cleanup. Protective and sorbent
> booms may be effective in controlling or reducing contamination along
> the coast, Intercostal Waterway, near warm-water effluents, and
> natural springs.
>
> **[Manatees are known to entangle in booms, and therefore frequent
> monitoring of booms is required.]{.smallcaps}**

**o Debris removal**

> Collection of oiled carcasses, oiled vegetation, and oiled debris from
> open water and the shoreline should be made regularly.

**o In situ burning**

> Depending on the type of oil discharged into the tropical environment,
> weathering will most likely be rapid. Therefore, in situ burning is
> not recommended.

**o Dispersant application**

> There is no data available for manatees indicating any advantages or
> disadvantages of dispersant use in their environment. Due to the
> inhabitation by manatees of protected or calm waters and
> channel/lagoon settings, dispersants would likely not be effective
> (these are not the ideal conditions under which dispersants should be
> used).

**Secondary Response**

It is important when employing a deterrent designed to move an animal
away from or toward a specific site, that the individuals conducting the
techniques be trained and advised so as not to put the wildlife in any
additional jeopardy. All secondary response activities must have the
approval of appropriate federal and state wildlife trustee agency
representatives (see Appendix M).

**o Visual methods**

> There are no data for manatees indicating that visual methods are
> effective in keeping manatees away from a specific site.

**o Auditory methods**

> There is evidence to suggest that manatees communicate by auditory
> means, however, the use of auditory methods as a useful deterrent is
> speculative.

**o Herding methods**

> Herding animals away from an oil spill site may be feasible for West
> Indian Manatee only in severe cases. This method would require special
> permits from the Fish and Wildlife Service.

**Tertiary Response**

The U.S. Fish and Wildlife Service directs capture and treatment and/or
relocation, of all distressed manatees in its jurisdiction. These
activities are conducted by FWS or other Federal personnel, State
personnel acting on behalf of the FWS, or through authorized cooperators
judged by the FWS to be sufficiently qualified. Any tertiary response
activity must have the approval of appropriate federal and state
wildlife trustee agency representatives (see #8 Wildlife Response
Personnel for a list of agency contacts).

**o Capture with traps**

> Manatees are captured and restrained with nets, ropes, boats,
> enclosures, and stretchers or slings as needed. One method of capture
> is to surround the manatee with a net that is gradually drawn toward
> shore until the animal is in water shallow enough for the handlers to
> physically restrain it. Guidance is available through the Manatee
> Coordinator at the U.S. Fish and Wildlife Service Jacksonville,
> Florida Field Office.

**o Handling**

> Any handling should be accomplished by trained wildlife response
> personnel.

**o Transportation**

> As soon as the animal is restrained (or pulled into shallow water) it
> is maneuvered onto a padded platform and secured. Once out of the
> water manatees generally become calm and may need little restraint.
> They should be approached quietly, from the front. Covering the eyes
> and wrapping a small piece of netting over the snout helps to calm the
> animal. Transportation may occur by a variety of motorized vehicles to
> rehabilitation facilities.

**o Care - Cleaning/Rehabilitation/Holding/Young**

> No information is available on the cleaning of oiled manatees.
> Manatees have been successfully maintained in seawater exhibits since
> 1957 at the Miami Seaquarium in Miami, FL (White 1984). Housing
> requirement for manatees are defined in the Animal Welfare Act
> (Chapter 26) (USDA 1978). Temperature is most important to the holding
> of manatees. They have relatively meager layers of subcutaneous fat
> compared to cetaceans and pinnipeds. A temperature range of 61E to
> 86EF has been suggested for manatees maintained in a captive
> environment (Zeiller 1978).

**o Release**

> Manatees are released only if they are cleared for return to the wild
> through standard health screenings by certified/licensed
> veterinarians. If possible animals are returned to an area at or near
> their capture location.

**Diseases**

Manatees are known to be particularly susceptible to secondary fungal
infection and sometimes bacterial infections following damage during
capture or transportation. It is assumed that similar infections occur
in nature when skin is damaged. Cases of general respiratory infections
such as bronchitis, pleurisy, and pneumonia as a result of cool air and
water temperatures have been reported in captive manatees. But, by far,
the major causes of death in manatees have centered around anthropogenic
activity (Buergelt, et al 1984).