Tuesday, October 20, 2020

Florida’s Mascot: The West Indian Manatee (Trichechus manatus)

 

 

Averaging ten feet in length and between 800 and 1,200 pounds as an adult, the West Indian Manatee, commonly see in the Marco Island canals, Marco River, the bays, inlets and Gulf of Mexico, is closely related to an elephant.  Scientists believe this mammal could have evolved from wading, plant eating mammals. One could almost see that, with the gray skin and large body.  Most of the visible likeness stops there.  This gentle giant, never leaving the water, has a large rounded gray body that tapers to a large paddle-shaped tail.  “Arms” are flippers that are used in coordination with the powerful tail to swim in shallow, slow-moving waters particularly where sea grasses and freshwater vegetation is abundant. The snout is wrinkled and whiskered which can be briefly glimpsed when a manatee takes a breath of air at the water’s surface.

Like our “snow bird” residents, West Indian Manatees are migratory; staying in Florida, especially southwest Florida, in the winter months where water temperatures are the warmest, but can disperse to a range as far west as Texas and north east to Maine in summer months.  Alabama, Georgia and South Carolina coastal residents can easily come across a manatee in the very warm months of June, July, and August.

A day in the life of a manatee is simply eating, resting, and traveling.  Strictly herbivores, they can eat up to ten percent of their body weight each day.  So, an adult will consume 80 to 120 pounds of sea grass per day! Resting on the surface or submerged at bottom of the water body, when completely at rest, breathing can be 20 minutes apart.  Typically, if it is moving, breaths are taken at the water’s surface every three to five minutes.  A “footprint” of the large, flat, paddle-shaped tail on the water’s surface can help track the direction the manatee or group of manatees are moving at a three to five mile an hour pace.

Population growth is very slow.  The female manatee does not reach reproductive maturity until five to seven years of age.  Taking close to a year to gestate, young manatees, or calves, are not weaned from their mothers until they are an average of two years old.   A calf can be produced about once in five years.  State biologist estimate the population is about 3, 800 manatees.

There are no natural predators of this large marine mammal but both natural and human related activities keep this species population from thriving to large numbers. Living to be 60 years in age, mortality can occur naturally from cold stress, pneumonia, gastrointestinal diseases, and red tide impacts.  In 1996, red tide lingered for close to a year in near shore waters from Tampa south to the Keys.  On the southwest coast of Florida, a record number of manatees died that year, approximately 150 manatees, or 12% of the population, succumbed to upper respiratory disease caused by the inhalation of the toxic red

Watch out for manatees!

Watch out for manatees!

tide.  Last winter’s sustained freezing temperatures caused the mortality numbers to surpass the 1996 numbers. Close to 409 manatees died related to cold stress. This is one hundred more deaths than the prior season.  Human stressors are boat hits, ingestion and entanglement of fishing line and/or hooks, and getting stuck or crushed in water control structures such as locks and canal gates.

In 1972, the federal Marine Mammal Protection Act, then in 1973, the Endangered Species Act spawned the Manatee Sanctuary Protection Act in 1978 and ultimately, the Florida Manatee Recovery Plan.  Recognizing the high numbers of manatee injuries and deaths, in 1989, the State of Florida focused on thirteen key counties that manatees were most abundant and had human related stressors.  Manatee Management Plans for conservation and protection were required that has driven regulatory boat speed zones, research, monitoring, response to strandings, and public awareness statewide.  Marco Island has its own approved Manatee Management Plan that guides dock, dredge, and nourishment activities within the city waters.

Oil Spill Impacts

To date, no manatees have been observed to be impacted or killed due to oil exposure from the BP Deep Water Oil Spill.  Sea turtles and dolphins are reported in high numbers found washing up on shores or dead within the spill perimeter.  As it is the summer months, manatees will be in the range of the spill area due to natural migration activities. Currently, there are pods of manatees being tracked in the panhandle and Mobile Bay vicinity that may have to be evacuated due to impending oil.  Oil impacts to manatees could be, but limited to, the inhalation of toxic fumes and volatile chemicals causing blisters and irritation to mucus membranes and lung tissues; burning or blistering skin; ingesting oil or sea grasses covered in oil; and internal organs shutting down causing mortality.

Since there is no history of manatee mortality due to oil exposure, the unknown toll on this species is a focus. No oil or tar balls have reached the Marco Island beach or canals, but wildlife escaping the spill or ones that forage in open Gulf waters, may end up in this area.  The Florida Fish & Wildlife Conservation Commission (FWC) is working with the National Oceanic & Atmospheric Association (NOAA) and the U.S. Coast Guard (USCG) and taking direction in Florida from the lead response agency, the Department of Environmental Protection (FDEP), regarding the Deepwater Horizon oil spill in the Gulf of Mexico.  Tri-State Bird Rescue and Research, along with the U.S. Fish and Wildlife Service, is overseeing the wildlife rehabilitation response along the Gulf coast, but the FWC is receiving many questions about how people can help wildlife that may become oiled. The following information is provided to coordinate rescue and response efforts:

IMPORTANT CONTACT INFORMATION:

  • Anyone interested in efforts to rehabilitate oiled wildlife may register online at www.DeepwaterHorizonResponse.com or call 866-448-5816
  • To report oiled wildlife: 866-557-1401.
  • To discuss spill-related damage: 800-440-0858.
  • To report oiled shoreline: 866-448-5816.
  • To request volunteer information: 866-448-5816, or visit www.volunteerflorida.org

Leave a Reply

Your email address will not be published. Required fields are marked *