Floridian Manatee Populations and Anthropogenic Influences

Introduction:

The West Indian manatee, Trichechus manatus, is a distinct species of manatee that is found in the warm coastal waters and rivers of Florida (Lefebvre et al. 2001). Globally the West Indian manatee is listed as vulnerable by the International Union for Conservation of Nature (2014). The populations of West Indian manatees that call Florida’s waters home are not doing as well. The U.S. Fish and Wildlife Service and the Florida Fish and Wildlife Conservation Commission (FFWCC) list the West Indian manatee as endangered (2014).

The predominate cause of declines in Florida’s manatee populations are considered to be anthropogenic. Anthropogenic activities strongly influence manatee behavior and food sources (FFWCC 2007). Manatees have a relatively slow life history manatees calve approximately every three years, gestation is eleven to thirteen months and sexual maturity is reached between four and seven years old (FFWCC 2007). Calves are dependent upon their mothers for at least the first two years of life and Manatees life expectancy is approximately 60 years old (FFWCC 2007). The primary threats that manatees face from anthropogenic influences include entanglement, habitat loss, and watercraft collisions.

Entanglement:

Manatees can become entangled in traps and fishing gears that can cause drowning and scarring (FFWCC 2007). Entanglement may also lead to crushing by watercraft, canal locks, or other structures (FFWCC 2007). Manatees can also drown because manatees may become trapped in or by structures and pipes used for water control devices. Debris from fisheries operations or pollution can be accidentally ingested and this is very harmful for manatees.

Habitat Loss:

Manatees are a highly migratory species, locat...

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