Florida Manatee: Pahrsa Hashemi
By: Pahrsa Hashemi
Florida Manatee Recovery Blog
Trichechus manatus latirostris
Considered a marine mammal, the Florida manatee is one of two
sub-species of the West Indian manatee. The Florida manatee resides in the Gulf
and Atlantic coasts of the United States; they are suited for warmer water
regions due to thermoregulatory issues. They show more ancestral roots to
elephants than that of whales and dolphins. In regards to their physical
description, the Florida Manatee presents a dirty-grayish exterior with thick,
wrinkled skin. Although they are known for their small eyes and lack of outer
ears, they maneuver through shallow waters with ease; this is done with aid of
their front flippers and robust tails which allows them to efficiently steer. Adult
manatees range from 9-15 feet in length and weigh as much as 2,200 pounds.
Map Credits: Jane Cooke (U.S. Fish and Wildlife Services)
Photography Credits:
Jane Reyneirs (Defenders of Wildlife)
Manatee’s are herbivores,
mainly consuming sea grass and freshwater vegetation. Their grazing tendencies
make them an engineer species as they play a crucial role for plant growth in
river, bays, and coastal regions. Manatee’s are K-strategists, producing little
offspring throughout their life spans. Having no specific mating season, the Florida
manatee normally births 1 calf during a span of 1-5 years. This makes this
species more susceptible to extinction and other threats to their well-being.
In addition, manatees are a seasonal, migratory species; this is based on the
water temperatures within their habitat (Preferred water temperature: 68°F)
Geographic and Population
Changes
Recent studies have shown that as of
the year 2017, the manatee population within the Floridian area resides at
roughly 6,620 individuals. This survey had shown scientists an increase in the
aggregation of manatees within this area as the number in 1991 was at a mere
1,267 (500% increase in population size). History had shown a detrimental impact
on the number of manatees through habitat fragmentation, hunting, and other factors;
this led to a complete disappearance of the species near the Guadalupe Islands.
The population status of those bordering the
Florida coast have been accounted for through the division of 4 management units/regions.
These sites monitor the survival and reproduction rates, as well as the
population growth, which are doing very well. The US Fish and Wildlife Services
also implemented restrictions around swimming and kayaking in certain springs
where these manatees go to find warmer waters. This has allowed for more
efficient seasonal migratory patterns for the species.
Listing Date and Type of
Listing
Manatees were listed as an endangered
species on March 11, 1998; Their recovery plan was not established until
October 30, 2001. According to Conserving the Nature of America, the Florida
manatee is protected under the Marine Mammal Protection Act.
Cause of Listing and Main
Threats
Graph Credits: Smithsonian Marine at Fort Pierce
1.
Habitat Loss
a. Warm water is essential to
the survival of the Florida manatee. Manatees migrate to canals and springs in
order to live comfortably in warmer temperatures, however, the development of
residential communities are invading in the space in which they reside. If they
are left without a suitable temperature and/or habitat, the populations can see
a diminishment in the sizes. For example, 2010 saw nearly 300 manatees killed
from an extended period of living in cold water.
2.
Harassment/Human Interactions
a. Human disturbance and/or harassment
can potentially harm the breeding, sheltering and natural behaviors of the
manatee. Due to conservation acts regulated throughout the past few decades,
3.
Red Tide
a. Red tide is a natural,
harmful algal bloom that occurs within the Gulf of Mexico. Once the bloom
spreads near the coasts of Florida it contains a natural neurotoxin that can be
fatal to the Florida manatee. Urban runoff also creates larger blooms near the
shores.
4.
Natural Predators
a. Predators such as sharks,
alligators, and crocodiles predate on young manatee calf’s during the first few
years of their lives; this is especially concerning to the adult manatees who
become extremely defensive of their young, going out of their way to protect their
young; this puts them in harm’s way as well.
Recovery Plan
According to the US Fish and Wildlife Services,
the recovery plan issued in October of 2001 has a goal of retaining healthy,
self-sustaining, and long-term populations of the Florida Manatees in the wild.
The goal of this plan is to ultimately remove this species from the endangered
species list.
1. The reduction of habitat
destruction and threats from human exposing factors
a. Protection of warm-water
springs that manatees reside in
b. Protection of general manatee
areas
c. Reduction and restriction of direct,
unauthorized human interaction
2. Rejuvenate population status
within 4 divided regions in Florida
a. Monitoring survival rates
amongst the adult population; ensuring the survival rate is at least 90%
b. Focusing attention towards maintaining
a population growth greater than 0
3. Diminish disturbances that
ultimately cause stress, injury, or death
5. Initiate public awareness and
education of the recovery plan for the Florida manatee
6. Annual budget for this recovery
approach estimates about $10,000,000
What Can You Do?
1. Stay informed in environmental
issues and become more aware of endangered species through research
2. Donate to organizations
striving towards the protection of endangered species
Specific:
1. While operating a water
craft, be aware of your surroundings, reduce your watercrafts speed, and stay
in deep water channels
2. Do not feed or provide any
water to the manatees
3. Keep out of authoritative
manatee areas
4. Report any manatee deaths, harassment,
or accidental incidents to the Florida Fish and Wildlife Conservation
Commission
Other Sources
https://www.fws.gov/northflorida/manatee/manatee-gen-facts.htm
http://www.manatee-world.com/manatee-predators/
http://www.defenders.org/florida-manatee/how-you-can-help.
http://www.iucnredlist.org/details/22103/0
https://voices.nationalgeographic.org/2014/08/23/the-last-spring-protecting-floridas-manatees/
http://www.manatee-world.com/manatee-reproduction/
https://ecos.fws.gov/docs/recovery_plan/011030.pdf
http://www.cnn.com/2017/03/31/us/florida-manatee-threatened-species/index.html
https://www.livescience.com/27405-manatees.html
http://myfwc.com/education/wildlife/manatee/facts-and-information/
I think that although they are still considered endangered, it is still amazing that they have had a 500% increase in population size since 1991. It seems they are a great example of what happens when time and money is put into protecting an animal. I did not expect that their biggest threat was water craft collisions. I also did not expect that they thrive best in warm water, I wonder if they will be affected positively by oceans warming due to climate change. Lastly, I did not know they are eco engineers, what a great point to bring up since we learned about it in class. -Amber Jaitrong
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ReplyDeleteMy grandmother lives on the south eastern coast of florida and ive been lucky enough to see the manatees a few times a year since I was young! It's so awesome that they are doing so well and that the recovery process is working so fluently. I find it very interesting that they thrive so much better in warm water. It is sad for most sea life, but maybe global warming and sea temperature rise will have a positive effect on these creatures. Awesome blog!
ReplyDeleteIt makes me really upset the fact that the new residences are invading the manatees' habitats, forcing them out. Humans affect the species in many ways as you said and the residence of southern Florida should be more aware of the issues that the manatees have. -Rachel Kenison
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