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First Manatees Sighted at Chassahowitzka National Wildlife Refuge,
Crystal River, FL
|Underwater photos help identify Manatees.
|Photo credit:s USFWS
November 17, 1997
It's an exciting time of year in the Crystal River area of Florida's Chassahowitzka
National Wildlife Refuge! The Manatees are returning again, and the scientists are
working as fast as they can to identify the Manatees as they arrive.
"We've just come back from swimming with Manatees at the Crystal River. A large
number of Manatees are moving into the area right now. The Crystal River is remarkably
clear this year. We can take pictures of the Manatees underwater. It's important
that we photograph as many Manatees as we can so that we can identify which have
returned to the Crystal River for the winter months and which may have gone elsewhere,"
reports Bob Bonde, research biologist with the Sirenia Project.
You may remember Bob Bonde from last spring's Journey North program. Bob works along
with biologists Cathy Beck and Jim Reid as part of the Sirenia
Project, a team of scientists dedicated to research and conservation of the endangered
West Indian Manatee. Bob, Cathy, Jim and other scientists with the Sirenia Project
have tracked population trends and movements of Manatees for over 18 years.
Last year, Journey North had the opportunity to collaborate with the Sirenia Project
as they tracked five manatees that were equipped with satellite transmitters. As
these Manatees migrated along Florida's Atlantic coast, Bob, Cathy, and Jim received
the satellite tracking data on each of the manatees, and after studying the tracking
data they would share it on-line with the Journey North students. Through this collaboration,
students across North America were able to "work alongside" the scientists,
tracking and mapping the manatees movements from their own classrooms.
More On Manatees
Manatees are marine mammals. They have large, gray seal-like bodies, two forelimbs
or "flippers", a paddle-shaped tail, and a whiskered face and snout. Most
manatees grow to an average of 10 feet long and weigh approximately 1,500 pounds.
Sometimes called "gentle giants", Manatees are herbivores, and they spend
a good deal of time each day feeding on sea grass. Manatees eat between 10% to 15%
of their body weight each day in plants! How many pounds/kg of food would that be
for a 1,000 pound manatee? How many pounds/kg of food would you have to eat to equal
10% to 15% of your body weight?
As Bob Bonde described, large numbers of Manatees are migrating into the Crystal
River right now. Why do you think so many Manatees come into the Crystal River?
A clue to answer this question lies in the fact that Manatees cannot survive for
long periods in water temperatures below 68 degrees Fahrenheit(20 degrees Celsius.)
Therefore, when the winter months come and temperatures drop, manatees need to find
The Crystal River is one of four refuge units of the Chassahowitzka National Wildlife
Refuge complex and is located about a third of the way down Florida's Gulf coast.
Warm water from more than 30 natural, fresh water, warm springs continuously flows
into the Crystal River. This helps to keep the temperature of the water at a constant
72 degrees Fahrenheit (22.2 C) in the Crystal River while the water outside the River
in the Gulf of Mexico may dip well below 68 degrees Fahrenheit (20 C) during the
winter months. Manatees move into the Crystal River to take advantage of the warmer
water. Here, many Manatees will spend the winter months feeding on aquatic plants
in order to restock their fat reserves for spring migration.
|Crystal River, FL. (Click map to enlarge)
Other Manatees spend the winter months distributed all along Florida's Gulf and Atlantic
coastlines. In fact, many Manatees are now wintering further north than their historic
wintering grounds. If the ocean water drops below 68 degrees Fahrenheit(20 C), how
do you think these Manatees will withstand these low temperatures in winter? Many
of these Manatees will seek out large electric power plants along Florida's coast,
which discharge hot water that warms up water in the ocean around the power plant.
Currently, scientists are debating whether El Nino may affect global weather patterns
this winter. Do you think El Nino or other weather patterns could have any effect
on the movements of the Manatees?
In March, as the weather is warming up in Florida, and ocean water temperatures rise
above 70 degrees (21.1 C) , Manatees that have wintered at the Crystal River will
move out to areas in the northern reaches of the Gulf of Mexico to breed. While newborn
and young Manatees are capable of swimming on their own, calves will stay with their
mothers for up to two years. Young Manatees are dependent on their mothers for learning
about migration travel routes, feeding areas, and nutrition.
Unfortunately, Manatees only give birth every two to five years. This is a relatively
slow reproduction rate, and is even more troubling because Manatees are an endangered
species. In fact, based on aerial surveys scientists estimated last year that there
were only about 2,200 West Indian Manatees in Florida.
Manatees and Motors
During November and early December, the number of Manatees at the Crystal River increases.
This is also a time of the year when many people come to the area for vacation, and
so there are many more power boats too. Many Manatees have been injured or killed
from collisions with boats, and those that survive the collisions are often scarred
by the propeller of the boat. These scars have become an important way to identify
To prevent injuries to Manatees from boating collisions, government and volunteer
organizations have worked to set-up low speed zones so that the boaters can see the
manatees and the manatees will have time to avoid the boats.
Manatee Tracking In 1998
Right now, Bob, Cathy, and Jim are working to tag up to twelve Manatees with satellite
transmitters. They have already tagged seven, four of which are Manatees that were
injured, captured, and rehabilitated at Busch Garden's Sea World. Their names are
Nicky, Georgia, Brian, and Dakota. The Sirenia research team hopes to learn how Manatees
which have been held in captivity will readapt to the wild. Will they remember the
location of their breeding grounds? Will they be able to recall their general migration
route? Thanks to the Sirenia Project, Journey North students will have the chance
to follow along with the Sirenia research team as they track several manatees next
spring, and look for the answers to these and other questions.
"We hope our research helps to build the body of knowledge available about
Manatees and also helps people to understand and conserve Manatees and their marine
habitats," reports Bob.
You can learn more about Manatee research, education, and conservation, including
how to participate in a successful Adopt-a-Manatee program, by visiting the following
The Next Journey South Update Will be Posted November 24, 1997.