FINAL Manatee Migration Update: April 26, 2000
Today's Report Includes:
Thanks to the Manatee Scientists!
As our manatee migration season comes to a close, we'd like to recognize scientists
Cathy Beck, Jim Reid, Bob Bonde, Susan Butler, Dean Easton, Bruce Ackerman, and Ranger
Wayne Hartley. In addtion to their already busy jobs, each found extra time to share
their research and knowledge about manatees with us.
Journey North would not be possible without the dedication of scientists like these,
who contribute their expertise voluntarily. Their gift to students is given in hope
that concern about the long-term survival of manatees will become part of students'
own lives. Thank you Cathy, Jim, Bob, Susan, Dean, Bruce and Wayne for a fantastic
season studying the manatees!
Want to Say Thank You?
If you'd like to write andthank
the scientists, their addresses are provided at the end of this report.
Final Field Notes From Cathy Beck
Photo: U.S. Geological Survey, BRD, Sirenia Project
"Since the time of my last report, we do have a tidbit of news. As you know,
Susan and I could not find that little rascal Comet when we went into the field on
Friday 4/7. But Dean passed through that area on Tuesday 4/11 and picked up Comet's
strong, signal - back in his old haunts - along the east side of Lake Monroe near
Stone Island in the Bethel Creek Cove area. Dean was truck tracking and could not
get a visual sighting of Comet, but the VHF signal strength from his belt-mounted
transmitter was good, and moving around a bit as if he were feeding.
"In addition, Xoshi lost her PTT tag for a second time. We suspected this just
after my last report on 4/12, because her PTT was still transmitting but didn't move
(no tips). Susan recovered Xoshi's tag on 4/14 - broken at the weak link in the tether.
This is not an uncommon occurrence for a manatee in a mating herd and that is exactly
what Jim suspects happened. It was floating in a large mat of vegetation in Lake
Woodruff, at the mouth of Garden Spring Run, DeLeon Springs. There was no sign of
boat or alligator damage to the tag.
"Having lost Xoshi's tag again, that means that none of the four manatees tagged
with PTTs and released in the St. Johns River this winter is still carrying a PTT
tag. But this Thursday, Dean and Susan will try again to locate Comet, Calista, Brian,
and Xoshi using the VHF signals from their belts. A plane will simultaneously aerial
track while Dean and Susan try to pick up VHF signals by boat. If they are able to
locate any of these manatees, they will attempt to re-attach floating PTT tags."
Looking Ahead--Cathy's Final Comments
"I hope you have all enjoyed following along with us as we tracked these
radio-tagged manatees for the past few months. Each year the manatees teach us more
about their daily habits, habitat preferences, individual references, and individual
responses to the environment in which they spend their lives. Manatees face many
dangers in their everyday lives, including boat traffic through their "home"
and trash in their "playground." However these are dangers that we can
alleviate, and I am optimistic that we will.
"Through the efforts of researchers, managers, caretakers at the oceanaria,
and the public, the chances for long-term survival for manatees are improving. Bob
Bonde, Susan Butler, Dean Easton, Jim Reid, the rest of our entire team, and I, all
thank you for your interest in manatees and your commitment to the conservation of
wild habitats. Your concern for manatees and other endangered species can make a
"I have truly enjoyed participating in the Journey North adventure again this
year and hope that each of you has learned more about this unique mammal. I hope
that you will carry your knowledge and concern for manatees, and for the many other
animals with which we share our earth, with you throughout your lives."
Still Cautiously Optimistic: What Does the
Dr. Bruce Ackerman
Dr. Bruce Ackerman has also shared his outlook for the future of the Florida manatees.
After reviewing all the factors, Dr. Ackerman and other scientists are still "cautiously
optimistic that the Manatee population can recover to a larger healthy population,
but manatees need even more help from humans."
Dr. Ackerman explained "we counted the highest number ever back in February
1996, 2,639 manatees. We think that this indicates that the population has been slowly
increasing over the last 20 years. This is supported by other kinds of data as well.
But since 1997, we have counted fewer manatees. We know that more manatees died in
1996 than ever before, 415 manatees. This was because of red tide in southwest Florida
in the spring of 1996, plus the cold winter of 1995-96. So we believe the population
is actually smaller now than it was in 1996, but we've also had four warm winters.
That is good, because usually not as many manatees die in warm winters. And the higher
count of 2,353 manatees in March 1999 helps confirm that the population trends are
probably staying pretty steady. But I wish we had been able to count more than the
2,222 we saw in January 2000."
Red tide has also been a problem in southwest Florida again this winter. About a
dozen manatees are believed to have died there since January, but the red tide seems
to have ended now, so hopefully that is over! Three manatees were rescued and are
doing better now in captivity, and will be released assoon as the red tide is completely
Like Living on a Fixed Income
There still is cause to worry about the future of the endangeredManatees. Researchers
at the Florida Fish and Wildlife Conservation Commission's (FWC) Florida Marine Research
Institute (FMRI) previously noted that "Manatee deaths are increasing at a faster
rate than the manatee population can support. The number of carcasses recovered has
grown 5.7% each year since 1976. The population is only estimated to increase by
two to four percent each year, based on the best scientific data available."
Dr. Ackerman puts this in perspective: "There is evidence that the manatee population
had been slowly growing over the last 20 years, but the numbers of deaths are growing
even faster. However, the number of deaths in 1999 and so far in 2000 were even higher!
It's like living on a fixed income, but your monthly expenses keep going up. That's
got to catch up with you. If you take more money out of your bank account than you
put in, you're going to go broke!"
What Does the High Mortality Rate Mean: Discussion
of CQ #16 & 17
This leads us to Challenge Question #16 which asked how you think the increased manatee
deaths in 2000 will affect the manatee population. Dr. Ackerman says that "with
269 total deaths in 1999, and 100 so far in 2000, it's very possible that the population
has started to drop a little in some parts of the state." FWC scientists will
be carefully monitoring the deaths this year, to try to detect whether the population
is going down in any parts of the state.
In Challenge Question #17, we also asked you to estimate how many watercraft deaths
there were by March 31 last year, based on the information that the 32 watercraft
deaths by that date in 2000 were a 41 percent increase over the same time last year.
According to Kipp Frohlich, biological administrator for the FWC's Bureau of Protected
Species Management, there were 22 watercraft collisions by that same date in 1999.
One way to protect manatees more is better watercraft law enforcement. The FWC and
USFWS are stepping up efforts to get boaters to obey posted speed limits in manatee
It's Not Just Boats
"Human population is increasing in Florida at alarming rates and existing growth
management legislation doesn't seem to be doing much to curb it," said Patti
Thompson, Staff Biologist for Save The Manatee Club (SMC). "More humans mean
less habitat for manatees and other wildlife. So, in addition to better law enforcement,
we also need better growth management regulation."
Growing By The Minute!
Ever wondered what the human population estimate for your hometown is? The world?
Check out these popular population sites:
Increasing human population impacts the manatees in many different ways, and one
of the most significant is damage to the seagrasses, the primary food of the manatees.
Dr. Ackerman says that "seagrass beds are very sensitive to having good water
clarity, and seagrasses are declining in some areas due to poor water clarity. Water
clarity can be reduced by turbidity from sediment runoff from construction of buildings
on land, and from farms, and from sediment churned up by lots of boat propellers.
And pollution continues to increase in some areas, from pesticides and herbicides,
urban run-off, and septic tanks. That causes problems for seagrasses too. After all,
it is every bit as important to have enough habitat for manatees. You can't have
enough manatees without enough habitat!"
Saving the Gentle Giant
"Our success in saving this gentle giant will depend on our ability to convince
the citizens of Florida of the need for continued compliance with the minimal regulations
that are already in place," said David Arnold, Bureau Chief of the FWC's Bureau
of Protected Species Management. "We also need to understand more about manatees
and red tide, as a mortality factor, it has the potential to overshadow our hard
work and accomplishments in reducing human related mortality."
What are some new or creative ways that people could use to protect manatees better?
Dr. Ackerman sent this list:
- Slow down the boats
- require propeller guards
- require driver's licenses for boaters
- exclude boats from warm water areas
- install sensors on canal locks to protect manatees passing through
- protect seagrass habitats
- don't allow people to damage seagrasses
- reduce sources of water pollution
- create more public awareness of need to protect manatees with billboards and
- write a song to put on radio
- buy a manatee license plate
- join the Save the Manatee Club
- write a letter to your congressman.
More Things You Can Do To Help
Don't let the end of the Manatee season stop you. You can continue to learn about
and help manatees by going to these related resources:
Manatees On Wheels
If you see a car from Florida with a Manatee license plate, give them a big "thumbs-up"!
They are one of the 150,000 people who have helped fund manatee research in Florida
by voluntarily buying Save the Manatee license plates. It is very unusual for a large
state program to be funded voluntarily, NOT by tax dollars.
These drivers have helped raise $2 Million dollars each year for manatee research
like Dr. Ackerman's.
Scientist Says: How Scientists Communicate
One of the most important steps in a scientist's work is sharing research results
with other scientists. This is how the body of scientific knowledge is built--and
how it constantly changes as new research findings replace the old.
As a way to synthesize your learning this spring, write your own scientific paper
based on the Manatee research you have witnessed--just as the scientists are preparing
to do! This lesson guides you through the steps of writing a real scientific paper:
Send Your Thanks
If you liked tracking the manatees this year, let the scientists know! Write and
thank the scientists, here are their addresses:
Ranger Wayne Hartley
Cathy Beck, Jim Reid, Bob Bonde, Susan Butler and Dean Easton
412 NE 16th Ave., Room 250
Gainesville, FL 32601
Ranger Wayne Hartley
Blue Spring State Park
2100 West French Ave.
Orange City, FL 32763
Dr. Bruce B. Ackerman
Florida Marine Research Institute
Florida Fish and Wildlife Conservation Commission
100 Eighth Ave. S.E.
St. Petersburg FL 33701-5095
Teachers, Share Your Thoughts
If you and your students have enjoyed tracking the manatees, it's important for you
to let us know! Simply fill in the Evaluation below.
Your feedback is very important to the program because each year we assess which
species to track next year. You may even win an Official Journey North T-shirt!
We hope you have enjoyed learning about the Manatee this
This is the FINAL Manatee Migration Update. Have a Great Summer!
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