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Manatee Migration Update: March 20, 2002
Today's Report Includes:
- Field Notes from Dr. Ackerman: Challenge Question #13
- Numbers Don't Always Tell the Whole Story: Discussion of CQ #8
- Warm Weather Increases Mortality Count: CQ's #14 & #15
- Field Notes from Cathy Beck: Discussion of CQ #9
- Link to Latest Data
- The Fab Four's Trip to POI: Challenge Question #16
- Cows and Calves: Discussion of CQ #10
- Daring Dean: Challenge Question #17 & #18
- Amazing Manatee Adaptations: Challenge Question #19
- Field Notes from Ranger Wayne: Now the Lone Ranger
- Try This! Where Would You Rather Dip Your Flippers?
- Mystery of The Boil: Challenge Question #20
- You Made the Call! Discussion of CQ #11
- A Tale of Two Rivers: Discussion of CQ# 12
Field Notes from Dr. Bruce Ackerman
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Hello Students,
The results of our March 1 aerial Manatee count are in. With the help of 29 people in the air and on the ground from 11 different agencies, we counted 1,796 manatees. In comparison, last year's count total was 3,276 Manatees. Why such a big difference in the count from last year? One word: WEATHER.
As we discussed in the last Update, one essential condition for a successful aerial Manatee count is a significant drop in water temperature, which pushes the cold-sensitive Manatees into warm water gathering areas. Compare the Florida water surface temperature maps for the aerial count days last year and this year, and see if you can answer:
Challenge Question #13:
"A) The coldest Florida water temperature on the 2001 Map was_____degrees Celcius
B) The coldest Florida water temperature on the 2002 Map was______degrees Celcius"
2001
2002
Click on Maps to enlarge
Credit '02 Map: Johns Hopkins Applied Physics Lab
(To respond
to this question, please follow the instructions below.)
A second element for an aerial Manatee count is good visibility. Clear, calm, wind-free
days after the cold spell are ideal. This year's conditions were not what we hoped
for. The count day unexpectedly turned out to be windy and cloudy, which impaired
the observers' ability to see and count manatees. Take a look at these two photos
to get an idea of what a difference the water surface can play in visibility (you
can see the wind on the spanish moss in the trees):
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Wind |
Less Wind |
Numbers Don't Always Tell the Whole Story: Discussion of CQ #8
In Challenge Question #8, I asked you "What conclusions can you draw about the size of the Florida Manatee population if this year's count is higher than last year? If it's lower than last year? What reasons might cause the count to change from one year to the next?"
This year's lower count does not reflect any drastic decrease in the Manatee population. Rather it shows only that visibility was poor due to the weather conditions. As you know, the counts can be highly variable due to weather conditions, which can work both ways. For example, last year's prolonged cold temperatures, during one of the longest cold spells on record, contributed to the record high Manatee count.
As you can see, the number of Manatees counted from one count to the next can be the result of many things, that may or may not be related to the actual population size. Be careful with numbers. They are very exact--but sometimes their meaning may not be so clear or complete. That is why we use additional methods to evaluate the overall status of the Manatee population. We use photo identification; we track individual animals' movements; and we perform necropsies on Manatees that die throughout the year; and we include all that data in assessing the populations.
Warm Weather Increases Mortality Count
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This January had the highest one-month total of boating-related Manatee deaths on record. In that month, there were 16 confirmed manatee deaths from boat collisions. Scientists suspect that unseasonably warm weather this winter may be a factor in this record number of boating-related deaths.
Challenge Question #14:
"How could the unseasonably warm winter weather have contributed to the higher number of boating-related deaths? (Hint: Consider how unusually warm winter weather would influence a boater and a Manatee. Ask yourself, how do your own winter activities change when you get an usually warm day or two? Or a warm week or two?)
Challenge Question #15:
"In addition to boat collisions, what are the other risks that cause disease or death in Manatees. Which ones are 'natural causes', and which ones are 'human-related?' Which risks cause the most Manatee deaths? The least?"
(To respond
to these questions, please follow the instructions below.)
See you next time.
Dr. Bruce B. Ackerman
Florida
Marine Research Institute
Florida Fish and Wildlife
Conservation Commission
St. Petersburg FL
Field Notes from Cathy Beck
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Latest All Manatees Migration Map |
Here are the latest Individual Maps and Data for your own Maps!
Link to Latest Data and Maps:
(Courtesy of U.S. Geological Survey's Sirenia Project)
- Data & Individual Map for Actual
- Data & Individual Map for Addison
- Data & Individual Map for Albert
- Data & Individual Map for Grace
- Data & Individual Map for Megan
- Data & Individual Map for PeggyLee
- Data & Individual Map for Santina
- Data Only for All Manatees--Printer-friendly Format
The Fab Four's Trip to POI: Discussion of
CQ #9
Several of you figured out the answer to Challenge Question #9 which asked "What
interesting thing did four Manatees do in this latest data? "
Seventh graders Katie, Sarah, Maggie, Stephen and Brian from Iselin Middle school
studied the data carefully and answered correctly:
"Albert, Megan, Addison, and Santina all met at the Port of the Islands(POI) on March 1st 2002. We think all of them went there because of the warm weather and the water there."
This was quite an event. On one single day four separate manatees all moved into the same place. They moved in to POI in response to a late-in-the-season cold front we had. (It dipped to the low 20's here in Gainesville). Santina and Addison showed long moves in response to this front. Looking at the new data in today's report, can you tell what the "Fab Four" have done since then? And who "ducked in" to Port of the Islands after they left?
Challenge Question #16:
"Other than thermal or warm water refuge, can you think of another reason that Manatees return to Port of the Islands in winter?"
(To respond
to this question, please follow the instructions below.)
Cows and Calves: Discussion of CQ #10
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In Challenge Question #10, we asked "How do Actual's movements compare to the movements of the other manatees you're tracking? What reasons can you think of to explain Actual's movements?"
Actual hasn't moved much in comparison to the other manatees. Why? Because Actual has a small calf with her. Based on our observations of many, many cow/calf pairs over the last 2+ decades, we are all in agreement as to why cows with calves may restrict their movements. Pregnant females seek out quieter waters when ready to give birth. Optimally, the area chosen will also have an adequate food source for the cow, allowing them to stay put for a while until the calf grows a little and becomes stronger. In the case of Actual, whose calf is very small, they have been in an area where all the needed resources were available: good food and freshwater sources, protected from heavy boat traffic because they are not using channels. And we are coming out of winter in Florida so there is no need to move to seek out warm water. As the weather continues to warm and the calf grows we are likely to see more frequent and farther moves."
Daring Dean
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You've probably been wondering about the "tags" we use to track Manatee migrations. What do they look like? Who builds them? How are they attached to a Manatee? How does the tracking data get transmitted to scientists? For this and more information about transmitters, take a look at this lesson:
Then come back and see if you can answer:
Challenge Question #17:
"If you had Dean's duty to attach the GPS tag to Peggy Lee in the wild, how would you get close enough to her? How might Peggy Lee react? What suggestions would you give him about things to be careful of when tagging a Manatee? (Put yourself in his place--you're the Scientist--and think of as many things as you can.)
Challenge Question #18:
"How are GPS tags different from PTT/VHF tags? Why do GPS tags have to be recovered to use their data?"
(To respond
to these questions, please follow the instructions below.)
We'll see you next time!
Cathy Beck
Sirenia Project
Gainesville, FL
Amazing Manatee Adaptations
In addition to behavioral adaptations (like the pregnant cow that locates good habitat before giving birth and restricts travel with her calf), Manatees also have several unique PHYSICAL adaptations. We'll talk about several of these adaptations over the next few weeks.
Breathing/Respiration
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How much air can you breathe in? |
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Movie Clip |
Take a look at the movie of a Manatee breathing. She rises to water surface, and in only a few seconds, she exhales, and then inhales just once. What adaptations help make Manatees exceptional breathers? You'll find out here:
As you read, think about their powerful, unique lungs. Then catch your own breath, and come back to answer this:
Challenge Question #19:
"How can a Manatee take just one breath and so quickly be able to stay under water so long? What device would a human need to stay under water like a Manatee?"
(To respond to this question, please follow the instructions below.)
Field Notes from Ranger Wayne: Now the Lone Ranger
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Coming Back Empty-handed |
During Stormy's capture, the team also captured another Manatee named Pistachio, and they gave him a physical examination too. He passed with flying colors.
As it turns out, Pistachio would be the only Manatee in the Run on March 10 and 12. By March 14 there were no manatees here at all. Before I knew it, I was the Lone Ranger paddling right back to shore!
If you take a look at the newest data below, you'll see why there were no manatees. Compare the temperatures in the River column to the number of Manatees each day. What do you see happening? What do you think will happen now that Spring is officially here (Happy Vernal Equinox!), and temperatures will continue increasing? Will there be any Manatees coming back in with the warm weather?
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Date |
Air Temp Low(C) |
Air Temp High(C) |
River Temp (C) |
Run Temp. (C) |
# of Manatees |
| 03/07 |
9.5 |
21.5 |
15.7 |
22.7 |
82 |
| 03/08 |
13.0 |
21.2 |
16.1 |
22.5 |
56 |
| 03/09 |
15.0 |
28.0 |
17.3 |
22.6 |
06 |
| 03/10 |
14.0 |
28.5 |
19.5 |
22.6 |
01 |
| 03/12 |
7.0 |
28.0 |
21.1 |
22.7 |
01 |
| 03/14 |
11.0 |
29.0 |
21.5 |
22.5 |
00 |
Try This! Where Would You Rather Dip Your Flippers?
Get a feel yourself for what the water temperature feels like in the Run at Blue Spring and in the St. John's River. Try this easy experiment:
Finally, be sure to look at my Discussion of CQ #11 below, where you can HEAR
ME tell you who the manatees were in the last report.
Bye for now,
Ranger Wayne Hartley
Blue Spring State Park
Orange City, FL
Mystery of The Boil
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Challenge Question #20:
"What is the source of all the water that keeps coming out of the Boil? Where does it all come from, and why is it warm?"
(To respond to this question, please follow the instructions below.)
You Made the Call! Discussion of CQ #11
Here is the moment you've all been waiting for--see if you identified all of the Manatees correctly. But first, here's a note from Ranger Wayne:
"Nice work Kids! Great job on the Roll Call. It's not easy to identify Manatees, but you all made a great effort. Now, listen to me in the canoe, telling you who's who! (You can even hear me paddling!)"
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Manatee D is? |
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If Ranger Wayne ever needs any help identifying the Manatees at Blue Spring, have
we got the crew for him!
Kate, Julie, and Avery from Ferrisburg, VT were careful observers and correctly
identified all of the Manatees. They also wrote that:
"We don't like the fact that people don't follow the boating speed limits, and how the manatees are all scarred up by boats."
Nice work everyone!
A Tale of Two Rivers: Discussion of CQ# 12
In the last update we asked "Why do you think the dark river water comes farther up the Run on some days than others? Are there any explanations in the daily data for those days? What is the location of the manatees relative to the dark water?"
Ranger Wayne explained that the dark river water comes farther up the Run when the river water is coldest. "The colder it gets, the heavier it is, and the further it comes up into the Run. The dark water comes in along the bottom of the Run, displacing the Run water which is warmer and lighter in weight".
You can see this on Ranger Wayne's sketches of the River water on his Attendance sheets. The river water comes the farthest into the Run on the days when the river water is the coldest. On his sheets, you can also see how the manatees position themselves in relation to the dark water. Because of its cooler temperature, the manatees will generally be found up further in the Run, located "above" (on the warm side of) the cold dark water.
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December 23 |
December 31 |
January 5 |
Coming in the Next Reports
- What Hazards Face the Manatees?
- Latest Migration Data and Comments
- More Manatee Adaptations
- Gator Tails or Tales?
How to Respond to Today's Challenge Questions
IMPORTANT: Answer only ONE question in each e-mail message.
1. Address an E-mail message to: jn-challenge-manatee@learner.org
2. IMPORTANT: In the Subject
Line of your message write: Challenge Question #13(OR #14 OR #15 OR
#16 OR #17 OR #18, #19 OR #20)
3. In the body of the EACH message, give your answer to ONE of the questions above.
The Next Manatee Migration Update will Be Posted on April 3, 2002
Copyright 2002 Journey North. All Rights Reserved.
Please send all questions, comments, and suggestions to our feedback form
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