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Manatee Migration Update: April 3, 2002

Today's Report Includes:

Field Notes From Cathy Beck

Latest All Manatees Migration Map
(As of March 29, 2002)
Click on Map to Enlarge

Hello Students:

Peggy Lee's PTT/VHF transmitter has broken loose! And so far we have not been able to find her. The other Manatees that we're tracking are all doing fine. Here are their latest Individual Maps and Data:

Link to Latest Data and Maps:
(Courtesy of U.S. Geological Survey's Sirenia Project)

Where's Peggy Lee?
Manatee with Transmitter Tag attached
Photo Credit: FWC

The last location we had when her tag was still attached was back on 3/24 near Cape Romano (25.843N, 81.655W). Two days later on 3/26 we knew that her transmitter was off. Several things told us that. First, although we were still receiving location data from the transmitter, we were not receiving any data about her "activity" (# of dives, duration of dives, # of times the transmitter "tips" greater than 90 degrees). The absence of tips and dives data indicated the tag was likely floating and almost certainly off of the manatee.

Second, the 3/26 location data also told us the tag had broken loose. The location we received for 3/26 was 25.925N, 81.860W.

Listen to the VHF Signals
Audio Clip
(.aif format)
(.wav format)

The transmitter was picked up for us on 3/26 by a cooperator who was out in his boat in that vicinity that day; he located it after we provided him with the latest satellite location data - and he saw the transmitter floating! The transmitter had separated from Peggy Lee as it was designed to do, by breaking at the "weak link" between the tether and the peduncle belt.

Since recovering her tag, Jim Reid has tried looking for her in the field. Normally, if her transmitter were still attached he would be listening for the "beeping" signals of her VHF transmitter using a receiver. Listen to the signals here. However, because her transmitter broke loose, he has been trying to locate her by listening for the sonic signal that comes from a sonic transmitter built into her belt. He uses a hydrophone and receiver to listen for the sonic signal.

The Search is On!
We hope to have more news on Peggy Lee by the next report. In the meantime, see if you can answer:

Challenge Question #21:
"If you were Jim Reid, where would you start your search for Peggy Lee? What if she wasn't there? Where would you look for her next? Why?"

Challenge Question #22:
"What do you think could have happened to cause Peggy Lee's transmitter to break loose? Think about how the transmitter is attached, and about all the possibilities."

Challenge Question #23:
"What if you were asked to recover Peggy Lee's transmitter? Where would you begin? Here's what you know: The last coordinates for the transmitter on 3/26 were (25.925N, 81.860W). Now, plot that location on your map. Then 'chart your course'! Describe how you would navigate to that location--what is the nearest Florida city? What direction is the transmitter from there? How far?"

Challenge Question #24:
"What is it about the 3/26 location of Peggy Lee's transmitter that made the Sirenia scientists suspect it had broken loose from her? (Hint: compare this location to her other location points this season.)"

(To respond to these questions, please follow the instructions below.)

We'll see you next time!

Cathy Beck
Wildlife Biologist
Sirenia Project
Gainesville, FL

Santina Spotted by Journey North Family
Just last week, Cathy Beck received a call from a vacationing Michigan family, telling her that they had spotted Santina! Cathy wrote that "they had called here last Friday to report the sighting and they were all pretty excited"

The Fitzgeralds had been on a charter boat and sent in this note: "We spotted Santina during a trip with Captain Barry. Caitlin is just starting school. We were very excited to find a Manatee with a transponder and the opportunity to let our daughter experience and learn about science, conservation, and humanity from this event. Thank you all for your efforts that have provided our children with the opportunity to learn and care about nature and earth sciences."

Welcome Aboard Fitzgerald Family!

Field Notes from Ranger Wayne--It's a Wrap!
The Season Ends

Hi Kids!

The 2001-2002 Manatee season at Blue Spring is complete. We have no more Manatees in the Run! To understand why, I've provided a recap of the March data below. Study the temperatures for the River and Run and see if you can answer:

Challenge Question #25:
"What major change in conditions finally occurred in the River to make the Run less appealing to the Manatees? What day did that occur, and how does that change make the Run less appealing?"

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

0

03/18

16.0

33.0

25.1

22.7

0

(To respond to this question, please follow the instructions below.)

You Look Good Enough to Eat
Click here to hear a
Sound"BITE"of an Alligator!
Photo Credit: Birmingham Zoo

Pistachio was this season's final Manatee in the Run back on March 12. His most recent location was picked up by Argos satellite signal on March 22 near Deland, FL. But ever since then his transmitter has been 'off the air', which means we're getting no signals from it since then. I presume an alligator bit his tag off and it sank. They may have to fly to pick up his backup sonic transmitter in his belt.

Speaking of alligators, I remember that one was VERY interested in me while I was snorkeling in the Run one time. Get the details of this close encounter and listen to an alligator Sound "bite":

Then, come back and answer:

Challenge Question #26:
"Why do you think Ranger Wayne feels that Pistachio's transmitter was bitten by an alligator, instead of just having broken loose? Compare what Cathy Beck reported about Peggy Lee's transmitter to the information Ranger Wayne reported about Pistachio's transmitter. What's different? Are there other explanations you can think of for the status of Pistachio's transmitter?"

Challenge Question #27:
"Inspect these photos of damaged transmitters very carefully. From the type of damage you see, can you determine who/what caused the damage? How can you tell?"

Who "attacked" the Transmitter?
Click on each image for a closer look

"Predator" One was ____

"Predator" Two was _____

(To respond to these questions, please follow the instructions below.)

I'll have a few season wrap up remarks in the next report. Bye for now.

Ranger Wayne Hartley
Blue Spring State Park
Orange City, FL

More Amazing Manatee Adaptations

Photo Credit: FWC

In addition to their amazing breathing abilities, the Manatees possess several other unique PHYSICAL adaptations. Can you imagine having all these characteristics yourself?:
  • Lips that work as several separate parts
  • Nostrils that close tight like valves; and
  • New Teeth endlessly: a lifetime of "Marching Molars."

Find out more about these adaptations:

Then, come back and see if you can answer:

Challenge Question #28:
"What dental problem do Marching Molars solve for Manatees? Do humans have the same problem? How do you solve it?"

(To respond to this question, please follow the instructions below.)

Manatee Math: You Eat How Much Each Day?
Click image to see just how BIG this "salad" really is!
Credit: Mote Marine Laboratory

Speaking of amazing, although appetite is not truly an adaptation, the Manatee's appetite does deserve honorable mention. Manatees maintain their giant size by feeding primarily on seagrass. Lots of seagrass--between 10% to 15% of their own weight everyday! (Or lettuce if a Manatee is in captivity--see photo)

Challenge Question #29:
"a) If a Manatee eats between 10% to 15% of its body weight each day, how many pounds (or kg) of food would that be for a 1,000 pound Manatee?

b) Now let's talk pizza! An average thin crust frozen pizza weighs about a pound. How much do you weigh? How many pizzas would you have to eat in one day to equal 10% to 15% of your body weight?"

(To respond to this question, please follow the instructions below.)

Dr. Ackerman's Discussion of CQ #13, and #14
Hello Students:

In Challenge Question #13, I asked about temperatures during the 2001 and 2002 aerial surveys. As you can see below, water temperatures in 2001 were far better for a count because they were cooler, and those cooler water temperatures contributed greatly to the record aerial Manatee count that year:

"A) The coldest Florida water temperature on the 2001 Map was approximately 5 degrees C
B) The coldest Florida water temperature on the 2002 Map was approximately 15 degrees C"

2001

2002

Click on Maps to enlarge
Credit '02 Map: Johns Hopkins Applied Physics Lab

In Challenge Question #14, we asked "How could the unseasonably warm winter weather have contributed to the higher number of boating-related deaths?"

Hannah, Stephanie, Jack and Emily from Ferrisburgh, VT got off to a great start with their answer: "More people boat when it is warmer. When the weather is warmer than we think it is going to be, people might fool around. They might be active and excited to be on the boat and not thinking about the manatees and other sea animals. Maybe more manatees are hanging out near the top of the water when it is warmer."

The FMRI has issued a press release suggesting that a the increase in watercraft mortality for January may be explained by the combination of warmer than average weather, resulting in (1) dispersion of Manatees and (2) a likely increase in boating activity throughout Florida. For more information on this see:

Warm Weather Increases Mortality Count: Discussion of CQ #15
Just one of the many threats
Photo Credit: FWC

In this Challenge Question, we asked "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?"

Take a look at what some students said:

Dylan and Kate from Ferrisburgh Central School VT did a nice job describing several of the causes in their answer:

"Manatees could die from natural causes such as old age, weather changes where the water gets too cold, could have a disease that spreads. Manatees could also die from human related causes such as: Water pollution, contaminated food, loss of habitat and food source. The biggest problem is the danger that humans pose to the manatees. There are many dangers that threaten manatees and without our help they could soon be extinct"

And David, Kevin, Jaime & Victoria from Iselin Middle School in NJ clearly laid out the differences between natural causes and human causes:

"The disasters that are 'natural causes' are: Changes in climate, not enough food, not the right temperature, and bad weather. Human related causes are pollution and boating."

Manatee deaths are broken down into eight categories:

1) Watercraft
2) Crushed/Drowned in Flood Gate or Canal Lock
3) Other Human-Related
4) Perinatal
5) Cold Stress
6) Other Natural
7) Undetermined
8) Verified/Not Recovered

Categories 1 - 3 are human related causes; 4 - 6 are natural causes; and 7 and 8 are unknown categories.

See you next time.

Dr. Bruce B. Ackerman
Florida Marine Research Institute
Florida Fish and Wildlife Conservation Commission
St. Petersburg FL

The Fab Four: Discussion of CQ #16
In Challenge Question #16, we asked "Other than thermal or warm water refuge, can you think of another reason that Manatees return to Port of the Islands in winter?"

Cathy Beck explained that aside from getting warm there, manatees use Port of the Islands for another very important reason, which is that "they are able to drink fresh water from a spillway there located at the end of one of the canals. During the winter (i.e. dry) season, we have seen regular moves, about every two weeks, into POI or into a river, for fresh water. During the summer (i.e. wet) season, these moves upriver or into POI do not occur regularly, as the manatees are able to drink rainwater from the surface or from runoff in other locations nearer the coast.

Daring Dean: Discussion of CQ #17 and #18
Snorkeler observing a manatee from below
Photo Credit: Sirenia Project/FCSC

In CQ #17 we asked your advice about "free tagging" a manatee in the wild.

Once again, Cathy Beck explained how Dean achieved his daring duty:

"To attach a GPS tag to Peggy Lee's existing tag assembly, Dean first located her and the entered the water himself to swim toward her. This may sound easy, but it's quite an accomplishment. Dean had to be very careful to remove the old tag and put on the new one without startling her. If she were to quickly buck away, Dean could be endangering himself. After all, Peggy Lee weighed 1,670 pounds (when tagged), and manatees can swim very fast in a short burst--up to 20 mph! So Dean swam VERY quietly, to approach Peggy Lee close enough to attach the GPS tag without alarming her. Mission accomplished! Oh, and one more thing. . . since Dean was swimming in the water, he also had to keep an eye out for something else--alligators!" (For more about alligators and scientists, see Ranger Wayne's story: "You Look Good Enough to Eat")

In Challenge Question #18, we asked you "How are GPS tags different from PTT/VHF tags? Why do GPS tags have to be recovered to use their data?"

Telemetery Transmitter Tag
Photo Credit: FWC

Julie, Avery, and Kate from Ferrisburgh, VT knew the difference and sent in their answer.

"The difference between the GPS (Global Positioning System) and the PTT/VHF (Platform Transmitter Terminal or Very High Frequency) is that the GPS holds the information that it gathers inside its tag. On the other hand, the PTT/VHF sends the information that it gathers back to the receiver. The GPS has to be recovered to get the information because the information is stored in the unit." As Jim Reid described these differences, GPS tags "listen" for location data, while the PTT/VHF tags "beep" or send location data. As of this time, there is research underway to find a way for GPS tags to send their stored data back to the scientists without having to retrieve the transmitter.

Some other important differences between the transmitters are that GPS tags provide location data which are much more precise than PTT/VHF, and GPS tags can give many more location coordinates in the same period of time. GPS can be programmed to provide several locations per hour, whereas PTT/VHS will generally give locations about four times per day.

Amazing Manatee Adaptations: Discussion of CQ# 19
In this question we asked "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?"

Kate, Julie, and Avery from Ferrisburgh, VT came up for air and answered correctly that:

"When the manatees take a breath, they push 90% of their air from their lungs. When we watched the movie, we heard the big puff of air. It sounded like a water balloon popping. With one breath, manatees can stay underwater up to 20 minutes. This is because they get so much oxygen with each breath. A human would need a diving gear and air tanks."

Mystery of The Boil: Discussion of CQ #20
Blue Spring Boil

In this question we asked "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?"

The source of all this endless flow of water actually began as rainwater which fell last year on higher areas or uplands north of Blue Spring. That rain water seeped down through the sandy soil and into the porous limestone. It then moves underground slowly downhill, and builds pressure as more rains fall in the uplands. The Blue Spring boil is actually an opening at a lower elevation, and water is driven out of the ground by pressure in the Aquifer below.

Note to Teachers: We Hope to Hear From You Soon
Have you and your students enjoyed following the Manatees this year? Let us know. Watch for our Year-End Evaluation later this month. We'd love to hear your suggestions and comments. The information you provide is the single most important tool used to guide our planning for next year.

Coming in the Next Report
  • What Does the Future Hold for Manatees? For People?
  • Latest Migration Data and Comments
  • More Manatee Adaptations and Matching Game
  • Final Comments from Our Scientists
  • Want to Say Thank You?


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 #21(OR #22 OR #23 OR #24 OR #25 OR #26 OR #27 OR #28 OR #29)
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 17, 2002.

Copyright 2002 Journey North. All Rights Reserved.
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