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Manatee Migration Update: April 2, 2003

Today's Report Includes:

Field Notes from Cathy Beck

Latest All Manatees Migration Map
(As of April 2, 2003)
Click on Map to Enlarge

Hi Students:
As you'll soon read, the manatees and our own Susan Butler were caught in stormy weather and high seas. I've got all the details below, and the latest Migration Map and Data too.

Some of the data points this week are not from Satellite readings, but instead come from Susan's actual visual sightings in the field (called "visuals" for short). Susan was working very hard to try to get the "visuals" on the manatees--do you know why?

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

The Perfect Storm: Tracking in Rough Water
Susan was still out on the water as of late Friday afternoon 3/28, when I sent these field notes. She had been calling in her updates by radio, as she was motoring around in a boat trying to visually locate each of the manatees.

The day before, Thursday 3/27, we had a huge, severe storm here--it extended the length of the state. Susan was out in the rough water, in 4-6 ft. waves, until she finally had to get in for shelter. Before she came in, she did get a visual sighting on Gulliver in the channel East of Panther Key, where there was some protection from the storm.

Take a look at the weather loop movie of this powerful storm, and see if you can answer:


Click on image to watch the storm
Credit: Intellicast

The Perfect Storm


Challenge Question #23:
"Looking at the movie, at approximately what time did the heaviest rainfall of the storm pass over Susan and the Ten Thousand Islands area (TTI)? "

(Hint: Look at the color key--lower left, and the clock--upper left, and be sure to give your answer in military and standard time.)

Next, read Susan's first-hand account of what it was like in the boat. Then imagine what it must be like for a manatee during the storm, and see if you can answer the Challenge Question below:

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

The Quest for Visuals

Feeding on Seagrass
Credit USGS-Sirenia
While she was on the water, Susan was able to get visual sightings of several manatees. She observed Santina feeding with another manatee in the grass beds off of Jack Daniels Key on 3/26 (Wed), and observed Anna feeding on the gulf side of White Horse Key this afternoon (Fri). As of late Friday, Susan was heading toward the Round Key area, trying to locate Actual's signal.

If you were tracking manatees in the field with Susan Butler, why would you be trying to locate the tracked manatees to get a "visual", and how would you do it? Read through "Satellite Tracking and Manatees", and then see if you can answer the Challenge Questions below:

  • Satellite Tracking and Manatees

    Challenge Question #25:
    "If you were in the field with Susan Butler, what steps would you follow to locate the tracked manatees and get a visual sighting?"

    Challenge Question #26:
    "Why do you think Susan was working so hard to get 'visuals' on the manatees last week? Why not rely on the satellite locations alone?"

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

Thumper Loses His Tag
The disappointing news is that Thumper lost his tag on the weekend of Mar 21-22. Susan recovered it on 3/26 (Wed), tangled in mangrove roots--the tether had broken at the weak link, as it should. As of this morning (Fri), she had not been able to locate Thumper anywhere in her travels to track the other manatees.

We'll keep our eyes open for Thumper, and I'll be back with more news soon. Bye for now.

Cathy A. Beck, Wildlife Biologist
Sirenia Project

A Lone Ranger at Blue Spring

The Lone Ranger
"That's all folks!!", wrote Ranger Wayne, in his annual note announcing the end of the manatee season at Blue Spring. As explained below (see discussion of CQ #20), the river water temperature has warmed enough that the manatees can head out to other warm waters now.

We may still receive a few more comments and details from Ranger Wayne this season, but in the meantime he sent in "one more comment" late last Friday that is good news and very interesting too. Ranger wrote that:

"I wanted to say that at Blue Spring, I have only recorded 13 boat strikes during the season," which is fewer than previously. Think about the conditions that affect manatee migration and behavior during the season, and see if you can answer:

Challenge Question #27:
"Why do you think there were fewer boat strikes for the Blue Spring manatees this season?"

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

Manatee Math Challenge: Mortality Statistics for 2002
Compared to Ranger Wayne's note about boat strikes at Blue Spring, how do you think boat strikes impact the Florida manatee population as a whole? In January 2003, the Florida Marine Research Institute published its Manatee Mortality Totals for 2002.

The causes and number of deaths are summarized below. After you've read through this summary information, see if you can answer the Challenge Question below:

2002 Florida Manatee Mortality Summary
Cause of Death
Number of Deaths
Percentage of Total
Watercraft
95
__%
Flood Gate/Lock
05
__%
Other Human
09
__%
Perinatal
53
__%
Cold Stress
17
__%
Natural
59
__%
Undetermined
65
__%
Unrecovered
02
__%
Total
305
100%

Challenge Question #28:
"Fill in the blanks above: What percentage of the total 305 deaths in 2002 was caused by each category listed? Which category represents the largest cause?"

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

For more on FMRI 2002 Manatee Mortality information go to:

Amazing Manatee Adaptations

Photo Credit: USGS/Sirenia Project

In addition to behavioral adaptations, (such as Manatees returning inland to locate fresh water--see Discussion of CQ #17 below), Manatees also have several unique PHYSICAL adaptations. We'll talk about several of theses adaptations over the next few weeks.

Breathing/Respiration
One of the most amazing and unique physical adaptations of the Manatee is its ability to rapidly exchange almost all of the air in its lungs. With just one breath, a Manatee can stay underwater resting for 15-20 minutes before coming up for air again.

Take a look at the movie of a Manatee breathing. She rises to the water surface, and in only a few seconds, she exhales, and then inhales just once (we wouldn't recommend that you try this yourself!).



PhotoCredit: FWC

"One breath is all I need"

Movie Clip
Quick Time
Quick Time/Media Player

 

 

What adaptations help make Manatees such exceptional breathers? You'll find out in the Adaptations lesson below. As you read the lesson, think about their powerful, unique lungs. Then catch your own breath and try to answer the Challenge Question below:

  • Manatee Adaptations: Lungs

    Challenge Question #29:
    "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).

What's Attracting Manatees to POI? Discussion of CQ #17
In the last update, Cathy Beck and Susan Butler reported that several of the manatees had been returning to POI and other inland rivers. With the warm water and food-rich sea grass beds offshore, we asked you who was swimming back inland, and why they would want to come back inland?

The maps and data showed that Anna, Gulliver and Santina had all come in recently. Anna returned to POI on 3/7 and 3/11; Gulliver came up river on 3/14; Santina came up the Faka Union Canal on 3/11. (And today's data shows several recent inland trips too.)

But why did they come back up? The answer lies in the manatee's need for freshwater. Like you, manatees are mammals and they need fresh water, and periodic returns inland bring them to freshwater sources. Cathy Beck explained that "While they are in saltwater, Manatees will deliberately seek out fresh water to drink--from storm drains, marina hoses, and they have also been seen mouth open, skimming the water surface during a rain storm (since the fresh water will float on the salt water).

Try This! To learn more about the relations between saltwater and freshwater, try these experiments:

Can You ID This Moving Manatee? Discussion of CQ #18
Did you figure out who the moving manatee was? Congratulations to Daniella and Stephanie at Iselin Middle School, who correctly identified the moving manatee as "Juan"!

But how did you identify the manatee? Take a look at Ranger Wayne's comments, diagram and pictures--did you look at the same identifying features? As you'll read, sometimes it's not so easy, even for a veteran expert like Ranger Wayne!


Click to enlarge and see Juan up close

What's Your Aerial Count? Discussion of CQ #19
Were you able to find as many manatees as Airborne Ackerman in the aerial photo from Manatee Park? (Was it harder than you expected?)

Amanda from Mrs. Bonner's 4th grade class at Highview School in Nanuet, NY made her careful count and said: "The number of manatees that I can see in the picture is 73 (WOW that's a lot of manatee!!!) Am I close?"

 


72 Manatees Counted!

Yes, Amanda, it looks like you are very close, and that's really something when you're looking at images like these from the air.. Dr. Ackerman reported that "I zoomed the picture up, and printed it out in color, and I counted 72 manatees (including three outside the main group--1 is in lower left at edge of frame, 2 are in lower right near a power pole.) Some of them are faint and hard to see even in the blow-up, so--that's my story and I'm sticking to it!"

Exodus at Blue Spring: Discussion of CQ #20
What conditions lead to the reduced number of manatees in the Blue Spring Run? The same conditions that bring the manatees into the Run, except in reverse. That is, the water temperature of the River compared to water temperature of the Run directly affects how many manatees are in the run. It works like this: as the temperature of the River increases above 68F, more manatees will leave the run as the temperature rises because there is no more cold water threat outside of the run.

Understanding this, everyone was able to make a sound estimate of how to fill in the River water temperature on the Blue Spring data chart. The more manatees in the run, the lower the river temperature, and conversely, the fewer manatees in the run, the higher the river temperature. And on days when the manatee count was identical, one can look at the other temperature readings to guide you. Here's how the river water temperatures match up with the data chart:

Date
Air
Temp
Low(C)
Air Temp High(C
River Temp (C)
Run Temp. (C)
# of Manatees
02/06
1
25
14.8
22.5
73
02/11
6
22
15.1
22.4
73
02/17
2
28
17.9
22.5
6
02/21
20
28
19.2
22.5
1
03/03
16
28
21.0
22.4
1

What Drives the Dark Water? Discussion of CQ #21
In the last Update we asked "Why do you think the dark river water comes farther up the Run on some days than others? And do you see any kind of relationship between the location of the dark water and the location of the manatees in the Run?"

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."

Dark St. Johns River
Audio Clip
Listen to Ranger Wayne

Clear Blue Spring Run water
Audio Clip
Listen to Ranger Wayne

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 colder temperature, the manatees will generally be found up further in the Run, located "above" (on the warm side of) the cold dark water.

Ranger Wayne's Attendance Sheets
(Click on images to enlarge)

A

B

C

D

 

Binomial Nomenclature: Discussion of CQ #22

Carl Linnaeus
Credit:The Linnean Society

So who was it that developed binomial nomenclature? Kyle and Steven from Mrs. Bonner's 4th Grade class at Highview school in Nanuet, NY reported that: "According to our research, binomial nomenclature dates back to Bauhin, but was made popular by Carolus Linnaeus."

Gaspar Bauhin was a Swiss botanist who developed an early classification system in early 1600's, which foreshadowed or anticipated the binomial classification by Linnaeus.

In the 1700's, Linnaeus developed improvements in the classification system in his book Species plantarum (1753). He is regarded as a great "reformer of plant and animal classification", and also known as the gentle Prince of Botany.

Instructional Strategy Spotlight: Timelines/Circle or Pie Charts
Reading Writing SelectionWhen students read "The Perfect Storm", have them "create a timeline" that lists and describes the events from beginning to end. This is a helpful graphic organizer that helps "sequence events" in the text.
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. In the Subject Line of your message write: Challenge Question # 23(OR #24 OR #25 OR #26 OR #27OR #28 OR #29)
3. In the body of EACH message, give your answer to ONE of the questions above.

The Next Manatee Migration Update Will Be Posted on April 16, 2003

 

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