Manatee Manatee
Today's News Report Your Sightings How to Use Journey North Search Journey North

Manatee Migration Update: April 4, 2001

Today's Report Includes:

Three New Manatees Captured!
Courtesy of Naples Daily News

"Sirenia Project scientists have successfully captured and tagged three more manatees as part our current study near Ten Thousand Islands!

"They include two females and one male, captured on March 20 and 21 at Port of the Islands. All three manatees looked great, and one looked even greater!

"Here are their background data:

Name Sex Date Length Weight
Leslie adult female captured and tagged on 03/20/01 312 cm 1430 lbs.
Anna adult female captured and tagged on 03/21/01 314 cm 1270 lbs.
Rounder subadult male captured and tagged on 03/21/01 255 cm 675 lbs.

"Compare the differences in Leslie's and Anna's lengths and weights. Then see if you can answer this "short" and "heavy duty" question.

Challenge Question #23:
'What possible reasons can you think of to expain why Leslie is heavier than Anna?

Extra credit:
(a) Leslie is ____cm shorter than Anna, which is ____% of Anna's length?
(b) Leslie is ____ lbs. heavier than Anna, which is ____% of Anna's weight?'

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

Capture Continued: Discussion of Challenge Question #18
"This leads us back to CQ #18 from the last Update, where we asked 'Why do you think the scientists want to capture and tag more manatees for this same study? Also, is there any different characteristic you'd want in the new manatees?'

"Grade 7 New Jersey students Katie, Lythe, Usama and Noelia from Iselin Middle School provided a great answer
'In order for scientists to learn more about manatees, they need to tag and capture a bigger number of animals. The more animals you have in the study, the more accurate the information.' (iselin5@injersey.infi.net)

"Another response explained that scientists wanted more manatees for the study because: 'like people, animals don't react the same way to everything, so they want to get many different manatees to study.' (VidDaddy69@aol.com)

"Exactly right! More manatees are captured and tagged for this study so we can get 'a larger sample size.' Another important reason for capturing more manatees is that so far we had only tagged females for the study. We hoped to get some males, in case their movements are any different from the females.

GPS Unplugged: Challenge Question #24
Photo courtesy U.S. Geological Survey, BRD, Sirenia Project
"As planned, Jim and Dean successfully retrieved the GPS tag from Grace. Right now, we're still analyzing her data, which should let us determine Grace's movements on a finer scale. In the next Update, we expect to provide our interpretations of the data about her use of the habitat.

"At this time, we do know that during March 1-15 2001, Grace's GPS tag collected 1,331 observations, but there were only 1,047 location fixes. From what you already know about transmitters, try to answer:

Challenge Question #24:
'Why do you think Grace's GPS tag did not collect a location fix for ALL of the GPS observations?'

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

Surfing North
Migration Map
Click to enlarge













"Since our last report, Surfer swam quite a bit further north. How far north did she go? Look over the latest data and location map, and then see if you can answer. . .

Challenge Question #25:
'Did Surfer swim north of any of the other manatees on any date in March? On the date of Surfer's northernmost location, which other Manatee was she closest to?'

Landlocked?
"Hmmm, what's going on here? One of Nina's datapoints for 3/27 appears to plot on land. Unlike Surfer's earlier landlocked datapoints, which actually had her swimming in rivers too small to show up on most maps, this datapoint for Nina actually seems to be on the land.

Challenge Question #26:
'What reasons can you give to explain why one of Nina's 3/27 datapoints plots on land? Is she actually on land?'

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

"Finally, stay tuned for Grace's GPS data and maps in the next update!"

Cathy Beck
Sirenia Project
Gainesville, FL

Today's Satellite Migration Data
(Courtesy of U.S. Geological Survey's Sirenia Project)

Ranger Wayne's Roll Call: Things Are Heating Up!

Ranger Wayne Hartley

"Something interesting is happening here at Blue Spring. Take a look at my latest data below.

"Even though the 3/21-3/24 river temperatures were warm and all within five tenths of a degree of each other, there was still a very large number of manatees in the run on 3/22. Many times I'm all alone this late in the season! If the large number of manatees on 3/22 is not due to cold temperatures, what else could possibly be going on here?

Challenge Question #27:
'Can you think of any reasons other than cold temperatures that might have caused the large number of manatees in the run on 3/22?'"

Date

Air Temp Low(C)

Air
Temp
High(C)

River Temp (C)

Run Temp. (C)

# of Manatees

03/17

15

29

22

nt

1

03/21

10

27

19.5

nt

10

03/22

7

18

19.1

nt

40

03/24

8

29

19

22.5

12

03/25

15

29

20

nt

5

03/26

12

30

19.9

nt

2

03/27

12

28

19.5

nt

2

03/28

4.5

26

19.5

nt

6

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

As the Crow Flies: Discussion of Challenge Question #19 and #20
In CQ #19, we asked you to plot Surfer's locations and tell us the date she was in a particular location.

a) Surfer was on the coast on 3/7 and 3/15.
b) Surfer was swimming from the coast inland between 3/7 and 3/8.
c) Surfer was furthest south in the inland rivers on 3/12.
d) Surfer was moving back to the coast between 3/12 and 3/15.

In CQ #20, we asked:
"What is the total distance Surfer traveled between 03/07 and 03/15?"

Using the On-Line Distance Calculator, Surfer traveled approximately the following distances:

Dates Distance in miles and km
03/07/01 to 03/08/01 12 miles (20 km)
03/08/01 to 03/09/01 5 miles ( 7 km)
03/09/01 to 03/12/01 10 miles (17 km
03/12/01 to 03/15/01 5+ miles ( 8 km)
  Total Distance = 32 miles (52 km)

Like Playing In The Snow Without A Jacket: Discussion of CQ #21
In CQ #21, we asked "Why do you think a large marine mammal like a Manatee cannot tolerate cold water when another large marine mammal like a Whale can?"

Two groups of Grade 7 students from Iselin Middle School really got the feel of this question. Nice job! Dan, Mark, Jon and Alex answered:

"Manatees cannot withstand cold water because they have less blubber(fat) than a whale does. Whales have a great deal of blubber(fat) because they are bigger. Manatees are a lot smaller, so they have less blubber(fat) and are not as able to stay in cold waters." (susamel@verizonmail.com)

And Vickram, Zach and Kelly said:

"Manatees cannot tolerate cold water because they have less insulation than the blubber of the whale." (susamel@verizonmail.com)

According to Cathy Beck,

"Whales have a thick layer of blubber under their skin that insulates them from the cold water. Although manatees have a layer of fat under their skin, it is never as thick as a whale's blubber. Also, like you and me, their fat can vary in thickness depending on how much the animal has been eating. If there have been several cold spells and the manatees have not eaten often, the fat layer becomes thinner; then the manatee is less able to tolerate the cold water. It would be like you going out to play in the snow without a jacket!"

Ranger's Canoe Count Continues: Discussion of CQ #22

Ranger Wayne Hartley

In this CQ, Ranger Wayne told you that he recently counted 13, 24, 27, and 37 manatees in the Run on four different days, and he asked you to match the number of manatees he counted with the correct date.

Thanks to everyone who sent in their answers. According to Ranger Wayne, the "attendance numbers and temperatures ran together well for these dates." Thus, the date with the coldest river temperature, March 9, brought in the largest number of manatees seeking the warm water of the run. And similarly, the date with the warmest river temperature brought in the fewest number of manatees in the run because the river water was warm already. The correct answers are:

Date

Air Temp Low(C)

Air
Temp
High(C)

River Temp (C)

Run Temp. (C)

# of Manatees

03/05

10

32

22

nt

4

03/07

4

21

19

nt

27

03/09

3

24

18

22.5

37

03/10

13

26

20

nt

13

03/11

9.5

20

19.5

nt

24

03/13

13

32.5

21

nt

4

03/16

15

32

22.5

22.9

0



Ranger Wayne Hartley
Blue Spring State Park


Note To Teachers: We'd Appreciate Your Thoughts!
In our April 18th update, we'll be asking for your feedback on the Journey North program. Watch for our Year-End Evaluation Form and please plan to take the time to send your suggestions and comments. The information you provide at the end of each year is the single most important tool used to guide our planning.

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 #23 (OR #24, OR #25, OR #26 OR #27)
3. In the body of the EACH message, give your answer to ONE of the questions above.

The FINAL Manatee Migration Update will Be Posted on April 18, 2001

Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form

Today's News Today's News Report Your Sightings How to Use Journey North Search Journey North