USFWS

Manatee Migration Update: March 5, 1997

"It is supposed to get up to 80 degrees today!" wrote Cathy Beck on February 28th. "Definitely an early spring - and it looks like 'March' is ready to head north soon. As you can see from today's data, she moved slightly north since last week and is in what the trackers call a "staging area" - that part of the Indian River where they sit and feed before making a long and quick move to areas north. I'll keep you posted. March was seen on Thursday (2/24/97) feeding near a warm water site in the Indian River, ready to use it if needed. The other two have moved little. Dakota just a couple of miles south, to a well-used manatee spot. Mercury appears to be in the same general area.

"The retag attempt for Marmontel is still set for 5 March and we may tag a few new manatees then. In mid-March we also plan to recapture Dakota, our rehabilitated captive, to assess his condition. Hopefully, he will be fine and immediately released on site."

Cathy Beck
Florida Caribbean Science Center
Sirenia Project

• Click Here for Today's Satellite Data

Keep a close eye on Florida temperatures over the next week. Do you think "March" will move as Cathy predicts? What do you expect the others will do? Plot each manatee's location, then see if you can answer today's Challenge Question:

Challenge Question # 4
"According to satellite data for 2/21/97, where was Sonny located? Based on what you've learned about manatees, how do you interpret this data?"

To respond to this Challenge Question please follow the instructions at the end of this report.

Missing a Few Manatees?
In our last report we asked Challenge Question #2:
"How many more manatees were counted in January, 1997 than were counted in February, 1997? What percent change is this? What reasons does Dr. Ackerman give for this difference?"

According to all students who answered this question, there were 520 fewer manatees counted in February, a drop of 23% from the January figure. Great math, everyone! HOWEVER, we're happy to say Florida did not lose 520 manatees between January and February--the scientists simply lost sight of them. Congratulations to 4th graders David, Craig and Andrea from Ferrisburgh Central School in Vermont who were the ONLY students to realize the drop was due to weather conditions during the survey, not death of manatees.

Look back at the annual survey data collected between 1991 and 1997. You now know the count can be off by 520 simply due to weather conditions! Be careful with numbers. They are very exact--but sometimes people draw exactly the wrong conclusions from them.

USFWS

Challenge Question # 5
"How do you think Ranger Hartley identifies the individual manatees swimming at the hotsprings?"

To respond to this Challenge Question please follow the instructions at the end of this report.

This week, Ranger Hartley has given us data from 5 Roll Calls. All were conducted in the last 2 weeks. Do you see a relationship between temperatures and the numbers of manatees present? What air and/or water temperatures seem to be warm enough for the animals to leave the refuge? The Ranger added this note on one of his one field reports. You might want to take it into consideration:

"Whenever Judith came & left, the others came & left with her. Shane, Luke, Dan, Precious, Phud and Greg were following her everywhere she went."

Date	# Manatees	Air (C)	River Water(C)	Run Water(C)
2/20/97	2	15-28 C	19 C	N/A
2/23/97	0	13-32 C	21.5 C	N/A
2/25/97	11	13-32 C	21 C	N/A
2/27/97	4	14-29 C	21 C	N/A
3/03/97	0	18-32 C	23 C	22.7 C

Challenge Question # 6
"Why do you think so many manatees were following Judith? Which days do you think she was at Blue Springs?"

To respond to this Challenge Question please follow the instructions at the end of this report.

Mrs. Berger's 5th grade class at the East Hills School in Roslyn, NY did an amazing job answering Challenge Question #3: "Why do you think a large marine mammallike the manatee cannot tolerate cold water when another large marine mammal, the whale, can?"

"This is Jake Kimmelman and Valerie Glibbery, the manatee team from Mrs. Berger's class. We used the Internet and did a search and found The Florida Department of Environmental Protection's WWW Site. This site is all about the manatee and we found the following under the heading of Physiology of the Manatee:

"The manatee's metabolic rate is unusually low compared with other mammals, which in part may account for its susceptibility to cold and slow healing rate. A low metabolic rate is adaptive for a large tropical animal that must keep cool and that lives on a relatively poor quality diet. However, this adaption can be a liability for populations at the northern edge of the species' range where metabolic heat is needed to maintain body temperature. The manatee's body temperature is reported to be 36.4 deg.C, but this may vary seasonally or with water temperature." So that because it has a metabolic rate (the speed at which it burns its fuel) lower than other mammals, it cannot maintain a high body temperature and needs warm water to compensate." Jake and Valerie
c/o Joan Berger, East Hills School,
Roslyn, NY( K12ROBZJ@vaxc.hofstra.edu)

• Click Here to View Student Answers for Challenge Question # 3

Here are comments from 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!

"Most manatees in the world live in the warm tropics. Although many people do not realize it, Florida winters can be quite cold, even with freezing temperatures! When air temperatures fall, soon after the river water temperatures will fall below the minimum that is comfortable for manatees (20 degrees Centigrade). When this happens, manatees are reluctant to venture away from the warm water sources to feed, because they are not able to endure cold water for long periods of time.

Cathy's husband and manatee-tracker, Bob Bonde reminded us of a great classroom activity you can do to test the insulating powers of fat. It's on our WWW site as part of whale specialist Anne Smrcina's report. We hope you enjoy it!

• Click Here for Classroom Activity.

How to Respond to Today's Challenge Questions:
Please do not answer both questions in one message!

How to Respond to Journey North Manatee Challenge Question # 4

1. Address an e-mail message to: jn-challenge-manatee@learner.org
2. In the Subject Line of your message write: Challenge Question # 4
3. In the body of the message, give your answer to this question:

Challenge Question # 4
"According to satellite data for 2/21/97, where was Sonny located? Based on what you've learned about manatees, how do you interpret this data?"

1. Address an e-mail message to: jn-challenge-manatee@learner.org
2. In the Subject Line of your message write: Challenge Question # 5
3. In the body of the message, give your answer to this question:

Challenge Question # 5
"How do you think Ranger Hartley identifies the individual manatees swimming at the hotsprings?"

1. Address an e-mail message to: jn-challenge-manatee@learner.org
2. In the Subject Line of your message write: Challenge Question # 6
3. In the body of the message, give your answer to this question:

Challenge Question # 6
"Why do you think so many manatees were following Judith? Which days do you think she was at Blue Springs?"

Don't Forget!
Please include the name of your school and your location so we can credit you properly for your answers.

The Next Manatee Update Will be Posted on March 19, 1997.