Manatee Migration Update: April 7, 2004

Today's Report Includes:

• This Week's Manatee Migration Update
• Transmitter Troubles? Discussion of CQ #15
• Latest News on Anna and Actual
• CSI Manatee: How Do You Search for the Missing? Discussion of CQ #16
• Manatee Math: You Eat How Much Each Day? Discussion of CQ #17
• What's Next? Coming Next Week

"Hi Students!
Many factors can interrupt or stop satellite tracking signals from being received.

Seventh grade students from Iselin Middle School correctly pinpointed several in their answer:

Credit: FWC

Whether 'the manatee's tag is at the surface when the satellite passes' If 'there are a lot of structures or vegetation that come in the way' If the transmitters might 'be damaged or destroyed by a boat or an alligator.' Morli, Kiran, Smriti and Shanela

"Nice job Iselin students! Your answer gives examples of two categories of tracking problems. One is when the tag is working fine, but something interferes with the signal. If the tag's antenna is under water when the satellite passes, no signal will be broadcast. Watch the video below to see how close the antenna comes to going under water when the manatee swims. A satellite signal's quality can also be impaired by structures or vegetation.  

Tag on the Move Watch it Now (Viewing Tips)

Photo Credit: FWC Video Credit: Save the Manatee Club

The antenna of the tag needs to be above water when the satellite passes overhead in order for the signal to be received. Watch the video to see just how close the antenna gets to going under water just when a manatee is pulling it slowly.

"The second category of tracking problems comes when the tag itself is actually damaged or malfunctioning, as a result of such things as alligators that bite them or boats that strike them, or just when the equipment malfunctions.

	Can you match the damages to these tags with the suspects below?
Suspect #1	Suspect #2	Suspect #3

"As of the last Friday, 4/02, there was still no sign of Anna, but at least her satellite tag had been found. Terry Doyle, an FWS biologist, went out tracking for us and recovered Anna's tag near Neal Key, Gullivan Bay. Now we know why we received no signals from it. There was a chunk missing from the collar around the tube, and the tether had been cut approximately 1 foot below the tag. But what caused this damage? We investigated the evidence pretty carefully, and we think we have a pretty good idea (and you can find out too when you read about CSI Manatee below). Since her satellite tag is not attached anymore, searching for her is unfortunately going to be very difficult.

So for now, we really don't know what has happened to Anna. On the one hand she may be fine, but on the other, its possible that whatever struck and damaged her tag may also have injured her. We'll keep our fingers crossed that no news is good news.


"As for Actual, there's good news! I finally located her alive and well last Wednesday March 31. Mario Alvarez, a biologist with Everglades National Park had flown an aerial survey on March 19 but received no location signals, and since we received no satellite signals since March 13, we had been concerned. But I found Actual using VHF tracking in some grassbeds offshore of Cape Romano. And her tag is floating and the VHF seems to be functioning properly, but we still haven't received any satellite location data. Jim is planning a trip down there this week to try to get a new tag on her. We will keep you posted.

"To find a manatee in the field we start wide and then work to narrow the search to a specific location. But sometimes we can't start wide, and we have to start with the narrowest approach. Why? And now that you know the latest news on Anna and Actual, are you also wondering?:

• what damaged Anna's tag, and can we tell what's happened to her?
• how did biologist Terry Doyle go "tracking" for Anna?
• how do you still track a manatee like Anna, who's transmitter isn't attached?
• what did biologist Mario Alvarez use in the aerial search for Actual?

"Find out how we search, what evidence we look for, and who might be the suspects?"

Could they be suspects? Link to CSI Manatee
Photo Credit: USGS-Sirenia

	Third graders Jennifer, Ashley and Mary from Linda Thurber's class in Vermont, and several groups of seventh graders from Iselin Middle School in Iselin, NJ, all correctly calculated that the manatee eats 100 to 150 pounds (10% to 15%) every day!
A giant Salad Bar eaten all in one day! Credit: Mote Marine Laboratory

Pizza Percentages
But how does that convert into 1 pound pizzas? If a human ate 10% to 15% of her/his own body weight in pizza, how many pizzas would that be? It all depends on what their individual weight is:

	Hey kids--you all did a great job--and we at Journey North hope you did your pizza calculations in the classroom and not in the kitchen--that's way too much pizza to eat!

Here are some pizza percentages from Linda Thurber's students and from Iselin Middle School. Learn how they figured their own pizza intake--Bon Appetit:

"This group of girls weighs between 50 to 85 pounds. So that means that they would have to eat between 5 to 12 pizzas a day. That's a lot of pizza. We would get sick of it. We can't even eat more than two slices a meal!!!"
Jennifer, Ashley and Mary from Linda Thurber's class

"Our group average weight is 100lbs. Therefore, if we had to eat 10% and 15% of our weight every day, we would have to eat 10 to 15 pizzas every day ." Kiran, Morli, Smriti, Shannella, Iselin Middle School

"One member of our group weighs 104.5 pounds. This person must eat 10.5 -16 pizzas in one day to equal 10% to 15% of the body weight."
Fawad, Michael, Tiffany, Hiral, Iselin Middle School

"If one member weighs 132lbs, in order to eat 10% of his weight, he must eat 13.2 pizza pies and at 15%, 19.8 pies each day."
Indragit, Perry, Allison, Nikhar, Iselin Middle School

Do you know what the light-colored objects are on the back of this manatee?
	Some marine mammals can carry up to a ton of these on their body--what a drag! Next time we'll tell you more.
Photo: Naples Daily News

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