Migration Update: April 14, 2004
Since my last report, two important things have been 'changed' on two of the manatees. As you may remember, no ARGOS satellite signals had been received from Actual's tag for some time; and recently Belvedere's tag had not been functioning properly either. So my fellow Sirenia Project biologist, Jim Reid, actually removed and replaced Actual's and Belvedere's tracking tags. Here's the amazing part--Jim did this all without ever recapturing the manatees.
"Although Jim is a veteran tagging and tracking expert, this type of tag change procedure (called 'free tagging') can be difficult and dangerous. How do you think Jim went about doing this? Do you think you could do it? Just put yourself in his place, and remember how big manatees are! Actual is 298 cm in length and weighs 980 lbs.; and Belvedere is even bigger and heavier measuring 312 cm in length and 1,089 lbs. Do you think you could do the duty?
"When Jim removed Actual's original PTT/VHF tag, he replaced it with one of the new GPS tags. This will be an improvement in the tracking data we receive from Actual, since the GPS tracking tags can record more locations per day, and are usually very accurate too. See Satellite Tracking and Manatees
"As you can see from the latest Tracking Maps and Data, the manatees have not made any unexpected movements since the last report. For those of you following Actual and Giffer, they were still located near Cape Romano. And Belvedere remained in the north, while Leslie had just moved out of Turner River. There is still no news on Anna.
"I'll update you again soon."
to Latest Data and Individual Manatee Maps:
Try This! How Big is Big Belvedere?
Complete this sentence with what you think is accurate: "I think that Belvedere is as big as a _________." (Susan told us that Belvedere is 312 cm in length and 1,089 lbs.) So, what comparisons can you make? (A horse? A car? What can you find that 'weighs in' close to Belevedere?) To help you get a real-life idea of how big he really is, try taping or using chalk to draw a life size outline of big Belvedere on your classroom or playground floor (with permission of course).
More Manatee Adaptations: Skeleton, Flippers and Fat
We've already discussed several unique Manatee adaptations so far, and this week is going to be no exception because we've got a few more to feature.
Saline and Skin-the Barnacle Connection
Some manatees have visible organisms living on their skin. "Mossback", a manatee at Blue Spring, was named that because of a moss-like algae living on its back.
Did you know that barnacles can also live on manatees' skin? Have you ever seen a barnacle up close? They look like hard shells that bunch up on the bottoms of boats and on pier posts and shoreline rocks. But they are really much more. Inside the hard exterior, an active living organism exists. And you can actually see it coming, reaching out of the shell, like a feather, combing the sea water for food. (Take a look at this video within the Lesson below)
Barnacles can accumulate in massive amounts on whales, and adult gray whales have had up to a ton of barnacles on one whale's skin. Can you imagine what that would be like? What a drag! Just look at the amount of barnacles accumulated on this buoy!
Fortunately, barnacles do not accumulate as much on the skin of manatees. But why? Take a look below, and think back on what you learned already about how a manatee's migration is affected by the salinity of the water. Then come back and try the Journaling Question below:
This! Jounaling Question:
A Lone Ranger (Wayne) at Blue Spring?
But in the meantime, I've gathered this data for several days leading up to the season's end. Can you figure out what factor led to fewer manatees swimming into the Run? Here's a hint-- the same conditions that operated to bring the manatees into the Run now act in reverse to send them out of the Run. To illustrate, see if you can answer:
*(All temperatures are in degrees Celcius; "nt" = temperature not taken)
I'll be back
Manatee Math: CSI Lab Investigation
As you know, the manatee is an endangered species, and because of this scientists closely investigate the causes and number of deaths. This often involves using forensic procedures in the laboratory--sound like CSI to you? Earlier this year, the Florida Marine Research Institute published its Manatee Mortality Totals for 2003. The statistics are summarized below, along with background on the mortality categories, so you can uncover what evidence leads to classifying these deaths. After reviewing those, see if you can answer the Challenge Question below (Note to Teachers: some mortality photos in the Mortality Categories are graphic, so please preview and decide if you they should be used by your students):
How to Respond to Today's Challenge Questions:
IMPORTANT: Answer only ONE question in each e-mail message.
an e-mail message to: email@example.com
The Next Manatee Migration Update Will Be Posted on April 21, 2004.
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