Manatee Migration Update: March 6, 2002
Today's Report Includes:
Round Up the Airplanes! The Aerial Manatee Count Takes Off
The cold weather we were waiting for finally arrived last week! So on Wednesday Feb 27, on very short notice, we sent out word to mobilize 17 aircraft and many hurried volunteers to conduct the first Manatee Synoptic Aerial Survey of the year. Here's the message I sent out to the troops:
To plan an aerial survey, we look for the weather conditions to meet our prescription(Rx)
for a count. Ideal conditions include very cold weather, a significant drop in water
temperature, followed by clear, calm and sunny days. The cold weather is essential
because manatees are very susceptible to cold temperatures, which drive them to congregate
near warm-water sources such as power plants and natural springs, where observers
can make a count. Sunny days move manatees to the water's surface to warm themselves,
and calm winds allow smooth waters and good visibility for counting. (See Discussion
of CQ #6 at the end of this report)
to this question, please follow the instructions below.)
Field Notes from Cathy Beck: Amazing Manatee Migrations
The manatee migrations really were quite remarkable last week! After traveling far and wide since their initial release, four manatees did something very unique, and all on the same day to boot! Plot the recent data on your maps, or take a look at the current maps here.
Latest Satellite Migration Data
While you're at it, step back and take a closer look at Actual's movements so far this season. Are her movements equally exciting? Then, see if you can answer:
to these questions, please follow the instructions below.)
Field Notes from Ranger Wayne: Manatees, Gators and Otters?
It's been busy and interesting here at Blue Spring. Since the last report, there has been both good news and sad news. First the good news. On Feb 20 and Feb 28, two manatees, Bertram and Flash respectively, showed up for their first appearance of the season. It's always a relief when an animal returns to Blue Spring each season! Also, I think Lillith is in estrous. And, Peaches gave us an interesting display on Feb 24, when he was seen trying to eat air plants along the banks of the Run--his head and shoulders were out of the water!
We've had some sad news too. On Feb 23, we were notified of a dead manatee near the fishing dock just outside the Run. It was Pippi, the calf of Phyllis. There were no obvious indications of the cause of death, so we'll wait for results of a necropsy. Also, Destiny was showing signs of starvation, so on Feb 28 she was captured and taken to SeaWorld for treatment. This happened to her last year too, and we hope she recovers just like she did before. I'll keep you up to date about her. (Her calf Doom is staying here with us at Blue Spring this time.)
Here are the most recent Attendance Sheet data. Does the number of manatees in the run continue to respond to river water temperature changes, as you saw in the last Update?
Bye for now,
Ranger Wayne Hartley
Blue Spring State Park
Orange City, FL
How Do You Tell One Manatee From Another?
But wait! How do Manatee scientists like Ranger Wayne identify individual Manatees? How do they tell one from another?
Fortunately for the scientists, each Manatee has unique physical features that distinguish it from other Manatees. Unfortunately for the Manatees, most of their unique features are actually scars and injuries the Manatees received in collisions with powerboats. The propeller of a boat is like a spinning knife blade under water. When it strikes a Manatee, the Manatee is cut by the propeller blades, and may even lose a part of it's body, like part of it's tail. A boat motor can also cut a Manatee with a "skeg", which is like a vertical metal fin at the bottom of the motor. If the manatee survives the boat strike, it is left with unique scars, which scientists use for identification.
On a different scale, Ranger Wayne takes photographs and maintains a Blue Spring "Scar Sheet", which shows drawings of the identifying scars and features for the Manatees at Blue Spring. (You'll use this below.) And on an even smaller scale, if a scientist spots an unidentified manatee while snorkeling or scuba diving, she can still sketch the manatee's scars and markings on this waterproof plastic sketch template using a grease pencil.
It's Your Turn: You Make the Call! (Roll Call That Is)
But wait! Before you paddle up the Run and try to identify the Manatees, you'll need a few essential supplies to help you. Be sure you have these: Your Key, Sketch Worksheet, the Scar Sheet, and a few simple instructions to follow (oh, and your life jacket too, of course).
A Tale of Two Rivers
What happens when two rivers meet? If you're the St. John's River and the Blue Spring Run--a lot. From the canoe, you would see that the dark water of the St. John's River looks like dark tea, while the clear water of the Run is so clear you can see the bottom and everything in it!
Did you notice on the Attendance Sheets that Ranger Wayne records the changing location of the dark St. John's River water as it meets the clear water of the Blue Spring Run? Ranger Wayne draws heavy dark lines or shading at the top of the Attendance Sheets to show how far the dark River water extends up into the Run.
Need a Hint? Try This!
Raise Your Flipper When Your Name is Called: Discussion of CQ #4
In this Challenge Question, we asked your help interpreting some of Ranger Wayne's Attendance Sheets:
One Day They're Here, The Next Day They're Gone: Discussion of CQ #5
Ranger Wayne explained that it all relates to the River temperature:
Way to go Iselin! Several students answered this question correctly:
A Rx for Aerial Surveys: Discussion of CQ #6
In this question, we asked why the following conditions are the perfect prescription(Rx) to have an effective aerial census:
Manatees are extremely cold sensitive, and Dr. Ackerman explains that "the colder water temperatures cause the manatees to seek out warm water sites, and the warmer air of the sunny day encourages them to float. These conditions encourage the manatees to float at the surface, which makes it easier to see and count them."
You got it Ferrisburgh, VT students! Avery and Julie used their own weather experience to answer: "We think that there would be more manatees on the first warm day following a series of cold days because all the manatees would want to come up and travel to another spot to find more food. It would be easier to travel when the weather is nice. For instance, yesterday was the first nice day we have had in a while. It felt like spring. We were all running outside cheerfully when the day before we had been moving slowly in the cold and wind! It's a lot easier to move when the weather is warm."
Cape Romano: Discussion of CQ #7
In this question we asked "What do you think is attracting the manatees to the Cape Romano area?"
New Jersey's Iselin Middle School students Jaime, Kevin, David and Victoria wrote the Menu on Cape Romano: "We think that what is attracting the manatees to the Cape Romano area is the warm and shallow waters producing good food."
Cathy Beck confirmed that Cape Romano indeed has seagrass beds that draw manatees there to feed. Plus its not a bad looking place either--Dean described the manatees feeding there in "gorgeous emerald green water."
Coming in the Next Reports
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