Manatee Migration Update: March 19, 2003
Field Notes from Cathy Beck
Hi Students:
We had warmer temperatures again last week, and Susan Butler reports that the manatees continued to use the outer islands and associated grass beds. However, several manatees have been making occasional trips back to Port of the Islands (POI) and back up the other rivers. Take a look at the latest manatee maps and data. Can you tell which manatees have recently been back to POI and up in the rivers? Why are they coming back inland? Think about what a manatee needs to survive, and then see if you can answer:
(To respond to this question, please follow the instructions below.) Farewell to Daring Dean Dean is going to work with the U.S. Fish and Wildlife Service at the Okefenokee National Wildlife Refuge. Good luck Dean! Cathy Beck You Made the Call! Discussion of CQ #16 Here is the moment you've all been waiting for--see if you identified all of the Manatees correctly. But first, here's a note from Ranger Wayne:
If Ranger Wayne ever needs any help identifying the Manatees at Blue Spring, have we got the crew for him!
Nice work everyone! Now Playing: Can You ID This Moving Manatee? Now that you've mastered manatee identification from still photos, do you think you're ready to identify a moving manatee? That's what Ranger Wayne wants to know. You see, scientists like Ranger Wayne have to do this all the time, identifying manatees as they swim by, all the while making sure their observations are accurate. Here's your challenge. When Journey North's Julie Brophy was visiting Ranger Wayne, she filmed a manatee swimming by in the Blue Spring run. "Who was that?" she wondered. Well, of course Ranger Wayne knows the secret identity, and now he's putting you to the test. Do you think you can tell Ranger Wayne who the moving manatee is? Grab your gear--you'll need to view the video very carefully. What identifying features can you see on the animal through the ripples on the water? Compare the features you see on the manatee in the movie to the scar sheet below. Then, see if you can answer:
(To respond to this question, please follow the instructions below.) Climb in the Classroom Cockpit--What's Your Aerial Count? As you know, scientists like Airborne Ackerman count manatees from the air. Looking down from small airplanes and helicopters, getting an accurate count is hard work, and can be dangerous. Often you're flying low and slow with windows open, circling above an area to get a good view from the air. This aerial photo of manatees was taken high above the water from Dr. Ackerman's plane. Sitting in the comfort of your classroom chairs, can you count each and every one of the manatees that Airborne Ackerman counted on this flight? Take a good look, and see if you can answer the question he has sent you:
(To respond to this question, please follow the instructions below.) Instructional Strategy Spotlight: ListMaker Activity What do the manatees look like to you from up in the air? Remember Airborne's Ackerman's favorite description that they looked a little like Rice Krispies in coffee? But we bet you can come up with some other descriptions. What do the manatees look like to you? Brainstorm a list of all the things you can think of that manatees might look like to you from an airplane. What's the Explanation for the Exodus at Blue Spring? Ranger Wayne reports that the number of manatees in the Run has been getting fewer and fewer. "Counts of 70 to counts of 1-6 manatees almost overnight!" Can you figure out what is causing fewer manatees to come into the Run? Take a look at the most recent data from Ranger Wayne and see if you can answer:
(To respond to this question, please follow the instructions below.) What Drives the Dark Water? A Tale of Two Rivers What happens when two rivers meet? If you're the St. John's River and the Blue Spring "Run", the answer is "a lot". If you were actually in Ranger Wayne's canoe, you would see that the dark water of the St. John's River looks like dark tea or coffee, 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 draws the location where the dark St. John's River water meets the clear water of the Blue Spring Run? On every Attendance Sheet he draws heavy dark lines or dark shading at the top of the Attendance Sheets to show how far the dark River water extends into the Run. (See Attendance Sheets in the experiment below)
Need a Hint? Try This! (To respond to this question, please follow the instructions below.) How do you Say "Florida Manatee" in Science-speak? Did you know that scientists discovered a long time ago that they needed a universal language for talking about animals and plants? They created a system called "taxonomy", which is a way of classifying things into established categories. Taxonomic classifications are used throughout the scientific community, and most living things are classified using these categories. Taxonomy may look complicated, but the approach is quite simple. You put things into established categories, starting with the broadest and most inclusive category, and progressing to the narrow and most specific. The basic categories, moving from broad at the top to narrow at the bottom, are:
How is a manatee described using taxonomic terms? How does a manatee compare to a human being? How do you ever remember this list of taxonomic categories? Read on for the full story and tips: Saying It in Fewer Words: Binomial Nomenclature Scientists often refer to a species using only two parts of the taxonomic system, and this is called "binomial nomenclature." This method identifies a species with two words that are usually Latin words. The first word is the genus of a species, followed by a second word which is the species name--example: Homo sapiens. Until this system was developed, often it was difficult to tell whether two authors were referring to the same species.
(To respond to this question, please follow the instructions below.) Answers from the Manatee Expert
FAQ's About Journey North Species Grab Your Boarding Pass: Discussion of CQ #13 Many of you came up with ideas of what kinds of living and non-living things might be mistaken for a manatee from the airplane. Just take a look at some of your "cockpit comparisons":
Looking for Footprints on Water: Discussion of CQ #14
Airborne Ackerman said that "Excellent answers, kids! When manatees are swimming along, they leave a distinctive mark on the surface of the water. Their tail (fluke) goes up and down when they are swimming, and every time it goes up, it leaves sort of a swirl on the surface of the water. We call it a 'footprint', since they are left behind the manatee as it travels along, but of course it really is not really like a footprint at all. "The 'footprints' are visible even when the manatee is not visible because it is down under the surface of muddy water. Sometimes the location of the manatee can be tracked along clearly, without ever seeing it. Also, manatees that are feeding on seagrass often create a cloud of mud by pulling up grass stalks and stirring up the bottom. We call this a 'mud plume', and when there is a slight tidal current, this plume is clearly visible downstream of the manatee." Why are Aerial Manatee Count Numbers Controversial? Discussion of CQ #15
"What conclusions can you draw about the size of the Florida manatee population from the fact that this year's count is higher than last year? What if this year's count had been lower than last year?" This year's higher counts do not reflect any significant increase in the Manatee population. Rather they show only that visibility was better due to the weather conditions. As you know, the counts can be highly variable due to weather conditions, which can work both ways. For example, last year's prolonged warm temperatures, during one of the longest warm spells on record, contributed to the low manatee count. As you can see, the number of Manatees counted from one count to the next can be the result of many things that may or may not be related to the actual population size. Be careful with numbers. They are very exact--but sometimes their meaning may not be so clear or complete. That is why we use additional methods to evaluate the overall status of the Manatee population. We use photo identification; we track individual animals' movements; and we perform necropsies on Manatees that die throughout the year; and we include all that data in assessing the populations. How to Respond to Today's Challenge Questions:
1. Address an e-mail message to: jn-challenge-manatee@learner.org
Copyright 2003 Journey North. All
Rights Reserved. |