Manatee Manatee
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FINAL Manatee Migration Update: April 18, 2001

Today's Report Includes:

Special Thanks to the Manatee Scientists!
As our manatee migration season comes to a close, we'd like to thank our dedicated scientists. In addition to their already busy jobs, each found extra time over the past 4 months to share their research and knowledge about manatees with us. Journey North would not be possible without the dedication of scientists like these, who contribute their expertise voluntarily.

Thank you Cathy Beck, Jim Reid, Bob Bonde, Susan Butler, Dean Easton, Bruce Ackerman, and Ranger Wayne Hartley for another fantastic season studying the manatees!

Want to Say Thank You?
If you'd like to write and thank the scientists, their addresses are provided at the end of this report.

Good-bye From Cathy Beck

"This has been an exciting year for us with the radiotagging and tracking of manatees in a new region! We began this season knowing very little about the manatees in the western Everglades and how this group of manatees uses the Florida Everglades habitat. From the observations and data collected on the six tagged manatees tracked this year, we are beginning to learn a lot!

From Questions to Insights to Hypotheses

"Each day, as we received the manatee's locations from the satellite, Susan and Jim would plot the locations on our maps to see where (or if) they had moved. Then the questions would fly - Why did she go there? What's there that she likes? Why did she take that route? Why did she stay so long? Leave so quickly?

"We cannot claim to have answers to these questions yet; but we are learning and we hope that you have learned along with us. I know many think we will have immediate answers and explanations for what manatees do, and why, where they are going, and why. From our research we gain only insight, and with enough insight we eventually formulate hypotheses, but rarely are we so confident to believe we have any absolute answers!

What Manatees Teach US!

"If you have been with us in past years, you know that I have spoken about what manatees teach us, and the dangers they face every day. Manatees encounter numerous hazards in the world that they must share with people, more and more people each year. Much emphasis has been placed on the high number of manatees that are accidentally killed by boats each year, a source of mortality that could nearly be eliminated if we'd just slow down.

"But entanglement injuries, and sometimes deaths, are increasing as well. Discarded monofilament fishing line has wrapped around the flippers of many manatees resulting in horrible scarring or even the loss of the flipper, and sometimes death. Of course this type of debris in our marine environment can hurt many other species as well.

"All of us at the Sirenia Project are encouraged that so many students are truly interested in the plight of manatees, and other endangered species; and that you are willing to learn about the science, the animals, and the issues that surround them. Thank you very much for joining Jim Reid, Susan Butler, Dean Easton, Bob Bonde, and me to learn more about manatees this year.

"And thanks for all your great answers to the Challenge Questions - what good thinkers you all are! We have enjoyed our Journey North adventure and sharing our manatee information with you.

It's Worth It!

"Please remember that the only way to help a species is to learn what it needs to survive (minimally food and safe habitat - just like us), then work to protect those needs. Providing for other species will require sacrifices on our part, but I feel that is our obligation as humans, and isn't it worth it?

Final Field Notes
Latest Migration Map
Click to enlarge

"It's the end of another season, and I'm glad to report that all the manatees we've been tracking are doing well.

Latest Satellite Migration Data

"Right now, Grace remains in the Marco area, and has been going between Cape Romano and the canals of Marco. Do you have any ideas about why she is using these two areas so heavily? (Be sure to read about Grace's GPS data below).

"Nina continued to use the canals of Marco Island too, but moved out into Tarpon Bay early this week! Addison has also been in the Marco area near the mouth of Three Island Cove and Bear Pt. Cove, as well as Tarpon Bay, Unknown Bay and Charity Island.

"To the east, Santina is spending more time out in Gaskin and Chokoloskee Bays, and Megan is still moving between POI and the area around Turtle Key.

"And to the south, Surfer has remained near the mouth of Lostman's River and Broad River Bay.

Grace Goes GPS!
"As I mentioned earlier, Jim and Dean successfully retrieved the GPS tag from Grace, and now we have some preliminary data interpretations about her use of the habitat. We also have two GPS maps that are real eye openers! The maps show her movements from March 1-7 and March 7-15 in very fine detail--and now you'll understand why its called the 'Ten Thousand Islands' area! (We don't include the GPS data itself because there were over 1,047 location datapoints!).

March 1-7

March 7-15

"On the first GPS map, Grace moved from POI down the canal and out toward Hog Key, arriving there on 2 March. By 4 March she reached the canal on the east side of Marco Island. Why does the map show her going through an island? She likely traveled north of the island (not through it!); but because she was traveling, her tag was pulled underwater and the GPS locations did not fix. On 5 March she was in the Cape Romano seagrass beds, moving even farther out to a shallow water area on 6 March, then back into the grass beds on 7 March. At nearly midnight on 7 March she was back in the residential canals on the west side of Marco Island.

"On the second map, it looked like she was heading back to the Cape Romano grass beds on 8 March, but instead she moved back to Hog Key, then into POI on 9 March. Early on 10 March she came back to Hog Key, returning to POI again on 12 March. On 13 March she left POI and took the more eastern route around Panther Key to again reach Hog Key. She meandered around Hog Key, then Gullivan Key and Turtle Key to the west, before following a deep channel into Santina Bay, where the GPS tag was removed on 15 March.

Preliminary Interpretations
"During both weeks that Grace carried the GPS receiver, she spent much of her time at Hog Key, where there is a small seagrass bed. Other manatees we are radio tracking also are visiting habitats just outside of the many small islands in the Ten Thousand Islands area. The numerous small seagrass beds in these less sheltered areas are apparently very important to this group of manatees. We have not determined why the manatees are using the canals at both POI and Marco Island, but it may be to drink freshwater (from underground seeps, surface runoff, or residential hoses) and for quiet areas to rest. (These canals have less, and slower-moving, boat traffic.)

Manatee Tags--Beeping or Listening?
"Did you notice anything unique about how the scientists obtain data from a GPS tag, as opposed to the customary Radio tag? Jim Reid explains that the two methods are fundamentally different."

Cathy A. Beck
Sirenia Project

Ranger Wayne's Season Summary and Final Roll Call

Ranger Wayne Hartley
Alone in the Run

"The season started on 17 November 2000 and came to an end on 2 April 2001, when I counted two manatees in the run. Since that time, I've not counted any manatees in the run. (See roll call data below)


Air Temp Low(C)


River Temp (C)

Run Temp. (C)

# of Manatees





































"Between those dates we saw 152 individual manatees, a new record by twenty. Twelve of these were calves, equaling last yearís record. (We only reached that because Ann brought in her twins, Amanda and Amber on 5 March.)

"Our highest single count was 96 on two different days. We saw 114 during the course of a day, one below our record. The season was one of the coldest in years, but as February came on it became one of the warmest.

"The manatees and boaters went out to play and we had a record seventy boat strikes recorded during the season as a result.

Hope to see you next year!
Ranger Wayne Hartley

"Destiny was captured and taken to Sea World with her calf Doom. She was starving, perhaps due to plastic obstructions in her bowel. She was there to nurse Amber when she arrived at Sea World. Amber's mother Ann had abandoned her at Blue Spring. Manatee mothers with twins appear to have a problem counting past one!

"I have enjoyed sharing the Blue Spring data with you again this year, and I hope you have enjoyed learning more about the manatees and the perils they face in the world they share with us humans. Hope to see you next year!"


The Human Touch

Growing By The Minute!

Ever wondered what the human population estimate for your U.S. hometown is? The world? Check out these popular population sites:

"Human population is increasing in Florida at alarming rates and existing growth management legislation doesn't seem to be doing much to curb it," said Patti Thompson, Staff Biologist for Save The Manatee Club (SMC). "More humans mean less habitat for manatees and other wildlife. So, in addition to better law enforcement, we also need better growth management

Increasing human population impacts the manatees in many different ways, and one of the most significant is damage to the seagrasses, the primary food of the manatees. Dr. Ackerman says that "seagrass beds are very sensitive to having good water clarity, and seagrasses are declining in some areas due to poor water clarity. And pollution continues to increase in some areas, from pesticides and herbicides, urban run-off, and septic tanks. That causes problems for seagrasses too. After all, it is every bit as important to have enough habitat for manatees. You can't have enough manatees without enough habitat!"

Three New Manatees: Discussion of CQ #23
Challenge Question #23 asked "What possible reason(s) can you think of to explain why Leslie is heavier than Anna?" If you did the extra credit calculations, you saw that Leslie and Anna were very close to each other in length, but their weight difference was pronounced!

(a) Leslie is only 2 cm shorter than Anna, which is 99.36% of Anna's length.
(b) In contrast, Leslie is 160 lbs. heavier than Anna, which is 112 % of Anna's weight?'

So what's the reason for the big difference in weight? The answer--Leslie is pregnant!

GPS Unplugged: Discussion of CQ #24
"Why do you think Grace's GPS tag did not collect a location fix for ALL of the GPS observations?" was the focus of this Challenge Question.

Cathy Beck explained that if a manatee is swimming, pulling the tag underwater, the satellite and the tag are not able to communicate, and therefore are not able to obtain a fix on the manatee's location.

Surfing North: Discussion of CQ #25
In this Challenge Question, we asked "Did Surfer swim north of any of the other manatees on any date in March? On the date of Surfer's northernmost location, which other Manatee was she closest to?"

Surfer was farthest north on March 28, when her location was
25.69 N, -81.34 W. On that date, the manatee closest to her was Santina, whose coordinates were 25.80 N, -81.43 W.

Landlocked? Discussion of CQ #26
In this Challenge Question we asked "What reasons can you give to explain why one of Nina's 3/27 datapoints plots on land? Is she actually on land?"

According to Cathy Beck, Nina was not on land. Instead, what we have is a datapoint that is of doubtful quality--something that scientists must assess on an ongoing basis as they review and evaluate their data. Locations datapoints obtained with transmissions using the ARGOS satellite provide quality ratings on a scale of 1 (low quality) to 3 (high quality). The landlocked datapoint for Grace here is explained by the Quality (1) reading of the data received by the satellite. Actually, Grace had hardly moved at all.

Things Are Heating Up! Discussion of CQ #27
In this Challenge Question, we asked "Can you think of any reasons other than cold temperatures that might have caused the large number of manatees in the run on 3/22?" It's mating season! Ranger Wayne explained that the high number of manatees in the run on even warmer days was due to the fact that it was mating season--a time when many males will follow a female manatee.

"Where the females went changed the number of manatees in the run more than water temperature. For example, on March 22, we counted 40 manatees in the run. But only 10 to 20 were here because of the river temperature change--the remainder had come in the run chasing females."

Scientist Says: How Scientists Communicate Research Results
One of the most important steps in a scientist's work is sharing research results with other scientists. This is how the body of scientific knowledge is built--and how it constantly changes as new research findings replace the old.

As a way to synthesize your learning this spring, write your own scientific paper based on the Manatee research you have witnessed--just as the scientists are preparing to do! This lesson guides you through the steps of writing a real scientific paper:

A Sea of Resources
Just because the Manatee season is ending, don't let that put a stop to your interest in Manatees! Check out the manatee resource page for many links to information, ways to take action, and other helpful resources.

Send Your Thanks
If you liked tracking and learning about the manatees this year, let the scientists know! Write and thank them--here are their addresses:

Cathy Beck, Jim Reid, Bob Bonde, Susan Butler and Dean Easton
Sirenia Project
412 NE 16th Ave., Room 250
Gainesville, FL 32601

Ranger Wayne Hartley
Blue Spring State Park
2100 West French Ave.
Orange City, FL 32763

Dr. Bruce B. Ackerman
Research Scientist
Florida Marine Research Institute
Florida Fish and Wildlife Conservation Commission
100 Eighth Ave. S.E.
St. Petersburg FL 33701-5095

Year-End Evaluation: Please Share Your Thoughts!
Please take a few minutes to share your suggestions and comments in our Year-End Evaluation Form below. The information you provide at the end of each year is the single most important tool used to guide our planning.

Journey North
Year End Evaluation
Please share your thoughts

We hope you have enjoyed learning about the Manatee this spring.

This is the FINAL Manatee Migration Update.Have a great summer! Thanks for your participation.

Copyright 2001 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form

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