Manatee
Migration Update: April 21, 2004
Today's
Report Includes:
- This Week's Manatee Migration Update
- Two Big Changes--Susan's Discussion of CQ #18
- Lone Ranger (Wayne) at Blue Spring: His Discussion of CQ #19
- Manatee Math: CSI Investigation: Discussion of CQ #20
- Earth Day is Coming- Take the Ecological Footprint Quiz
- Our Impact on Manatees
- What's This? Coming Next Week
- Year-end Evaluation: Please Share Your Thoughts!
This Week's Manatee Migration Update
This "CQ" Update discusses last week's Challenge Questions, plus several features for Earth Day too.
Two Big Changes--Susan's Discussion of Challenge Question #18
Hi Students:
Last week I reported that Jim Reid had retagged Actual and Belvedere without ever recapturing them, and I asked you: "If you had Jim's task to remove and replace Actual's and Belvedere's tags in the wild, how would you get close enough to them? How might they react? What suggestions would you give Jim about things to be careful of when tagging a manatee?"
Attaching a new tag to a manatee in the wild is quite an accomplishment! We have all the details on Free Tagging below, including Jim Reid's comments on how he retagged Belvedere and Actual.
| How
did Jim Retag without Recapture? |
 Credit: USGS-Sirenia |
I'll be back
next week with our final Manatee Update
Susan Butler
Sirenia Project
Lone Ranger (Wayne) at Blue Spring: His Discussion of CQ #19
Hi Students:
Well, it's that time of year! Yes, I'm all alone now at Blue Spring.
To understand when and why the manatees left Blue Spring this year, I asked you to look over a data chart of several final days there and "match the River water temperature with the correct date/line. The temperatures to select from are: 15.7, 19.4, 17.8, 16.1, 18.5, and 18.2.
| The Lone Ranger It
works like this: |
 |
To do that
matching, you needed to understand what conditions lead to the reduced
number of manatees in the Blue Spring Run. Basically, it's the same conditions
that bring the manatees into the Run initially, except in reverse. That
is, the water temperature of the River compared to water temperature of
the Run directly affects how many manatees are in the run. It works like
this: as the temperature of the River increases above 68F, more manatees
will leave the run because there is no more cold water threat outside
of the run.
Understanding this, everyone was able to make a sound estimate of how to fill in the River water temperature on the Blue Spring data chart. The more manatees in the run, the lower the river temperature, and conversely, the fewer manatees in the run, the higher the river temperature. Here's how the river water temperatures match up with the data chart:
| Date | Air Temp Low(C) |
Air
Temp High(C |
River
Temp (C) |
Run
Temp. (C) |
#
of Manatees |
| 02/20
|
2 |
20 |
15.7 |
22.5 |
128 |
| 02/21
|
4
|
18 |
16.1 |
22.4 |
88 |
| 03/12
|
2
|
23
|
17.8 |
22.6
|
39+ |
| 03/13
|
7
|
26
|
18.2 |
22.5
|
17 |
| 03/14
|
9
|
27 |
18.5 |
22.5
|
3 |
| 03/15
|
9.8 |
27.5
|
19.4 |
22.5 |
0 |
Great work! I'll be back with some final comments for the final report next week.
Ranger
Wayne Hartley
Blue Spring State Park
Manatee Math: CSI Investigation: Discussion of CQ #20
After we received FMRI's annual statistics on manatee mortality for 2003, we asked you to study the numbers and 'Fill in the blanks above: What percentage of the total 380 mortalities was caused by each category listed? Which category caused the most deaths?'
Here's how
the math works out. The specific manatee mortality categories each have
the following percentages of deaths (* rounded to the nearest 1/10th of
one percent):
2003 Florida Manatee Mortality Summary |
||
| Cause of Death | Number
of Deaths |
Percentage
of Totals |
| Watercraft | 73
|
19.2% |
| Flood Gate/Lock | 03
|
0.8% |
| Other Human | 07
|
1.8% |
| Perinatal | 71 |
18.7% |
| Cold Stress | 47 |
12.4% |
| Natural | 102 |
26.8% |
| Undetermined | 67 |
17.6% |
| Unrecovered | 10 |
2.6% |
| TOTAL | 380 |
100
%* |
Compared to the prior year, there was an increase in reported manatee deaths in 2003. 380 total manatee deaths were reported in Florida waters that year, compared to 305 in 2002 and 325 in 2001. Watercraft-related mortalities fortunately declined from 95 in 2002 to 73 in 2003, but that figure still shows that almost 20% of all manatee deaths were power boat related. Also, there was a very substantial increase in the number of natural deaths that occurred, with 102 manatees dying in 2003. This increase in "natural cause" deaths illustrates an important point about how delicate the manatee population is. Even if human-related deaths can be reduced, natural death outbreaks can result in large numbers of manatee deaths on their own.
Be sure to read next week about one of main causes of natural deaths in manatees.
Earth Day is Coming- Take the Ecological Footprint Quiz
Among all species, humans have the greatest capacity to shape and adapt to our physical environment. But ALL species have one thing in common: We all depend on the Earth for survival.
What can YOU do to help make it a healthier planet for all living things? This online quiz helps you think about what you use and how you live. You will be astonished!
The average U.S. citizen has a "footprint" that is more than five times larger than the world average. How do you measure up?
Try This! |
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Our Impact on Manatees
Manatees, like all animals, need food, water, shelter and space. The area where these requirements meet is called habitat.
Rapidly increasing human population in Florida impacts the manatees in many different ways, including their habitat.
| More people in Florida means more boats that have to share the waterways with manatees. |  |
|
Credit:
FWC
|
|
When you were mapping this year's manatee migrations, do you remember how they regularly visited certain offshore areas over and over to feed in the lush seagrass beds. But what would happen if the seagrass beds were threatened?
 Scarring of Seagrass beds |
 Manatee Sanctuary |
| Credit:
USGS-Sirenia
|
Credit: FWC |
Dr. Ackerman
indicates that seagrass bed damage is a risk with a growing population
in Florida. In addition to damage from boat propeller scarring, he 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!"
(More on seasgrass)
Journaling/Discussion
Question:
How do Seagrass beds provide the four elements of habitat?
What's This? What's Next?
Do you know what is shown in these two photos?
| How can something so small, "bloom" into something so big? | |
|
|
 (View from an airplane) |
Come back next week and find out!
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.
In the coming year, Journey North will be fundraising to secure increased support from foundations, corporations and individuals. Your supportive comments will be a tremendous help. Thank you!
Journey North
Year End Evaluation
Please share your thoughts
The Next Manatee Migration Update Will Be Posted on April 28, 2004.
Please send all questions, comments, and suggestions to our feedback form
