Manatee Manatee
Today's News Report Your Sightings How to Use Journey North Search Journey North

Manatee Migration Update:February 21, 2001

Today's Report Includes:

Welcome Back Dr. Bruce and Ranger Wayne!
It's great to have manatee experts Dr. Bruce Ackerman and Ranger Wayne Hartley back again, letting us "fly" and "paddle" along during their important research.

Dr. Ackerman is a manatee biologist and population expert with the Florida Marine Research Institute. He has been in charge of the state's annual aerial census of manatees for many years. This year's first census counted a record number of manatees, and Dr. Ackerman is ready to share the results--and a few questions--with you.

Ranger Wayne Hartley also has record-breaking news on the wintering manatees at Blue Spring State Park. He has been with the Florida Park Service since 1974, and has worked with manatee research there since 1979. Each day, he conducts a manatee "Roll Call", where he identifies each individual manatee and collects other key data.

Airborne Ackerman!
"Hello Students--It's great to be back with you for another Manatee season with Journey North! We've completed the first aerial census of manatees for 2001, and I'm eager to share the results with you.

A Record Year!
"On January 5-6, 2001, 16 crews of observers in small planes and helicopters and 9 crews on the ground counted manatees at all the wintering sites on both coasts. The final count was a record 3,276 manatees. The previous record was 2,639 back in 1996, so we're thrilled by this year's record count of manatees.

Why the Difference?
"Based on my past experience, counts can be highly variable due to weather conditions. Prolonged cold temperatures, one of the longest cold spells on record, contributed to the high count this year.

A Rx for Surveys
"Biologists have a prescription (Rx) of favorable weather conditions for manatee surveys:
  1. A prolonged cold front,
  2. A significant drop in water temperature, and
  3. A sunny and windless day following the cold front"

Challenge Question #8:
"Why is this the perfect prescription for manatee surveys? Give reasons why you think each of the three weather factors might make counts higher."

Challenge Question #9:
"Why might the prolonged cold spell that contributed to the high manatee count also have a negative impact on the manatee population?"

Challenge Question #10:
"Look at the Sea Surface Temperature Maps below. If you were a manatee scientist, which day would you choose to conduct your manatee count? A, B, or C? Why?"

A

B

C

Click on maps to enlarge.


(To respond to these questions, please follow the instructions below.)

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

A Record Season for Ranger Wayne

Ranger Wayne Hartley

One of the manatees' favorite Florida hangouts is Blue Spring State Park near Orange City (28.940N, -81.338W). Each winter, many manatees swim from the adjacent St. John's River into the "run" at Blue Spring, which is like a creek that "runs" for 1/3 mile from the park into the River. Ranger Wayne reports that it's another record breaking season:

"Hello Students:

"The official day for the start of the manatee season at Blue Spring was 17 November. But even before that, in October, several manatees were seen here in the run as far up as the Boil. October was as cool all month as it usually is at the end of the month. By the end of November, I had seen over 100 manatees.

"To date we have seen 146 individuals, a new record for a season. (Last year was a record year too, but only had 132 manatees) One day I saw 96 for the morning count, far from the 107 on 27 Dec. last season, but still a lot of manatees. I also happened to see 114 during the course of a day, one short of the record during a synoptic survey last season. My count for the first synoptic survey this season was 112.

"Calves seem to run in high low cycles. The highest was 12, last season, and the low this season is 10. I can live with that!"

Ranger Wayne Hartley
Blue Spring State Park

Canoe Count
Each day, Ranger Wayne canoes into the "run" to conduct his manatee "Roll Call." In addition to identifying each individual manatee and counting the total, he also measures water temperatures in the "run" and the river, and the high and low air temperatures too.

A sample of Ranger Wayne's data for this season is below. Discuss the changes that you see from one date to another, and then see if you can answer:

Challenge Question #11:
"Can you see a pattern or trend in Ranger Wayne's data that might explain the changing number of Manatees counted in the run at Blue Spring each day?"

Date

Air Temp Low(C)

Air
Temp
High(C)

River Temp (C)

Run Temp. (C)

# of Manatees

11/21

nt

nt

20.1

nt

39

11/24

9

21

17

22.5

85

12/09

16

29

18

nt

50

12/18

1

31

20.2

22.3

9

12/23

3

23

13

nt

85

01/02

-3

12

11.5

nt

92

01/22

0

30

16.5

nt

59

01/27

4

23

14.9

22.2

37

02/06

3

23

nt

nt

57

02/10

15

30

18

nt

4



*(All temperatures are in degrees Celcius; "nt" = temperature not taken )

(To respond to this question, please follow the instructions below.)

Field Notes From Cathy Beck
"As we reported in our unscheduled News Flash on 2/14, six new female manatees were successfully captured and tagged in southwest Florida. Three of the six--Megan, Addison and Grace--had been named by the time of the News Flash. The other three were named a little later--Nina, Santina and Noel.

Be sure to visit last week's News Flash and see if you can answer the Challenge Questions too:

"Unfortunately, one of the tagged manatees, Noel, has since been recovered dead. Apparent signs at this time are chronic stress from cold winter weather, but we hope to learn more about the exact causes of her death.

Today's Satellite Migration Data
(Courtesy of U.S. Geological Survey's Sirenia Project)

Sea Cow Conversions
"The first tracking data for the new manatees (and Surfer) are near the base of this report, with some additional details and background too. Test your measurement conversion skills with this short summary of their length and weight at the time of tagging:

Challenge Question #12:
"What are the new manatees' lengths in inches, and what are their weights in kilograms?"

Name Length(cm) Weight(lbs.)
Megan 319 cm 1,085 lbs.
Addison 248 cm 680 lbs.
Nina 270 cm 885 lbs.
Santina 285 cm 990 lbs.
Grace 286 cm 970 lbs.


(To respond to this question, please follow the instructions below.)

Surfer Side Trip
"Meanwhile, Surfer's been making her way back north since the last report. My fellow scientists Jim Reid and Susan Butler reported that 'she found time for a side trip up the Broad River.'

"Take a look at Surfer's travels these past few months and compare it to her latest data below and see if you can answer:

Challenge Question #13:
'Why do you think Surfer would swim up a river? Are there any daily conditions that you can think of that might affect when she would leave the ocean and head up river?'"

(To respond to this question, please follow the instructions below.)

Cathy Beck
Sirenia Project
Gainesville, FL

Surf's Up! Discussion of Challenge Question #1
On 2/7 we asked "Can you figure out where Surfer was released? Using the latitude and longitude provided for 6/22/00, name the nearest large coastal city."

Surfer was released at Rookery Bay in Collier County on June 22, 2000 (26.161N, 81.695W), and the closest large coastal city is Naples.

Discussion of Challenge Question #2
We asked "Using Surfer's latitude readings, can you determine how far south she migrated between June 22, 2000 and January 1, 2001? Between November 22 and 26, 2000? During these November 22-26 dates how many miles per day did she travel on average?"

Surfer's June 22, 2000 and January 1, 2001 latitude readings are 0.953 degrees apart; her November 22 and 26 latitude readings are 0.429 degrees apart. By using the worksheets from the Latitude, Longitude and Distance Traveled lesson, you would have been able to calculate that the distance between latitude degrees was as follows:
  • a change of 1.0 degree latitude = 69.00 miles
  • a change of 0.1 degree latitude = 6.9 miles
  • a change of .01 degree latitude = .69 miles

Multiplying 69 miles by 0.953 or by 0.429, we learned that Surfer traveled a distance of approximately 65.757 miles/105.211 km between June 22 and January 1; and 29.601 miles/47.362 km between November 22 and 26. On average between November 22 and 26, Surfer traveled approximately 7.4 miles/11.84 km per day. (To convert the mileage distances into kilometers, simply multiply the mileage by 1.6).

Discussion of Challenge Question #3
"Can you explain WHY Surfer might have moved WHEN and WHERE she did between November 22 and 26? Plot her travels between those dates. Then find Florida on the SFSU weather maps and study them for the dates November 19-22"

The SFSU weather maps for the dates November 19-22 show that temperatures near Surfer's Ten Thousand Islands location dropped dramatically just before she headed south. Cathy Beck notes that "through October, Surfer used habitat in the Ten Thousand Islands region, then in Nov. made a move south to Whitewater Bay. Her move south coincided with the first cold front of our winter season (over Thanksgiving weekend)."

Cold temperatures can be a serious threat to the health of manatees. Cathy notes that "Manatees are susceptible to cold-related disease, and in the winter they gather near warm water sources such as natural springs or warm water effluents of power plants."

Manatee Ask the Expert Now Open!
We're lucky to have Nancy Sadusky back as our expert for her fifth year to answer your questions! Nancy is the Communications Director of Save the Manatee Club. Hurry, Nancy will accept your questions until March 2.

How to Respond to Today's Challenge Questions

IMPORTANT: Answer only ONE question in each e-mail message.

1. Address an E-mail message to: jn-challenge-manatee@learner.org
2. IMPORTANT: In the Subject Line of your message write: Challenge Question #8 (OR #9, OR #10 or #11 or #12 or #13)
3. In the body of the EACH message, give your answer to ONE of the questions above.

The Next Manatee Migration Update will Be Posted on March 7, 2001

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

Today's News Today's News Report Your Sightings How to Use Journey North Search Journey North