This document provides an overview of a central Florida freshwater turtle study being conducted at Wekiwa Springs State Park. The study aims to capture and collect data from multiple turtle species to estimate their population sizes. Researchers use marking and capture-recapture methods along with the Jolly-Seber model to calculate population point estimates and confidence intervals. Key turtle species discussed include snapping turtles, softshell turtles, chicken turtles, musk turtles, and cooters. Over 2,100 individual turtles representing seven species have been captured and measured since 1999.

1. Snappers and Stinkpots and
Softshells, Oh My!
An Overview of the Central Florida
Freshwater Turtle Study

2. This project is made possible by
funding from the Peninsula
College Teacher-Scholar Grant
and
Peninsula College Foundation’s
Floyd Young Scholarship

5. Eric Munscher
Jon Freezer Gabby Hrycyshyn
Josh Brown Andy Weber Joel and Emily Kuhns

6. Justin Brown Brian Hauge Brad Lidyoff
Satori Noël Angela Little

7. The Study Site:
Wekiwa Springs State Park

17. What we are trying to
accomplish with this study?
• Capture as many turtles as possible
• Measure them and collect data
• Mark them so we can identify them if
we capture them again at a later
date
• Use the data we collect to estimate
population sizes for each species

18. Since 1999, we have captured more
than 2,100 different turtles (of severn
species) and have had over 5,000
total captures.
For population estimation, we use
the Jolly-Seber Method, which
is appropriate for an open population

19. Assumptions of the Jolly-Seber Method
• Every individual has the same probability of
being caught.
• Every individual has the same probability of
surviving from sample time to sample time.
• Individuals do not lose their marks and
marks are not overlooked at capture.
• Sampling time is negligible in relation to the
intervals between samples.

20. What one page of data looks like…
(this particular data set is 96 pages long)
Wekiwa Springs State Park: Lagoon/Proximal Run
Pseudemys floridana peninsularis
Sample ID# Date CL (Max) CW PL (Max) SH Weight Sex Run Comments
16 1 3/8/2002 211 153 191 92 1100 F Damage L2, 11, R7
17 2 5/10/2002 256 170 222 101 1878 M
1 3 3/7/2000 357 242 318 153 6000 F
34 R3 3/7/2004 360 245 319 155 5900 F
46 R3 3/7/2005 360 246 319 159 5900 F
R3 8/20/2007 360 245 322 155 6000 F
17 4 5/10/2002 330 234 296 148 4950 F
R4 3/14/2008 365 258 325 159 6000 F Mark like damage L1, L12
3 5 3/9/2000 237 166 213 101 1800 F
1 6 3/7/2000 275 187 246 119 2300 M Exten dam post cara, crack R9-L11, 2 loose secs of cara
1 7 3/7/2000 331 232 309 144 5300 F
15 R7 3/7/2002 330 227 309 148 5400 F
1 8 3/7/2000 358 244 329 157 6100 F Only 11 scutes on right side
10 R8 3/8/2001 361 244 331 159 6000 F
17 R8 5/10/2002 361 244 331 160 6300 F Same
34 R8 3/7/2004 361 243 334 159 6000 F
47 R8 3/8/2005 363 245 333 160 6050 F Same
R8 3/19/2006 362 245 335 159 5900 F
R8 3/13/2009 365 245 335 162 6000 F 11 scutes on R-side
R8 3/19/2010 365 245 337 162 6400 F Plastron scarring, pits, missing l-hind foot.
1 9 3/7/2000 293 191 257 127 2800 F Very large notch in L4
8 R9 3/5/2001 311 194 271 133 3505 F Very large notch in L4
1 10 3/7/2000 212 152 185 87 1300 M
27 R10 3/13/2003 283 196 247 117 2606 M Reddish plastron
R10 8/17/2007 305 209 264 129 3750 M
R10 3/14/2008 305 209 264 128 3300 M
R10 8/16/2008 312 214 269 130 3600 M
1 11 3/7/2000 244 179 225 111 2200 F Ext cara dam (Posterior L9-R9), marginals nearly gone
26 R11 3/12/2003 313 224 287 139 4302 F Ext cara dam L9-R9, marg nearly gone (affects measurement)
1 12 3/7/2000 257 171 213 110 2150 M Cloudiness in right eye damage R8-9, R11-12, L9
1 13 3/7/2000 337 224 299 150 5200 F
36 R13 3/9/2004 340 226 301 151 5200 F plastron rub damage
R13 11/12/2005 342 230 305 152 5500 F
R13 3/19/2010 342 230 303 153 5300 F
1 14 3/7/2000 217 145 183 83 1400 M
1 15 3/7/2000 216 153 189 87 600 M
1 16 3/7/2000 297 194 259 124 2500 M
15 R16 3/7/2002 301 192 262 124 2894 M barrier

21. Time of Capture
Time of
Last
Capture A B C D E F G H I J K L M N O P Q R S T U
A 3 15 10 2 5 3 3 2 1 0 0 2 0 0 0 0 0 0 0 2
B 13 12 6 5 0 3 1 0 0 0 2 0 0 1 0 0 0 0 0
C 21 22 13 11 6 5 2 1 0 1 1 0 0 0 0 1 0 0
D 18 22 17 6 4 6 0 0 4 3 0 1 0 0 0 0 0
E 8 13 8 9 3 3 0 2 2 2 1 1 1 2 0 1
F 31 19 7 4 3 1 4 0 0 3 1 1 0 1 0
G 32 17 6 3 2 5 0 0 2 1 1 2 0 1
H 35 10 6 3 5 3 2 2 1 2 1 3 0
I 23 12 5 8 4 1 3 4 0 1 1 1
J 21 9 9 1 2 5 1 0 0 1 2
K 8 14 6 2 7 4 1 1 1 0
L 6 6 3 2 1 1 0 2 1
M 10 6 10 4 2 4 2 1
N 5 12 1 1 0 1 4
O 10 1 0 2 2 1
P 16 15 6 3 3
Q 20 3 3 7
R 8 8 12
S 13 9
T 31
U
Total
Marked (Mt) 0 3 28 43 48 53 75 77 80 55 49 28 62 36 23 59 36 45 31 41 76
Total
Unmarked
(Ut) 74 67 91 89 54 41 26 30 23 27 22 7 25 10 11 33 25 31 39 48 41
Total
Caught (Nt) 74 70 119 132 102 94 101 107 103 82 71 35 87 46 34 92 61 76 70 89 117
Total
Released
(St) 74 70 119 132 102 94 101 107 103 82 71 35 87 46 34 92 61 76 70 89 117
Total 77 70 129 147 108 111 126 127 122 96 78 38 92 47 38 102 61 84 77 107 152

22. Jolly-Seber is used to calculate a “Point
Estimate” (best guess) of the population size

23. • Jolly-Seber also provides estimates of:
– Recruitment (number of births and individuals
moving into the population
– Probability of survival from one sampling
period to the next.
• For our population estimates, we also
calculate 95% Confidence Intervals to
indicate the reliability of our estimates.

24. Population Estimate with 95%Confidence Intervals
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02 Jan-04 May-05 Oct-06
Point Estimate Lower Confidence Level Upper Confidence Level

25. Turtle Capture and Handling

26. Turtles 101 - Parts of a Turtle

27. More than 90% of the
turtles are captured by
hand while snorkeling.

32. A few turtles are captured
with hoop or Fyke nets
baited with sardines,
chicken, cat food, or
watermelon…

34. Checking the turtle
For previous marks

35. Sexing the turtle
(this one is female)

36. (this one is male)

37. Each Turtle
is Carefully
Measured
Carapace Length (CL)
Carapace Width (CW)
Plastron Length (PL)
Shell Height (SH)

38. CL CW PL
SH

49. 10
6
600
500
400
4
3
60
70
80
90
100
200
300
50
40
30
2
1
20
7
8
9
5

57. Turtles with limited captures
Snappers, Softshells, and
Chicken Turtles

58. Chelydra serpentina osceola
“Florida Snapper”
• Distribution: This
subspecies of the common
snapping turtle is restricted
to peninsular Florida. The
species ranges from Nova
Scotia to Central America.

59. Chelydra serpentina osceola
“Florida Snapper”
• Diet: This species is
omnivorous, essentially
consuming anything it can fit
into its mouth. It eats both live
prey and carrion, and both
algae and higher plants.

60. Chelydra serpentina osceola
“Florida Snapper”
• Size: This aggressive turtle
can reach 49.5 cm (19.5
inches) in carapace length.
Males are larger than females.

61. Chelydra serpentina osceola
“Florida Snapper”
• Reproduction: Clutch
size is 6 to 100 eggs
(usually 20-40). Eggs are
tough and spherical (23-
33 mm in diameter) and
take 75-95 days to hatch.

63. Apalone ferox
“Florida softshell”
• Distribution: Southwestern South Carolina and southern
Georgia southward through Florida and west to southern
Alabama at Mobile Bay.

65. Apalone ferox
“Florida softshell”
• Diet: The bulk of the diet
consists of crayfish, snails,
mussels, frogs, fish, and
waterfowl. It is also known to
do some scavenging. For
some reason, watermelon is
an effective bait for trapping
them.

66. Apalone ferox
“Florida softshell”
• Size: Females can reach just over 60 cm (24 inches) in
carapace length while males reach 30 cm (12 inches).

67. Apalone ferox
“Florida softshell”
• Reproduction: Clutches consist of 4-38 (usually 17-22)
eggs. Five or six clutches may be laid per year, but some
females may not reproduce every year. Hatching occurs
in August and September, after about 60-70 days of
incubation.

68. We have captured only 35
individuals of this species at WSSP,
so no population estimate is possible
at this time.

69. Deirochelys reticularia chrysea
“Florida Chicken Turtle”
• Distribution:
This subspecies
of the chicken
turtle is restricted
to peninsular
Florida. The
species lives in
the southern half
of the eastern
US, west to
Oklahoma.

71. Deirochelys reticularia chrysea
“Florida Chicken Turtle”
• Diet: This species is omnivorous, eating crayfish, aquatic
insects, spiders, snails, tadpoles and adult frogs and
plants. Juveniles are more carnivorous than adults.

72. Deirochelys reticularia chrysea
“Florida Chicken Turtle”
• Size: This species reaches 25 cm (about 10 inches) in
carapace length and has a very long neck. Females are
larger than males.

73. Deirochelys reticularia chrysea
“Florida Chicken Turtle”
• Reproduction: Females lay at least two clutches per year.
Clutch size is from 2 to 19 eggs. The eggs are white,
flexible, and oblong (28-40 mm x 17-23.6 mm). Incubation
takes 78-89 days.

74. This species prefers still ponds
with muddy bottoms. Only 3
individuals of this species have
been captured at WSSP.

75. Turtles of the genus
Sternotherus
(the Musk Turtles)

76. Sternotherus odoratus
“Stink Pot” or “Common Musk Turtle”

80. Sternotherus odoratus
“Stink Pot” or “Common Musk Turtle”
Diet: Insects, crabs, fish eggs, leeches, aquatic plants, etc.

81. Sternotherus odoratus
“Stink Pot” or “Common Musk Turtle”
Size:
• Can reach 12.5 cm (5 inches)
• Males mature faster than females

82. Sternotherus odoratus
“Stink Pot” or “Common Musk Turtle”
Reproduction:
• Females lay up to 4 clutches of 1-9 eggs.
• Incubation period is about 75 or 80 days.

83. 0
500
1000
1500
2000
2500
Oct-00 Apr-01 Nov-01 May-02 Dec-02 Jun-03 Jan-04 Aug-04 Feb-05 Sep-05 Mar-06
Point Estimate Lower Confidence Level Upper Confidence Level
Sternotherus odoratus – Population Estimate

84. Sternotherus minor minor
“Loggerhead Musk Turtle”

85. Sternotherus minor minor
“Loggerhead Musk Turtle”
Male Female

88. Sternotherus minor minor
“Loggerhead Musk Turtle”

89. Sternotherus minor minor
“Loggerhead Musk Turtle”
Diet: Very similar to Stinkpot and shifts with increasing size.

91. Sternotherus minor minor
“Loggerhead Musk Turtle”
• Reproduction: Females lay 2-5 clutches of 1-5 ellipsoidal
eggs per year (28.5 x 17.2 mm)

92. 0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Oct-00 Apr-01 Nov-01 May-02 Dec-02 Jun-03 Jan-04 Aug-04 Feb-05 Sep-05 Mar-06
Stenotherus minor minor - Population Estimate
Point Estimate Lower Confidence Level Upper Confidence Level

93. Turtles of the genus
Pseudemys (the Cooters)

94. Pseudemys nelsoni
“Florida Red Belly”
• Distribution: This species
ranges from the Okefenokee Swamp in southern Georgia,
west to Apalachicola, Florida, and south through peninsular
Florida.

96. Pseudemys nelsoni
“Florida Red Belly”
• Diet: Adults are highly herbivorous, eating a variety of
aquatic plants; the young are more carnivorous, feeding on
aquatic insects and other small invertebrates.

97. Pseudemys nelsoni
“Florida Red Belly”
• Size: Average Adult Size
• Males mature at plastron lengths of 17-21 cm in 3-4 years
• Females mature at plastron lengths of 26-27 cm in 5-7
years

98. Pseudemys nelsoni
“Florida Red Belly”
• Reproduction: Females lay 3-6 clutches of 6-31 eggs per
year. Many nest in an alligator's nest. Eggs are ellipsoidal
(37-47 x 19-26 mm) and hatch after 60-75 days.

99. 0
100
200
300
400
500
600
700
Mar-97 Jul-98 Dec-99 Apr-01 Sep-02 Jan-04 May-05 Oct-06
Pseudemys nelsoni - Population Estimate
Point Estimate Lower Confidence Level Upper Confidence Level

100. Pseudemys floridana peninsularis
“Peninsula Cooter”
• Distribution: This subspecies of the Florida cooter is
restricted to Peninsular Florida

102. Pseudemys floridana peninsularis
“Peninsula Cooter”
• Diet: Adults are highly herbivorous, eating a variety of
aquatic plants and algae; the young are more carnivorous,
feeding on snails, aquatic insects and other small
invertebrates.

103. Pseudemys floridana peninsularis
“Peninsula Cooter”
• Size: Adults males can
reach 30 cm (12 inches)
and females can reach 43
cm (17 inches)

104. Pseudemys floridana peninsularis
“Peninsula Cooter”
• Reproduction: Clutches range from 9-29 (usually 19-20)
pinkish white, ellipsoidal eggs (29.0-44.0 x 22.0-30.5
mm). Eggs hatch in approximately 80-100 days,
depending on temperature.

105. 0
100
200
300
400
500
600
700
800
900
1000
Oct-95 Mar-97 Jul-98 Dec-99 Apr-01 Sep-02 Jan-04 May-05 Oct-06
Pseudemys floridana peninsularis - Population Estimate
Point Estimate Lower Confidence Level Upper Confidence Level

106. More than turtles:
Outreach, Invasive Species, Trash…

111. Other Parts of the WSSP Study
• Tattoo as a Viable Marking System
– Softshell tattoo paper in revision now
• Growth Rates
– Pseudemys paper in revision now
– Sternotherus paper to be written this
summer
• Food Habits of Turtles
– Stomach flushing technique
• Modeling of Population Dynamics

112. The Future of the Project…

114. Wekiwa Springs
Rock Springs Run
Blue Spring
De Leon Springs
Peacock Springs
Fanning Springs
Manatee Springs

115. Blue Spring State Park

121. De Leon Springs
State Park

122. Peacock Springs
State Park

123. Fanning Springs
State Park

124. Manatee Springs
State Park

126. References/Images
• http://images.google.com/imgres?imgurl=http://www.dfo-mpo.gc.ca/canwaters-
eauxcan/bbb-lgb/creatures-animaux/images/c_turtl2.gif&imgrefurl=http://www.dfo-
mpo.gc.ca/canwaters-eauxcan/bbb-lgb/creatures-
animaux/reptiles/index_e.asp&usg=__R7hY0P730AF3TL1Ur3koVZY2fws=&h=300&
w=300&sz=7&hl=en&start=1&um=1&itbs=1&tbnid=zmqrTfOdbJ77JM:&tbnh=116&tbn
w=116&prev=/images%3Fq%3Dparts%2Bof%2Ba%2Bturtle%2Bshell%26um%3D1%
26hl%3Den%26sa%3DN%26rlz%3D1T4ADFA_enUS365US366%26tbs%3Disch:1
• Diagrams of Turtle Shells
http://images.google.com/imgres?imgurl=http://reptilis.net/index4/shell.jpg&imgrefurl=
http://reptilis.net/chelonia/bodyplan.html&usg=__0PxewKegtLCcryQzDHj97yRthog=&
h=303&w=400&sz=96&hl=en&start=4&um=1&itbs=1&tbnid=gESiUDBukeiCkM:&tbnh
=94&tbnw=124&prev=/images%3Fq%3Dparts%2Bof%2Ba%2Bturtle%2Bshell%26um
%3D1%26hl%3Den%26sa%3DN%26rlz%3D1T4ADFA_enUS365US366%26tbs%3Di
sch:1
• Range Maps
– http://www.iucn-tftsg.org/deirochelys-reticularia-014/
– http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=1273
• Turtle Info: “Turtles of the World”
http://nlbif.eti.uva.nl/bis/turtles.php?menuentry=inleiding