Table 5. Distribution, Distances and Dates of Tag Returns from Wassaw Island, GA

1973-2000.
Return | Source of | Date Originally Date of Return Minimum Return Location
# Return Tagged Distance Traveled
(km)

1 NE June 8, 1973 1973 40 Hilton Head Island, SC

2 TRAWL June 10, 1973 July 5, 1973 : Wassaw Sound, GA

3 NE June 10, 1973 July 19, 1973 10 Little Tybee Island, GA

4 TRAWL June 15, 1973 1973 - Wassaw Sound, GA

5 DOB June 17, 1973 1973 4 Ossabaw Island, GA. i
6 NE June 3, 1974 1974 14 Ossabaw Island, GA. |
7 NE June 4, 1974 August, 1974 2 Unknown i
8 TRAWL June 5, 1974 July, 1974 35 Off of Sapelo Island, GA |
9 NE June 5, 1974 1974 14 Ossabaw Island, GA |
10 NE June 8, 1974 1974 4 Ossabaw Island, GA i
u NE June 12, 1974 1974 14 Ossabaw Island, GA i
12 TRAWL June 19, 1975 July 13, 1975 2 Unknown jl
B TRAWL June 20, 1975 January 24, 1977 410 Cape Canaveral, FL i
4 TRAWL July 1, 1975 May 27, 1983 35 Off of Sapelo Island, GA i
5 NE May 25, 1976 1979 48 Blackbeard Island, GA i
16 NE May 27, 1976 1976 110 Little Cumberland Island, GA |
17 TRAWL June 4, 1976 June 5, 1980 35 Off of Sapelo Island, GA |

L_18. NE June 5, 1976 1976 no Little Cumberland Island, GA
19 NE July 5, 1976 1976, 1979, 1980 118 Little Cumberland and Cumberland
Islands, GA :

20 NE June 16, 1977 1977 103 Jekyll Island, GA Hl
21 NE June 27, 1977 1977 14 Ossabaw Island, GA. |
22 NE June 30, 1977 1977 18 Cumberland Island, GA 1
3B NE July 3, 1977 1979 2B Blackbeard Island, GA i
24 NE June 2, 1978 1978 14 Ossabaw Island, GA i
25 NE Tune 10, 1978 1981 48 Blackbeard Island, GA |
26 NE June 15, 1978 1978 410 Cape Canaveral, FL

27 NE June 16, 1978 1978 335 Ocean Isle, NC
28 NE June 30, 1978 1978 14 Ossabaw Island, GA.
29 NE June 30, 1978 1984 12 Cabbage Island, GA

30 NE July 1, 1978 1978 48 Blackbeard Island, GA __t
31 Traw/DOB. July 17, 1978 Aug. 3/Aug 7/78 14 Ossabaw Sound/Green Island, GA__|
2 NE May 27, 1979 1979 48 Blackbeard Island, GA

33 NE May 29, 1979 1979 48 Ossabaw & Blackbeard Islands, GA

34 NE/DOB May 29, 1979 1979/Aug 15 1982 48 Blackbeard Island/Hilton Head Island, |

GA

35. TRAWL June 3, 1979 1980 2 Off of Tybee Island, GA i
36 NE June 4, 1979 1979 14 Ossabaw Island, GA |
37 NE June 7, 1979 1979 14 Ossabaw Island, GA i
38 NE June 10, 1979 1979 14 Ossabaw Island, GA. _]
39 TRAWL June 27, 1979 1980 30 Sapelo Sea Buoy, GA i
40 NE June 28, 1979 1979 14 Ossabaw Island, GA |
a NE July 10, 1979 1983 48 Blackbeard Island, GA |
42 NE May 26, 1980 1980 14 Ossabaw Island, GA
B Tag Ret. May 28, 1980 November, 1982 700 Nag’s Head, NC i
44 NE June I, 1980 1980 14 Ossabaw Island, GA. |
45 2 June 2, 1980 27 Colonel's Island, GA i
46 DOB June 10, 1980 July 26, 1980 19 Cape Romaine Seashore, SC i
47 NE June 13 1980 14 Ossabaw Island, GA

48 NE June 22 1980 48 Blackbeard Island, GA
49 TRAWL June 22, 1980 __| September 14, 1983 860 Off of Hog Island, VA

30 NE June 26, 1980 1980 48 Blackbeard Island, GA

31 TRAWL July 3, 1980 August 28, 1980 18 (Off of Cumberland Island, GA

15


Frick, M. G., K. L. Williams, D. Veljacic, J. A. Jackson, and S. E. Knight. In press.
Epibiont community succession on nesting loggerhead sea turtles (Caretta
caretta) from Georgia, USA. Proceedings of the 20" Symposium of Sea Turtle
Biology and Conservation, Orlando, FL. March 1-4, 2000.

Johnson, A. S., H. O. Hilestad, S. F. Shanholtzer and G. F. Shanholtzer. 1974. An

ecological survey of the coastal region of Georgia. Natl. Park Serv. Sci. Monogr.
Ser. No. 3.

Limpus, C. J. 1992. Estimation of tag loss in marine turtle research. Wildl. Res., 19:457
-69.

Margaritoulis, D. 1985. Preliminary observations on the breeding behaviour and ecology
of Caretta caretta in Zakynthos, Greece. Biologia Gallo-Hellenica 10: 323-332

Musick, J. A. and C. J. Limpus, 1996. Habitat utilization and migration in juvenile sea
turtles. P. 137-164. In: P. L. Lutz and J. A. Musick (eds.). The Biology of Sea
Turtles. CRC Press, Boca Raton, FL.

Richardson, T. H., J. I. Richardson, C. Ruckdeschel, and M. W. Dix. 1978. Remigration
patterns of loggerhead sea turtles (Caretta caretta) nesting on Little Cumberland
and Cumberland Islands, Georgia. Florida Mar. Res. Publ. 33:39-44.

Richardson, J. I. and T. H. Richardson. 1982. An experimental population model for the
loggerhead sea turtle (Caretta caretta). Pages 165-176 in K. Bjorndal (ed.),

Biology and Conservation of Sea Turtles. Smithsonian Institution Press,
Washington, D.C.

Richardson, J. I. 1999. Priorities for studies of reproduction and nest biology. Pages 9
-11. In: Eckert, K. L., K. A. Bjorndal, F. A. Abreu-Grobois and M. Donnelly
(Eds). Research and Managements Techniques for the Conservation of Sea
Turtles. IUCN/SSC Marine Turtle Specialist Group Publication No. 4.

Turtle Expert Working Group. 1996. Status of the loggerhead turtle population
(Caretta caretta) in the western North Atlantic, 50 p.

van Dam, R. P. and C. E. Diez. 1999. Differential tag retention in Caribbean hawksbill
turtles. Chelonian Conservation and Biology 3(2):225-229.

Witzell, W. 1998. Messages in bottles. Marine Turtle Newsletter. Vol. 40:3-5.

Wood, D. W. and Bjorndal, K.A. 2000. Relation of temperature, moisture, salinity, and
slope to nest site selection in loggerhead sea turtles. Copeia 2000(1): 119-28.

32


1.3. Habitat Composition

The sand from Georgia’s beaches and dunes are of finer median grain size than those
farther north and south (Johnson et al. 1974). The sand on Wassaw Island is comprised
primarily of quartz and an uneven mixture off the following minerals: epidote, garnet,
hornblende, illmenite, kyanite, leucoxene, monazite, rutile, sillimanite, staurolite,
tourmaline and zircon. The principle sources of the aforementioned sand (minerals) on
Wassaw Island are the Savannah River watersheds that originate in the Piedmont and
mountain areas of the state and the suspended material from the continental shelf adjacent
to the island. Although molluscan gravel and calcium carbonate are present, in relatively
minute quantities, they are not important contributors to Wassaw’s beach sediments
(Johnson et al. 1974).

Several types of vegetation can be encountered throughout the loggerhead’s nesting
habitat on Wassaw Island. This habitat includes areas located in front of the foredune
area, the lee slope of the foredune, and herbaceous flats located between the foredune and
the maritime forest. The following dune vegetation occurs, in varying frequencies, in
these areas: sea oats (Uniola paniculata), sea rocket (Cakile endentula), beach croton
(Croton punctatus), beach sand spur (Cenchrus tribuloides), salt meadow cord-grass
(Spartina patens), Russian thistle (Salsola kali), sea purslane (Sesuvium portulacastrum),
beach spurge (Euphorbia polygonifolia), seashore elder (Iva imbricata), railroad vine
(Ipomoea stolonifera), beach pennywort (Hydrocotyle bonariensis), Spanish bayonet
(Yucca aloifolia), camphor weed (Heterotheca subaxillaris), little blue-stem
(Andropogon scoparius), prickly pear (Opuntia humifusa), hitch-hiker cactus (Opuntia
pusilla), seaside goldenrod (Solidago sempervirens), evening primrose (Oenothera
humifusa), juniper (Juniperus virginiana), yaupon holly (Ilex vomitoria), wax myrtle
(Myrica cerifera), live oak (Quercus virginiana), red bay (Persea borbonia), cabbage

palm (Sabal palmetto), saw palmetto (Serenoa repens), groundsel bush (Baccharis
halimifolia) and slash pine (Pinus elliottii)

1.4, Habitat Utilization

The average number of loggerhead crawls observed on Wassaw Island per year from
1973-2000 is 147 (range = 54 — 287, n=4103 crawls). There is an average of 81 false
crawls per year (range = 29-170, n=2256 false crawls) and an average of 66 nests per
year (range = 23-135, n=1848 nests). Crawl frequencies in respect to the associated
habitat type were determined for all turtle crawls observed during the 1980-1990 nesting
seasons. Table 1 presents the frequencies of loggerhead nesting emergences (crawls)
within each beach type on Wassaw Island from 1980-1990. Refer to Figure 4 and the
description of beach/dunes types discussed above for the following section.

Nesting emergences occur throughout all six beach types depicted in Figure 4. Most
emergences occur in beach types A, B and C (Fig 4; Table 1), probably as a result of the
slope associated with each type (see Wood and Bjorndal 2000). Also, possibly as a result
of respective beach slope, nesting emergences are lower in beach types D, E and F (Fig 4;
Table 1).

Although nesting occurs throughout the six beach types, turtles that emerge onto a
wide sloping beach are more likely to nest than turtles that emerge into truncate dunes,
wide flat beach areas or barren areas (Fig. 4 (A, C, E and F); Table 1). Turtles that


Section 5: Differential Tag Retention

From 1973 through 2000, 114 individual turtles were tagged and subsequently
‘recaptured’ on Wassaw Island. A total of 350 tags were placed on these turtles and 183
tags were confirmed as lost. Figure 6 depicts the probability of tag retention for plastic,
inconel, and PIT tags. Figure 7 and Table 7 summarize the tag data for each tag type
applied. Due to similarities in size, style, and application of both the Roto and Riese
plastic tags, we have combined both tag types into the same data set and collectively refer
to the two types simply as ‘plastic’ tags herein.

5.1. External Tags

Of the three external tags used to mark loggerheads on Wassaw Island (monel
alloy, inconel and plastic), plastic tags placed on the hind flippers had the highest
retention rates in the 25 year period since they were applied to turtles (1975-2000; Table
7, Fig. 6, 50%-80% chance of remaining on the flippers). For example, one loggerhead
tagged on Wassaw Island in 1980 was found nesting on Ossabaw Island, a neighboring
island, in 1999 still possessing her original plastic tags on her rear flippers. As can be
seen in Table 7 and Figure 6, the probability of plastic tags remaining on the front
flippers steadily decreases over time and at a faster rate than observed for plastic tags
applied to the rear flippers.

Some plastic tags that had numbers imprinted on them rather shallowly became
abraded and unreadable. These tags had to be removed. However, several abraded and
unreadable tags were brought over to the Savannah Police Department’s Forensic
Sciences Lab and electron microscopy and other forensic techniques were used to
identify the tag numbers. Over time, plastic tags have become rigid and quite brittle. As a
result, the identification number bearing tabs have fallen off or been broken off by the
turtle. However, plastic plugs left behind in the turtle’s flippers still mark the animal as a
‘cohort’ of the marked population.

Inconel tags had no greater than a 50% chance of remaining attached to the front
flippers over the 12 year period of time since we began double tagging with this tag type
(1988-2000; Table 7; Figs 6 and 7). However, one inconel tag has remained upon the
front flipper of a turtle for an 11-year period. As monel tags were only applied singly
during 1973 and 1974 and were only used sporadically after that until 1977, only eleven
monel tags have been recovered. As a result, the information we provide on monel tag

retention is less complete than desired and appears in Table 7 and Figure 7. One monel
tag was retained by a turtle for 7 years.

5.2. Internal Tags (PIT tags)

Thirty-two turtles implanted with PIT tags were recaptured over an eight-year
period (1992-2000). Eight PIT tags (25%) were either lost or unreadable (Table 7; Fig.
7). Since we routinely scan the entire flipper it is unlikely that PIT tags have migrated
from the elbow region of the turtle to the shoulder or the tip of the flipper. However, it is
possible that migration has occurred outside of the scanning range and into other areas on
the turtle, but this too seems highly unlikely. Instead, we believe some PIT tags were
missed or unreadable due to the variety of PIT tag and scanner brands that have been
used by our project since PIT tagging began in 1992. Apparently, the Infopet and Trovan
brand scanners that were used simultaneously in some seasons were not entirely

19


Section 8: Description, Morphometrics and Mass of Eggs and Hatchlings...22

8.1. Hatchling description, Morphometrics and Mass...........

cece eet eeeeees ...22
8.2 Size and Mass of Eggs....000.0..0..0 0.0... ccc cece eee eee cece eee e ee eee tee tee eeee 23
Section 9: Hatch Rates and Hatchling Emergence Success................ oe 23
9.1. Hatch Rates...0..000... ee. Feb eee eee cece e eee eee eee ee tesa eseedeeee eet eree 23
9.2 Emergence Success..................... cee eeeeeeeeseeenes cece eee ceceeeee 24

Section 10: Predators of Loggerhead Nests and Hatchlings......................24

Section 11: Epibiont Information...

cee e beet eee cee ete ete eeeseeeerececeseeereens 25
Discussion 222.000 220 2. cee tee cee teetetetteeeeeeeees 27
Acknowledgements... 2... eee .29
Literature Cited... eee 31

iv


Island Leaders: Patti Ackerman, Guerry Beam, Kris Williams Carroll, John
“Crawfish” Crawford, Robert Moulis, Mike Frick, Todd Gedamke, Robert Graham,
Anne Kerner, Win Seyle, Charles Warnock and Gerald Williamson

Assistant Island Leaders: Ray Aument, Richard Daniel, Danny Ginsberg, Michael
Holliday, Todd Johnson, Gail Kreuger, Emily Markestyn, Bill McLaughlin, Lianne
Pierrard, Robert Redmond, Ed Strosahl, David Veljacic, James Waples, Leslie
Warnock, Becky Yeomans

Interns: Leigh Creech, Jennifer Cutraro, Kristine Davis, Paul Hotchkin, Adam
Mackinnon, Janet Mackinnon, Kate Mansfield, Stephen Saari, Caleb Montana-
Spiegel, Heather Woodson

Members of the Wassaw Island Trust, Island managers and Caretakers-for supporting
the project and allowing the “turtlers” to stay on the family compound

Charles Warnock for his undying support and enthusiasm for the loggerhead turtles
and volunteers

US. Fish and Wildlife Service Savannah Coastal Refuges Staff: Randy Cook, John
Davis, Sam Drake, Randy Isbister, Preston Lane, Mark Musaus, Earl Possardt, Peter
Range, John Robinette and Gene Singleton

Georgia Department of Natural Resources Staff- Mark Dodd, Mike Harris, Adam
Mackinnon, Charles Maley, Brad Winn and Barb Zoodsma,

Wayne Witzell for recognizing the importance of long-term tagging projects and
encouraging us to make our results available to other biologists

National Marine Fisheries Service Staff: Kelly Foster, Wendy Teas, Wayne Witzell
and Amy Woodhead and Peter Eliazar at the University of Florida at Gainesville
Archie Carr Center for Sea Turtle Research for supplying tags and for maintaining the
tagging database

John “Crawfish” Crawford and Jim Whittid at the University of Georgia Marine
Extension Service for boat transportation and island assistance

Landings Harbor Marina and Delegal Creek Marina for the use of the facilities
throughout the seasons

Volunteer Boat Captains for their cheerful and reliable assistance in transporting crew
members and their gear to and from the island every Saturday

Over 2,000 volunteer participants from all over the United States, Canada and Europe
who have donated their time, sweat and money to protect the loggerhead sea turtles
Individual Contributors who have donated goods, services and cash to support the
project

Local and Corporate Contributors: A Boater’s Paradise, Inc., American Association
of University Women, AllPage, AlPage, Aly Camera, CellularOne, Coastal
Computers, Coastal Museum Association, Colonial Foundation, Inc., Curl Family
Foundation, Custom Car and Truck, Earthlight Photography, Guerry Lumber, John G.
Kennedy Foundation, Inc., Kroger Super Markets, Linedrive Communications of
Savannah, Logan’s Supply, Lowe’s, Maryed International, Inc., Mattress Depot,
PressWorks, Publix Super Markets, Remer Lane Memorial Fund, Inc., Sam’s Club,
Savannah Color Separations, Savannah Electric, Savannah Honda/Yamaha,
Savannah Kawasaki and SunTrust Bank

Foundations: Bay Foundation, Beavertides Foundation, Arthur M. Blank Family
Foundation, Citigroup Foundation, John and Emma Derst Foundation, Inc. Max and

30


32 NE May 26, 1981 1981 70 Fripp Island, SC

33 NE May 29, 1981 1981 48 Blackbeard Island, GA

34 NE May 30, 1981 1981 48 Blackbeard Island, GA |

35 TRAWL June 6, 1981 July 31, 1983 825 Smith Island, VA

36 NE June 6, 1981 1981 10 Little Tybee, GA

37 TRAWL July 3, 1981 March 17, 1982 410 Cape Canaveral, FL

38 NE July 10, 1981 1984 110 Little Cumberland Island, GA.

39 TRAWL July 10, 1981 377 & 10/30 1982 325 Diamond Shoals, NC/ St. Andrew's
Sound, GA

60 NE July 10, 1981 1981 140 Fernandina Beach, FL

61 TRAWL June 20, 1982 June 24, 1982 27 Off of St. Catherine’s Island, GA

62 NE June 21, 1982 1982 93 Edisto Beach, SC

63 TRAWL June 23, 1982 | September 2, 1983 1935 Gulf Shores, AL i

64 DOB June 28, 1982 July 1, 1982 40 Hilton Head Island, SC

65 NE May 27, 1983 1983 150 Little Talbot Island, FL

66 NE June 7, 1983 1983 18 Cumberland Island, GA

67 NE July 10, 1983 1983 48 Blackbeard Island, GA

68 TRAWL June 21, 1983 July 20, 1983 215 Georgetown, SC

69 TRAWL June 13, 1984 June 27, 1984 27 Off of St. Catherine’s Island, GA |

70 NE June 25, 1984 1989 118 ‘Cumberland Island, GA |

7 NE July 2, 1984 1984 110 Little Cumberland and Jekyll Islands. |
GA |

R NE June 16, 1987 1994 4 Ossabaw Island, GA |

B NE July 22, 1988 1994 48 Blackbeard Island, GA i

iz) NE July 29, 1988 1991 10 Little Tybee Island, GA

3 NE June 21, 1989 1994 48 Blackbeard Island, GA

76 DOB May 28, 1990 1990 410 Cape Canaveral, FL _

71 NE May 29, 1990 1993 48 Blackbeard Island, GA |

78 DOB June 8, 1990 July 26, 1993 980 Fenwick Island, DE |

79 NE June 15, 1990 1992/1998 82 St. Simon’s / Ossabaw Islands, GA__|

80 NE May 24, 1991 1991 50. Sapelo Island, GA |

81 NE June 16, 1991 1994 27 St. Catherine’s Island, GA i

82 NE June 21, 1991 1991 10 Little Tybee Island, GA |

83 NE June 28, 1992 1992 82 St. Simon’s Island, GA

84 NE June 30, 1992 1992 82 St. Simon’s Island, GA

85 NE July 23, 1992 1996 40 Hilton Head Island, GA.

86 NE July 3, 1993 1999 40 Hilton Head Island, GA

87 NE May 25, 1994 1994 93 Edisto Island, SC |

88 NE June 9, 1994 1994 63 Hunting and Pritchard's Islands, SC

89 NE July 5, 1994 1994 4 Ossabaw Island, GA |

90 NE June 1, 1995 1998 48 Blackbeard Island, GA

an NE Tune 20, 1996 1996 40 Hilton Head Island, SC

2 NE June 28, 1996 1996 370 Bald Head Island, NC

33 DOB July 4, 1996 40 South Carolina |

94 NE June 14, 1998 1998 110 Little Cumberland Island, GA

95 NE June 15, 1998 1998 93 Edisto Island, SC |

96 NE May 30, 1999 1999 130 Folly Beach, SC |

7 NE June 6, 1999 1999 400 Onslow Beach, NC

8 NE June 21, 1994 Tune 9, 2000 130 Folly Beach, SC

99 NE May 29, 2000 June 17, 2000 40 Hilton Head Island, SC |

100 NE June 21, 1991 July 7, 2000 30. Sapelo Island, GA |



compatible. Not until we acquired a Destron brand universal reader did we realize that
turtles that were implanted with Trovan brand PIT tags were not readable to Infopet
brand readers (universal readers are those can detect any type of PIT tag currently on the
market). As a result, some turtles have both Trovan and Infopet brand tags implanted in
the same flipper. Since we now use only Destron brand tags and scanners it is possible
that the retention rates observed for PIT tagged turtles on Wassaw Island may increase as
the turtles return to nest and are scanned for internal tags using more reliable equipment.

Section 6: Remigration and Internesting Intervals

The average remigration interval (179 observations from n=114 individuals)
observed for Wassaw Island remigrants is 3.15 years between nesting seasons (range = 1-
8 years). Using data collected from 1995-2000, since these years represent seasons where
over 90% of the turtles nesting on Wassaw Island were observed within each season, the
average observed internesting interval is 17.4 days between successive nests (range=10-
52 days; n=93 turtles). However, it should be noted that since turtles are missed during
nightly patrols and beaches adjacent to Wassaw Island are not monitored every night, the
aforementioned intervals might not represent the actual intervals that are occurring.

Section 7: Fecundity

Nest sizes ranged between | to 196 eggs per clutch and averaged 116.4 eggs/nest
(n = 1848 nests from 1973-2000). Since tagging began on Wassaw Island in 1973,
loggerheads encountered during subsequent nesting observations have deposited an
average of 2.89 nests per season (n= 294 turtles; range=1-6 nests per turtle). Yet, since
turtles will migrate to other nesting areas within the same season and some turtles are
missed during nightly patrols, it is very possible that the average number of nests laid
within a season by an individual turtle could be greater than that presented above.
Supplemental research would help to clarify the reproductive potential of Wassaw
Island’s loggerhead turtles (i.e. ultrasonography).

Section 8: Description, Morphometrics and Mass of Eggs and Hatchlings
8.1. Hatchling Description, Morphometrics and Mass

There is a considerable range of coloration from the hatchlings observed from
Wassaw Island, even within the same clutch. Most hatchlings appear gray dorsally to
light cream ventrally. Some hatchlings are dark brown to almost black dorsally and
ventrally. Lighter colored hatchlings are reddish-chestnut brown to tan, dorsally.
Occasionally albino specimens are observed. A few of the observed albinos had pink eyes
but most have either brown or blue eyes. A single nest in 1995 contained 11 snow-white
hatchlings with blue eyes. All of the aforementioned hatchlings appeared relatively
healthy. Four of these turtles were raised in captivity and subsequently released four
years later in good condition.

The morphometrics and mass of 110 hatchlings from seven different nests were
recorded. Morphometrics were recorded in mm using Vernier calipers. Straight carapace

22


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Victoria Dreyfus Foundation, Courtney Knight-Gaines Foundation, Inc., Georgia
Power Foundation, Hillsdale Fund, Inc., Mobil Foundation, Inc., Norcross Wildlife
Foundation, Inc., Patagonia Foundation, Publix Super Market Charities, Sapelo
Foundation, Savannah Presbytery Ecology Fund, Shared Earth Foundation, Turner
Foundation, Inc., Union Camp Foundation, Wormsloe Foundation, and the Wal-Mart
Foundation

- Sally Murphy, Mark Dodd, Sandy MacPherson for reviewing an earlier draft of our
results.

Literature Cited

Balazs, G. H. 1999. Factors to consider in the tagging of sea turtles. Pages 101-109. In:
Eckert, K. L., K. A. Bjorndahl, F. A. Abreu-Grobois and M. Donnelly (Eds).
Research and Managements Techniques for the Conservation of Sea Turtles.
TUCN/SSC Marine Turtle Specialist Group Publication No. 4.

Bell, R. and J. I. Richardson. 1978. An analysis of tag recoveries from loggerhead sea
turtles (Caretta caretta) nesting on Little Cumberland Island, Georgia. Florida
Mar. Res. Publ. 33:39-44.

Bowen, B. W. and S. A. Karl. 1997. Population genetics, phylogeography, and molecular
evolution In: Lutz, P. L. and J. A. Musick (Eds.). Biology of Sea Turtles, pp. 29
-50. CRC Press, Boca Raton, 432 p.

Caldwell, D. K. 1959. The loggerhead turtles of Cape Romain, South Carolina. (abridged
and annotated manuscripts of W. P. Baldwin, Jr. and J. P. Loftin, Jr.). Bull. Fla.
State Mus. Biol. Sci. 4:319-348.

Dodd, C. K., Jr. 1988. Synopsis of the biological data on the loggerhead sea turtle

(Caretta caretta) (Linnaeus 1758). U. S. Fish and Wildl. Serv., Biol. Rep. 88(14).
110 p.

Frick, M. G., K. L. Williams and M. Robinson. 1998. Epibionts associated with nesting

loggerhead sea turtles (Caretta caretta) in Georgia, USA. Herpetological Review.
29(4): 211-214.

Frick, M. G., K. L. Williams, D. Veljacic, J. A. Jackson and S. E. Knight. 2000. Newly
documented epibionts associated with nesting loggerhead sea turtles (Caretta
caretta) in Georgia, USA. Marine Turtle Newsletter No. 88.

Frick, M. G., K. L. Williams and D. Veljacic. 2000. Additional evidence supporting a

cleaning association between epibiotic crabs and sea turtles: How will the harvest
of sargassum seaweed impact this relationship? Marine Turtle Newsletter No. 90.

31


Excluding neophytes tagged during the 2000-nesting season (since they could not
remigrate within a season), a Type I remigration rate was used to measure the remigration
activity per turtle within our study area. A Type 1 remigration rate is defined as the ratio
of the number of remigation records to the total number of individuals marked
(Richardson et al., 1978). Applying this definition to Wassaw Island turtles, we find an
10.3% (114/1110) remigration rate.

Several points must be taken in to account when determining a rate of remigration
for turtles that nest within Barrier Island sequences. For instance, while we only consider
a turtle as a remigrant when she returns to nest at the study site where she was originally
tagged, a broader definition of remigration might include beaches surrounding or within
close proximity to the original saturation tagging study site. Since the islands adjacent to
Wassaw Island are not patrolled at night, the remigration rate for nesters may be
considerably higher. Additionally, Georgia’s barrier islands are very dynamic
environments and seasonal storms may drastically change the condition of any island’s
beaches from one nesting season to another. As a result, loggerheads will shift their
nesting concentrations from island to island. Point being, until saturation tagging is
supplemented by additional coverage on beaches surrounding the study site, it is not

possible to maximize the amount of information that can be accumulated by tagging
nesting sea turtles.

Section 4: Tag Returns and Recoveries

In this section we are differentiating between the terms ‘tag return’ and ‘tag
recovery’ to imply the origin of the tags placed upon the observed loggerheads. For
instance, a ‘tag return’ is locality/migration information from a turtle that was originally
tagged on Wassaw Island but was observed in a locality other than Wassaw Island. A ‘tag

recovery’ is locality/migration information from a turtle that CRP staff observed nesting
on Wassaw Island but was originally tagged elsewhere.

4.1. Tag Returns

From 1973 through 2000, the Caretta Research Project has tagged 1110
loggerhead turtles. We have received 107 tag returns (9.6 % tag return rate) from 99
individual turtles. These returns come from three sources: females encountered nesting or
crawling on other nesting beaches (74.8%, n=80), turtles captured in shrimp trawlers
(18.7%, n=20) and turtles reported dead on the beach (6.5%, n=7). The distribution,
distances and dates of tag returns appear in Table 5 and Figure 5.

Of the 80 turtles found crawling or nesting on other beaches, 22 (27.5%) were
found north of Wassaw Island and 58 (72.5%) were found south of Wassaw Island. The
distances of nesting beaches also utilized by loggerheads observed on Wassaw Island
range from <125 km - 410 km away (Fig. 5; Table 5). The furthest north we have had a
nesting tag return was from Onslow Beach, NC (400 km) and the furthest south was from
Cape Canaveral National Seashore, Florida (410 km; Fig. 5; Table 5).

Commercial shrimp trawlers have also provided tag returns (n=20). Five (25%)
turtles were captured north of Wassaw Island, 12 (60%) were captured south of Wassaw
Island, two (10 %) were captured in waters adjacent to Wassaw Island and one (5%) was
captured from an unknown location (Fig. 5; Table 5). The distances recorded for turtles


wooden-framed screen (1/2-inch x 1/2-inch mesh size) was used as a cover. Each
hatchery held a maximum of 8 nests placed ~ 2 feet apart from each other. The hatchery
cover was propped up (~ 4 inches) when nests were due to emerge but otherwise sat flush
on top of the buried frame. Due to water build-up within the hatchery after torrential
rainstorms, the buried framed was excluded from the hatchery design in 1997. Currently,
only the hatchery covers (described above) are used as screened panels for protecting
multiple relocated nests. It should be noted that no panels were used during the 2000
season due to the high availability of suitable nesting habitat.

Nests were monitored daily throughout their incubation for signs of predation,
erosion, or hatchling activity. Evidence of first hatching was recorded and nests were
subsequently exhumed three days after first emergence. Nests that showed no signs of
hatching were dug up after 75 days. Nest contents were examined to determine the hatch
rate, hatchling survival rate, and the stage of embryological development from unhatched
eggs

Differential Tag Retention
For each observed turtle the condition of previously applied tags was noted and
degrading or improperly applied tags were replaced. PIT tags were scanned prior to and
after application to test reader and tag performance. Tag loss was documented only from
turtles still bearing additional tags. Turtles that only showed tag scars were not used to
determine tag loss since scarring can be similar between different tag types. We

examined tag retention rates using the following equation from Limpus (1992) and van
Dam and Diez (1999):

P; = bj/ (a;+b;)
where i = elapsed time in whole years since tag application:
a;= number of tags confirmed present on sampled turtles, i years since application, and
b; = number of tags no longer present on sampled turtles, i years since application.
The previous equation estimates the probability of tag loss as a time-series. The

following equation calculates the standard error of the determined probability (van Dam
and Diez, 1999):

SE,i = [pi(1-pi) / (aitby] ”

Equation 2 is with 95 % confidence limits of p; = 1.96 + SE,i. Elapsed time in
years of tag retention was determined by rounding to the nearest whole year of the actual
elapsed time between tag application and tag detection upon subsequent observations.

RESULTS
Section 1: Nesting Habitat Characterization, Composition, and Utilization

1.1. Tidal Amplitude in Georgia
The different beach types on Wassaw Island, discussed below, are formed as a
result of the tidal influence in these areas. The average tidal amplitude throughout the
state is approximately 7 ft., the highest tidal amplitude in the southeastern U.S. However,
tides surrounding the new and full moons (spring tides) can have tidal amplitudes of 8-9
ft. Moreover, spring tides associated with strong offshore winds (15-20 m.p.h.) can
increase the distance that water is pushed (wash) above the spring tide high tide line by a


Carolina (~ 230 km to the north) and Jekyll Island, Georgia (~ 85 km to the south). The
lack of tagging programs neighboring Wassaw Island undoubtedly lowers the numbers of
immigrants and tag scarred turtles we observe per season, and in turn, increases the
number of neophytes we observe each season. Finally, the possibility exists that the large
percentage of neophytes observed on Wassaw Island each season may also be attributed
to the recruitment of ‘new’ turtles into the nesting population.

The remigration rate reported for Wassaw Island loggerheads (10.3%; 114/1110
turtles) is considerably lower than that reported by Richardson et al. (1978) for
“Cumberland beaches” (68 %; 453/671 turtles). Richardson et al. (1978) combined
remigration data collected from LCI with data collected from Cumberland Island (located
immediately south of LCI; Fig. 1), hence the study area “Cumberland beaches”. This
point might help to explain such a large difference between our presented remigration
rate and the rate reported by Richardson et al. (1978). Warranting the beaches
surrounding Wassaw Island were extensively covered for nesting loggerheads,
incorporation of such data into the Wassaw Island database would undoubtedly increase
our remigration rate as some of our turtles are occasionally seen nesting on these islands.
However, within this report we consider a remigrant to be one that was originally tagged
on Wassaw Island and observed in following nesting seasons on Wassaw Island. Thus,
tagged turtles observed on beaches adjacent to Wassaw Island were not considered to be
remigrants.

The tag returns and recoveries documented by our program encompassed a
similar range as reported for turtles tagged on LCI (Bell and Richardson, 1978; Fig. 5;
Table 5). Figure 5 shows the distribution of tag returns and recoveries associated with
Wassaw Island’s saturation tagging program. The range of rookery beaches utilized by
loggerheads, that also nest on Wassaw Island, encompasses ~ 800 km of coastline in the
southeastern United States (Tables 5 and 6).

Long range tag return data obtained from adult female loggerheads is helpful
when determining the nesting range utilized by an individual turtle. Such data can also be
used to chart within season migrations undertaken by an individual turtle. However, a
problem exists when gleaning information from tag returns since adult female
loggerheads will also utilize the coastal region adjacent to rookery beaches as foraging
grounds during years when they are not nesting (Musick and Limpus, 1997). Thus, it
becomes difficult to determine if a tag return represents a reproductive or foraging
migration if the turtle in question was not observed nesting, within the same season, prior
to or subsequent to the tag return observation. For instance, tag return # 35 (Table 5)
represents a turtle that nested in 1979, again in 1980 and was captured later that summer
in a shrimp trawl operating off Tybee Island, not far away from where she was previously
observed nesting on Wassaw Island. Taking an observation like this into account, one can
not assume that a turtle observed nesting in one season and then captured the next season
(not nesting) is an ‘off-nesting season’ capture, since loggerheads can nest in subsequent
seasons.

Out of the 100 tag returns presented in Table 5, 12 turtles (return #’s 12, 14, 31,
34, 35, 46, 51, 61, 64, 68, 69 and 76; Table 5) were observed nesting on Wassaw Island
prior to the aforementioned tag return observations. A general analysis of these returns
shows nesting loggerheads moving north and south of Wassaw Island to other nesting
beaches and coastal areas adjacent to rookery beaches throughout the summer (Table 5).

28


hatchlings in a wide flat beach area during a daytime emergence apparently induced by
heavy rains. A scarlet snake (Cemophora coccinea) was found in a hatched nest, located
in a narrow flat beach area, but was not seen consuming any unhatched eggs. Like the
aforementioned rat snake, the scarlet snake apparently entered the nest via a ghost crab
hole.

Section 11: Epibiont Information

Eighty epibiotic species have been recorded as commensals or parasites of nesting
loggerheads on Wassaw Island between 1997-2000 (Table 8). See Frick et al. (1998) for
additional epibionts recorded from nesting loggerheads elsewhere along the Georgia
coast. Frick et al. (in press) use epibiont data to suggest that nesting loggerheads in
Georgia may set up residency adjacent to nesting areas up 56 days to prior to the start of
the nesting season. Other sources of information regarding epibionts collected from

loggerheads on Wassaw Island include Frick et al. (2000) and Frick, Williams and
Veljacic (2000).

Epibiont Species
Porifera

Cliona celata
Haliclona loosanoffi
Mycale americana

Cnidaria

Aiptasia pallida
Anemonia sargassiensis
Astrangia danae
Calliactis tricolor
Diadumene leucolena
Halocordyle disticha
Hydractinia echinata
Leptogorgia virgulata
Stylactis hooperi
Tubularia crocea

Mollusca

Anadara ovalis
Brachidontes exustus
Chaetopleura apiculata
Chione grus
Costoanachis avara
Cratena pilata
Crepidula fornicata
Crepidula plana
Doriopsilla pharpa
Doris verrucosa

Table 8. Epibionts associated with nesting loggerhead sea turtles (Caretta caretta) on
Wassaw Island.

Common Name
Sponges

Boring sponge
Eroded sponge
Flabby sponge

Hydroids, Corals and Anemones

Brown anemone
Sargassum anemone
Star coral

Hermit crab anemone
Pale anemone
Feather hydroid
Snail fur

Sea whip coral
Hooper’s hydroid
Wildflower hydroid

Snails, Sea slugs and Bivalves

Blood ark

Scorched mussel
Eastern beaded chiton
Grey pygmy venus clam
Greedy dove snail

Ivory sea slug

Atlantic slipper snail
White slipper snail
Lemon drop sea slug
Sponge sea slug

25


SOUTHEAST U.S,

} Tybee Island
" Little Tybee Island
Wassaw Island arsHN
Pine Island

Cumberland Island

-——____4
20 km

8I°00'Ww

Fig. 1. Location of Wassaw Island on the Georgia coast.


INTRODUCTION

The southeastern U.S. is considered one of the most important loggerhead sea
turtle (Caretta caretta) rookeries in the world (Bowen and Karl, 1997). The majority of
loggerhead nesting in this region occurs in Florida (~90%), while only ~10% of the
population deposit their eggs on barrier island beaches north of Florida (Dodd, 1988).
Yet, these relatively small islands allow biologists the opportunity to develop and
implement research practices and monitoring efforts that may not be considered cost
effective or feasible on larger beaches where turtles nest en masse (Richardson, 1999).

The Georgia barrier islands remain in a relatively natural state because of their
inaccessibility and the good stewardship of those who have owned them (Johnson et al.,
1974). However, the future development of the coastal region of Georgia is now of major
public interest. Various proposals for dredging, mining, recreational development, and
preservation have stimulated much controversy in the press and at public hearings.
Unfortunately, much of the information appropriate for making management decisions is
lacking. Accordingly, data collected by long-term sea turtle monitoring programs have
become increasingly valuable to government agencies for developing updated
management plans throughout the loggerhead’s nesting distribution (TEWG, 1996). Yet,
much of the information that has been collected regarding the nesting ecology of
loggerheads north of Florida remains largely unpublished (Witzell, 1998).

Here we present a summary of long-term data collected from nesting loggerheads
on Wassaw Island, Georgia from 1973-2000. The purpose of this compilation is to make
the results of our long-term monitoring data set available to other researchers that are
working to elucidate the nesting ecology of loggerhead sea turtles. Whereas we provide
limited discussions and comparisons between our results and nesting information
reported from other areas, we hope that in the future the information presented herein can
be used to formulate a comprehensive review of the nesting ecology of the loggerhead
sea turtle. However, before any accurate comparisons can be made we must strongly

encourage other long-term monitoring programs to make their data available to other
individuals and institutions in a suitable report format.

MATERIALS AND METHODS
Study Site

Wassaw Island is part of the Wassaw National Wildlife Refuge located 12 km south
of the South Carolina/Georgia border (Figure 1). The refuge consists of three islands:
Wassaw, Pine, and Little Wassaw. Although loggerheads nest on all three islands, only
Pine and Wassaw were monitored daily. The beach on Wassaw Island is ~ 14 km long
and receives most of the nests recorded for the refuge. Since nesting turtles infrequently
use Pine and Little Wassaw, these islands are not included in this summary.

Standard Beach Monitoring Data Collections
Prior to the start of the nesting seasons, the beach was sectioned off into 100-
meter intervals for the purposes of mapping turtle activity. Each section was marked with
a numbered PVC stake and placed on the first visible dune ridge. When a turtle or crawl

was encountered its distance and direction from the closest numbered marker was
recorded.


captured in shrimp trawls that were originally tagged on Wassaw Island range from <125
km - >1935 km away (Fig. 5; Table 5). The farthest migratory distance/location recorded
for a turtle originally tagged as a nester on Wassaw Island was a turtle that was
recaptured 14 months later in a trawler off Gulf Shores, Alabama, in the Gulf of Mexico
(~1935 km; Fig. 5; Table 5).

Seven tag returns (7 %) were reported from turtles that washed up dead on various
beaches. The distances recorded for turtles originally tagged on Wassaw Island that
washed up dead on beaches elsewhere range from <125 km — 980 km away (Fig 5; Table
5). The furthest distance indicated above represents a tag return from Fenwick Island,
Delaware (Fig 5; Table 5).

Refer to Table 5 for the dates associated with each tag return. The longest interval
between the date a loggerhead was tagged on Wassaw Island and the date the turtle was
recovered again was 7 years. This turtle was tagged on Wassaw Island in 1987 and then
she was seen nesting on Ossabaw Island, Georgia in 1994. There were also two returns
reported to us 6 years after the turtles were originally tagged on Wassaw Island; one from

Blackbeard Island, Georgia and one from Hilton Head Island, South Carolina (Fig 5;
Table 5)

4.2. Tag Recoveries

From 1973-2000, the Caretta Research Project has identified 57 turtles crawling
or nesting on Wassaw Island that were originally tagged elsewhere (immigrant turtles).
See Figure 5 and Table 6 for the tagging origins of immigrant turtles that have been
observed on Wassaw Island. Fifty-six of the observed immigrants were originally tagged
as nesters on other beaches. One immigrant was tagged after being caught in a pound net
in Chesapeake Bay, Virginia. The majority of immigrants (91.2%, n=52) have come from
beaches south of Wassaw Island, while only 8.8% (n=5) have come from northerly

beaches. Fifty-three (93.0%) were originally tagged on beaches within 125 km of
Wassaw Island.

14


Fig. 2. Tagging locations of external and internal tags on front and rear flippers. Closed
circles denote tagging locations for external tags (plastic, monel and inconel). Open
circles denote tagging location for internal tags (P.LT. tags).

Fig. 3. Diagram of self release hatchery design.

NEST LOCATIONS

WITHIN PANELS, V2" X 1/2" SCREEN

COVERING EACH
PANEL
REMOVABLE/RECTANGULAR.
PANEL
2x4's RESTING ON
EACH OTHER 3
<I> Seat
—
AFT. 2x4 t < ++ SANDISURFACE LEVEL

SAND/SURFACE LEVEL -- 7
16 FT. 2x4 . * 2

20° DERP GALVANIZED SHEET METAL
TACKED TO 24'S AROUND THE ENTIRE
” BASE OF THE HATCHERY



Probability of Tag Loss

| 12

1 2 al
| a a
| Eos
i)
| Bos} —S
| 2
[ae
jo
H 0.2

)

Tag Age (years)

|
|
f —¢— Inconel —a— Plastic Front —a— Plastic Rear —x— PIT |

Figure 6. Probability of tag retention for inconel, plastic (placed on the front and back
flippers) and PIT tags placed on loggerhead sea turtles on Wassaw National Wildlife

Refuge, GA 1973-2000.

Distribution of Tag Loss

|
\
| 200
|
| 150
| 3
| — 100
| 5
(2
50 +
(gL ees ame]
' monel plastic inconel PIT
Tag Type

@retained Dlost

Figure 7. Comparison of tag retention and loss for monel, plastic, inconel, and PIT tags

placed on loggerhead sea turtles on Wassaw National Wildlife Refuge, GA 1973-2000.

20


NOAA Technical Memorandum NMFS-SEFSC-446

RESULTS FROM THE LONG-TERM MONITORING OF NESTING LOGGERHEAD
SEA TURTLES (Caretta caretta) ON WASSAW ISLAND, GEORGIA: 1973 — 2000

Kristina L. Williams
and

Michael G. Frick

U. S. Department of Commerce
National Oceanic and Atmospheric Administration
National Marine Fisheries Service
Southeast Fisheries Science Center
75 Virginia Beach Drive
Miami, FL 33149

January 2001


Fig. 4. Profiles of each beach/dune type present on Wassaw Island (adapted from
Caldwell, 1959). A= truncate dunes, B= ledge section, C= wide sloping beach, D=
narrow flat beach, E= wide flat beach, F (1 and 2)= barren areas (two distinct types), H=
average high tide line, S= tidal amplitude during spring tide high tides, W= average
distance covered by tidal wash when spring tides are pushed by offshore winds. Scale bar

indicates 10 feet. See text (Section 1.2) for descriptions of each beach/dune type. 1


distance of up to 10 ft. or more. Taking into account the variation in tidal amplitudes that
a barrier island can experience over the course of a nesting season, one can imagine the
difficulty that exists when deciding whether or not a turtle nest is in danger of tidal
inundation. See Figure 4 for a representation of the -approximate tidal amplitudes
experienced within the varying beach profiles present on Wassaw Island.

1,2. Habitat Characterization and Tidal Influence on Habitat
Six distinct dune/beach profiles or types, similar to those described by Caldwell

(1959), occur on Wassaw Island (Fig. 4). The dynamic state of Wassaw’s beach often

produces a gradation from one type to another. The location of each dune/beach type

changes from year to year, depending upon the occurrence and frequency of sand shifting
storms. As a result, the frequencies at which loggerheads utilize particular latitudes on

Wassaw Island also change from season to season, since all six dune types are utilized by

loggerheads for nest deposition at varying frequencies (Table 1). Loggerhead dune type

preference will be discussed in a Section 1.4. Descriptions of each dune/beach types and
how they are affected by tidal influences (adapted from Caldwell 1959; Figure 4) are as
follows:

A. Truncate dunes: Sharply eroded dunes that back a beach 5-10 feet wide at an average
high tide. This dune type is usually eroded further during spring tides and unusually
high tides pushed by offshore winds.

B. Ledge section: A stretch of dunes having a 0.5-3 foot ledge breaking the middle of its
natural slope. This type is formed by the action of wind and tide (undertow).

C. Wide sloping beach: Twenty-five to 40 foot wide section of dry sand from the
average high tide line to the base (toe) of dunes. If spring tides and accompanying
winds are strong enough, this habitat type will become a ledge section (above).

D. Narrow flat beach: Ten to 20 foot wide section of dry sand backed by small and
separated dunes. The maritime forest is situated closer to the average high tide mark
in this area than in other beach type. As a result, dead or dying trees can be found
littering the beach anywhere from below the average high tide mark all the way up to
the wood line. Spring tides and associated winds will often push the surf closely to
the edge of the maritime forest.

E. Wide flat beach: Similar to the narrow flat beach but is composed of up to 30-50 feet

of dry sand backed by small isolated dunes. Unusually high tides will sometimes push

water over the crest of the beach and cause a trough or slough of salt water to form at
the base of the small isolated dunes when the tide retreats. Such troughs usually
disappear 1-2 hours after high tide.

Barren areas: Dry, but occasionally inundated, sand stretching 100-400 feet back

from the crest of the beach, with only traces of vegetation or low dunes to break their

flatness. Shorebirds commonly utilize these dune/beach types for ground nesting. A

combination of high wind and spring tides will wash this area with advancing waves

approximately 1-2 hours before and after high tide. Some barren areas possess a

build-up of sand at the crest of the beach (Fig 4 (F2)), in this type of barren area

spring tides will create troughs of water similar to those troughs described for wide
beach areas, but much larger.


Aplidium constellatum Constellation tunicate or sea pork

Didemnum duplicatum Paintsplash tunicate
Molgula manhattensis Sea grape sea squirt
Perophora viridis Honeysuckle tunicate
Plants Algae
Bryopsis plumosa Green plume algae
Calothrix sp. Blue-green algae
Chaetomorpha sp. Green algae
Cladophora sp. Green algae
Ectocarpus sp. Brown algae
Enteromorpha sp. Green algae
Noctiluca sp. Dinoflagellate
Polysiphonia sp. Red algae
Unidentified green algae Single-celled algae
Unidentified diatoms Diatoms
DISCUSSION

Loggerheads deposit their nests within all six nesting habitat types found on
Wassaw Island (Fig. 4; Table 1). However, habitat types with the greatest visual slopes
are more often utilized (Fig. 4; Table 1), indicating that the slope of the beach may be an
important nesting cue for loggerheads. A study and review by Wood and Bjorndal (1999)
also implicates beach slope as an important cue for loggerheads during nesting
emergences in Florida

Comparing our tagging data to information collected from Little Cumberland
Island (LCI), Georgia, several differences appear that are worthy of discussion. The
population structure of LCI turtles reported by Richardson and Richardson (1981) is
significantly different than the population structure presented here for Wassaw Island
nesters. For instance, Richardson and Richardson (1981) reported that the average
number of neophytes per season on LCI was 30-40 %, while immigrants, remigrants, and
tag scarred turtles represented 60-70 % of the turtles observed per season, collectively.
The observed average neophytes per season on Wassaw Island (70 %) and the collective
averages of immigrants, remigrants, and tag scarred turtles (30 %) contrasts the data
reported by Richardson and Richardson (1981). It should be noted that LCI’s tagging
project and the Caretta Research Project have used the same tagging methodologies
throughout the entirety of both programs, so differing methodologies should not account
for any major differences observed in population structure comparisons between the two
programs. Instead, a few points might explain the differences between the two historical
data sets. The beach on LCI (~ 4 km long) is considerably smaller than Wassaw Island’s
beach. A smaller beach would undoubtedly reduce the probability of missing turtles
during nightly patrols and thus increase the number of remigrants observed in the future.
Secondly, Jekyll Island (~ 3 km north of LCI) also supports a long-term saturation
tagging program. As turtles shift their nesting efforts between the two islands, the number
of immigrant turtles observed on LCI per season would increase and consequently, the
number of neophytes observed per season would decrease. Moreover, there are no long-
term saturation tagging programs neighboring Wassaw Island. The closest saturation
tagging programs to Wassaw Island are Onslow Beach and Bald Head Island, North

27


Mitrella lunata
Musculus lateralis
Rupellaria typica
Sphenia antilliensis

Platyhelminthes

Bdelloura candida
Oligaclado floridanus

Annelida

Dorvillea sociabilis
Filograna vulgaris
Ozobranchus margoi
Podarke obscura
Procerea fasciata
Sabellaria floridensis
Syllis spongicola

Arthropoda

Ampithae ramondi
Balanus amphitrite
Balanus eburneus
Balanus trigonus
Callipallene brevirostris
Cancrion carolinus
Caprella andreae
Caprella equilibria
Caprella penantis
Chelonibia testudinaria
Chthamalus fragilis
Chthamalus stellatus
Colomastix halichondriae
Dulichiella appendiculata
Lepas anatifera

Lepas pectinata

Lysmata wurdemanni
Menippe mercenaria
Panopeus herbstii
Paracaprella tenuis
Pinnotheres ostreum
Planes minutus
Podocerus chelonophilus
Porcellana sayana
Sphaeroma quadridentatum
Stomatolepas praegustator

Bryozoa

Anguinella palmata
Bugula neritina
Membranipora tenuis
Urochordata

Lunar dove snail
Zig-zag mussel
Atlantic rock borer
Soft-shelled clam

Flatworms

White flatworm
Variable flatworm

Segmented worms

Millipede polychaete worm
Lacy feather polychaete worm
Marine leech

Swift footed polychaete worm

Red, white and blue polychaete worm
Florida mason polychaete worm

Sponge polychaete worm
Crabs, Barnacles and Allies

Amphipod

Acorn barnacle

Ivory barnacle

Pink-striped acorn barnacle
Sea spider

Entonioscid isopod

Skeleton shrimp (amphipod)
Skeleton shrimp (amphipod)
Skeleton shrimp (amphipod)
Temperate turtle barnacle
Fragile barnacle

Star barnacle

Amphipod

Big-clawed. amphipod
Goose barnacle

Goose barnacle

Peppermint shrimp

Stone crab

Atlantic mud crab

Skeleton shrimp (amphipod)
Pea crab

Columbus crab

Testudinous amphipod
Spotted porcelain crab
Marine roly-poly

Barnacle

Moss animals

Bushy bryozoan

Bushy bryozoan

White crust bryozoan
Tunicates and sea squirts

26


Monitoring for nesting loggerheads generally started in early May and ended by
the middle of August. Patrols began at dusk (~ 2100 h) and ended at dawn (~ 0600 h).
Two teams of up to four people per team patrolled the beach. Patrols were conducted
using three- or four-wheeled vehicles and/or by walking depending on the tide stage,
weather conditions, and vehicle performance.

Patrol teams only approached turtles once egg deposition had begun. Carapace
morphometrics were determined by both straight-line and over-the-curve measurements
(length=CCL, width=CCW). Straight-line measurements were taken with calipers from
1973 until 1990. Since then over-the curve measurements have been taken with a
fiberglass measuring tape for convenience. Length was recorded as the distance from the
inner nuchal notch to the longest pygal tip. Width was recorded as the widest distance
from marginal edge to marginal edge.

Turtles were also surveyed for epibionts during the 1997-2000 seasons. Epibionts
were collected using a putty knife and/or pair of stainless steel forceps. Specimens were
preserved in either 10% formalin or 70% isopropyl alcohol, sorted and identified. See
Frick et al. (1998) for more detailed methodologies regarding epibiont sampling.

Tagging methodology differed from season to season. Four tag types have been
interchangeably utilized. Originally, monel metal flipper tags were applied singly to
turtles in 1973 and 1974. Nylon “jumbo” rototags were adopted, and used in addition to
monel metal tags, from 1975 to 1977. From 1978 to 1986, turtles were triple tagged with
either, rototags, monel tags, or Riese (size 2) tags. Inconel (mid-sized) tags were
introduced in 1987 and were used exclusively from 1988 to 2000. From 1992 to 2000,
Passive Integrated Transponder (PIT) tags were implanted in turtles to supplement double
tagging with inconel tags. Infopet and Trovan brand PIT tags and readers were used prior
to 1998. Currently, Destron brand PIT tags and readers are used.

Turtles weré marked with flipper tags in three fashions. Singly tagged turtles were
outfitted with a tag on either the first or second large scale on the posterior edge of the
right front flipper. Double-tagged turtles received tags in either the first or second large
scale on the posterior edge of each front flipper. Triple tagged turtles received tags on
both front flippers and into the first or second large scale on the posterior edge of either
the right or left back flipper. All pit tags were implanted subcutaneously just proximal to
the center elbow region of the right front flipper. See Figure 2 for tagging locations.

A diagram of the beach profile associated with each encountered turtle crawl was
drawn. Diagrams were then compared to specific nesting habitat types as defined by
Caldwell (1959) and classified accordingly. Crawls were recorded as either false crawls
or nests. Nest protection and relocation did not begin until 1976, during this season all
nests (n=50) were relocated into styrofoam coolers. During the 1977-78 seasons all nests
were relocated into 5-gallon plastic buckets (n=142 nests). Nests that were placed in 5-
gallon buckets were also housed in a roofed shed. From the 1979 season to the present,
nests that were considered to be in ideal locations were left in situ. Nests that were
deemed in danger of tidal inundation were either relocated to areas higher up in the dunes
or moved to an open air, self release hatchery, also on the beach. Both in situ and
relocated nests were protected with galvanized screening to deter animal predation.

Self release hatcheries consisted of a 8 foot x 4 foot wooden frame with attached
galvanized sheet metal buried to a depth of ~ 2 feet (Fig. 3). The edges of each buried
frame remained slightly exposed ~ 5 inches above the sand surface. An 8-foot x 4-foot


Table 6. Distribution, Distances and Dates of Tags Recovered on Wassaw Island, GA

1973-2000.
Recovery # Tag Origin Date Originally Tagged | Date of Recovery | Minimum Distance Traveled (km)
1 Little Cumberland Island, GA 1972 June 3, 1974 110
2 Jekyll Island, GA. 1973 July 9, 1975 103
3 Kiawah Island, SC 1975 May 24, 1978 123
4 Little Cumberland Island, GA. 1975 June 15, 1981 110
5 ‘Ossabaw Island, GA 1978 July 8, 1978 14
6 Little Cumberland Island, GA 1978 July 15, 1978 110
7 Little Cumberland Island, GA 1978 July 20, 1978 110
8 Ossabaw Island, GA, 1979. June 17, 1979 14
9 Ossabaw Island, GA 1979 June 19, 1979 14
10 ‘Ossabaw Island, GA 1979 June 25, 1979) 14
in ‘Ossabaw Island, GA 1979 June 28, 1979 14 |
12 Little Cumberland Island, GA 1975 July 12, 1979. 110
13 Jekyll Island, GA 1979. July 14, 1979. 103
14 Ossabaw Island, GA, 1979 July 16, 1979 14
15 Ossabaw Island, GA| 1979. July 25, 1979 14
16 Ossabaw Island, GA, 1980, July 17, 1980 14 |
7 ‘Ossabaw Island, GA 1980 July 24, 1980 14 i
18 ‘Ossabaw Island, GA 1978 May 27, 1981 14
19 Little Cumberland Island, GA 1978 June 5, 1981 110
20 Little Cumberland Island, GA’ 1978 June 14. 1981 110
21 Ossabaw Island, GA, 1978 June 16, 1981 14
22 Little Cumberland Island, GA 1979 June 20, 1981 10
B Ossabaw Island, GA, 1979. June 22, 1981 14
24 ‘Cumberland Island, GA 1974 July 20, 1981 118
25 ‘Cape Canaveral, FL. 1982 May 27, 1982 410
26 Ossabaw Island, GA, 1979 June 23, 1982 14
27 Little Cumberland Island, GA 1982 June 30, 1982 110
28 ‘Ossabaw Island, GA. 1980 June 7, 1983 14
29 Cumberland Island, GA 1983 June 17, 1983 118 :
30 Little Cumberland Island, GA 1974 June 23, 1983 110
EN Little Cumberland Island, GA 1980, July 6, 1983 no
32 Jekyll Island, GA 1981 July 26, 1984 103
3 ‘Cumberland Island, GA 1982 June 9, 1985 18
34 Cumberland Island, GA 1979 June 17, 1985 118
35 Jekyil Island, GA 1982 June 22, 1985 103
36 Little Cumberland Island, GA 1982 June 27, 1985 110
37 ‘Cumberland Island, GA 1985, July 25, 1985 118
38 Ossabaw Island, GA 1978 July 28, 1985 14
39 Cumberland Island, GA 1983 June 26, 1986 118
40 Jekyll Island, GA 1983 July 12, 1988 103
4 Hilton Head, SC 1989 July 1, 1989 40
a2 Hilton Head, SC 1989 July 2, 1989. 40
a3 Cumberland Island, GA 1989 July 3, 1989) 118
44 Little Cumberland Island, GA 1985 July 31, 1989 110
45 Jekyll Island, GA 1985 May 23, 1990 103
46 ‘Cumberland Island, GA 1983 June 9, 1990 118 |
a7 Jekyll Island, GA 1982 July 15, 1990 103 _|
4B Cumberland Island, GA. 1988 June 23, 1991 118 I
49 Jekyll Island, GA 1992 July 27, 1992 103
30 Chesapeake Bay, VA (pound net 1989 June 4, 1994 801
capture)
31 Little Cumberland Island, GA 1990 July 7, 1994 110
32 ‘Cumberland Island, GA 1991 July 14, 1994 118
33 Jekyll Island, GA 1996 June 28, 1996 103
34 Little Cumberland Island, GA 1994 July 16, 1996 and 110
July 17, 2000
35 Jekyll Island, GA 1995 June 17, 1998 103
36 Jekyll Island, GA 1997 May 24, 1999) 103
37. Little Cumberland Island, GA June 25, 2000 July 5, 2000 110

17


length (SCL) was determined by measuring from the nuchal notch to the division
between the post-central scales. Straight carapace width (SCW) was determined by
measuring the widest portion of the hatchling carapace from marginal edge to marginal
edge. Depth was determined by measuring the highest profile of the hatchling carapace.
The average morphometrics recorded were SCL= 44.5 mm (range = 40.4 mm —- 47.1
mm), SCW= 33.8 mm (range = 28.2 mm — 36.9 mm), depth = 19.1 mm (range = 16.3
mm — 21.0 mm). Hatchling mass was determined using a spring scale and read to an
accuracy of 0.1 g. The average mass observed from Wassaw Island hatchlings was 18.4 g
(range = 14.0 g- 23.0 g).

8.2. Size and Mass of Eggs

We recorded the size and weight of 298 loggerhead eggs from 15 different nests
during the 2000 season. Mass was determined using a spring scale read to an accuracy of
0.1 g. The size or diameter of each egg was determined by measuring the greatest
diameter using calipers. All sand was wiped clean from eggs using a small brush. The
average egg mass recorded was 36.2 g (range = 26.0 g -47.0 g.). The average greatest
egg diameter recorded was 41.3 mm (range = 37.2 mm — 43.9 mm).

Occasionally turtles will lay small (15-25 mm greatest diameter) yolkless eggs
within a nest containing other eggs of ‘normal’ size. Loggerheads will also lay highly
deformed eggs, which appear to consist of several eggs fused together via the shell or by
long calcium ‘streamers’. One turtle, in 1995, laid 35 eggs and a large deformed egg mass
(as described above) that filled ~ 2/3 of the entire nest chamber. These deformed eggs
also lack yolks and occur rather infrequently.

Section 9: Hatch Rates and Hatchling Emergence Success

9.1. Hatch Rates

By combining hatching data from 1973 to 2000, the average hatch rate (# of
hatched eggs divided by the total # of eggs in the nest x 100 = percent hatched or hatch
rate) observed from nests deposited on Wassaw Island is 59.2% (n=1848 nests). It should
be noted that the average hatch rate for the first three seasons of the program (1973-
1975), before nests were relocated or protected with galvanized screening, was 0.00%
(n=152 nests). By averaging the hatch rates for only the seasons where there was nest
protection and relocation (1976-2000), the observed average hatch rate is 67.0% (n=1696
nests). All nests from the 1976 season (n=50) were stored in styrofoam coolers, the
average hatch rate for these nests was 27.0%. From 1977 to 1978, all nests (n=142) were
incubated in 5-gallon buckets stored beneath a roofed shed. The average hatch rate for
these nests was 35.7%. The average hatch rate for nests deposited during the 1979-2000
seasons (relocated and in sitw; n=1656), which were nests incubated on the beach, was
71.4%.

With the exception of 121 nests that were not recorded as being either left in situ
or relocated, we compared the hatch rates between nests left in situ and those that were
relocated from their original site of deposition (includes nests relocated to open-air, self-
release hatcheries and to safe zones or higher areas in the dunes) for the 1979-2000
seasons (n=1535 nests). The average hatch rate for in situ nests (n=220) was 47.9 %.
Relocated nests (n=1315) had an average hatch rate of 70.5%. However, any comparisons


TABLE OF CONTENTS

Introduction............ Fete eee eect retort ttetterteetere L

Materials and Methods...........00......0000. 0.0 ccc ceecee cee cee ee eee cee eee ee eeetee eee nes 1
Study Site... 00.00.00 eee cee ee teen eeeceeceeeeedeeteeeeeeeeeeeveeteeeeeees 1
Standard Beach Monitoring Data Collections...........0.0.....00...0..05. rerrre |

Differential Tag Retention

Results... 000... eee tees etett ttt 5

Section 1: Nesting Habitat Characterization, Composition, and Utilization.....5

1.1. Tidal Amplitude in Georgia.........0000.. 0c bo SD
1.2. Habitat Characterization and Tidal Influence on Habitat... : . 6
1.3 Habitat Composition.................... voce tteeeteeneteeeteeesteseeseeteteeeeessreens D
1.3. Habitat Utilization........ . . voce eee tee eeeeev estes eeeeeees 9

Section 2: Morphometrics of Nesting Loggerheads..

Section 3: Population Structure................ levees ees vevecveteeeeeees 12
Section 4: Tag Returns and Recoveries..................000.00..0...ccccceeeeeeeeeeeee 13
4.1. Tag Returms...... 00.000 .00 coc ceeeee eee rer reer rrrrereeeeere 1}
4.2. Tag Recoveries........0..0...... cece bec veeeee eee ueeeeseeeeeeeees eereeeere C1
Section 5: Differential Tag Retention..................000 000s 19
5.1. External Tags...... 2.200000... cece cee eee cece eect eeseeeceeceeceeeseeeseeeeeeeaee 19
5.2. Internal Tags (P.I.T. tags)...0.00... 2.000 eee cee cee eee tet eteeeeeeees 19
Section 6: Remigration and Internesting Intervals............................0005 22
Section 7: Fecundity..0...000...000 o.oo eee cee eeeees 22

iii


emerge into ledge sections (Fig 4 (B); Table 1) have a 54 % chance of nesting, possibly
depending upon the height of the ledge or the ‘determination’ of the emerging turtle.

Turtles emerging into narrow flat beach areas (Fig 4 (D); Table 1) will nest 40 % of
the time. On Wassaw Island, narrow flat beaches usually occur where the maritime forest
is very close to the average high tide mark. As a result, there are many dead or dying
trees (oaks, pines and palms) littering the beach. We have observed many emerging
females hit such obstacles and return to the water in this area. Narrow flat beaches
containing large amounts of dead wood or beach wood are commonly referred to as
“boneyards’ on many of undeveloped barrier islands in the southeastern U.S.

Nesting emergences onto wide flat beaches and into barren areas (Fig 4 (E and F))
often result as false crawls (Table 1). It should be noted that, on Wassaw Island, these
areas are associated with offshore sandbars. It is possible that sandbars might inhibit
nesting emergence approaches by loggerheads.

Table 2 shows the number of false crawls and where they commonly occur in relation
to the average high tide line within each beach type. In truncate dune areas (Fig. 4 (A))
the majority of the false crawls in this area occur at the average high tide line (Table 2).
Since the average high tide line usually occurs at the base of the truncate dunes (Fig. 4
(A)), it might be possible to surmise that inaccessibility to higher ground may have
contributed greatly to false crawling in this area. We only occasionally see turtles ‘carve’
out truncate dunes, creating access to higher ground, and subsequently nesting (n=3;
Table 3). Instead, the nests laid in this area are usually laid at the average high tide line
(Table 3).

Turtles also false crawl regularly at the average high tide mark in ledge section beach
types (Fig. 4 (B); Table 2). Ledges form at the average high tide mark as a result of wave
action and wind (Fig. 4 (B)). Even though most turtles are capable of traversing a small
(6-12 inches high) ledge, it appears that a ledge feature will sometimes cause emerging
turtles to false crawl (Table 2). However, the majority (54%) of the turtles that emerge
into the ledge section beach type do traverse ledges and deposit nests (Tables | and 3).

The wide sloping beach type (Fig. 4 (C)) is utilized for nest deposition more than
any other beach type on Wassaw Island (Table 1). Easy access to relatively large dunes
probably accounts for the large percentage of nests laid above the average high tide mark
in this area (94 %; Table 3). However, most false crawls (80 %) also occur above the
average high tide mark in this area (Table 2).

Comments recorded onto our data sheets for particular false crawling events
associated with the wide sloping beach often times implicate buried debris as a primary
factor for the observed false crawls. That is, turtles begin to either excavate a body pit or
dig a nest chamber and encounter immovable debris in the process. We have found
buried dock pilings, fluorescent bulbs, 5-gallon buckets, ship’s hull pieces, shrimp nets,
and bags of tin cans among many other objects buried in the sand where loggerheads
have aborted body pits and nests. It should be noted that, within all beach dune types,
Wassaw Island nesters perform the stereotyped nesting behavior reported by
Margaritoulis (1985) for Greek loggerheads. However, some turtles are observed missing
rear flippers. As a results these turtles will attempt to dig nest chambers to no avail and
will subsequently false crawl or deposit eggs onto the beach as the turtle returns to the

water. Thus, some digging and subsequent false crawling episodes can be attributed to
reasons other than buried beach debris.


Section 3: Population Structure and Rate of Remigration

Using tagging information we classify an individual turtle as either a neophyte,
remigrant, immigrant or tag-scarred turtle. A neophyte is a turtle that has not previously
been tagged, although she may have nested before. By tagging neophytes we can
determine if a turtle is a remigrant or an immigrant. A remigrant is a turtle that has been
tagged on Wassaw Island and continues to use Wassaw’s beaches during subsequent
nesting attempts and nesting seasons. An immigrant is a turtle that was previously tagged
on another beach that also utilized Wassaw Island for nest deposition. A tag-scarred turtle
is one that has lost all external tags, and only bears tagging scars. A tag-scarred turtle
could represent either an immigrant or a remigrant turtle. However, with the introduction
of PIT tags in 1992, the number of tag-scarred turtles that cannot be identified as either
immigrants or remigrants has begun to decrease. See Section 5 for an analysis of tag
retention for turtles tagged on Wassaw Island.

Currently, we have identified 1110 individual loggerhead turtles from Wassaw
Island between the 1973-2000 nesting seasons. Each year an average of 46 individual
turtles (range = 18 — 69) utilize the island for egg deposition. Neophytes account for 70 %
of the turtles observed each year, while remigrants, immigrants, and tag scarred turtles
accounted for 10.3%, 7%, and 12.7% of the turtles observed each year, respectively.

Out of the 1110 individual loggerheads identified by our project, 114 individuals
have returned to Wassaw Island during subsequent seasons to nest. Seven individuals
have a documented nesting history of 10 years or greater. Of the 114 loggerheads that
have returned to Wassaw Island, 81 (71.1%) have returned only once, 21 (18.4%) have
returned twice, and 12 (10.5%) have returned more than two times (Table 4).

Table 4. Multiple Remigration rates for 33 loggerhead sea turtles on Wassaw National
Wildlife Refuge, GA 1974-2000.

INTERVALS (YEARS)
2.1

2.1.2

2.2

2.2.2.2.2.2

2.2.2.3.2.3
2.2.4
2.3

2.3.2

24

3.2

3.2.2
3.2.3.3
3.3
3.3.2.2.3.3
3.3.30.

Hlefe|e} lets) pop efro}—l—fo)—]—fa]—j—|-_]a|—l-|s



NOTICE

The National Marine Fisheries Service (NMFS) does not approve, recommend or endorse
any proprietary product or material mentioned in this publication. No reference shall be
made to NMFS, or to this publication furnished by NMFS, in any advertising or sales
promotion which would indicate or imply that NMFS approves, recommends or endorses
any proprietary product or proprietary material herein or which has as its purpose any

intent to cause directly or indirectly the advertised product to be used or purchased
because of NMFS publication.

Correct citation of this report is:

Williams, K.L. and M. G. Frick. 2000. Results from the long-term monitoring of nesting

loggerhead sea turtles (Caretta caretta) on Wassaw Island, Georgia: 1973 - 2000. NOAA
Technical Memorandum NMFS-SEFSC-446. 32 p

Technical Editor: W.N. Witzell

Author addresses: Caretta Research Project, P. O. Box 9841, Savannah, Georgia 31412
Copies of this report can be obtained from:

National Marine Fisheries Service
Miami Laboratory

Sea Turtle Program

75 Virginia Beach Drive

Miami, FL 33149

or

National Technical Information Service
5285 Port Royal Rd.

Springfield, VA 22161

(800) 553-6847 or (703) 605-6000


Table 7. Probability of Tag Retention for each of the four tag types.

Tag Type | Years Since Tags Tags Total Pi SEpi 95%
and Appplicatio | Confirmed- | Confirmed- (@robability Confidence
Location n@) Present Lost of tag loss) Intervals
MONEL:
Front: 2 3 3 6 -500 04 +-.400
3 2 1 3 333 07 +-.533
7 0 1 1 1.00
Rear: 2 1 0 1 0.00
PLASTIC:
Front: 1 1 2 3 -667 07 ++.533
2 30 19 49 388 i} +-.136
3 16 23 39 590 Ol +-.154
4 7 17 24 -708 01 +-.182
5 1 8 9 889 01 +-.205
6 0 3 3 1.00 )
7 0 2 2 1.00 0
8 0 2 2 1.00 0
Rear: 1 0 1 1 1.00 0
2 12 6 18 333 Ol +-.218
3 10 6 16 375 O1 +-.237
4 8 2 10 -200 02 +-.248
5 2 2 4 5 06 +-.49
6 2 1 3 -33 .07 +-.533
8. 1 0 1 0
9 0 1 1 1.0 0
19 1 0 1 0
INCONEL:
Front: 1 1 1 2 =) 125 +-.693
2 10 16 26 615 .009 +-.187
3 16 26 42 619 -006 +-.147
4 4 ay 15 -733 013 +-.224
5 4 7 u 636 021 +-.284
6 3 8 1a 727 018 +-.263
7 2 2 4 -500 .063 +-.490
8 3 3 6 500 042 +-.400
ll 1 0 1 )
Rear: 2 1 0 1 0
8 0 1 1 1.00
9 1 0 1 0
PIT TAGS:
Front: 1 1 0 1 0
2 3 0 3 i)
3 at 3 14 214 02 +-.215
4 2 2 4 500 .063 +-.490
5 3 1 4 .250 047 0.00
6 2 2 4 -500 063 +-49
7 1 0 i 0.00
8 1 0 1 0.00

21



Ry ;
‘ NOAA Technical Memorandum NMFS-SEFSC-446
=

<i

RESULTS FROM THE LONG-TERM MONITORING OF NESTING LOGGERHEAD
SEA TURTLES (Caretta caretta) ON WASSAW ISLAND, GEORGIA: 1973 — 2000

Kristina L. Williams
and

Michael G. Frick

U.S. DEPARTMENT OF COMMERCE
Norman Mineta, Secretary

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION
D. James Baker, Administrator

NATIONAL MARINE FISHERIES SERVICE
Penelope D. Dalton, Assistant Administrator for Fisheries

January 2001

Technical Memoranda are used for documentation and timely communication of
preliminary results, interim reports, or special-purpose information, and have not
received complete formal review, editorial control, or detailed editing.


Turtles moving north of the study area appear to do so in late summer (mid-July to
August), whereas; turtles migrating south of the study area do not show any such
consistency and have moved southward throughout the nesting season (June-August). A
more detailed analysis of the conditions surrounding each migration (i.e. weather
conditions, phylogenic origin of the observed turtle, age of the turtle, etc.) are needed
before any detailed conclusions derived from any long-range tag return data can be made.

Utilizing flipper tagging to track individual nesters is, by far, not the best
methodology available (Witzell, 1998). However, it is an important methodology to adopt
when conducting long-term studies that depend upon a large sample size to create
averages that are representative of the overall nesting population (Balazs, 1999). Without
a means to identify individual turtles, such studies would contain sampling errors as a
result of duplicating sampling attempts or data collections on individual turtles that have
already been sampled. Thus, it becomes important to evaluate the performance and
reliability of the available tag types that are applied to nesting loggerheads.

Comparing the four tag types used on Wassaw Island from 1973-2000, plastic
flipper tags applied to hind flippers and P.1.T. tags had the highest retention rates (Fig. 7)
Inconel tags appear to be satisfactory for identifying turtles over an extended period of
time, warranting they are replaced when the tags or tagging site begins to degrade (Fig.
6). However, since inconel tags were only tested on the foreflippers, it is possible that the
retention rate of inconel tags on the hind flippers may be greater than that observed for
inconel tags on the front flippers. Further study is needed to clarify retention rates
between all tag types in respect to the available tagging locations on turtles.

Loggerhead nest monitoring from 1973-75 revealed that, without any type of nest
protection on Wassaw Island, 100 % of the nests deposited would either be inundated by
high tides or predated (Section 9). A 0% hatch rate for the 1973-75 years combined
initiated a decision to protect nests beginning in the 1976 season. Although well
intentioned, moving all nests to styrofoam coolers and 5-gallon buckets did not produce
the highest hatch rates we have observed from Wassaw Island nests. However, the
average hatch rate has increased substantially (to 71.4 %) by incubating nests on the
beach (relocated and in situ) since 1979.

From our observations and studies on Wassaw Island, it is evident that more work
is needed before we can fully understand the nesting ecology of loggerhead sea turtles.
By supplementing long-term programs with newer methodologies and collaborative
efforts from other scientific disciplines, we hope that such opportunities will provide us
with newer angles by which to view our historical data. However, there is still the need

for other programs to report their long-term data sets so that accurate comparisons and
management decisions can be generated.

Acknowledgements

The Caretta Research Project would like to thank the following people and institutions
for their support and assistance since 1973:

- Charles Milmine, Gerald Williamson and the Savannah Science Museum
Herpetology Club for initiating the project

29


made between relocated and in situ nests on Wassaw Island should be generated carefully
as the same criteria used to determine if a nest can be left in situ are the same criteria
used when determining where to relocate a nest or place a self-release hatchery.
Additionally, there were many more nests relocated than left in situ.

9.2. Emergence Success

Although hatch rates are useful for assessing the results of the incubation period
experienced by nests, they do not accurately represent the percentage of the hatchlings
actually emerging into the outside environment. Therefore, it becomes important to
determine the emergence success experienced from any given nest. Emergence success
represents the percentage of all the hatchlings produced in a nest that successfully exited
the nest chamber, thus the emergence success does not include dead hatchlings located in
the nest. The emergence success of a nest is determined by subtracting the number of
dead and live hatchlings encountered in a nest from the number of hatched eggs, the
difference is then divided by the total number of eggs originally deposited within the nest
and multiplied by 100. The average emergence success for nests deposited from 1973-
2000 (n=1848 nests) was 57.3 %. Excluding the first three seasons (1973-1975), since all
nests (n= 152) had a 0.00 % hatch rate due to predation and/or tidal inundation, the
average emergence success rate for the 1976-2000 seasons (n=1696 nests) was 64.0 %.
The average emergence success rate for nests incubated in styrofoam coolers (1976, n=50
nests) was 10.8 %. Average emergence success for nests incubated in S-gallon buckets
(1977-78, n=142 nests) was 34.5 %. Averaging the emergence success for all nests (n=
1656) incubated on the beach (relocated and in situ; 1979-2000), the rate was 69.1 %.

From 1979-2000, in situ (n= 220) and relocated nests (n= 1313) had average emergence
success rates of 45.7 % and 68.4 %, respectively.

Section 10: Predators of Loggerhead Nests and Hatchlings

A variety of vertebrates and invertebrates utilize the loggerhead’s nesting habitat
as foraging grounds on Wassaw Island. Ghost crabs (Ocypode quadrata), fire ants
(Solenopsis invicta and S. globularia littoralis) and raccoons (Procycon lotor) are
predators of nests and emerging hatchlings in all six beach types discussed in Section 1
(Fig 4). Great horned owls (Bubo virginianus) and screech owls (Otus asio) have only
been observed feeding on hatchlings in narrow flat beach areas. Apparently, the close
proximity of the maritime forest to the average high tide mark in this area provides these
avian predators with the appropriate foraging habitat, which allows them to perch and
scan for emerging hatchlings. Another predator only observed from narrow flat beach
areas is the yellow rat snake (Elaphe obsoleta quadrivittata). On one occasion, a rat
snake was found consuming a single egg from a loggerhead nest. The snake had entered
the nest via a ghost crab hole.

Minks (Mustela vison) can be found foraging in narrow flat beach and wide flat
beach areas where they will dig underneath protective screening and consume loggerhead
eggs. Hogs or European wild boars (Sus scrofa) are only rarely observed as predators of
both nests and emerging hatchlings, possibly due to their low numbers on the island.
Instances of hog predation have occurred in narrow flat beach areas and wide flat beach
areas. Another documented predator was an unidentified seagull that was seen consuming

24


Table 1. Frequency of crawls observed within each beach/dune type present on Wassaw

Island (1980-1990). Refer to text (Section 1.2) and Figure 4 for beach/dune type
characterization.

Total No. Crawis

Beach Type A B c Do E E (%)
No. False Crawls 156 149 130 97 120 135 787
No. (%) FC Below AHT 2(1) 171) 1743), 3(3),—s«96(80) 13197) 250(32)
No. (%) FC Above AHT 0(0) 3(2) 104(80) 9396) (2) 4(1) 203(26)
No. (%) FC @ AHT 154(99) 145(97) 97) 11) 22018) 32) 334(42)

Table 2. Frequency and location of false crawls with respect to the average high tide line

within each beach/dune type present on Wassaw Island (1980-1990). Refer to Section 1.2
and Figure 4.

Total No. Crawls

Beach Type A B c D E E %.
No. False Crawls 156 149 130 97 120 135 787
No. (%) FC Below AHT 2(1) 1(1) 17(13) 3(3) 96(80) 131(97) 250(32)
No. (%) FC Above AHT 0(0) 3(2) 104(80)  93(96) 2(2) 1(1) 203(26)
No. (%) FC @ AHT 154(99) 145(97) 97) 4(1) 22(18) 3(2) 334(42)

Table 3. Frequency and location of nests deposited within each beach/dune type present

on Wassaw Island with respect to the average high tide line (1980-1990). Refer to
Section 1.2 and Figure 4.

Beach Type
Total No. Crawls
No. of Nests A B c D = E (%)
No. (%) Nests Below AHT 44 174 301 65 15 10 609
No. (%) Nests Above AHT —4(9) 2(1) 17(6) 3(5) 0(0) 0(0) 26(4)
No. (%) Nests @ AHT 3(7) 163(94) 272(90)  49(75) 13(87) — 10(100) 510(84)
37(84) 9(5) 12(4)  13(20)—-2(13) 0(0) 73(12)

FC=False Crawl
AHT=Average High Tide


As discussed above, narrow flat beach areas (Fig. 4 (D)) are often associated with
the eroded maritime forest. As a result, dead trees are found at, above and below the
average high tide mark in this area. A large number of the false crawls we witness in this
area are easily attributed to turtles crawling into downed trees. Yet, fair percentages
(40%) of turtles do pass across the ‘boneyard’ to deposit nests (Table 1), usually above
the average high tide mark (75%; Table 3). However, since the maritime forest is in such
close proximity to the average high tide mark in this area, nests laid on the narrow flat
beach are easily accessible to predators that also forage within the forest. As a result, the
nests laid in this area are at risk to a higher diversity of predators than anywhere else on
the island. See Section 10 for a list of nest/hatchling predators and their associated beach
type foraging area(s).

On Wassaw Island, wide flat beach types (Fig. 4 (E)) are located adjacent to or
just southward of offshore sandbars. As a result, high tides push large amounts of sand up
into this area. Thus, decreasing the slope of the beach and increasing the distance
between the average high tide mark and relatively higher ground. At high tide turtles
must traverse 50 feet or more of dry sand before reaching areas that will not be washed
by unusually high tides. At low tide turtles sometimes have to crawl up to 100 yards to
reach the average high tide mark in this area. From 1980-90, 95% of the nests laid in this
area were laid either during mid tide or high tide and 99% of the false crawls observed
occurred during mid tide and low tide. Additionally, the percentage of false crawls
(89%) observed is much greater than the percentage of nests (1 1%) that occurred in this
beach/dune type area (Table 1). Such information also suggests that as the distance
between the water line and the average high tide mark increases so does the chance that a
nesting emergence will result in a false crawl.

Barren areas (Fig. 4 (F)) are also associated with offshore sandbars, but more
intimately so. On Wassaw Island, these areas represent locations where Cape Charlotte, a
sandbar spit located on Wassaw’s northeastern-most tip, connects to the island (Fig. 1).
This area is very similar in width and slope to the wide flat beach areas described above.
Additionally, false crawling and nesting observations are very similar between the two
areas (Tables 2 and 3). Most turtles emerge here during high tide when much of the Cape
is covered by water. However, on several occasions turtles have emerged and nested at
low tide. Consequently, the long crawls apparently tired the turtles to the point where
they would not return to the water. Some turtles remained by the nest site for up to twelve
hours before research crews had to transport them back to the surf and out of the intense
sunlight. Additionally, turtles have crawled into a tidal pond located behind the barren
areas (Cape Charlotte) and, apparently disoriented, swam around for several hours before
climbing out and onto the bank surrounding the pond. These exhausted turtles also had to
be transported back to the surf and out of the morning sun.

Section 2: Morphometrics of Nesting Loggerheads

The most accurate morphometric data collected from Wassaw Island nesters was
between 1991-2000. By combining these years, carapace length and width was averaged
from 437 measured turtles. The average CCL of Wassaw Island nesters was 100.3 cm
(range = 82-120). The average CCW was 91.5 cm (range = 88-110).

ll