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St. Catherines Sea Turtle Conservation Program; 2007

Slide Script: Conservation of Georgia’s Sea Turtles

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GeoTrec Sea Turtle Slide Show

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00-001.

The St. Catherines Sea Turtle Conservation Program

sponsored byEisenhower Higher Education Program

(50%)St. Catherines Island Foundation, Inc.

Georgia Southern UniversitySDSMT Museum of Geology

Ga. Department of Natural Resources

00-002.

Index Map of Georgia Coast

St. Catherines Island is one of Georgia’s Golden Isles lying midway on the Georgia Coast at the head of the Georgia Bight.

St. Catherines has 20 km of beach separated into North Beach, Middle Beach and South Beach.

(Map after Shadroui 1990)

00-003.

Aerial Photograph of St. Catherines Island

St. Catherines Island is the fifth largest of Georgia’s 15 barrier islands, 8 mi. [13.0 km.] long and averaging about 2 mi. [~3.2 km] wide with a total acreage of 14,640 including 6,870 upland acres.

As one of Georgia’s undeveloped barrier islands, St. Catherines Island supports conservation and research programs for threatened and endangered species and the management of the Island as wildlife habitat through the St. Catherines Island Foundation, Inc.

00-004.

Picnic Bluff and Sea Side Spit and Marsh

The position of St. Catherines at the head of the Georgia Bight and away from influences of fresh water sedimentation from coastal rivers makes the Island and its beaches a very dynamic environment which is reflected in its complex geomorphology. The Island hosts an eight foot tidal range with semidiurnal (twice daily) tides but a moderate wind and wave regime.

The tidal range and occasional storms result in wide, firmly packed beaches which present quit different appearances during times of quiescence and storm!

00-005. History of Georgia Loggerheads

(Graph from Decline of Sea Turtles)

Baseline data gathered by conservationists and the Georgia DNR from studies of Sea Turtles nesting on Little Cumberland Island indicates a dramatic decline in the numbers numbers of turtles nesting on Little Cumberland Island on the Georgia Coast during the last three decades. This decline is thought to be due directly to the negative influences of human activities including gathering and eating of turtle eggs, the incidental drowning of turtles during shrimping (prior to the use of TED’s), and the continuing urbanization of the Georgia coast and its encasement in revetments, sea walls, and other detrimental human modifications.

00-006

TEDs

TED’s (Turtle Excluding Devices) are metal or mesh barriers which cross the neck of the shrimp net and are linked with an associated trap-door in the side of the net.

When a turtle is caught in the trawl, it hits the cross-net barrier and is shunted out the trap door in the side of the net. This prevents turtles from entering the end of the net and drowning during extended "drags" of the nets.

It appears that Georgia’s sea turtles are weakened by repeated capture in trawl nets, which can eventually lead to drowning.

00-007.

Nesting Loggerhead

St. Catherines 22 kilometers of Sandy Beaches provide nesting habitat for Loggerhead Sea Turtles which utilize the Island’s beaches as rookeries from May until October. Each summer female Loggerhead Sea Turtles (Caretta caretta) return to St. Catherines’ sandy beaches to deposit from one to seven clutches of 114 ping pong ball-sized eggs. The eggs are deposited in a small urn-shaped hole dug by the sea turtle on the back of the beach or in the dunes during the night. The turtle returns to nest on land after spending 20-30 years maturing in the ocean. This long interval of time leading to maturity led to the decline in sea turtle population because the dissemination of the population occurred without being noticed by scientists. The eggs remain in the warm beach sand for about 50-60 days as the embryonic turtles develop and hatch within their sandy domain.

Depositing the Eggs This photograph is from the

Internet.

The female has dug an egg chamber and is depositing a clutch of eggs into it.

Eggs are extruded from the cloaca through the enlarged ovipositor.

When the ovipositor touches the top eggs, the deposition of eggs stops.

00-008. Morphology of Georgia Loggerhead Nests

Direct observation of over 1000 Loggerhead Sea Turtle nests on St. Catherines Island has allowed Bishop and Marsh to develop a model depicting the morphology of a typical Loggerhead sea turtle nest.

Over 250 nests have been measured, photographed, and documented by sketching in the field and approximately 40 nests have been trenched after hatching. These data have been compiled into a diagram depicting a typical Loggerhead sea turtle nest on a Georgia Beach.

Body PitCovering PitEgg ChamberEntranceCrawlway

ExitCrawlway0 cm50 cmSNinactive beachactive beach

00-009.

Patrolling the Beach

Each summer Georgia Southern University students join faculty on St. Catherines Island to patrol the beaches on a daily basis to work toward conservation of the threatened and endangered Loggerhead Sea Turtle population nesting on the Island.

School teachers and other students are trained and work as scientific colleagues in a hands-on program from mid-May until mid-September; living on the Island and daily traversing all beaches in all terrain vehicles.

Each day the entire beach is monitored for new nests, changes in previously documented nests, and for "stranded" sea turtles or marine mammals.

QuickTime™ and a decompressor

are needed to see this picture.

00-010.

Sea Turtle Crawlway

For the first half of the summer program conservationists primarily patrol the beaches looking for crawlways of turtles entering the beach to search for a place to nest. Crawlways look like large tire marks crossing the beach. If the turtle does not nest, the crawlway is termed a non-nesting crawlway and its presence and position are recorded in the conservationists notebook.

Entrance crawlways are made as the turtle enters the beach and exit crawlways as she exits the beach. The direction a turtle was crawling can be determined from claw marks, rear flipper push marks, crossing patterns of the respective crawls, and by lengths of the respective crawlways.

00-011.

Sea Turtle Nest

Nests may be read by observing the traces made by the turtle as she crossed the beach.

The fact that a turtle has nested is often indicated by the presence of an oval disturbed area on the backbeach , by thrown sand, or by differing lengths of crawlways.

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Validating the Nest

Once a possible nest is discovered, the presence of eggs is confirmed by validation by digging on St. Catherines Island.

The loose sand in the body pit is removed from where the we estimate the posterior of the turtle was located at the time of nesting. The bottom of the bioturbated sand filling the body pit is scraped clean with a trowel to expose the sedimentary layering of the undisturbed beach which forms a pattern of continuous lines arranged in circles or stripes.

00-013.

Locating the Egg Chamber

The position of the egg chamber is indicated by an oval or circular patch of mixed-up sand which was backfilled into the top of the egg chamber by the turtle as she began covering the nest.

The sand filling the egg chamber neck usually stands in stark contrast to the patterned layering of the undisturbed backbeach laminated sediments.

The size and orientation of the egg chamber and the nest are measured with a tape measure and compass, sketched in a notebook, and then photographed.