Ancient Reptile’s Plight Shows Conservation Need
Ancient Reptile’s Plight Shows Conservation Need
With fossil records dating back 40 million years, this scaly-skinned, hard-shelled reptile reaches about 4 feet long and weighs up to 350 pounds. Mostly carnivorous, it has a big head with powerful jaws that crush and devour prey like crabs, mollusks, shrimp, sea urchins, fish and jellyfish. Although primarily an ocean dweller, this creature breathes with lungs and lays eggs on land. Revered in many cultures as a symbol of longevity, it lives up to 70 years. With as many as 100 types of animals and plants living on its body, it is a mobile ecosystem unto itself.
What animal is this? The loggerhead sea turtle, scientifically known as Caretta caretta.
Despite thriving since prehistoric times and ranging in oceans across the globe, populations of loggerhead sea turtles started dwindling about 200 years ago, with sharper declines in more recent years. Loggerheads are federally listed as threatened and state-listed as endangered. In an effort to restore populations and prevent extinction, the State Wildlife Action Plan, or SWAP, considers Georgia’s sea turtles and their habitats high priorities.
But for a look at the challenges sea turtles and wildlife managers face, let's follow the life of the state's primary sea turtle species – the loggerhead. ...
From May through September, sexually mature females (30 years and older) leave the ocean to laboriously crawl on the beach and nest on one of Georgia’s eight barrier islands. To prevent salt water from inundating the nest, a female finds a dry spot along the foredunes and digs a hole using her rear flippers.
Although loggerheads can lay up to six clutches per season with an average of 120 eggs per nest, they only come ashore every two to four years to nest. Humans collect and eat sea turtle eggs as a delicacy in other parts of the world, but a bigger problem in the U.S. is the loss of nesting habitat due to beachfront development, especially where sea walls and jetties block access to dunes or where dunes are eroded because of unmanaged recreational use. Common nest predators here include non-native species like feral hogs, dogs and cats, as well as raccoons and ghost crabs.
After incubating in the warm sand for about two months, the eggs hatch at night and the young turtles scramble to reach the ocean – unless the hatchlings mistake artificial lights for the moon and head toward roads and swimming pools instead. Even without the confusion of lighting from houses and hotels, hatchlings often fall victim to predators on the beach or soon after entering the ocean. Biologists estimate only one out of a thousand survive to adulthood, which is why sea turtles lay so many eggs – a reproductive strategy to ensure at least some young reach maturity.
Hatchlings that make it to the ocean swim toward brown seaweed concentrations called sargassum where ocean currents meet, gaining protection from predators and also finding food. These mats provide egg-laying habitat for several fish and crab species, serving as important temporary homes for young sea turtles. Unfortunately, the sargassum in the Gulf of Mexico is absorbing oil from the Deepwater Horizon/BP spill, damaging this habitat and the species that use it. Biologists are searching for affected sea turtles in the sargassum and excavating eggs from some nests on Gulf beaches in hopes of hatching the eggs and releasing the young into the oil-free Atlantic.
Given that the sargassum supports the young turtles well, they continue on a journey along currents that circle from America’s coast to the Azores and the eastern Atlantic, south to West Africa and back to the western Atlantic. At this point, the turtles are about 6 to 10 years old and will remain in the shallow coastal waters for the rest of their lives. They will mate upon maturity, and females will return to their natal beach every two to three summers to nest.
Threats during their migration (pdf) and into adulthood include poaching, boat strikes, ingestion of plastic litter mistaken for food and entanglement in shrimp and fishing nets. Turtle excluder devices, or TEDs, greatly help reduce sea turtle mortality, but their use alone is not enough to recover sea turtle populations.
Successful protection of the turtles and their habitats requires a concerted effort from state, federal and local governments, as well as local residents, educational groups and civic organizations. According to DNR senior wildlife biologist Mark Dodd, “Loggerhead recovery is dependent on healthy oceans and coastal ecosystems.”
Fortunately, partner groups like the Georgia Sea Turtle Cooperative, the Sea Turtle Stranding and Salvage Network and other organizations monitor sea turtles, helping combat threats on beaches and in the open ocean, efforts guided by the State Wildlife Action Plan.
How you can help
See a sea turtle on the beach?
This is the fourth article in a five-part series on the State Wildlife Action Plan. Read the entire series here.
Linda May is the environmental outreach coordinator with the Nongame Conservation Section.
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