Sea Turtles in the Gulf of Mexico

Image: Wikipedia

Sea turtles seem to hold a permanent place in our culture, and rightly so.  They have been swimming the seas since the time of the dinosaurs, so the first humans saw essentially the same species that exist today.  A visit to the Georgia coast reminded me how fascinating—and threatened—sea turtles are.

Types of sea turtles

Eight species of sea turtles have been identified worldwide.  Of these, five are found in the Gulf of Mexico.

The loggerhead sea turtle is the most common in Florida, with over fifty thousand nests recorded each year.  As an adult, this turtle is around three feet long and weighs two hundred pounds.  It is named for its disproportionately large head.

The green sea turtle is the only herbivorous (plant-eating) sea turtle.  It is the largest hard-shelled sea turtle, weighing in at over three hundred pounds.  Green-colored flesh gives this turtle its name.

The largest sea turtle is the leatherback turtle, which can grow to over six feet long and 1400 pounds.  Instead of a hard shell, it has a leather-like carapace with bony ridges underneath the skin.  The leatherback makes long migrations from its nesting beaches in the tropics to areas as far north as Canada.  Like other sea turtles, this species is immune to the sting of box jellyfish and regularly eats them.

The Kemp’s Ridley sea turtle is the rarest and smallest in the world, weighing one hundred pounds on average.  This turtle has a unique nesting habit.  Large groups gather off one particular beach in Rancho Nuevo, Mexico, and waves of females come onshore to nest in the arribada or “arrival.”  Scientists have yet to determine what triggers the arribada; theories range from offshore winds to lunar cycles.

The medium-sized hawksbill sea turtle lives near coral reefs, feeding on sponges.  It was hunted to near extinction for its shell.

Habitat

Sea turtles are found in all non-polar regions.  They spend much of their lives in continental shelf waters.  Males do not leave the water, and females come ashore only to lay their eggs.

Migration and navigation

Sea turtles migrate throughout their lives.  During its first hours, a hatchling must travel to a place in the ocean where it is relatively safe from predators and where it can find food.  Each year adult turtles migrate hundreds (sometimes thousands) of miles from feeding grounds to nesting grounds.  Females faithfully return to nest on the beach where they were born.  You can learn more about sea turtle migration and navigation here.

Threats

All sea turtles are considered endangered, and three of the seven species are critically endangered.  One threat to sea turtles is habitat loss, caused by uncontrolled development of nesting areas.  Hunting and poaching is another problem.  Although the sale of sea turtle products is prohibited in the U.S. and many others countries, poaching is rampant.  In addition, legal hunting and trade continues is some areas.

Each year thousands of turtles are caught accidentally in shrimp trawls, gill nets, and other fishing operations.  In the U.S., shrimpers are required to use Turtle Exclusion Devices (TEDs), which allow turtles to escape the nets, but not all fishermen comply.  Many turtles are also injured by boat propellers.

Pollution is another threat to sea turtles.  They may mistakenly ingest plastic garbage or become tangled in discarded fishing gear.  Turtles are also vulnerable to oil spills and other forms of water pollution.  A cancer-like disease called fibropapillomas is on the rise in sea turtles; research suggests it is caused by marine pollution.

As the effects of climate change continue to worsen, they will likely impact sea turtles.  Since the gender of hatchlings depends on the sand temperature, an increase in the world’s average temperature could change the ratio of males to females.  This could easily destabilize populations.  In addition, rising sea levels encroach on nesting area.

Why should we protect sea turtles?  Conservationists point out that humans could probably learn a lot from animals that have survived for so long.  It took us thousands of years to invent a GPS system, yet sea turtles seem to have a built-in sense that tells them where they are.  Besides that, turtles are ecologically important in the beach and marine systems—both of which connect to humans.

Here are some ways you can help sea turtles:

  • Never disturb sea turtle nests or eggs.
  • Fill in holes in the beach that could trap hatchlings.
  • Stay off sand dunes; they are important nesting habitats.
  • Recycle used fishing lines.
  • Don’t use lights on the beach after dark during nesting/hatching season.  Artificial lights near the shore can deter females from nesting and disorient hatchlings.

On a recent trip to Georgia’s Golden Isles, I visited the Georgia Sea Turtle Center at Jekyll Island.  The Center is essentially a sea turtle hospital, rescuing stranded turtles and providing veterinary care, from antibiotics to physical therapy.  It also sponsors programs to educate the public about sea turtle conservation.  Donating to the Georgia Sea Turtle Center — or other similar facilities — is another way to help sea turtles.

Learn more:

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