Sea turtle

Overview
Seven species of sea turtles exist with six species found within the United States waters. Sea turtles occupy all the world’s oceans, except the Artic, and some species swim throughout multiple oceans. The seven sea turtle species include: Kemp’s ridley, olive ridley, loggerhead, hawksbill, green, leatherback, and flatback sea turtles. The flatback is the only sea turtle not found in the United States waters. The leatherback sea turtle is the largest of the seven, measuring on average 6 or 7 feet in length and 3 to 5 feet in width, and weighing as much as a ton. Smaller species measure between 2 feet and 4 feet with a proportionate width. The leatherback is also the only species without a hard shell, instead having a mosaic of bony plates beneath leathery skin.

Sea turtles are super sensitive to the Earth’s magnetic field and have a great sense of time and place. Sea turtles are able to navigate back each year to the beach they were born on to lay their eggs.

Reproduction
Females typically return to the same beaches from which they hatched and lay anywhere from 70 to 190 eggs, then cover them in sand. The temperature of the sand determines the sex of the hatchlings. Eggs take about two months to hatch and since turtles lay eggs in mass, they tend to hatch in mass. Hatchlings dig their way out of the sand and make for the ocean, though only approximately one in about a thousand will be successful. A number of predators stand by ready to gobble up the torrent of turtles.

Diet
Sea turtles can be meat eaters, or carnivores, vegetarians, called herbivores, or omnivores, a little of both. It all depends on the species.

The green turtle, for example, has a finely serrated jaw for eating a diet of algae and sea grass, while the hawksbill’s narrow head and beak-like jaw allow it to feed on sponges, shrimp and other smaller creatures living on coral reefs. Loggerheads and ridleys have jaws adapted for crushing and grinding their prey, which consists of jellyfish, crabs, mollusks, and vegetation. Leatherbacks have very delicate scissor-like jaws and could be damaged if they veered from their diet of soft-bodied animals like jellyfish. Their mouths and throats are lined with spiny projections that help them swallow their food. Flatbacks are opportunistic feeders that eat seaweed, cuttlefish and sea cucumbers.

Threats
All six species of sea turtles in U.S. waters are either threatened or endangered. Sea turtles were once hunted for their meat, shells, and fat but now fall victim to becoming bycatch in the nets and lines of fishermen. Since turtles need to surface to breathe, fishing gear can trap them below the surface and suffocate them. Alternative gear selections, such as circle hooks and turtle excluder devices, are relatively inexpensive measures fishermen can utilize to reduce sea turtle mortality rates.

Coastal development poses another huge threat to sea turtle survival. Sea turtles return to the same nesting beaches each year, regardless of the size and quality of the area, but with more land being developed, sea turtles are quickly losing their critical habitat. The loss of quality beaches isn’t the only problem; the lights from the development mimic the moon light, misguiding the newly hatched sea turtles away from the ocean. While locals are starting to band together to protect the nurseries, others are digging up the eggs for consumption. Global climate change is also becoming a threat to the survival of sea turtles through the increase in temperature. Marine debris choke sea turtles that mistakenly dine on plastic bags instead of jellyfish.

The leatherback, hawksbill and Kemp’s ridley are listed as critically endangered; the green and olive ridley turtles are considered endangered; and the loggerhead is a threatened species. More research needs to be done on flatback turtles to determine their numbers.