Animal House is a new addition to What the Waste?!?!? This new feature will be scheduled on the second Monday of each month. Animal House is a piece that talks about a selected animal, its habitat, how our actions impact the animal and habitat, and most importantly, what we can do to help. Once people are aware of a problem we can work together to make it right. I've selected sea turtles as the first featured animal because June 16th is World Sea Turtle Day and that is right around the corner.
There are 7 species of sea turtles and 6 of those are vulnerable, endangered, or critically endangered. The species that are not classified as such is the flatback sea turtle and that is because there is insufficient data to make that classification. The seven species of sea turtles are the Green sea turtle, Loggerhead, Kemp's ridley, Olive ridley, Hawksbill, Flatback, and the Leatherback.
Sea turtles are very different from land turtles. They live all of their life in the water except for when the females return to the same beach where they were born to lay her eggs, which she does every 2 to 4 years. Returning to these spawning beaches requires migrations of thousands of miles and they are able to navigate because of their sensitivity to the earth's magnetic fields. This magnetic field sensitivity acts as a sea turtle GPS. Another difference is that of the unique shell of the sea turtle. Sea turtles have less tapering on the ends of its shell and therefore is not able to retract its head, legs, or tail into the shell. This unique shell reduces drag in the water and allows for improved swimming ability.
The leatherback is the largest of the sea turtles. A leatherback can grow as large as 6 to 9 feet in length, 3 to 5 feet in width, and can weigh as much as 1,500 pounds. The leatherback has a slightly different shell than other sea turtles and this is how it got its name. Instead of a hard outer shell, it has boney plates under its leathery skin. Other species of sea turtles can reach a size of 2 to 4 feet in length.
There are few spawning beaches that sea turtles utilize which makes migration a must. Male sea turtles can mate each year and female sea turtles mate every 2 to 4 years. A female sea turtle is able to lay between 1 and 8 clutches per mating season with each clutch containing between 50 and 350 eggs. It takes decades for a sea turtle to reach sexual maturity which is quite an accomplishment as only 20 in 1000 sea turtles reach adulthood and 1 in 1000 reach sexual maturity.
After mating, a female sea turtle will return to the beach where she hatched to lay her eggs. She leaves the water, usually at night, and uses her hind flippers to dig a hole in the sand that is 16 to 20 inches deep. She lays her clutch in this hole and then backfills the hole taking great care to smoothe out the sand on top and some turtles will even cover the spot with vegetation in an effort to disguise the nest from predators. She then heads back into the water and swims away from her nest only to return again when she needs to lay more eggs. This process of digging, laying and covering takes from 30 to 60 minutes to complete. Ridley turtles do this in large groups and both Ridley and Kemps do this during the day instead of at night.
The eggs will incubate in the sand for 50 to 60 days and the sex of the turtles will be determined by the temperature of the surrounding sand. Warmer sand will produce females and cooler sand will produce males. When the new turtles are ready, they will break out of their egg and crawl through the sand to get out of the nest. They always do this at night because they are naturally drawn to the brightest light source. At night with the light of the moon, hatchlings are drawn to the bright horizon in the water and that is how they know which way to head. Once in the water, the hatchling will spend its first 3 to 5 years in the open ocean eating things like zooplankton. After 3 to 5 years, the young turtle will move inshore to the seagrass meadows where other adult sea turtles live.
Sea turtles have an extremely low survival rate, here's why. Sea turtle eggs and hatchlings have an abundance of predators on the beach. Eggs and new hatchlings are eaten by raccoons, foxes, seabirds, and many other animals. Humans eat these eggs as well and are popular in some coastal areas. Light pollution is an issue for hatchlings because they are instinctually drawn to the brightest light source. This causes hatchlings to wander into traffic or head towards city lights instead of the ocean where they need to be to survive. If a hatchling manages to make it to the water, it must then avoid falling prey to seabirds, large fish, and other sea turtles.
Adult sea turtles must contend with sharks and crocodiles in the water as well as plastic pollution, fishing nets and other marine debris, and poachers. It is estimated that 1 in 2 sea turtles has ingested plastic which is usually plastic bags that have been confused for a jellyfish. Sea turtles are considered fine dining in some areas which makes their meat and eggs a valuable commodity. They are caught by poachers for their meat, skin, shell, and eggs. The shells are used for ornamental material that is popular in Japan and China. Their flipper skin is used for shoes and other leather goods. Poachers will capture turtles in the water or on the beach. While on the beach laying eggs turtles are at risk for Jaguar attacks.
We need sear turtles because they provide a valuable service to the ocean that ensures life for other species. Sea turtles eat seagrass that grows in underwater meadows. This seagrass grows across the ocean floor but only when kept short by the sea turtles that eat it. The seagrass plays an important role as a breeding ground and habitat for countless other marine life. Other sea turtles provide a service keeping jellyfish, sponges, and seaweed in check for the health of the ocean.
What can you do to help? Stop using plastic, especially plastic bags. Reduce the amount of garbage you produce and the chemicals that you use. Make sure you buy fish and seafood that was caught in a way that doesn't harm sea turtles. Clean up beaches, fill in holes and knock down sand castles before you leave. Donate to sea turtle conservation.
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