If you're ever out snorkeling or scuba diving, you may get a glimpse of a beautiful and prehistoric looking animal grazing on algae or just resting at the bottom of the ocean. The endearing green sea turtle, one of seven species of sea turtles in the world, are the most abundant in Hawaiian waters. An adult turtle can grow to an impressive size, weighing between 200 and 400 pounds with a shell length up to 4 feet.
Green sea turtles are an important part of two ecosystems - the beach and dune environment and the marine environment. It begins when the females first lay their eggs, crawling out of the water and onto the beach where they dig holes and bury them in the sand - sometimes over a hundred eggs at a time. Not all eggs will hatch, however, and the ingredients of those eggs, plus the empty shells of the hatched eggs, provide the beach environment with important nutrients. Dune vegetation is able to become stronger and healthier and the roots help to hold the sand in the dunes and protect the beach from erosion.
Once the new hatchlings dig their way to the top of the sand, they use their "magnetic compass" to guide them deeper into the ocean where they eat a variety of foods such as krill and small fish. When they are larger they come back to shallow waters, now depending on a diet mainly of algae and the occasional snacks of squid and sea jellies. Their constant grazing on algae and sea grass, using their serrated beak as a lawn mower, helps keep it short and healthy. In fact, they eat so much algae that they're a perfect example of "you are what you eat."
An adult turtle can grow to an impressive size, weighing between 200 and 400 pounds with a shell length up to 4 feet. They are an important part of the beach and dune environment as well as the marine environment.
LARISSA TREESE photo
On the outside, the turtle blends in with the rock and coral surrounding them with their muted colors of brown, grey and sometimes yellow. But it's what the inside looks like that gives them their name. Their internal fatty tissues are green due to their herbivorous (plant-eating) diet. Another benefit of keeping the algae short is that there is no risk of their suffocating and eventually killing coral - another important factor in the balance of the ocean.
The green sea turtles, or honu in Hawaiian, have also played an important role in the Polynesian and Hawaiian cultures. Not only were they used as a food source, but the carapace, or shell, was carved into utensils, tools and jewelry. There are also Hawaiian families that considered the green turtle an 'aumakua, meaning a family deity or guardian.
Green sea turtles were put on the endangered species list over 30 years ago and are still listed as threatened. Their challenges don't end there as they have threats including nest predation (other birds or animals stealing their eggs), disease, marine debris, entanglement, tiger sharks and habitat loss.
So if you ever do encounter the green sea turtle, you can remember their beauty while realizing their importance in both ecosystems. They are considered both predator and prey in the ocean, and carry nutrients to the beach and dunes.
Their importance and contribution to the health of the ocean is something that we should be proud to play a part in, whether it's picking up trash while walking the beach, volunteering in turtle-watching programs, or simply by observing from afar and respecting their space and home. If we learn to do a few of these things, we can help save one of Earth's most mysterious and endearing creatures. The balance of the ecosystems is important - if you lose one, the rest will eventually follow.
* Larissa Treese is the head aquarist and beach cleanup coordinator at Maui Ocean Center. "Ka Mo'olelo Moana," or "the Ocean Story," is a monthly column submitted by the Maui Ocean Center, which is open from 9 a.m. to 5 p.m. daily in Maalaea. For more information, call 270-7000.