The Green Sea Turtle in Galapagos
In the archipelago of the Galapagos Islands, off the southern coast of Ecuador, the wildlife is renowned for its unique adaptations to the remote volcanic habitat.
Much of it is endemic and, due to both environmental threats as well as human interference through predatory introduced species and disease, unfortunately many species are also classified as endangered.
One of these is the Galapagos Green Sea Turtle, the only species of sea turtle to nest in the archipelago. For nature lovers on a wildlife cruise in Galapagos, seeing these wonderful gentle creatures in their natural marine habitat is both a thrill and a privilege.
Identification and Behaviour
Chelonia agassizii differs in appearance from other marine turtles and is fairly easy to discern. They have a serrated lower jaw to deal with their mainly vegetarian diet and single scales that come down over their eyes. Their carapace is shaped like a teardrop and is very dark olive-green to brown. With an average lifespan of 80 years, adults can reach up to 130cm in length and weigh 136kg.
Green Sea Turtles are so-named due to the colouring of their body fat, which is green as a result of the high concentration of algae in their diet. Along with algae they feed on mangroves and sea grass, and juveniles may also eat small crustaceans and jellyfish.
As a predominantly marine-dwelling animal, their front and rear flippers are highly adapted to swimming (as opposed to the stocky limbs of terrestrial turtles) and they can cover long distances underwater in a relatively short amount of time. When feeding, they usually stay submerged for 10-minute periods, but while in resting mode they're able to stay down for over two hours without surfacing.
Nesting and Breeding
The male of the species never leaves the ocean and females only come ashore to nest and lay eggs, which generally takes place between the months of December to June. Under the cover of darkness they land on the beaches and dig pits in the sand, where they lay up to 100 eggs at a time. They then fill in the pits and return to the ocean at sunrise, never coming back to the eggs.
Once the eggs hatch (after an incubation period of 45-55 days) the hatchlings race for survival begins as they make their way down the beaches and into the ocean. The majority dont make it taken by the plethora of birds or crabs and even if they do, there are plenty more predators awaiting them in the ocean. Their life is a constant battle for survival until they reach maturity.
Although they can be seen year round on a wildlife cruise in Galapagos, it is during the breeding period that they are most prevalent. Pregnant females can be observed close to shore around the islands of the archipelago in the early evening, waiting for darkness to shroud the beaches so that they can nest.
Along with natural predation, the species population decline is also due to fisheries, introduced mammals (like feral pigs and cats) preying on hatchlings, and loss of habitat due to pollution. By outlawing the practice of hunting the turtles for their shells, meat and cartilage there are now better measures in place for their conservation, although currently their status remains at endangered.
Nature lovers who visit the area on a wildlife cruise in Galapagos can do their part by raising awareness through ecotourism, ensuring they travel with a reputable, accredited operator , and not interfering with the natural balance of the local environment.