The Bunaken National Marine Park is perfect for spotting sea turtles, whether you are snorkeling above the coral reefs or at depth along one of the walls, seeing turtles is always exciting. In this post, we celebrate World Sea Turtle Day by sharing a few turtle facts. Scroll down for a handy infographic.
The species of turtles
Basically, there are four main species of turtles that inhabit the Bunaken Marine Park: the green turtle, the hawksbill turtle, the leatherback, and the loggerhead. However, it’s the first two that you will mostly see during any dive.
Diving around Bunaken in particular, it’s very difficult not to see at least one turtle, lazily chomping away at some sponges or taking a nap at one of the coral walls.
While snorkeling, it’s quite exciting to see a turtle quickly come up for air, only to submerge again for hours. These characterful animals can become more than half a century old, it is thought up to 80 years on average. In evolutionary terms, sea turtles have been around a long time, at least since the dinosaurs’ reign 200 million years ago.
All sea turtles are avid travelers. They will always return to their place of birth to mate or lay eggs. To do this, they sometimes cover distances of over 2000 kilometers. How exactly they can find their way back is nothing short of amazing, as they use the earth’s magnetic fields to guide them.
Mating and laying eggs
The sandy beaches of Bangka, Siladen and sometimes Bunaken is where mating will take place. After mating, they return to the water and go their separate ways, as turtles tend to be mostly solitary creatures.
But when it’s time to lay her eggs, the female returns to the beach and drags her heavy body on to the sand. She then digs a hole with her rear flippers in which she deposits her eggs. Sometimes, this can be as many as 50 to 190 eggs! This is known as a « clutch ».
Sex by temperature
The climate is a huge factor in the determination of the turtles’ sex. When the temperature is consistently below 30 degrees Celcius, mostly males will hatch from the clutch. But if the temperature is above that, mostly females will emerge.
As a result of global warming, this means a lot of clutches can result in female turtles, upsetting the balance of sexes.
Hatching and the race for the ocean
After around two months, the baby turtles hatch and dig themselves out of the hole to return to the sea, purely on instinct.
This is the most dangerous part of their lives. Besides the sheer exhaustion of this physical feat, all kinds of animals lie in wait to pick up one of the tasty (and still soft) turtles. Especially crabs can’t wait for such an easy snack.
For those that do reach the water, it doesn’t mean they are safe yet either. Various sea birds will swoop in and pick them off one by one.
The ones that do survive all of this, are still facing danger from pelagic fish or other underwater creatures. It’s no wonder then, that an estimated 1 out of 1000 baby turtles grow old enough to become adults. With such a harsh way of life, you understand why so many initiatives around the world exist to nurture the hatching of sea turtles.
It’s still quite unknown what happens between this stage of their lives and adulthood, which they reach after about 20 years.
Most sea turtles start as carnivores, and their eating habits change as they get older. The hawksbill’s primary food source are sponges and the occasional jellyfish. Some sponges are poisonous to other creatures, but the hawksbill is well protected by its thick skin. On the other hand, the green turtle is mostly herbivorous, enjoying sea grass and algae as its main food source.
It’s important to understand that “our” turtles are quite vulnerable, this is because global population numbers are falling. By far the biggest threats to sea turtles are the unintentional ones, such as bycatch from fishing boats or ingesting plastic. I’m sure you must have heard of turtles accidentally mistaking a plastic bag for a jellyfish.
But with all of that said, seeing so many throughout the park on any given dive is quite special. The Bunaken’s Marine Park’s status as a natural reserve, allows all snorkelers and divers to enjoy these wonderful creatures for what they are: gentle giants that deserve our respect.