Marine Turtles and the Great Barrier Reef
There is nothing like seeing a graceful marine turtle in the wild. Boasting a variety such as the common Green, the small omnivorous Hawksbill, and the increasingly rare Loggerhead turtles, the Great Barrier Reef is home to 6 out of 7 species of marine turtles.
Turtles have been dying in alarmingly high numbers, with near-record stranding in the last few years. We know the Cyclones played their part. They wiped out vast areas of feeding ground. But what else is causing so many turtles to die? There is still so much we don’t know about these iconic creatures. If we want sea turtles to survive, we need to learn more about them. And its facilities like the Oceans 2 Earth Volunteer Cairns that can provide researchers with such an opportunity.
Turtles can be found throughout the year, but most activity is centred on the warmer months when they get ready to breed. The major nesting areas (known as rookeries) are situated within the southern and northern section of the great coral reef.
Breeding turtles don’t eat during the mating period, and the process can sometimes become frenzy, with several males attempting to mate with the same female. The females will keep the sperm from several different males for later use (this helps to increase genetic diversity and successful fertilization). After mating, the males will return to their feeding grounds while the female remains to start nesting.
Several weeks after the first mating, the females will drag their bodies ashore and start to dig a hole in the sand above the high water mark and lay their leathery eggs (Greens and Loggerheads will produce up to 100 eggs at a time). This process will be repeated throughout the season. The female does not keep any contact with her offspring once she covers up the eggs in the sand.
The eggs will incubate for up to 3 months. The interesting thing is that the temperature of the surrounding sand will determine the sex of the offspring (males result from cooler nests while females develop from warmer nests). This is natures’ way of ensuring that there are both viable male and females in the population. As soon as the eggs hatch, the young turtles will scramble madly to the water’s edge, hoping to gain safety, but there is always a danger. Some are eaten by ghost crabs, silver gulls, sharks, and other fish. The chances of survival are slim at best, with only 2-3% making it to reproductive age. Turtle tagging programs have been occurring in Australia for many years, and we are just starting to reap the benefits of this long term project. It has been estimated that some marine turtles, such as Greens, can live for up to 100 years.
The biggest danger to turtles these days are humans. All reptiles have been protected in Australia for more than 30 years, and during this time, Green turtle numbers have stabilized. However, many species, such as the Loggerhead, have a migration path that takes them away from these protected waters. Many countries historically hunt turtles for food and shell by-products. Also, they are vulnerable to litter, such as plastic bags, and the possibility of being caught in trawl nets.
In the pristine atmosphere of the outer coral reef, turtles are often discovered daily, gliding graciously through the blue waters and island cays like Low Isles. This amazing experience can continue if we all continue to treat the environment with respect where organisations like Oceans 2 Earth and Volunteers Cairns work to protect these species and ensure the survival of these ancient creatures.
There is nothing like seeing a graceful marine turtle in the wild. Boasting a variety such as the common Green, the small omnivorous Hawksbill, and the increasingly rare Loggerhead turtles, the Great Barrier Reef is home to 6 out of 7 species of marine turtles.
Turtles have been dying in alarmingly high numbers, with near-record stranding in the last few years. We know the Cyclones played their part. They wiped out vast areas of feeding ground. But what else is causing so many turtles to die? There is still so much we don’t know about these iconic creatures. If we want sea turtles to survive, we need to learn more about them. And its facilities like the Oceans 2 Earth Volunteer Cairns that can provide researchers with such an opportunity.
Turtles can be found throughout the year, but most activity is centred on the warmer months when they get ready to breed. The major nesting areas (known as rookeries) are situated within the southern and northern section of the great coral reef.
Breeding turtles don’t eat during the mating period, and the process can sometimes become frenzy, with several males attempting to mate with the same female. The females will keep the sperm from several different males for later use (this helps to increase genetic diversity and successful fertilization). After mating, the males will return to their feeding grounds while the female remains to start nesting.
Several weeks after the first mating, the females will drag their bodies ashore and start to dig a hole in the sand above the high water mark and lay their leathery eggs (Greens and Loggerheads will produce up to 100 eggs at a time). This process will be repeated throughout the season. The female does not keep any contact with her offspring once she covers up the eggs in the sand.
The eggs will incubate for up to 3 months. The interesting thing is that the temperature of the surrounding sand will determine the sex of the offspring (males result from cooler nests while females develop from warmer nests). This is natures’ way of ensuring that there are both viable male and females in the population. As soon as the eggs hatch, the young turtles will scramble madly to the water’s edge, hoping to gain safety, but there is always a danger. Some are eaten by ghost crabs, silver gulls, sharks, and other fish. The chances of survival are slim at best, with only 2-3% making it to reproductive age. Turtle tagging programs have been occurring in Australia for many years, and we are just starting to reap the benefits of this long term project. It has been estimated that some marine turtles, such as Greens, can live for up to 100 years.
The biggest danger to turtles these days are humans. All reptiles have been protected in Australia for more than 30 years, and during this time, Green turtle numbers have stabilized. However, many species, such as the Loggerhead, have a migration path that takes them away from these protected waters. Many countries historically hunt turtles for food and shell by-products. Also, they are vulnerable to litter, such as plastic bags, and the possibility of being caught in trawl nets.
In the pristine atmosphere of the outer coral reef, turtles are often discovered daily, gliding graciously through the blue waters and island cays like Low Isles. This amazing experience can continue if we all continue to treat the environment with respect where organisations like Oceans 2 Earth and Volunteers Cairns work to protect these species and ensure the survival of these ancient creatures.
