The turtle season was truly a busy one this year, with in excess of 200 nests recorded on the shores of Lady Elliot Island! Lady Elliot this year had over two-hundred green sea turtle nests recorded and many loggerhead turtles. The previous year was a very small one in comparison to this year with around 20 nests recorded; the reason for this put down to the fact that sea turtles will not nest within consecutive years, rather on a 2 to 8 year cycle.
The waters around Lady Elliot are home to three of the six sea turtles found in Australian waters with the Hawksbill, Loggerhead and Green sea turtles all found in the waters surrounding the island. The Hawksbill, however, does not nest on Lady Elliot but chooses to head to the top of Australia whereas on Lady Elliot we are lucky enough to have Loggerhead and Green sea turtles nesting on our beaches.
The season this year started with an influx of mature male and female Loggerhead and Green sea turtles swimming in the waters; amazingly enough these ancient reptiles do not reach sexual maturity until thirty to fifty years of age! The sea turtle, after this very long time, will return to the beach they themselves were hatched from to mate and lay for themselves. So how do they find their way back after all this time?
When a turtle hatchling emerges from its nest it will run down the beach gaining an imprint from the earth’s magnetic field allowing the turtle to navigate its way around the world’s ocean.
As the mating season begun we saw many turtle activities in full action, with turtle mating left, right and centre and many of the males fighting with one another for their chance to mate with the females. “Turtle stacks” were also another common occurrence, a turtle stack is when many males will stack upon one another in order to try and mate with the female on the bottom of the stack by trying to dislodge the male below. All this action continues for quite some time with many of the males harassing the females so much that the female will leave the water and come ashore to have a rest from the pesky males. The male’s job, however, is done once the female has been through her mating stage, with the female mating with as many males as possible within a three to four day period.
The female will release a sent indicating to the males that she is ready to mate and will store all the males sperm in a special pouch within her reproductive system, this sperm is saved until she requires it to fertilise her batch of eggs. Two weeks after the female has fertilised her batch of eggs she will drag herself up the beach to lay on a sandy area of the beach and once again return back to the water, turtles will typically only lay at night in the protection of darkness with the exception of a few turtles, usually Loggerheads, dragging themselves up the beach during the day. After the female returns to the water she will once again fertilise another batch of eggs returning to the shore in another two weeks; the Green sea turtle will typically lay around six nests a season and the Loggerheads nine nests with each of these nest typically having around one-hundred and twenty eggs! Unfortunately for our amazing sea turtles it is thought that only one in one-thousand will survive to adulthood.
[continued in part 2]