Sea turtles lumbering onto the sand to lay a clutch of eggs is just the beginning. To protect and monitor endangered loggerheads at Mon Repos, the eggs are often relocated to higher ground. And all nests are dug up after hatchlings have emerged and run for the ocean to see how many eggs succeeded in producing another generation.
When it is clear that a nest is at risk of being washed away by the tides, we carefully remove the eggs either as the turtle is laying them, when possible, or immediately after the female fills in the egg chamber and returns to the sea. The egg chamber is shaped like a lightbulb with a narrower opening leading to a wider compartment. Here the eggs incubate for about 8 weeks, plus or minus depending on sand temperature and other environmental factors.
The relocation hole is dug by hand in the same shape to a depth of about 60 centimeters to mimic the natural nest and in similar sand. If the nest was laid in the open, the relocated nest must be in open sand. If laid under a tree, then so should the new nest.
This must be done immediately and no later than within 2 hours of laying to avoid damaging the embryo inside. Rotating an egg can kill it, particularly in the first 3 weeks. Even within the first 2 hours, rotation in any direction must be avoided. So each egg is treated gently and mindfully as it is moved. The eggs are laid out in rows for counting before relocation. When no suitable location is available for some reason, the eggs are moved to a close-by hatchery on the beach to mature. (In photo, volunteer researcher Maelie gathers a loggerhead's eggs for relocation to a safer nest.)
Keeping the eggs in the same order as they were laid is also important. In nature, it is more likely that males will be produced by the eggs first laid and last laid, as they tend to be on the edges of the clutch and slightly cooler than those in the middle. More females are produced with warmer temperatures. In fact, at Mon Repos, most of the hatchlings produced are females due to the darker sands and warmer temperatures. On islands off the coast in the Great Barrier Reef, male hatchlings dominate.
An interesting ritual of sorts occurs on Mon Repos when visitors guided by Queensland Parks and Wildlife rangers are invited to help relocate the eggs. After counting, the bright white, round eggs are placed two-by-two from the original nest into the cupped hands of wide-eyed children and eager adults. They carry them in a short procession to the hands of a trained researcher who places the eggs gingerly into the relocated egg chamber. In silence and reverence, the 100 or so eggs are delivered into the safety of the dark sand and buried so they may grow into hatchlings.
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Comment by Liz, Mar 3rd, 2010 6:01am
This stuff is fascinating! I know that no one would be stupid enough to do this, but now that its in my head, i feel like I need to say it: No one but a trained professional should try to do this!!! :P You guys are great!!
Love, Liz <3
Comment by robyn, Feb 11th, 2010 5:20am
Thanks for the info. its very interesting to learn about stuff like this.