Wednesday, 11 January 2017

Ashmore Reef 10 -- Green Sea Turtles

Green Sea Turtles

We were privileged to be present at Ashmore Reef when female Green Sea Turtles Chelonia mynas came ashore each night to lay eggs on the sand at the top of the beaches around all three of the Ashmore islands.

As usual, Wikipedia is a source of information. Click here. Some interesting facts include ...
  • Mature turtles often return to the exact beach from which they hatched.
  • Females usually mate every two to four years.
  • Males, on the other hand, visit the breeding areas every year.
  • In the tropics, green turtles nest throughout the year.
  • Indian Ocean turtles nest year-round, but prefer the months of July to December.
  • After mating in the water, the female moves above the beach's high tide line, where she digs a hole with her hind flippers and deposits her eggs.
  • Clutch size ranges between 85 and 200, depending on the age of the female. This process takes about an hour to an hour and a half. After the nest is completely covered, she returns to the sea. The female will do this 3 to 5 times in one season.
  • The eggs are round and white, and about 45 mm in diameter. The hatchlings remain buried for days until they all emerge together at night. At around 50 to 70 days, the eggs hatch during the night, and the hatchlings instinctively head directly into the water.
  • Juveniles spend three to five years in the open ocean before they settle as still-immature juveniles into their permanent shallow-water lifestyle.
  • It is speculated that they take twenty to fifty years to reach sexual maturity.
  • Individuals live up to eighty years in the wild.
  • It is estimated that only 1% of hatchlings reach sexual maturity.

Each morning we would see some girls making their way back to the sea.


The beach would have the evidence of ingress to and egress from the nests. We did help a couple of girls that had become caught between the beach and the sea with rock barriers.

A fresh track to the water and old ones higher up the beach. You can see the
gradient that several hundred kilograms of turtle has to crawl up and down
using only flippers. They would do several "steps' then rest. Despite the
apparent slow rate of progress, you could look back at a turtle minutes later
and see they had made significant distance towards safety.
We found about 6 carcases always on the "inside" of the island. These were
animals that appeared to have made a wrong turn and headed away from the
beach. In the hot environment, it probably wouldn't take many hours for a
turtle to die.

On to nicer images. Their presence was an unexpected pleasure.

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