Sea turtle far from home…

Welcome back! We are now on day 4 since arriving in the study area.

Today (Monday 7 December 2015) we are busy surveying around Maret Island, Berthier Island, Albert Island and Suffren Island (see map below).

 

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RV Solander is surveying near the Maret Islands and vicinity today and tonight using multibeam sonar, towed video and sleds. The white X shows where we saw a turtle. The black dot on the map of Australia shows where the Maret Islands are along the West Australian coast.

 

We found a turtle!

The AIMS towed video system (see previous post) found a hawksbill sea turtle lazing on the sea floor between Albert Islands and Berthier Island (white X on map above).

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Hawksbill sea turtle observed by AIMS in the Bonaparte Archipelago, Western Australia. Can you see the barnacles growing on its shell?

 

Why is it called a ‘hawksbill’ turtle?

Hawksbill turtles have a mouth that look like a hawk’s beak. The narrow and curved shape of their mouth helps them search for food near coral reefs. Dr Scott Whiting from the Western Australian Department of Parks and Wildlife says that Hawksbill turtles in this region mainly eat sponges and sometimes seaweed.

Did you know that hawksbill turtles…

  • Spend the first 5 to 10 years of life drifting on ocean currents?
  • Hatch from eggs buried in the sand?
  • Are reptiles that need to breathe air?
  • Can hold their breath underwater for up to 7 hours if they are sleeping?

Why did we find it so far from home?

The size of the turtle we found means that it may be an adult. For this part of the world, that means it would be at least 30 years old. Over those 30 or so years, it has travelled a great distance from the beach where it most likely hatched from one of its mother’s hundreds of eggs. Dr. Whiting says that Hawksbills in Western Australia primarily nest at beaches on the Lowendal Islands, Montebello Islands and the Dampier Archipelago. These beaches are more than 1,100 km away from where we spotted the turtle today (see map below).

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AIMS scientists observed the turtle (today’s location) more than 1,100 km from where it likely hatched (nesting beaches).

Amazingly, it is quite common for Hawksbill turtles to move to feeding grounds even farther away from the beach where they were born! Scientists have attached tags to turtles and found them moving as far as 2,400 km away from their home beaches. Some studies show that once turtles select a preferred feeding location, they sometimes remain in the area for years – surely by the time they travel that far, they need a bit of a rest!

Perhaps because they travel so widely, scientists have seen hawksbill turtles throughout the world’s tropical and sub-tropical oceans (see map below).

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Locations where Hawksbill turtles have been seen (source)

Why are hawksbill turtles in danger?

Hawksbill turtles are identified as ‘critically endangered’ by the International Union for the Conservation of Nature (IUCN) and Natural Resources.

Threats to their survival in Australia occur when:

  • Hatchlings leaving the nest don’t reach the sea because they are led astray by artificial lights
  • Turtles are injured or killed when struck by vessels
  • Turtles are killed accidentally caught by commercial fishermen, especially trawlers
  • Turtles are killed or made ill by eating plastic or getting tangled in trash in the ocean
  • Turtles are killed or made ill by polluted waters
  • Fewer turtles hatch as beach temperatures getting too hot
  • Less space for nests as beaches get washed away by storms and sea level rise
  • People hunt turtles for their shells.

 

Thanks for reading – see you next time!

 

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