Raine Island’s baby turtles at risk from rising sea levels
Newly hatched sea turtles are famous for racing into the ocean: flopping from their nests, down the sand and into the safety of the sea.
But a new study says they might not make it that far for much longer and says rising sea levels could pose more of a threat to the little critters than their sandy scramble.
People love turtles and it is possible to mobilise large numbers of volunteers to physically move the nests further inshore.
Dr David Pike, James Cook University
The research, published in the journal Royal Society Open Science, found that rising sea levels could threaten the viability of turtle eggs and lower the number of baby turtles successfully hatched.
It analysed one of the largest green turtle populations in the world, on Raine Island near the outer edge of the Great Barrier Reef.
On the island, the likelihood that an egg will hatch ranged from 12 to 36 per cent between 2011 and 2015. That’s compared with a typical hatch success rate of more than 80 per cent elsewhere in the world.
Researchers involved set out to determine what effect rising sea levels might have on turtle eggs when they were laid. Taking eggs from Raine Island to a lab, they inundated select groups of eggs with saltwater for up to six hours at a time.
They found that eggs that were inundated with saltwater for six hours or more were up to 30 per cent less likely to hatch.
« Short periods of saltwater inundation, such as those associated with high tides during severe storms, substantially lower green turtle egg viability, » the study authors wrote.
James Cook University’s Dr David Pike, lead researcher of the project, said the saltwater findings could have implications for sea level rises as a result of climate change.
« We are trying to anticipate the early effects, » he said. « In some places it only takes a small rise in sea levels, when combined with a storm or a king tide, to inundate what had previously been secure nesting sites. »
He said human intervention may be necessary to protect green turtles in future.
« People love turtles and it is possible to mobilise large numbers of volunteers to physically move the nests further inshore. We might be able to save them with people power. The Queensland Department of Environment and Heritage Protection has also been out moving sand around the island to provide turtles with higher elevation nesting sites, » he said.
Dr Kathy Townsend from The University of Queensland’s Moreton Bay Research Station said the study was indicative of alarming climate changes worldwide.
« That is one of the issues that isn’t just happening here in Australia but is happening around the world, » Dr Townsend said. « If the sand temperatures get too hot they can basically cook the eggs, the young won’t be able to survive that either. »
Dr Townsend said that turtles may start migrating south, where sand temperatures are cooler.
Dr Pike said according to the current sea level trend, in as little as 50 years Raine Island and other small islands with turtle hatching ground could be inundated.
« The prediction is that within the next 50 to 100 years, with rising sea levels, the islands may be lost. »