By Kandy Curran
With sea turtles revered by cultures across the world, it was a privilege to have Yawuru Ranger Preston Manado open the Science on the Broome Coast presentation, Sea Turtles: Iconic ambassadors linking marine habitats, cultures and regions in north-western Australia on June 8, 2016.
Preston began by explaining the significance of the six Yawuru saltwater seasons – starting with the Laja and Man-gala seasons when the gurlibil (Flatback turtle – Natator depressus) lay their eggs on Broome’s beaches. The eggs of the gurlibil will hatch approximately 55 days after nesting.
“Gurlibil is out to sea during the colder months of Barrgana, which we are having now. During Wirlburu, the warming up season when the westerly winds start to blow, Gurlibil start mating and shouldn’t be disturbed.” Preston Manado said.
The next presenter, Dr Scott Whiting, who is the Principal Research Scientist with Parks and Wildlife in Perth, focused on the biology of sea turtles, the threats that they are facing – particularly from climate change, and research underway on the Kimberley coast.
Dr Whiting had the audience ‘taking their hats off’ to sea turtles, with their biology and evolutionary history so amazing.
“Sea turtles, which can weigh from 30kg to 600kg, frequently dive to depths of 100m, with some species diving to as deep as 1000m. The length of time they take to reach puberty (30 to 50 years) and their long breeding histories (over 30 years), is extraordinary too, as it means that conservation initiatives have to be considered in terms of decades and centuries.” Dr Whiting said.
A wandering microphone allowed the large audience of 76 to ask a stream of great questions. For example, the question of how turtles mate, revealed that female sea turtles are promiscuous and can be mated by several males, resulting in several fathers of the egg clutch. The next question – where are the most species of sea turtles found, delighted the Broome audience, with Roebuck Bay identified as an embayment visited by at least five species of sea turtles, with the Green turtle (Chelonia mydas) most dominant, and Flatback turtles the species nesting on Broome’s beaches. We also learned that whilst turtles have small brains, they have evolved with special ‘homing’ abilities, which will see them return when they reach puberty, to precisely the same beach where they hatched from 30 to 50 years ago.
The big question however is, will sea turtles, which evolved 200 million years ago, adapt quickly enough to cope with a rapidly changing climate and a world that is overpopulating?
The next Science on the Broome Coast presentations are Corals, canaries and cockroaches: A natural history of coral reefs on June 29, followed by Lustre: The allure of mother of pearl crosses time and cultures on July 6 – both at the University of Notre Dame Multipurpose Hall in Broome.
This innovative Science on the Broome Coast series is sponsored by Inspiring Australia, The University of Notre Dame Broome, Yawuru Land and Sea Unit, Western Australia Marine Science Institution, Rangelands NRM through the Federal Government Landcare Program and the Department of Parks and Wildlife.
The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.