We acknowledge the Digital Life project and the Department of Biodiversity, Conservation and Attractions’ North West Shelf Flatback Turtle Conservation Program for creation of the 3D flatback turtle model.
Main Club 1 September, 2023
We heard from two North West Shelf Flatback Turtle Conservation Program speakers. Tristan Simpson is their Senior Environmental Officer, and Sabrina Fossette-Halot is a Senior Research Scientist. Tristan referred to one of our Club patrons, Lyn Beazley, who is the Chair of their advisory body.
The Flatback Turtle is one of six species of Australian marine turtles but is the only one endemic to Australia, nesting on Australian beaches and feeding in adjacent waters. Previously, little was known about this species in WA, and its conservation status is still being worked on. The program is centred on the Northwest Shelf population. It aims to monitor and research the species, reduce interference to breeding and feeding locations, and establish information and education programs.
Genetic sampling and mitochondrial DNA analysis were used to help find nesting distribution and identified seven management units. High-definition aerial photography allowed researchers to distinguish this species from others and locate rookeries. Rookeries were found to be on islands from Onslow to Port Hedland, including Barrow Island and the Dampier Archipelago. Satellite tracking of tagged turtles shows migration pathways and mating and foraging areas. They typically stay close to the coastline, within 100m depth.
At Roebuck Bay, turtles were caught and fitted with a recording device. It included a video camera that showed the turtles digging for benthic invertebrates, including jellyfish and shellfish. (We saw a video of one biting a tiger shark!) It also maps their foraging and resting movements throughout the seasons. It is difficult to age the turtles, but research suggests sexual maturity around 16 years.
Most rookeries are in conservation reserves, but many are close to industry. Pressures and threats include habitat modification, artificial light, marine debris, noise, dredging and chemical discharge.
More development is proposed – salt ponds, hydrogen plants and more ports with their associated shipping. Hatchlings swim towards light sources (jetties and boats), concentrating their numbers, making them more vulnerable to predation. Climate change is a real danger because the sexual determination of hatchlings depends on temperature. Warmer eggs produce more females, and an imbalance can reduce the population. And sea level rise will erode rookery beaches.
The program works with traditional owners and local schools and invites volunteers to help with the research. There are many unanswered questions because little was known about these turtles initially. The program has achieved a lot but can achieve more, and the research will benefit more than just Flatbacks.
Mike Gregson