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Outcomes of the 2025 turtle monitoring season
April 2026
For five weeks over November and December, the North West Shelf Flatback Turtle Conservation Program (NWSFTCP) staff and volunteers were busy monitoring beaches at Delambre Island and Thevenard Island.
Around 50 volunteers contributed over 3000 hours of monitoring this season, collecting data essential for understanding long-term trends of the North West Shelf flatback turtle population.
Turtle nesting data
Delambre Island:
- A total of 723 flatback turtles were monitored, with 455 individuals identified.
- 22 per cent of these turtles were “new”, coming to the island for the first time.
- Overall, there were 535 nests recorded in the tagging area from night monitoring and morning walks.
Thevenard Island:
- A total of 203 flatback turtles were monitored, with 96 individuals identified.
- 7 per cent of these turtles were “new”, coming to the island for the first time.
- Overall, there were 107 flatback nests recorded in the tagging area from night monitoring and morning walks.
This year there were less turtles monitored at both sites compared to previous, which you can read about here. See the history of monitoring outcomes for Thevenard Island here, and Delambre Island here.
Nest excavations
In early February, teams of NWSFTCP staff and volunteers returned to Thevenard and Delambre Islands to conduct nest excavations. Performed after the incubation period, around seven weeks since eggs were laid, the teams located and dug up to 30 marked nests at each location and removed the remnants of the eggs and any deceased embryos or hatchlings inside.
The number of intact eggs (from which hatchlings have not successfully hatched) was counted, and the development stages of unhatched embryos were noted. The ‘hatching success’ (percentage of successfully hatched eggs from the total clutch) was calculated. By searching for any deceased hatchlings within the nest, the ‘emergence success’ was calculated as the percentage of hatchlings in the clutch that made it successfully out of the nest.
This year’s excavations produced higher hatching success and emergence success compared to the previous year, which you can read about here.
Thevenard Island:
- 32 nests were excavated (none were not found).
- The average nest had 46.2 eggs.
- On average, there was 50% hatching and 45% emergence success from found nests. This was higher than 2024/25 but still below the ten-year average.
Delambre Island:
- 30 nests were excavated.
- The average nest had 46 eggs.
- On average, there was 77% hatching and 74% emergence success from found nests.
Disclaimer: The data included in this Latest Update is the property of the Department of Biodiversity, Conservation and Attractions. This data is to be used only for educational purposes and not for distribution, publication or commercial use. Data may have been de-identified or excluded in the process of making it available to the public domain and is subject to change following further curation and analysis.
