Document ID: chunk:federal_register_of_legislation:F2017L00641:body:0:p69
Version: federal_register_of_legislation:F2017L00641
Segment Type: other
Provision Reference: 
Character Range: 326344–336107

or increasing                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         B1

Green – Ashmore Reef (G-AR)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   Unknown
Threats                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       A. Climate change and variability      Very high
B. Marine debris – entanglement                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Very high
C. Chemical and terrestrial discharge – acute and chronic                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     High
D. Terrestrial predation                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      High
Important nesting areas                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       Internesting Buffer: 20 km
Major: Ashmore and Cartier Reefs[79].                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Mating: Sep–Nov
Index beaches monitored: Census data for West Island[79].                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     Nesting: year round (peak: Dec –Jan)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              Hatching: Sep–May
Foraging habitat
Post-hatchling/young juveniles: Unknown. Likely to disperse through the waters of the Indian Ocean/Arafura Sea.
Juvenile-adult: Tidal/sub-tidal habitats with coral reef, mangrove, sand, rocky reefs and mudflats where there are algal turfs or seagrass meadows present[18]. A proportion of turtles may also remain resident in the open ocean as adults[92].
Foraging grounds monitored: Ashmore Reef foraging population is likely to be mixed genetic stock[50].
Distribution: See Figure 10.
Stock description
The Ashmore Reef stock nests in a localised area of the Indian Ocean in the Ashmore Reef and Cartier Island Commonwealth Marine Reserves areas. Management of this stock is the responsibility of Parks Australia.
Climate change may decrease hatchling production in this rookery through increased erosion at West Island and changes in sand temperature profiles. Although pivotal and lethal temperatures are not known for this stock, sand temperatures at Ashmore Reef have been recorded approaching lethal limits for successful incubation[167, 242]. Loss of Argusia spp. has been noted to be contributing to increases in sand temperatures on Ashmore Reef. It is not known whether this loss of vegetation will result in changes to the sex-ratio of hatchlings emerging from nesting beaches. A planting program was undertaken in 2005 with limited success, and has been suggested as a way to manage increases in sand temperature[161].
Egg predation by tropical fire ants (Solenopsis geminata) has been identified on West Island, and could be an increasing problem[79]. A tropical fire ant baiting survey conducted in December 2015 by Parks Australia in association with Australian Border Force and Monash University, concluded that the distribution and abundance of tropical fire ants have recovered to pre-baiting levels on Middle Island, with increasing activity on East Island and high coverage on West Island affecting nesting on those islands[104]. Given the localised nature of this stock, it would be beneficial to monitor impacts to nesting success.
The exposure to marine debris is not well quantified in Western Australia. However, turtles foraging in the open ocean are at risk from ghost nets in the Arafura-Timor Sea[255]. While the risk of an oil spill is generally considered low, the consequences would be substantial due to the small range and localised nature of this stock, and the risk increases with each new activity. The consequences of an oil spill have implications for