It is impossible to be present at all beaches where flatback turtles nest across the Pilbara to get an accurate picture of species distribution and abundance. Instead, the NWSFTCP investigated the use of aerial photogrammetry as a tool for assessing relative distribution and abundance of flatback turtles across this vast region, and for identifying nesting beaches exposed to industrial development impacts. 

The aerial survey covered most sandy beaches in the Pilbara region of Western Australia. It included 644 mainland beaches and offshore islands and was conducted over six days in November and December of 2016 (peak nesting season). High-resolution photos (1-3 cm) taken from the plane were reviewed by researchers to identify beaches with evidence of turtle nesting – tracks, nests, and body pits. The aerial tallies were validated with multiple ground surveys conducted at the same time. 

Flatback turtle tracks were identified at 174 beaches, spread across 308 km of islands and the mainland. Beaches with the greatest abundance were Delambre Island, Barrow Island and Mundabullangana. Overlaying locations of industrial and protected sites showed that a third of all flatback turtle nesting beaches were located within 5 km of at least one major industrial site, and almost all (97 per cent) were located within 50 km of major sites. Positively, 77 per cent of flatback nesting beaches were located within protected areas. Assessing the location of high abundance rookeries, protected, unprotected and exposed beaches is important for the future management and monitoring of this population. 

This research was conducted by DBCA/NWSFTCP.

Do nearshore structures such as jetties pose a threat to marine turtles? In this study, researchers compared predation levels for two nesting sites with similar activity; one near a jetty and one without any nearshore structures. The results revealed that around 70% of the tagged hatchlings at the site near the jetty were predated before they could transit the nearshore waters (irrespective of the presence or absence of artificial light), while between 3-23% of hatchlings were predated at a site with no nearshore structures. 

By providing daytime refuges for predators, nearshore structures such as jetties can concentrate predators and may pose a significant threat to populations of vulnerable species. This must be considered when assessing the environmental impacts associated with these structures. 

This research was led by the The University of Western Australia and the Australian Institute of Marine Science, in collaboration with DBCA/NWSFTCP and Pendoley Environmental.

2021

• Using aerial photogrammetry to assess stock-wide marine turtle nesting distribution, abundance and cumulative exposure to industrial activity

2019

• High predation of marine turtle hatchlings near a coastal jetty