(Eretmochelys imbricata)
Cover photo credit: Tim Hunt.
Listed as Vulnerable under the EPBC Act 1999 (Commonwealth) and BC Act 2016 (WA); Critically Endangered on the IUCN Red List.
Ningaloo is the southernmost rookery for hawksbill turtles, with low abundance compared to other areas further north (such as the Dampier Archipelago off Karratha). An estimated 162 to 365 female hawksbill turtles are in the breeding population that nest within the North West Cape and Cape Range rookeries at Ningaloo.
Hawksbill turtles are omnivorous, their diet consisting of sponges, sea cucumbers, soft coral, algae, and seagrass. They reach sexual maturity after 30 years, breeding every 2 to 4 years and laying between 1 and 6 clutches per season. They can lay between 100 and 200 eggs per clutch. Hawksbill hatchlings are smaller than green or loggerhead hatchlings, and a dark colour all over.
They get the name ‘hawksbill’ from their sharp, beak-like head – an adaptation that allows them to forage in cracks and crevices, where they find sponges and soft corals. They are distinct from green or loggerhead turtles because of this beak, as well as their overlapping scutes (scales) and the serrated trailing edge to their carapace, which is particularly distinct in juveniles. They have two pairs of prefrontal scales – scales between their eyes – compared to the green turtle’s single pair. Their carapace is a mix of brown, green, and amber, and they are on average much smaller than greens or loggerheads, with a carapace length of 80cm or less and weighing about 60 – 80kg.
There are 3 genetically distinct hawksbill stocks in Australia – one in WA. The WA stock is the largest population in the Indian Ocean.