Listed as Vulnerable under the EPBC Act 1999 (Commonwealth) and BC Act 2016 (WA); Endangered on the IUCN Red List.
Green turtles are the most commonly encountered species at Ningaloo, both foraging and nesting. An estimated 15,100 to 33,700 green turtles are in the breeding population that nest in the North West Cape and Cape Range rookeries, while foraging numbers remain unknown.
Green turtles are herbivorous, feeding almost exclusively on seagrass and algae. They take 30 – 40 years to reach sexual maturity, after which females nest every 3 – 5 years. They lay approx. 115 eggs per clutch and each season the females nest an average of five times at fortnightly intervals.
There are 9 genetically distinct stocks of green turtles in Australian waters, with those at Ningaloo belonging to the North West Shelf stock.
Physical characteristics include 4 pairs of large scales (costal scales) on either side of the carapace (shell) and a high domed carapace that is light to dark olive green with brown or reddish-brown mottling. They get their name ‘green turtle’ from the greenish colour of their fat, caused by their herbivorous diet. An adult female can weigh 150kg and have a carapace of more than 1m long!