The solitary conditions resulted in the soldiers assisting the prisoners' escape[6] in a stolen government stores boat.

In 1884, the colonial government gazetted the island as a quarantine station for Fremantle, but it appears never to have been used for that purpose.

[2] The Carnac Island Nature Reserve was gazetted on 8 March 1963, has a size of 0.22 square kilometres (0.085 sq mi), and is located within the Swan Coastal Plain bioregion.

[8] The island is home to Australian sea lions, bottlenose dolphins and a large range of marine bird life.

These blind snakes survive and thrive, relying upon scent and eating immobile prey such as seabird chicks.

[11] Carnac Island is classified as an Important Bird Area because it supports a large colony of the vulnerable fairy tern, as well as small numbers of other nesting seabirds.