Rottnest Island (known as Wadjemup to the local Noongar people, and otherwise colloquially known as Rotto) is an island off the coast of Western Australia, located 18 kilometres (11 mi) west of Fremantle. A sandy, low-lying island formed on a base of limestone, Rottnest is an A-class reserve, the highest level of protection afforded to public land. The island covers 19 square kilometres (7.3 sq mi) and is administered by the Rottnest Island Authority under a separate act of parliament. Rottnest is a popular holiday destination, and there are daily ferry services to Perth, the state's capital and largest city. It has a permanent population of around 100 people, with around 500,000 annual visitors (and up to 15,000 visitors during periods).
It was announced on 28 April 2017 that the Department of Parks and Wildlife would merge with the Botanic Gardens and Parks Authority, the Zoological Parks Authority, and the Rottnest Island Authority on 1 July 2017 to form the Department of Biodiversity, Conservation and Attractions.
Rottnest is perhaps best known for its population of quokkas, a small native marsupial found in very few other locations. The island also includes colonies of Australian sea lions and southern fur seals. A number of native and introduced bird species nest near the shallow salt lakes in the island's interior, and Rottnest has consequently been designated an Important Bird Area. The island also includes three endemic tree species, notably the Rottnest Island pine, and was heavily forested before settlement.
Along with several other islands, Rottnest was separated from the mainland around 7,000 years ago, when sea levels rose.