Rottnest Island is one of Perth's favourite holiday playgrounds. The rocky isle about 18 kilometres off the mainland lures holidaymakers seeking secluded bays, white beaches and ocean pursuits. The water is home to an ever-changing array of fish, marine plants, colourful invertebrates, corals and mammals. Common Marine Life of Rottnest Island covers some of the most common marine plants and animals you are likely to see while snorkelling, diving or sightseeing around Rottnest. Pocket sized publication.