What is a nudibranch or sea slug?
Although the term “slugs” conjures up all kinds of unpleasant ideas, nudibranchs (pronounced “noo-dee-branks”), more commonly known as sea slugs, are renowned for their boundless variety and beauty. Nudibranchs are gastropod molluscs. What do they look like? Nudibranchs are shell-less molluscs, so imagine a colourful snail without a shell. Different species have a vast variety of body shapes and range from a few millimetres to 30 centimetres long. The word nudibranch is Latin and literally means “naked gills”. The name refers to the circle of exposed gills on the back of many species. Where do they live? Nudibranchs can easily be seen by observant divers in all of Western Australia’s marine parks. On reef walls or reef tops of Perth’s Marmion Marine Park, or other parts of south-western Australia, slender blue and orange nudibranchs (Chromodoris westraliensis) may nestle among an array of other invertebrates, such as sponges, on which some predate. Another common species at Marmion is
