Species: At least 3000 different species found around the world

Also known as: Indo-Pacific Man O’ War

Bundjalung name: Unknown
Status (IUCN): Not evaluated

Characteristics

• Length/size: Nudibranchs are a diverse group of marine gastropod molluscs. Their size can range from just a few millimeters in length, to up to 30 centimetres long.

• Colour: They are commonly referred to as ‘butterflies of the sea’ with their vast variety of colouring and extravagant body forms. Their colours can range from vibrant purples, to vivid blues, fluorescent orange and more.

• Breeding/reproduction: All nudibranchs are hermaphrodites, meaning they can act as both male or female. Their eggs are primarily deposited in a coiled mass on underwater surfaces. Most species emerge from the egg as free swimming larvae with a tiny remnant shell, however a few species will emerge from the egg crawling along the seafloor as a juvenile.

• Diet: Carnivorous, feeding primarily on marine sponges, fish eggs, anemones, corals, barnacles and even other nudibranchs. As they are essentially blind, nudibranchs use two highly sensitive tentacles located on the tops of their head (called rhinophores) to identify their prey. Some species will absorb and display the pigment in their prey that gives it its colour once consumed.

Habitat: There are more than 3,000 known nudibranch species around the world, with more being identified almost daily. They are found throughout the world’s oceans, but are most abundant in tropical, shallow waters. Look for them on rocky surfaces, sponges and other hard substrate while snorkelling or diving in the Hope Spot. Some species, such as a few types of Glaucus (otherwise known as blue sea dragon or sea swallow), occasionally wash up on our beaches. 

Threats: Nudibranchs face a variety of threats in their natural marine environment. One of the most prominent is the degradation of their habitat due to pollution, coastal development and climate change. Overfishing, collection for the aquarium trade and the lack of legal protections of these species in many regions can leave them vulnerable to exploitation.