This list of molluscs of the Houtman Abrolhos includes 492 species of marine molluscs which have been recorded from the waters of the Houtman Abrolhos, an island group in the Indian Ocean off the coast of Western Australia.
These molluscs are predominantly gastropods (346 species, 70%) and bivalves (124, 25%); the remaining 5% of species consist of cephalopods (14 species), chitons (5 species) and scaphopods (4 species).
About two thirds of the species have a tropical distribution, temperate species account for 20%, and the remaining 11% are endemic to Western Australia. [1]
A cephalopod is any member of the molluscan class Cephalopoda such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.
The Houtman Abrolhos is a chain of 122 islands and associated coral reefs, in the Indian Ocean off the west coast of Australia, about 80 kilometres (50 mi) west of Geraldton, Western Australia. It is the southernmost true coral reef in the Indian Ocean, and one of the highest latitude reef systems in the world.
The blue-lined octopus is one of four species of highly venomous blue-ringed octopuses. It can be found in Pacific Ocean waters that stretch from Australia to Japan. It is most commonly found around intertidal rocky shores and coastal waters to a depth of 15 metres (49 ft) between southern Queensland and southern New South Wales. It is relatively small, with a mantle up to 45 millimetres (1.8 in) in length. In its relaxed state, it is a mottled yellow-brown with dark blue or black streaks covering the whole body apart from the underside of its arms, but its vibrant blue markings appear as a warning to predators when it feels threatened. Along with its other closely related species, the blue-lined octopus is regarded as one of the most dangerous animals in the sea, and its venom can be fatal to humans.
The Leeuwin Current is a warm ocean current which flows southwards near the western coast of Australia. It rounds Cape Leeuwin to enter the waters south of Australia where its influence extends as far as Tasmania.
The southern blue-ringed octopus is one of three highly venomous species of blue-ringed octopuses. It is most commonly found in tidal rock pools along the south coast of Australia. As an adult, it can grow up to 20 centimetres (8 in) long and on average weighs 26 grams (0.9 oz). They are normally a docile species, but they are highly venomous, possessing venom capable of killing humans. Their blue rings appear with greater intensity when they become aggravated or threatened.
North Island is the northernmost island in the Houtman Abrolhos, a coral reef archipelago in the Indian Ocean off the coast of Mid West Western Australia. Located about 14 km (9 mi) from the nearest island group, it is one of the largest islands in the Houtman Abrolhos, and one of the few to support dune systems. It has relatively diverse flora dominated by chenopod shrubs and fauna that includes the introduced tammar wallaby, around seven species of reptile, and about 15 resident bird species.
Melo miltonis, the southern bailer or southern baler, is a large sea snail, a marine gastropod mollusc in the family Volutidae, the volutes.
The Southwest Shelf Transition, also known as the Houtman marine ecoregion, is a biogeographic region of Australia's continental shelf and coastal waters. It includes the subtropical coastal waters of Southwest Australia.
The Percy Sladen Trust Expeditions to the Abrolhos Islands were two scientific expeditions, conducted in 1913 and 1915 under the leadership of Professor William John Dakin and funded by the Percy Sladen Trust. These expeditions conducted extensive research into the natural history of the Houtman Abrolhos, an archipelago in the Indian Ocean off the coast of Western Australia.
West Wallabi Island is an island in the Wallabi Group of the Houtman Abrolhos, in the Indian Ocean off the west coast of mainland Australia.
Cephalopod fins, sometimes known as wings, are paired flap-like locomotory appendages. They are found in ten-limbed cephalopods as well as in the eight-limbed cirrate octopuses and vampire squid. Many extinct cephalopod groups also possessed fins. Nautiluses and the more familiar incirrate octopuses lack swimming fins. An extreme development of the cephalopod fin is seen in the bigfin squid of the family Magnapinnidae.
Molluscs play a variety of roles in culture, including but not limited to art and literature, with both practical interactions—whether useful or harmful—and symbolic uses.