Pale octopus (Octopus pallidus) is native to Australia. They are a robust, muscular octopus with eight short arms and a total length of 54 cm. They live on sandy or muddy surfaces, often in sponge gardens or tunicate beds, to a depth of at least 600 m. If handled, they can bite. They feed at night, hiding in rubble to surprise pray. They lay large eggs that are attached singly to the roof of crevices or human refuse, such as discarded bottles. Immediately after hatching, they begin foraging, primarily on bivalves.
Southern Keeled Octopus (Octopus Berrima) is native to Australia. They are a muscular, moderate sized octopus and up to 36 cm in length. They prefer sandy surfaces in coastal waters to depths of at least 250 m. They emerge at night to feed, foraging over sand for crabs and other crustaceans.
During the day this species buries in the sand or hides in shells or human refuse. Once buried, it can raise one eye like a periscope to check for predators before emerging. Courtship consists of males standing on their arm tips and flaring their webs as they approach females. They quickly grab the females and use their long thin modified arm tip on the third right arm to pass sperm packages into the female’s oviducts. Females lay large single eggs that are attached singly to hard surfaces such as shells or human refuse. The young are well developed at hatching and immediately start foraging on the sea floor.
Source: Atlas of Living Australia
Interesting information about Octopus
Laboratory experiments with mazes and problem-solving have shown that octopuses have both short-term and long-term memory. They are the only invertebrate which has been proven to use tools. Octopuses have excellent eyesight and a very well-developed sense of touch. They move about slowly by crawling, walking on their arms, or by swimming but can use jet propulsion to move very fast for short distances.
Octopuses have the ability to hide in very small spaces, change their colour, shape and apparent size, and to modify their environment to suit themselves. Their most common defence is fast escape using jet propulsion. Other defences include using ink sacs and dropping limbs, with the crawling arm distracting the potential predator.
Octopuses are intelligent, active predators. They eat small fish, molluscs and crustaceans. They use their sharp parrot-like beaks to crush the shells of their prey. To prevent their prey from escaping, octopuses have modified salivary glands that produce a venom. Although all octopuses produce venom, only the small blue-ringed octopuses are deadly to humans.
Many octopuses leave “middens” or piles of debris, consisting of shells and the carapaces of their prey around the entrance of the protective lair in which they live.
The main predators of adult octopuses are some large fish, moray and conga eels, seals, dolphins, sharks and orca whales.
The life span of octopuses is short, ranging from six months for small species to three years in larger ones. When octopuses reproduce, the males use a specialized arm to insert packets of sperm into the female’s mantle cavity. Males die within a few months of mating. In some species, the female octopus can keep the sperm alive inside her for weeks until her eggs are mature. After they have been fertilized, the female can lay up to 200,000 eggs. Depending on the species, the eggs are hung in strings from the ceiling of the female’s lair or they are individually attached to a solid surface. The female cares for the eggs, guarding them from predators and gently blowing currents of water over them to increase the oxygen supply. She does not hunt during the roughly month spent taking care of her eggs and may eat some of her own arms for energy. When the eggs hatch, the mother leaves the lair and is too weak to defend herself from predators. Newly hatched octopuses live amongst the plankton and eat copepods and larval crabs and starfish.
South Australia –Negligible due to historically low catches in SA. Octopus is not a major component of recreational landings. Fishing is unlikely to be having a negative impact on the stock.