Southern Sand Octopus
Southern Australia from the Great Australian Bight to Tasmania and eastern Victoria (VIC, TAS, SA, WA).Features:
A moderate-sized elongate octopus with an armspan that reaches around 50 cm. The body is elongate, stretched into a long thin cylinder in some postures. The arms are long and narrow reaching fine points. They are around four times the body length, each with two rows of suckers. The webs are fairly short. The colour is generally pale orange to maroon red. Foraging animals sometimes show a pale base colour and a long dark red stripe down each side of the body extending along the side arms. The skin is covered in scattered small low bumps that are slightly larger on the sides of the body.Ecology/Way of Life:
This octopus lives on sand substrates in coastal waters to depths of around 50 m. It emerges at night to forage over the sand for small crustaceans by probing its thin arms down burrows and holes. During the day it buries deep in the sand, forming a burrow with a chimney to the surface. It uses mucous and the arm tips to hold back the sand grains to form the chimney. It draws water in from the sand surface by pumping water in and out of its gill cavity, creating the necessary current. If a predator detects the octopus and attacks the sand, the octopus can quickly withdraw its arms making the chimney collapse. It can then crawl out of reach of the attacker through the sand. This octopus can bury very quickly by producing its own quicksand. It pumps fast jets of water into the sad making the sand bubble and loosen. It then dives in before the sand resettles.
It is possible that females release a sexually attractive chemical as groups of males have been observed swarming over single females. Females lay large eggs that are attached singly to hard surfaces such as shells. The large young hatch and immediately head into the sand.Interaction with Humans/Threats:
This octopus is locally abundant and is sometimes collected by recreational fishers as bait.Further Reading:
Stranks, T.N. 1990. Three new species of Octopus (Mollusca: Cephalopoda) from south-eastern Australia. Memoirs of the Museum of Victoria, 50: 457-465.
Norman, M.D. and A. Reid. 2000. A guide to the squid, cuttlefishes and octopuses of Australasia. Gould League/CSIRO Publishing, Melbourne. 96 pp.
Norman, M.D. 2000. Cephalopods: A world guide. ConchBooks, Hackenheim, Germany.
Text, map and photograph by Mark Norman, Museum Victoria.Sponsorship welcomed:
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