Octopus kaurna are quite common on night dives, rarely seen in daylight. I saw 3 on this particular night dive at Port Noarlunga jetty, all near or under the outer jetty and adjacent reef.
Octopus kaurna can bury very deep in sand, during the day, using a few of the very long arms to make a snorkel for breathing. Most octopuses can only bury very shallow, with just a thin layer of sand as disguise, because they need water to ‘breath’, or they will asphyxiate.
Of course, many solve the oxygen problem by hiding deep in the back of rock crevices when resting, and only hide in surface sand if panicked by an approaching predator before they can reach their rock nook or den.
I recently read something about Octopus kaurna using their long arms to maintain oxygenated water for respiration while deeply buried in sand and silt, but I don’t remember where I read it, nor whether it was factual or speculation by that ‘author ‘.
But Octopus kaurna is a logical evolutionary response to our vast areas of sandy substrate, including in and around seagrass meadows, where they can go so deep that only the bigger eagle rays, etc… can eat them.
And like all cephalopods they are very inquisitive about divers, and often have found you rather than vice versa. They will touch you gingerly with a single, extremely elongated tentacle, if you behave appropriately and keep your torch beam off them.
Octopus kaurna are quite small, even the cigar-shape body (“tail”) is only about 15cm long in most cases. But those arms are amazing!
(Editor’s note: MICHAEL MATTHEWSON TOOK THIS PHOTO OF A SOUTHERN SAND OCTOPUS AT EDITHBURGH. IT FEATURED IN OUR 2008 CALENDAR OF SOUTH AUSTRALIAN MARINE LIFE AS THE MAY IMAGE.)
