Rock Pool Adventures: Part 5 – Gloomy Octopus
Common Sydney Octopus (Octopus tetricus):
This cryptic species can be found in temperate rock pools and sub-tidal waters along Australia’s East coast. However, its range is shifting poleward due to climate change. They feed on crustaceans and molluscs, and have a short lifespan of about 11 months. Their body (mantle) grows up to 80 cm, while their arms grow up to 2 m.
They are able to mimic the appearance of seaweed through changing their colouration and body texture.
Why is it nick-named the ‘gloomy’ octopus?
This is largely due to its dark grey exterior, and its tendency to be territorial and solitary. During the day they remain in their lair – which is decorated with the shells of its prey. Despite this, gloomy octopuses have been observed co-existing with each other – particularly in areas with high abundance. Perhaps they’re not so gloomy after all.
About this series: Its winter in Australia, which means I’m switching snorkelling for rock pool exploring! Armed with dive boots, dive gloves, and a cheap iPhone macro-lens attachment, I have set off to search the coastline!
Follow http://bitch-dont-krill-my-vibe.tumblr.com for more!
Pictures, from top to bottom: 1) Octopus tetricus in rock pool, next to M. calcar starfish. 2-4) Gifs of Octopus tetricus interacting with some string.
Photos taken at Bilgola Beach, NSW (2017), by Andrea Henning and Haley Henning.
 Norman, M. and Reid, A., 2000. Guide to squid, cuttlefish and octopuses of Australasia. CSIRO publishing.
 Godfrey-Smith, P. and Lawrence, M., 2012. Long-term high-density occupation of a site by Octopus tetricus and possible site modification due to foraging behavior. Marine and freshwater behaviour and physiology, pp.1-8.
 Ramos, J.E., Pecl, G.T., Moltschaniwskyj, N.A., Strugnell, J.M., León, R.I. and Semmens, J.M., 2014. Body size, growth and life span: implications for the polewards range shift of Octopus tetricus in south-eastern Australia. PloS one, 9(8), p.e103480.