Cephalopods of Sydney

Sydney has a rich community of Cephalopods. There are several types of Octopus including the Common Octopus, The Sand Octopus and the Blue Ring Octopus. There are three types of Cuttlefish. The world's largest one, Sepia apama; Sepia mestus and the Mourning Cuttle, Sepia plangon. The commonest squid are the Sepiteuthis australis, the Southern Calamari Squid. The tiny Many Lined Dumpling Squid is very common on night dives in the sand. The temperate waters have a much richer population of Cephalopods than the tropics. We see Cuttles and octopusses on most dives.

 

 
Blue Ring Octopus Octopus

The Blue Ring Octopus hunting in the dark. Blue rings are exciting to see becuase the octopus can be deadly. Providing that you do not touch them they are harmless because of their shy retiring and secretive nature. Like most marine life, they would prefer to slink away and be left alone. This one is actually the Blue Lined Octopus, Hapalochlaenea fasciata. You will notice the blue lines are not actually circles as in H. lunulata.

A common Octopus australia mimics the sponge with its clever skin.

The term "thinking skin" or "intelligent skin" is very appropriate when you learn about the thousands of up to three types of chromatophores each with up to 20 muscles and separate nerves. The colour change mechanism is extremely complex. It is explained simply and clearly in my marine biology course.

Sepia apama
A Scorpionfish is being eaten by a Mourning cuttlefish.. Scorpionfish too can become food for other hungry creatures. I have seen Sepia species hunting shrimp with their very long Hunting tentacles. These tentacles are double the length of the other eight arms.The speed of the strike by these two hunting tentacles is phenomenal. It is literally greased lightning! Sepia apama is the world's largest cuttlefish. It lives in Sydney. We are very fortunate to have many unique and special animals on our marine doorstep. Sydney waters have many world class marine treasures that are just as valued to divers as koalas and other Aussie treasures of the natural world are to land based nature lovers. Their eye is almost as sophisticated as a mammalian eye.