What it’s like to swim with giant Australian cuttlefish

Every winter along the coast in Upper Spencer Gulf Marine Park between Fitzgerald Bay and False Bay near Whyalla in South Australia, thousands of giant Australian cuttlefish congregate to mate.

Swimming out over the rock ledges and weed you suddenly see a flash, like sun glittering off a metallic object in the distance.

Swimming towards this glitter, it’s not long before you realise you are surrounded by huge yet incredibly graceful giant Australian cuttlefish – the larger males the size of a medium sized dog, the body measuring over 60 centimetres long and weighing 5 kilograms.

Despite their huge size, these creatures hover around effortlessly much like a spacecraft in orbit. Yet if threatened they can shoot water through their siphon and move through the water backwards at lightning speed.

In an area the size of the average rumpus room, you will see 20 to 30 individuals. You will witness large males putting on incredible colour shows pulsating through all the colours of the rainbow at the blink of an eye.

Small males will come in close, pull in their tentacles and change colour to mimic a female – when the large male isn’t watching the small cross-dressing male will swoop in and mate with the female.

At first the sheer size and rapid colour-changes of these creatures is intimidating, yet after a few minutes you realise that they are oblivious to your presence. There is one thing on their mind – procreation.

The best spot for young families to experience the giant Australian cuttlefish is Stony Point, about 20 kilometres north east of Whyalla, where there is easy access via a boardwalk to shallow water. The next best spot is nearby Black Point where you will also find shelter from a north or north-easterly wind on the north-west point of Black Point.

Giant Australian cuttlefish start to congregate to breed in mid-May but the best time of year to experience them is June and July when the breeding season is in full swing.

They are active day and night, but the best time to swim with them is normally in the morning before the winds pick up in the afternoon.

The breeding areas off Stony Point and Black Point have an average depth of 4 metres, so as long as the visibility is at least 4 metres you will easily see giant Australian cuttlefish while snorkelling in the shallows close to coast.

If you're careful to move slowly, you can get up close without disturbing the cuttlefish. In fact, they seem oblivious to people as they go about their activities of outsmarting other cuttlefish to find a mate.

In the winter months, the water is very cold so a well-fitting full 5-millimetre or 7-millimetre wetsuit with hood, gloves and boots is the way to go. If you haven’t got your own gear you can always hire it.

Snorkelling is safe along this bit of coast but you do need to be careful when entering water over rocks and boulders, as they can be unstable and slippery. Stony Point has a boardwalk down to the water and a waist-height chain to hold onto for support, making it the safest point to enter or exit.

I’ve been lucky enough to dive with the giant Australian cuttlefish many times since my first visit in 2005. In fact, my first dive trip to experience the giant Australian cuttlefish congregation and their incredible show of colour inspired me to buy my first underwater camera.

To witness something so awe-inspiring and special in my own backyard, which people travel from all over the world to experience, keeps me coming back. I’m always after ‘that’ special image that shows one of the many colours, textures and behaviours of these magnificent creatures.

The sheer number of cuttlefish makes the Whyalla breeding aggregations unique, not just in Australia, but the world. Swimming with Whyalla’s Giant Australian Cuttlefish congregation is a globally significant unique nature-based tourism experience in our own backyard.

Want to see it for yourself? Book a guided session to swim with giant Australian cuttlefish in Upper Spencer Gulf Marine Park near Whyalla this winter.

If you’d rather learn about the underwater creatures hanging out in SA’s waters from the comfort of dry land, check out our blogs about sea dragons, blue devil fish and squid.

(All images copyright Carl Charter)

This story was originally posted in July 2015.