Where to swim with giant cuttlefish in South Australia

Every winter thousands of giant Australian cuttlefish congregate in SA. Learn where, why and how to swim with them.

The giant Australian cuttlefish is exactly what its name suggests – the largest of all the cuttlefish species. Males measure up to 50cm long and weigh about 10kg.

They are expert colour-changers and masters of camouflage, and can change shape and texture to look like rocks, sand or seaweed – a spectacular sight to see.

(Image courtesy of Jamie Hicks) 

Giant cuttlefish can be found anywhere between the southern coastal waters of Australia to the east-coast of Queensland, and on the west-coast up to Ningaloo Reef in Western Australia.

But it’s off the coast of Whyalla in South Australia, along a 10km stretch of the Upper Spencer Gulf Marine Park, where a unique Northern Spencer Gulf sub-species congregate on mass to breed annually.

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

Why do they all get it on in SA?

It’s a natural phenomenon. SA’s waters are the only place in the world where the cuttlefish aggregate annually on mass and with such great predictability.

The waters around Point Lowly and Stony Point in the Upper Spencer Gulf Marine Park have rocky seabeds, which provide the perfect environment for females to lay and delicately attach their eggs.

The sheer number of cuttlefish makes the Whyalla breeding aggregations unique, not just in Australia, but in the world.

Why the colourful show?

As part of the breeding process, males put on a spectacular display of colours and shape-shifting to attract and keep a mate. Kind of like a dance-off!

How can you swim with them?

You can witness the giant Australian cuttlefish up-close by snorkelling or diving in waters around Point Lowly and Stony Point, also known as Cuttlefish Coast.

(Image courtesy of Jamie Hicks) 

You can go at it alone or book a guided snorkel tour

The best spot for young families to experience the giant Australian cuttlefish congregation is at Stony Point, about 20km northeast of Whyalla. There’s easy access via a boardwalk to the shallow water and a waist-height chain to hold onto for support, making it the safest point to enter or exit.

Top tip: You can sometimes find cuttlefish in less than a metre of water.

What should you wear?

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

Do the cuttlefish care that you’re there?

At first the sheer size and rapid colour-changes of these creatures is intimidating, yet after a few minutes you realise there is only one thing on their mind – procreation.

If you're careful to move slowly, you can get up close without disturbing the cuttlefish. They seem oblivious to people and are focussed on breeding.

But remember to respect their space – look but don’t touch.

(Image courtesy of Jamie Hicks) 

Are cuttlefish safe to swim near?

Snorkelling is safe along Point Lowly and Stony Point, but you do need to be careful when entering water over rocks and boulders, as they can be unstable and slippery.

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 dragonsblue devil fish and squid.

(Main image courtesy of Jamie Hicks) 

This story was originally posted in May 2019

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