GIANT RAINBOW CUTTLEFISH

Whyalla’s annual ‘Cuttle Fest’

The Great South Reef in South Australia

One of my dreams for years was to photograph and document this iconic natural event in South Australia. So I packed my warmest wetsuit, braced myself for some cold water dives, and set off in pursuit of the annual migration of the largest and most colourful cuttlefish on the Great Southern Reef.

The Great Southern Reef stretches along Australia’s southern coastline. It is a vast and interconnected system of temperate reefs that often flies under the radar. Famed for its biodiversity, sea dragons, Port Jackson sharks, and kelp forests, it’s every bit as important as its tropical counterparts. Spanning an incredible 8,000 kilometres, it weaves its way through five states, from Kalbarri in Western Australia all the way around to Brisbane on the east coast, even wrapping around the rugged coastline of Tasmania. Covering 71,000 square kilometres of ocean, this reef system is a lifeline for countless marine species and coastal communities, yet many Australians still don’t know it exists.

Every winter between May and August, something truly extraordinary happens beneath the surface in the cold, shallow waters off Whyalla, South Australia. Tens of thousands of giant cuttlefish (Sepia apama), some of the largest in the world, gather here for one purpose: to mate and lay eggs. It’s a wild spectacle of strategy, colour, and biological brilliance.

Photo above: Males facing off over a female captured by Brooke Pyke

These incredible creatures, often called the “chameleons of the sea,” can grow up to 50–100 cm long and weigh between 5–10 kg. They’re masters of disguise, able to shift their colour, texture, and even the shape of their bodies in an instant to mimic rocks, sand, or seaweed. Watching them pulse and ripple with iridescent blues, golds, and purples is like witnessing a living kaleidoscope.

But don’t let the beauty fool you—this is a battleground.

Here in Whyalla, the males vastly outnumber the females, creating intense competition and some of the most fascinating underwater behaviour you’ll ever see. Males flash vibrant patterns and square off in power displays, while the more cunning ones sneak in disguised as females to get close to a mate unnoticed.

When mating finally happens, it’s intimate and alien, two cuttlefish locking arms and tentacles in a head-to-head embrace. The male passes a packet of sperm into the female’s mouth area, fertilising her eggs. She’ll then carefully lay her eggs by tucking them safely beneath rocky ledges and into crevices where they’ll develop over the next few months.

Photo above: Two cuttlefish mating captured by Brooke Pyke

It’s believed this mass gathering occurs here because Whyalla offers something rare in the region: the perfect rocky substrate for egg laying. Without it, this migration simply wouldn’t happen.

But it almost didn’t. Years ago, commercial fishing severely threatened the population, putting this world-class natural event on the brink. Thankfully, protections are now in place, and these remarkable animals are safeguarded year-round.

Today, the Whyalla cuttlefish migration stands as one of the ocean’s greatest wildlife shows—a surreal underwater theatre of colour, intelligence, and life at its most creative. If you ever get the chance to witness it firsthand, don’t hesitate. It’s a bucket-list dive you’ll never forget.

Flying into the city of Adelaide (capital of South Australia), my dive buddy and I picked up a rental car, loaded our dive gear, and made the 4-hour drive to Whyalla—a small seaport town on the eastern side of the Eyre Peninsula in Barngarla Aboriginal country. We booked a stay in a beachside holiday park (Discovery Park Whyalla), which was a good vantage point for our stay, close to shops and restaurants and just a short 20-minute drive to the dive site.

We planned for five days in the water, in case of any turbulent weather. We wanted to have as much opportunity to dive as possible, since winds and swell can be unpredictable during winter along the south coast. On day one, we arrived at the dive site at Point Lowly, unloaded our equipment, and headed down to the shore to assess the conditions. Because the event is so popular with divers and snorkellers alike, the beach facilities are on point. There are bathrooms, tents for changing, a van serving food and hot drinks, and even a fire pit to warm up next to after your dive. The local dive centre, Dive Whyalla, has a truck parked there daily, loaded with rental equipment and tanks for hire.

We got very lucky with the weather during our trip. From day one the water was clear, calm, and the sun was shining. It almost could have passed as a summer vacation—except that the air temperature was 15°C and we knew the water was even colder. The calm seas made the shore entry easy. To enter the site you walk over some large flat rocks and swim about 20 metres from shore. Not overly difficult, but it can be tricky in swell.

Photo above: Brooke sitting on the shores at the dive site entry.

I pulled on my 8mm wetsuit, gloves, and booties, grabbed my camera, and set off from the car park down to the beach. The walk warmed me up and the excitement built as I got close to the water’s edge. Carefully navigating the entry, I swam out to about 4 metres depth. Descending onto the rocky, weed-covered seafloor, I scanned below me. Immediately, I saw cuttlefish everywhere. With the shallowness of the water, there was ample sunlight and the view was spectacular. Within eyesight, I could count over 20 cuttlefish around me—more than I had expected to see in an entire dive.

Following the seafloor along the coast between 3-4 metres, I came across more and more. Soon I began to notice the behaviours I remembered seeing in a David Attenborough documentary. The large males, around 100 cm long, were putting on spectacular displays. Flashing colours and patterns, fanning themselves out to intimidate their opponents. Some even attacked one another, fighting over the affection of a smaller female hiding between the weed nearby. Some of the males bore large scars and injuries from their battles.

Photos above: Gallery of images from the trip captured by Brooke Pyke

The ability of these animals to change their colour, pattern, and shape within seconds is astounding. One minute they’re nearly invisible among the seaweed, and the next they’re flashing bright purples and pinks. The experience was exhilarating, and these animals were certainly not camera shy. I aimed to keep my distance, as we don’t want to interrupt their natural behaviours. But if you hover near the bottom and stay still, they sometimes approach the camera, almost touching the lens. They were so busy in their activities that, despite the snorkellers, freedivers, and scuba divers watching on, they didn’t seem bothered.

It was hard to take my eyes off the action, but there was other marine life around too—sea urchins, colourful starfish, nudibranchs, and a variety of fish moved about, creating a great backdrop for the cuttlefish’s displays. The water was quite cold, so after two dives in 12°C, it was time to warm up on the beach by the fire on the beach and review the day’s captures.

Photo above: Diver poses with two cuttlefish captured by Brooke Pyke

Each of the five days we managed to do two one-hour dives and had some once-in-a-lifetime moments with the cuttlefish. The photos I captured and the behaviours I witnessed were well beyond my expectations. 

If you’re brave enough to dip below the chilly waters of the Great Southern Reef like we did, trust me you won’t regret it! This trip was so unique, something you can’t experience anywhere else in the world. It’s quite a remote part of the country, but if you want to make your trip worthwhile, you could also pair it with diving at Port Lincoln for great white sharks (if you’re chasing something with a bit of adrenaline, that is).

Getting There: Fly into Adelaide and rent a car to drive to Whyalla (4-hour drive one way), or take a short domestic flight from Adelaide to Whyalla.

Dive Centres: You can either hire gear and dive with your buddy or join a guided dive with the dive centre:https://www.whydive.com.au/

Camera Gear: For this trip I used my Canon R5II, Canon RF 14-35, Nauticam housing and dome, 2x Kraken S160 strobes.