Discover Australia’s largest underwater canyon, less than 20 kilometres from Rottnest Island.

Perth Canyon Marine Park protects a unique feeding site for blue whales, and is well known to local recreational fishers.

Nutrient-rich waters swirling up through the canyon boost the production of marine life, providing rich pickings for whales and people alike.

Perth Canyon was shaped by the ancient Swan River system on land, and today links the continental shelf to the deep ocean.

Swan River Traditional Owners have responsibilities for sea country in the park.

The park is 19 kilometres west of Rottnest Island. It covers 7409 square kilometres, with depths from 120 metres to 5000 metres.

It has National Park, Habitat Protection and Multiple Use zones.

Explore

Visit Perth Canyon Marine Park in autumn and you can witness the spectacular sight of blue whales gathering to feed.

This is the largest gathering of these whales in Australia.

Licensed tours operate from Perth and Fremantle, providing a safe and ethical way to enjoy watching and learning more about whales.

For those keen on fishing, you can take your own boat to Perth Canyon Marine Park or join one of the fishing charters operating from:

• Perth
• Fremantle
• Rottnest Island.

Some important areas over canyon heads are closed to fishing.

Discover

Four different marine regions meet here, bringing together a huge diversity of habitat types and species.

It’s not just the diversity that’s impressive, this area is renowned for its productivity. The sheer volume of marine life in its waters is breathtaking.

Why so many whales?

Blue whales are the largest animals in the world, so they need to eat a lot.

They feed on tiny shrimp-like animals called krill, and may eat 40 million of these in a day.

The whales are drawn to Perth Canyon where their food is concentrated in a small area.

It’s far more efficient for whales to feed here than in places where krill are scattered.

So, why so much whale food?

The shape of Perth Canyon and the way water moves through it concentrates nutrients and supports a huge volume of marine life.

A cold-water current (called the Leeuwin Undercurrent) brings cold waters from the south of Australia up along the West Australian coast.

These cold waters are high in nutrients and dissolved oxygen, both essential for marine life to flourish.

Where the Leeuwin Undercurrent funnels into Perth Canyon, eddies form on the canyon walls, swirling the cold nutrient-rich waters upward and sparking an explosion of growth in tiny plant-like marine organisms (phytoplankton) in the light-filled surface waters.

These phytoplankton are the basis of the food web. They support huge volumes of other marine life, including the krill that the blue whales feast on.