Spider Crabs – strange and spectacular

Every year in winter thousands of Australian Giant Spider Crabs march into the shallows of Port Phillip Bay.

Cloaked in seaweed and sponges they pile over the top of one another in a hectic battle for position. Why? They’re seeking safety in numbers so they can moult.

This phenomenom is the largest-known crab migration on the planet. People from far and wide flock to experience this important part of this spectacular creature’s lifecycle.

But in recent years this crabby congregation has been intensively targeted by harvesting.

Calling all lovers of Port Phillip Bay! Whether you’re out boating, fishing, diving, snorkelling, a licensed tour operator or even just walking along a pier!

Report your Spider Crab sightings

If you’re out and about in Port Phillip Bay, you can report your sightings of the Spider Crabs to ‘Crab Watch’.

This contributes to important work by Deakin University and the Victorian Government to better understand the ecological role of these mysterious marine creatures.Read more about the project here.

You can report sightings (or lack) of Spider Crabs in Port Phillip Bay through the citizen science platform iNaturalist.

Observations of the Spider Crabs aggregation event

These observations can be broader than just sightings of the crabs. You can include activities around the aggregation event– including the harvesting of crabs, the condition of the piers, and the impact of litter.

If you’re experiencing the Spider Crabs from above the water, by walking on the piers, or from below, please consider reporting your observations in our survey form or emailing [email protected] directly.