Spider Crabs homepage - Victorian National Parks AssociationVictorian National Parks Association

Every year in winter thousands of Australian Giant Spider Crabs, in the largest-known crab migration on the planet, march into the shallows of Port Phillip Bay to seek safety in numbers to moult.

This internationally recognised event attracts locals and tourists from far and wide to experience and celebrate such an incredible natural phenomenon and important part of this strange but spectacular creature’s lifecycle.

But in recent years this congregation of Spider Crabs has started to be intensively targeted by harvesting and the local marine environment impacted.

Sightings have recently been reported as we approach the 2022 season. If you are out and about in Port Phillip Bay, you can be a citizen scientist and report your sightings of the Spider Crabs to ‘Crab Watch’. This contributes to the important work being done by Deakin University and the Victorian Government to understand more about the movements and ecological role of these mysterious marine creatures.

Crab Watch – contribute to citizen science

Calling all users of Port Phillip Bay, whether you are out boating, fishing, diving, snorkelling, a licensed tour operator, or even just walking along a pier!

Report your Spider Crab sightings
Contribute your sightings of Spider Crabs in Port Phillip Bay (or lack of sightings) through the citizen science platform iNaturalist.How to log your sightings? Log in or create an account on iNaturalist platform and follow the instructions at the link to report your sightings. This data contributes to the research science project being run by Deakin University and the Victorian Government to understand more about these cryptic crustaceans. Read more about the project here.
Observations of the Spider Crabs aggregation eventThese observations are broader than reporting your sightings of the crabs, but also include your observations around the aggregation event in general, including of the harvesting of crabs, the condition of the piers, and the impact of litter.If you are experiencing the spider crabs from above the water, by walking on the piers, or from below, please consider taking this survey form with you and reporting your observations here.