PHD student Julian Finn with swarming spider crabs in Port Phillip Bay.
Image: Mark Norman
Source: Museum Victoria
Museum Victoria scientists encounter massive gathering of spider crabs.
Museum Victoria marine scientist Dr Mark Norman and PHD student Julian Finn have encountered and filmed a rare natural history event: a massive underwater gathering of spider crabs.
Tens of thousands of these crabs have recently converged on a sand plain in southern Port Phillip Bay, in a dramatic mass swarm that covers the area of a football field.
These crabs are normally found scattered throughout Port Phillip Bay in low numbers, as well as offshore in Bass Strait. The exact reason for the gathering is not known, but it is likely to be breeding behaviour. Individually, the crabs have a body around 20cm long with legs up to 40cm long. The crawling carpet of crabs reaches one metre deep, in places being up to 10 crabs high.
The Museum Victoria scientists encountered the swarm while filming for a new Marine Exhibition, due to open at Melbourne Museum in January 2006.
Museum Victoria presented the rare footage to media representatives and as a result images have appeared around Australia and the world, including The Age, Herald Sun, Channels 7, 9 and 10, ABC TV and NBC.