Did you know that Port Phillip Bay is home to a unique phenomenon each year in winter? Not a lot of Melbournians acknowledge the massive crustaceans’ aggregations that last for a few weeks in their underwater backyards and the drama associated with it!
As it turns out, the spider crabs crawl out of the deeper areas in which they usually live to seek safety in number in the shallows to shed their shells in order to grow bigger. Divers and snorkelers brave enough to face the chilly 12°C water rejoice as they get to observe piles of hundreds of spider crabs under the piers at Rye or Blairgowrie. The crabs’ mission is to avoid hungry predators on the lookout for soft shelled crabs before they can resume their out-of-mind and out-of- sight solitary lives.
Having missed them in previous years, I got very excited when I heard they were back in town in June and enjoyed enthusiastic locals’ familiarity with the crabs’ gatherings to understand them better! Our knowledge of the aggregation is surprisingly limited and diving alongside those people made me realize that there is a real need to carry out more research on the phenomenon. More and more divers share their sightings on social media though, including locations, numbers of crabs and their behaviours, which should increase our understanding of these amazing creatures’ ecology.
See full article @ WildMelbourne: Spider Crabs: No rest for the Wicked