Melbourne divers were surprised to see spider crabs migrating to Port Phillip Bay on February 25, an annual migration that normally occurs from May to July as ocean waters cools.

Chiharu Shimowada has been diving for over 10 years, but said she had never experienced anything like this. When she went diving, many crabs had congregated and could be seen tearing apart what looked like an octopus, an event which can seen in the video below.