Crab Migration in Port Phillip

Each year in Port Phillip Bay, there has been an increasing awareness of the incredible migration of the Spider Crabs around the Piers of the south eastern side of the bay. There is little known about why specifically Port Phillip Bay or why this time of year – it is thought it potentially has something to do with the currents and the protection of the bay. But why do these Spider Crabs congregate in the thousands under the piers of Port Phillip Bay? Each year, these crabs cluster up while undergoing their winter moult. When they shed their hard exoskeleton, it enables them to grow in size before their new skin hardens. During this period they become vulnerable to predators such as seals, sharks and rays. So by clustering in large patches, individual crabs become less likely to be eaten by their predators.

In recent times, this unique annual event has become more widely spread. With this knowledge more divers and recreational anglers have flocked to the site. For those who are hoping to catch either the sharks that feast on the crabs, or the crabs themselves; it is important that they are aware and follow the rules that the Victorian Fisheries Authority has set in place.

Crabs:

A combined total limit of 1 litre of crabs from one of more species not exceeding 30 whole crabs.

You can use up to 2 hoop nets.

In Port Phillip Bay with a Hoop Net – Nets must be labelled if set from a boat or left unattended. The label must float at the water’s surface, and must clearly display the recreational fisher’s full name and residential address.

• You cannot collect crabs in waters less than 2m deep (the intertidal zone) in Port Phillip Bay.
• If you plan on catching spider crabs outside of Port Phillip Bay you can use bait traps, by hand and by hoop nets.
• The closed season for hoop nets is from 15 September to 15 November every year. During this time, hoops nets can only be used in Port Phillip Bay, Western Port Bay, the Gippsland Lakes and any other inlet.

Image credit VFA website
Sharks

For sharks, measure from the rear most gill slit to the base of the tail fin on any side of the body.

• No minimum legal size
• Bag limit – 1 per species

Rays

Skates, rays and guitarfish can’t be taken within 400m of any pier, jetty, wharf, rock wall or breakwater

Feature image of crabs courtesy of Museums Victoria – https://museumsvictoria.com.au/article/melbournes-annual-congregation-of-giant-spider-crabs/