Lobsters

Western Rock Lobster Fishery

The Western Rock Lobster’s scientific name is Panulirus Cygnus. The Western Rock Lobster fishery is the most valued single-species fishery in Australia and represents about twenty per cent of the total Australian fisheries.

The Western Rock Lobster fishery is now under a quota management system, where commercial fishers have a total catch allocation for the season. The Rock Lobster season now operates 12 months of the year, from 15th January to 14th January the following year. The fishery was one of the first in the world to be
certified as ecologically sustainable by the Marine Stewardship Council.

Western Rock Lobster

Locally known as ‘Crayfish’, the Western Rock Lobster fishery extends from Shark Bay in the North to Cape Leeuwin in the South and is made up of three separate zones. Lobster can live for more than 20 years and can grow to weigh up to 5 kg, although fishing rules mean fishers rarely catch them heavier than 3kg. There is no difference between Western Rock Lobster and Crayfish. Western Rock
Lobster is the name of the species and Crayfish is a term that the Australian
industry uses.

Life Cycle

Mating: Lobsters mate in late winter/spring whereby the male deposits a packet of sperm (black spot) on the underside of the female’s belly.It is known in the industry as a tarspot. It remains there until the female is ready to spawn her eggs.
Spawning: The female uses her legs to scratch the tarspot which releases the sperm and at the same time she releases her eggs. The eggs are fertilised and attached to the fine hairs underneath the female’s tail. Females carrying eggs are known as ‘berried’.The eggs hatch between 4 to 8 weeks and form larvae.

Larvae:The larvae drift on the top of the ocean for the next 9 to 11 months, whereby they hatch once grown to approx 35mm long. Very few larvae
survive this journey.

Pueruli: The final stages of larvae moult and completely change their appearance to a miniature transparent rock lobster known as pueruli. The puerulis swim long distances to settle on the onshore reefs where they develop their red colour. Again many pueruli do not survive this journey.

Juveniles: The pueruli that survive this long journey continually moult and grow to become juveniles. The juveniles feed off the reefs for the next three to four years.

Whites Migration: At the end of the juvenile phase, the lobsters undergo a moult in late spring where they change from their deep red colour to a white/pale pink. They stay this colour until they return back to their traditional red colour at the following moult in 2 to 3 months’ time.

This white migration phase is typically from November to late January where large numbers of pale pink (whites) lobsters, recently moulted, migrate from inshore reefs to deep water. During this migration the lobster are highly exposed to fishing and large catches are taken by the fishermen.

Adult and non-migrating lobsters are known as ‘reds’ and form the catch between February through to November when the “whites” start again.

Predators

Western Rock Lobster fall prey to a number of fish species, however the majority are eaten by large fish and octopus. Octopus have become problematic for commercial fishermen as they enter their lobster pots and feed off all the fishermen’s catch.

Western Rock Lobsters can regrow all their legs and antennae’s they lose. This can serve as a defence mechanism for the lobsters whereby the predator takes only the lobster limbs and leaves the remaining part of the lobster to survive
another day.