West Coast Rock Lobster

Posted on Dec 23, 2014


The west coast rock lobster (Panulirus Cygnus) is part of the family of spiny lobsters that protects itself with a strong carapace (the upper section of an animal’s external skeleton or shell). Also called ‘crayfish’ or ‘crays’, the spiny lobster family gets its name from two big spines and hundreds of tiny forward-pointing spines covering the carapace. Their long antennae are used for navigation, self-defense and communicating.

Approximately eight species of rock lobster live in WA’s waters, but the most abundant by far is the western rock lobster. They like temperate conditions and are only found on the continental shelf off the coast, with most living between Perth and Geraldton, however there are healthy populations found also off the south west coast.

The west coast rock lobster lifecycle is quite complex. Adults reproduce externally and fertilised eggs hatch into phyllosoma (early larval stage). Unable to swim, the phyllosoma are carried by currents, being eventually swept inshore where they undergo metamorphosis to become puerulus (late larval stage). Now resembling the adult form of a western rock lobster, the puerulus settle in limestone reefs or seagrass meadows, which provide them with protection while they grow into adult lobsters. They will remain in these settlement homes for around 3–4 years.

West coast rock lobsters can live for more than 20 years and grow to weigh around 5 kg. Their food covers a wide range including coralline algae, detritus (dead and dying marine matter), molluscs and crustaceans.

The West coast rock lobster is fished commercially and is Western Australia’s most valuable fishery. West coast rock lobster fishing is also a major recreational activity but is managed through a combination of bag, size and possession limits. Populations have been depleted in the past though as a result of fishing pressures and environmental factors such as abnormally high temperatures leading to reduced rates of reproduction.

SWCC Strategic Priority

The West Coast Rock Lobster is identified within SWCC’s NRM Strategy as a first order priority asset under the Coasts and Marine Environment themes.

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