When rock lobster are born, scientists call them phyllosoma. They are very small and are carried on the ocean currents for up to 1500 kilometres offshore in the Indian Ocean. The phyllosoma spend nine to eleven months growing and feeding on plankton, before the currents bring them back to the coast.

When they are about 35mm long (size of a cockroach) they are known as puerulus. At this stage the young lobster start to settle on the bottom. Then they have to move back towards the shore so they can find a home on the reefs. Many of the rock lobsters don’t survive the long swim. For the next three to four years they will grow on shallow reefs near the coast.

The largest western rock lobster reported to researchers at the WA Marine Research Laboratories weighed a massive 5.5kg. It is believed that this large western rock lobster was between 20 to 30 years old.

Scientific and other names
Western rock lobster (Panulirus cygnus) are also known as crayfish and spiny lobster

What they look like
Western rock lobsters are crustacea, like crabs they have five pairs of legs. They have an elongated body and long antenna which they use to feel what is around them. The hard outer covering on the top part of the body is called the carapace. In rock lobster this carapace is covered in little spikes. The carapace has two smooth spines which look like they come out of the head. These horns are very distinctive. The rest of the body is divided into sections.

Where they live
Western rock lobster like to live in caves and under ledges in limestone reefs and seagrass beds. This is so they can hide from the sharks, stingrays, octopus and other creatures that like to eat them. Young rock lobsters live in waters that are 10 - 30 metres deep. Adults can live in waters about 60 metres deep. They can be found along the Western Australian coast from Albany to North West Cape. They also live in the Houtman Abrolhos which is about eight kilometres off the coast of Geraldton.