Giant Freshwater Lobster

Fishing Status

   Astacopsis gouldi

Astacopsis gouldi

The taking of any species of freshwater crayfish is prohibited. It is now illegal to take Giant Freshwater Lobster for any purpose without permission form the Director of Parks and Wildlife (PWS).

Distingushing Features

Adults can be identified from the other two species in their genus, from a prominent raised ridge on their forehead between the eyes. The juveniles are harder to identify as this raised ridge is often not apparent until later in life.

Colour

Colour seems to vary depending on location and habitat. Ranges from brown to dark-brown to greeny-black, with some specimens having a steely-blue colour on the sides of their carapace. Colour can also be bright blue all over.

Size

Commonly to 120 mm (carapace length) and 500 g, can reach weights in excess of 3 kg.

General

They are the largest freshwater invertebrate in the world. Due to over fishing, their slow growth and low reproductive rates, plus their sensitivity to degraded habitat, severe population declines have been recorded over most of their distribution. They are now listed as vulnerable, and are totally protected. They are believed to live to up to 60 years

Life Cycle

Females mature after about 14 years, and males smaller and younger at about 7 to 9 years. The females breed every two years with mating and spawning occurring in autumn. The female carries the eggs, and then the young, on her abdomen until late summer.

Habitat

They are typically shy and cryptic animals that prefer pristine rivers of various sizes. The smaller juvenile lobster are believed to favour the smaller rivers and headwaters, but are also found in the riffle zones of large waterways. Rivers that provide deep pools and undercut banks along with numerous instream snags, are ideal habitats.

Diet

Their diet consists mainly of decaying wood, but they will also consume leaves, small fish, and rotting flesh.

Why Is It Threatened?

Loss of riparian and instream habitat; In-stream barriers preventing dispersal, including culverts and bridge structures; Extensive stream siltation from erosion; Stream channel damage from sand and gravel extraction; Contaminants entering the waterway; Illegal fishing.

Tasmanian Distribution

Originally, populations were present in the Arthur River, and all rivers flowing into Bass Strait, except those of the Tamar, below 400 metres. Today their distribution is more broken.

Thanks to Inland Fisheries Service for fact sheet

AquaticsLuke