Freshwater Crayfish

Overview

Crayfish are heavy bodied crustaceans with an enlarged, pincer-like pair of front legs. They are Arthropods (as are insects, spiders, centipedes and millipedes), characterised by a hard outer shell made from calcium carbonate that acts as a skeleton. Crustaceans are distinguished from the other arthropods by their two pairs of antennae. Crayfish, like many crustaceans, have a shield running downwards from the head and over the entire thorax, known as a carapace. The carapace protects the gills and facilitates a continual flow of water that enables the crayfish to breathe.

All of Australia’s freshwater crayfish belong to the family Parastacidae, which includes more than 140 species – from the world’s smallest crayfish, the two-centimetre-long Eastern Swamp Crayfish (Gramastacus lacus) to the world’s largest, the Giant Freshwater Lobster (Astacopsis gouldi).

Crayfish can be found in a variety of freshwater habitats such as rivers, streams, dams, lakes and swamps. While crayfish are usually vegetarian, they’re actually capable of eating most things including meat. Crayfish are largely nocturnal, actively foraging at night. Many Australian native crayfish species are threatened and fishing is illegal without a permit.

The stamps in this issue feature illustrations by renowned painter, naturalist and zoologist Roger Swainston.

Technical specifications