while the medium sized western species is known as Astacopsis tricornis and Astacopis gouldi refers exclusively to the giant northern crayfish. It is a common misconception that A. gouldi is named after the convict artist William Buelow Gould. WB Gould's "Sketchbook of fishes" produced at the Macquarie Harbour penal settlement contains an image of the large western Tasmanian freshwater crayfish A. tricornis not A. gouldi. Biology and ecology A. gouldi are omnivorous crustacean, primarily eating decaying wood, leaves and their associated microbes. They may also eat small fish, insects, rotting animal flesh and other detritus when available. Colour varies considerably among individuals, with adults ranging from dark brown-green to black or blue. For undetermined reasons, populations in the Frankland River system on the West Coast are predominantly found to be blue-white in colour. Males can be identified by their larger pincers compared to females. Young juveniles moult several times a year, becoming less frequent as they mature. The species is long lived and known to live up to 60 years of age and attain weights of up to , however in recent years specimens of are considered large. Results from a genetic study indicated that specimens of A. gouldi from a site in the Pipers River catchment (north of Launceston) were significantly genetically distinct from the rest of the species. Behaviour The dispersal and migratory patterns of A. gouldi are largely unknown, but they are recorded to be most active during summer and autumn when water temperatures are higher, they are also known to walk over land. A 2004 study found the species appears to have periods of relative inactivity restricted to a "home-pool" for 1–10 days interspersed with movements involving travel over relatively large distances, including one crayfish moving over 700 m in a single night. Juveniles are suspected to migrate to seasonal creeks or shallow faster-flowing waters known as riffle zones where they are at less risk from predators including other crayfish, fish, platypus and rakali. Larger sub-adults (< carapace length) will move to deeper-flowing straight sections of the catchment. Adults have no natural predators and will take refuge in sheltered deep pools and appear to tolerate each other despite being aggressive elsewhere. Males are territorial and maintain a harem of up to several females. Reproduction Tasmanian giant freshwater crayfish have extremely slow maturation rates, with females reaching sexual maturity at approximately 14 years of age, a weight