of and a carapace length of . Males are thought to reach maturity more quickly at around 9 years, and carapace length. Females mate and spawn once every two years in autumn after a summer moult, producing 224–1300 eggs proportional to its size. Gestation of the eggs takes about nine months, with females carrying the eggs on their tail through winter. After hatching in mid-summer, the hatchlings of about attach to the female's swimming legs and will remain with the mother until a few months later in autumn. A long reproductive process means that females spend much of their life attached to their eggs and hatchlings. Distribution and habitat Distribution A. gouldi inhabit rivers and streams at elevations of approximately above sea level, with upper limits of . Approximately 18% of the waterways in which the species habitat is predicted to occur are protected in a formal reserve. Formerly, the species was distributed from the Arthur River in the west and eastwards across northern Tasmania, where it was found in all rivers flowing into Bass Strait, except for those of the Tamar catchment. Despite the two disjunct ranges, populations across these are genetically similar. The species has been introduced into the North Esk (St Patricks River) and the Derwent catchments where populations have become established. Today, distribution of A. gouldi is fragmented and limited to less disturbed areas. Large declines in numbers or localised extinctions are thought to have occurred in the Welcome, Montagu, Rubicon, Don, Brid, Boobyalla, Pipers, Ringarooma, Duck, Little and Great Forester Rivers and Claytons Rivulet. Eastern populations are particularly reduced. Habitat A. gouldi inhabit slow-moving rivers and streams of several sizes including headwaters and rivulets. Water should be of high quality with high dissolved oxygen content, little suspended sediment, and water temperatures between , although relatively low temperatures are preferred. Adults need still, deep pools with submerged decaying logs and overhanging, but not eroding, banks to shelter beneath. Juveniles prefer shallow, faster-flowing stream habitats with distinct cavities to hide under and higher portions of bolder substrate and moss cover. Excellent habitat requires intact, native riparian vegetation which is densely canopied and shades the waterways. However, the species has been recorded in confines of non-native riparian vegetation (e.g. pine plantations), without riparian vegetation and in farm dams. A 1994 study failed to find crayfish in waterways of established agricultural areas where all riparian vegetation had been removed.