Tasmanian giant freshwater crayfish

The crayfish

It has previously been reported to attain weights of up to 6 kilograms (13 lb) and measure over 80 centimetres (31 in) long. Even so, in recent years the majority of larger specimens are 2–3 kilograms (4.4–6.6 lb).

Range and habitat

A. Gouldi inhabit rivers and streams at elevations of approximately 20–300 metres (66–984 ft) above sea level, with upper limits of 400 metres (1,300 ft). Approximately 18% of the waterways in that 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.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Diet and breeding

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. Females mate and spawn once every two years in autumn after a summer moult, producing 224–1300 eggs proportional to its size.

The diet of the freshwater crayfish varies with age, but predominantly consists of decaying wood, leaves and their associated microbes. When full-grown the species has no natural predators due to its large size, while smaller individuals can be prey of platypus, river blackfish and rakali.

In crisis

It is listed as an endangered species on the IUCN Red List due to overfishing and habitat degradation, and it has been prohibited to catch it since 1998. The principal causes for the population declines of the Tasmanian giant freshwater crayfish have been previous overfishing, continued illegal fishing and habitat disturbance by agriculture, forestry and urban activities. Experts estimate there are less than 100,000 remaining in the wild.

A. Gouldi is protected under the federal government Environment Protection and Biodiversity Conservation Act 1999 and Tasmanian state government Threatened Species Protection Act 1995 that prohibit the fishing or handling of the species without permit. The effectiveness of some current conservation efforts are not fully determined and are subject to review in the 2016 Recovery Plan.

Tasmanian giant freshwater crayfish is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Tasmanian giant freshwater crayfish, Wikidata item Q136116. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.