Giant Freshwater Crayfish Project

The Giant Freshwater Crayfish Project engages landholders located within priority stream reaches of the Pipers, Brid and Boobyalla catchments to co-invest in on-ground habitat restoration works. These works may include livestock exclusion fencing, controlling riverbank weeds, native riverbank revegetation and providing alternative livestock water sources.

The project also engages the community by involving volunteers in habitat planting days and a citizen science program that raises awareness of the species and its threats. Trained citizen scientists are equipped to collect data on potential crayfish habitats for adults and juveniles. The data collected is important for improving knowledge about the species’ distribution and where to focus on-ground habitat restoration investment.

These actions will reduce threats to giant freshwater crayfish by:

• maintaining and improving critical habitat for the species and reducing habitat disturbance;
• improving soil stability and riverbank integrity;
• providing a steady food source;
• filtering sediment and effluent runoff;
• mitigating the impacts of climate change such as potential changes to flow and flood events, water temperature extremes, and streamside vegetation health; and
• improving community knowledge of the species, its threats and habitat requirements.

The Tasmanian giant freshwater crayfish (Astacopsis gouldi) is the largest freshwater invertebrate in the world, capable of growing to over 80 centimetres in length and weighing up to six kilograms. Endemic to northern Tasmania, it is only found in rivers that flow into Bass Strait and the Arthur catchment (except for the Tamar catchment) and is culturally significant to the Tasmanian Aboriginal community.

Once a common sight in northern Tasmania, the species is now listed as vulnerable under both the Threatened Species Protection Act 1995 and the Environment Protection and Biodiversity Conservation Act 1999 and as endangered under the International Union for Conservation of Nature’s Red List of Threatened Species. In recent years the recorded weight of most large mature adults has been less than three kilograms.

Threats to the giant freshwater crayfish include habitat disturbance or loss, sedimentation of waterways, illegal fishing, drought and climate change. Any form of land clearing or habitat disturbance that results in increased sedimentation of waterways, including in-stream erosion, bank destabilisation, slope run-off and clearing in upstream reaches of catchments present high risks, particularly for juveniles.

NRM North works with landholders and the community to exclude livestock from waterways, establish dense native vegetation in place of exotic weeds and install alternative water sources for livestock within high priority reaches of the Pipers, Brid and Boobyalla catchments. Delivery of the project includes:

• the provision of advice and planning towards best practice management for waterways and threatened species;
• on-ground riverbank protection and rehabilitation work with a focus on improving water quality and contiguous native streamside habitat quality and connectivity within high priority stream reaches;
• establishing a database of baseline and end-of-project fauna and habitat condition data for giant freshwater crayfish within priority stream reaches of the three catchments;
• increasing the knowledge and awareness amongst landowners and the community about giant freshwater crayfish and threats to the species; and
• establishing a citizen science program and providing ongoing training opportunities to involve the community in surveying water quality and potential habitat for adult and juvenile giant freshwater crayfish.