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Giant Freshwater Crayfish (Astacopsis gouldi)

The Giant Freshwater Crayfish is an endemic Tasmanian freshwater species found in northern river systems. It depends on shaded streams with good water quality, low sediment, pools, snags and undercut banks, so protecting stream and riparian habitat is important for works planning.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Tasmania, Threatened Species Protection Act 1995: Vulnerable.

Seasonal planning

Hatchlings remain attached to the female until May.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Young remain attached: Hatchlings remain attached to the female until May.

Identification: Appearance

It is described as the world’s largest freshwater invertebrate. It can reach weights of up to 6 kg and an outstretched length of more than one metre.

It is described as the world’s largest freshwater invertebrate. It can reach weights of up to 6 kg and an outstretched length of more than one metre.

Identification: Confirming identity

Confirm the identity of any suspected record with a specialist and a photograph or voucher, as required by the relevant permit.

Distribution: Known range

The species occurs in northern Tasmania. Historically, it was found in rivers flowing into Bass Strait from the Arthur River eastwards, excluding the Tamar catchment; its present distribution is more fragmented, and it has also established in the North Esk and Derwent catchments.

The species occurs in northern Tasmania. Historically, it was found in rivers flowing into Bass Strait from the Arthur River eastwards, excluding the Tamar catchment; its present distribution is more fragmented, and it has also established in the North Esk and Derwent catchments.

Distribution: National mapping

The Commonwealth species distribution model (SNES) maps where the species or its habitat is known, likely or may occur. Use it with local records and site inspection.

Habitat: Habitat

It uses shaded streams of varying sizes, in flowing and still water, with good water quality, low sediment, pools, snags and undercut banks. Native riparian vegetation provides shade and structural inputs, and the species is associated with relatively low water temperatures.

It uses shaded streams of varying sizes, in flowing and still water, with good water quality, low sediment, pools, snags and undercut banks. Native riparian vegetation provides shade and structural inputs, and the species is associated with relatively low water temperatures.

Foraging habitat: Diet

It forages for decaying wood, fish, insects and rotting animal flesh.

It forages for decaying wood, fish, insects and rotting animal flesh.

Breeding habitat: Breeding

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Sheltering habitat: Shelter

Adults are typically found in still, deep pools beneath decaying logs and undercut banks. Juveniles use shallow, faster-flowing areas with cavities beneath stable rocks or logs.

Adults are typically found in still, deep pools beneath decaying logs and undercut banks. Juveniles use shallow, faster-flowing areas with cavities beneath stable rocks or logs.

Threats: Threats

Identified threats include habitat loss, fishing pressure and climate change. Large-scale habitat disturbance, pollution and over-harvesting have also been associated with population declines.

Identified threats include habitat loss, fishing pressure and climate change. Large-scale habitat disturbance, pollution and over-harvesting have also been associated with population declines.

Threats: Works risk

Clearing riparian vegetation or disturbing stream habitat could remove shade and important features such as snags, pools and undercut banks. In-water works that increase sediment or degrade water quality could affect habitat conditions the species requires.

Survey methodology: 1. Species-specific methods

Use methods consistent with the Commonwealth survey guidelines and engage a specialist with the right permits.

A probe-based environmental DNA assay has been developed to detect the species in DNA samples, including environmental DNA. The assay detected the species at a reported limit of 10 copies per microlitre and did not amplify the co-existing crayfish species tested.

Survey methodology: 2. Commonwealth guidance

For EPBC Act referrals, survey effort and methods should be consistent with the on-ground surveys and data for referred actions under the EPBC Act, read with the Significant impact guidelines 1.1.

Survey methodology: 3. Limits

A non-detection is not proof of absence. Match survey timing to the species and season, and record effort.

Vegetation associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific vegetation association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Ecosystem associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific ecosystem association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Soil and substrate associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific soil association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Water and wetland associations: Water-associated habitat mentioned in profile

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

It uses shaded streams of varying sizes, in flowing and still water, with good water quality, low sediment, pools, snags and undercut banks.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: TAS.

Habitat use: general

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before disturbance: 1. Desktop and approvals

Confirm whether the project could affect the species before works begin.

Check national mapping, state records and recent surveys for the site. An action likely to have a significant impact on this nationally listed species needs EPBC Act referral, and state permits apply where it is state listed.

Before disturbance: 2. Plan to avoid

Design the footprint, timing and access to avoid known or likely habitat, and brief crews on what to look for and who to call.

During disturbance: 1. Controls

Keep works inside the approved footprint and conditions.

Fence or mark habitat to be retained and keep machinery, stockpiles and spoil out of it.

During disturbance: 2. Stop and report

If the species is found unexpectedly, stop work at that spot and contact the project ecologist and the relevant agency.

After disturbance: 1. Records

Record outcomes.

Record sightings, habitat lost or retained and any injury or death, and report them under the approval conditions.

Rehabilitation: 1. Restore

Restore disturbed habitat where possible.

Reinstate disturbed ground with local species, return logs, rocks and litter, and control weeds and erosion until the site is stable.

Sources