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Murray Crayfish (Euastacus armatus)

The Murray Crayfish is a freshwater crayfish found in the southern Murray to Darling Basin, including the Murray and Murrumbidgee river systems and their tributaries. It inhabits permanent rivers and large streams, where pools and glides, overhanging vegetation, and structural cover such as boulders and snags are important.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Australian Capital Territory, Nature Conservation Act 2014: Vulnerable.

Seasonal planning

Mating usually occurs in May. Eggs hatch in late spring, around 140 days after fertilisation.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Mating: Mating usually occurs in May. Eggs hatch in late spring, around 140 days after fertilisation.

Identification: Appearance

It has a generally dark green, brown or black body, large white claws, and white spikes on the body. It averages about 200 mm in length and has been reported to reach 500 mm.

It has a generally dark green, brown or black body, large white claws, and white spikes on the body. It averages about 200 mm in length and has been reported to reach 500 mm.

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 the Murray and Murrumbidgee river systems and their tributaries, in the southern Murray to Darling Basin up to approximately 700 metres above sea level. In the ACT region, it is known from the Murrumbidgee, lower Cotter, Tumut, Goobragandra and lower Goodradigbee rivers.

The species occurs in the Murray and Murrumbidgee river systems and their tributaries, in the southern Murray to Darling Basin up to approximately 700 metres above sea level. In the ACT region, it is known from the Murrumbidgee, lower Cotter, Tumut, Goobragandra and lower Goodradigbee rivers.

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 inhabits permanent rivers and large streams, and also occurs in some lakes. It prefers intermediate flow velocities, deeper pools and glides with overhanging vegetation; boulders, cobbles and snags can provide important cover.

It inhabits permanent rivers and large streams, and also occurs in some lakes. It prefers intermediate flow velocities, deeper pools and glides with overhanging vegetation; boulders, cobbles and snags can provide important cover.

Foraging habitat: Diet

Murray Crayfish are opportunistic feeders that eat decaying animals and plants.

Murray Crayfish are opportunistic feeders that eat decaying animals and plants.

Breeding habitat: Breeding

Mating usually occurs in May. Females carry eggs under the tail, and eggs hatch in late spring, around 140 days after fertilisation; juveniles remain attached to the mother until they have moulted several times.

Mating usually occurs in May. Females carry eggs under the tail, and eggs hatch in late spring, around 140 days after fertilisation; juveniles remain attached to the mother until they have moulted several times.

Sheltering habitat: Shelter

In lowland areas, the crayfish may construct burrows in clay banks. Where soft banks are unavailable, boulder and cobble spaces, along with snags, can provide cover.

In lowland areas, the crayfish may construct burrows in clay banks. Where soft banks are unavailable, boulder and cobble spaces, along with snags, can provide cover.

Threats: Threats

Identified threats include overfishing, riparian vegetation removal, sedimentation, residential development and river regulation. Hypoxic blackwater events are also a major threat in some lowland habitats.

Identified threats include overfishing, riparian vegetation removal, sedimentation, residential development and river regulation. Hypoxic blackwater events are also a major threat in some lowland habitats.

Threats: Works risk

Works that remove riparian vegetation, increase sedimentation, regulate rivers or involve residential development may affect the species and its river habitat. In-water works that alter flow or disturb the pools, glides and structural cover it uses may also affect habitat conditions.

Survey methodology: 1. Commonwealth guidance

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

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: 2. 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 inhabits permanent rivers and large streams, and also occurs in some lakes.

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: ACT, NSW, VIC.

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