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Narrow Euastacus (Euastacus angustus)

The Narrow Dwarf Crayfish is a dwarf spiny freshwater crayfish recorded in the Border Ranges of New South Wales and East Gippsland, Victoria. Euastacus crayfish are associated with permanent waters, and reliable flow and good water quality are important for their habitat.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Seasonal planning

Breeding commences in May and June, with juveniles released in December in highland rainforest streams of north-east New South Wales.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Breeding season: Breeding commences in May and June, with juveniles released in December in highland rainforest streams of north-east New South Wales.

Identification: Appearance

It has a laterally compressed body and a prominent ventromesial carpal spine.

It has a laterally compressed body and a prominent ventromesial carpal spine.

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

Records include a tributary of Brindle Creek in the Richmond River drainage, New South Wales, and a Beehive Creek tributary in East Gippsland, Victoria.

Records include a tributary of Brindle Creek in the Richmond River drainage, New South Wales, and a Beehive Creek tributary in East Gippsland, Victoria.

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

Euastacus species are associated with permanent waters, particularly upland rivers and streams, and depend on reliable flows, good water quality and adequate dissolved oxygen. The genus is also commonly associated with cool, clear flowing water and forested highland habitats.

Euastacus species are associated with permanent waters, particularly upland rivers and streams, and depend on reliable flows, good water quality and adequate dissolved oxygen. The genus is also commonly associated with cool, clear flowing water and forested highland habitats.

Foraging habitat: Diet

Spiny crayfish eat a broad range of material, including rotting vegetation and carrion.

Spiny crayfish eat a broad range of material, including rotting vegetation and carrion.

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

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Threats: Threats

Loss or modification of forested highland stream habitat is identified as a concern for Euastacus crayfish. Climate change is also noted as a potential risk to the genus's preferred habitat.

Loss or modification of forested highland stream habitat is identified as a concern for Euastacus crayfish. Climate change is also noted as a potential risk to the genus's preferred habitat.

Threats: Works risk

Clearing near occupied streams, or works that disrupt flow or reduce water quality and dissolved oxygen, could affect the stream conditions Euastacus depend on. Impacts to forested highland habitat may also affect the species.

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.

Euastacus species are associated with permanent waters, particularly upland rivers and streams, and depend on reliable flows, good water quality and adequate dissolved oxygen.

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: 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