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Orbost Spiny Crayfish (Euastacus diversus)

The Orbost Spiny Crayfish is a small freshwater crayfish found in eastern Victoria, in tributaries of the Brodribb, Bonang, Rodger and Yalmy river systems. Clear streams and smaller intermittent streams with abundant riparian vegetation are important habitat, so works near these waterways may affect habitat and streamside shelter.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

Seasonal planning

Mating commences in May and June.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Breeding season: Mating commences in May and June.

Identification: Appearance

This is a small freshwater crayfish. Its maximum recorded size is 45 mm orbital carapace length.

This is a small freshwater crayfish. Its maximum recorded size is 45 mm orbital carapace length.

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 eastern Victoria, in the upper tributaries of the Rodger, Yalmy and Bonang rivers and the mid to upper Brodribb River system. Records place it at elevations of about 200 to 1,400 m.

The species occurs in eastern Victoria, in the upper tributaries of the Rodger, Yalmy and Bonang rivers and the mid to upper Brodribb River system. Records place it at elevations of about 200 to 1,400 m.

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 is usually found in clear, flowing rivers and streams, and in smaller intermittent streams with abundant riparian vegetation, including rainforest.

It is usually found in clear, flowing rivers and streams, and in smaller intermittent streams with abundant riparian vegetation, including rainforest.

Foraging habitat: Diet

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

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

The species generally shelters in complex burrows at or below water level along densely vegetated streams. It may also shelter under rocks and vegetative debris.

The species generally shelters in complex burrows at or below water level along densely vegetated streams. It may also shelter under rocks and vegetative debris.

Threats: Threats

About 95% of the species’ range was burnt in the 2019 to 20 bushfires. Initial results indicated reduced population numbers, although further research was considered necessary.

About 95% of the species’ range was burnt in the 2019 to 20 bushfires. Initial results indicated reduced population numbers, although further research was considered necessary.

Threats: Works risk

Clearing dense streamside vegetation could reduce habitat, while works that disturb stream margins or watercourses could affect its burrows and other shelter. The species also uses smaller intermittent streams, so these should be considered alongside larger waterways.

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: Rainforest or vine thicket

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

It is usually found in clear, flowing rivers and streams, and in smaller intermittent streams with abundant riparian vegetation, including rainforest.

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: VIC.

Habitat use: general

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 is usually found in clear, flowing rivers and streams, and in smaller intermittent streams with abundant riparian vegetation, including rainforest.

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: 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