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Derwent River Seastar (Patiriella littoralis)

The Derwent River seastar is a small marine seastar endemic to Tasmania, known from five sites in the Derwent River. It occupied rocky, shallow mid-littoral habitat, so works affecting nearshore rocky areas or water quality are relevant.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Tasmania, Threatened Species Protection Act 1995: Endangered.

Seasonal planning

No species-specific activity or breeding months were found in the published sources used. Use the following as a works-planning prompt, not as seasonal biology.

Seasonal knowledge: Not documented in the sources used.

The month values are a general planning prompt only and do not represent known activity or breeding months for Patiriella littoralis.

  • Plan checks before disturbance: General planning window only. Check the work area before disturbance whenever works are scheduled.

Identification: Appearance

It grows to about 17 mm across and usually has five arms forming a rounded pentagonal shape. The upper surface is bluish-greenish-brown with an off-white outer edge, and the underside is off-white.

It grows to about 17 mm across and usually has five arms forming a rounded pentagonal shape. The upper surface is bluish-greenish-brown with an off-white outer edge, and the underside is off-white.

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 is endemic to Tasmania and is known from five Derwent River locations: Cornelian Bay Point, Powder Jetty, the Botanical Gardens near Pavilion Point, Granville Avenue, and Risdon and Paloona Street at Lindisfarne.

The species is endemic to Tasmania and is known from five Derwent River locations: Cornelian Bay Point, Powder Jetty, the Botanical Gardens near Pavilion Point, Granville Avenue, and Risdon and Paloona Street at Lindisfarne.

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 has been recorded in rocky, shallow waters in the mid-littoral zone, between the shore and about 1.5 m depth.

It has been recorded in rocky, shallow waters in the mid-littoral zone, between the shore and about 1.5 m depth.

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

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Threats: Threats

Its habitat has been severely affected by urbanisation and poor water quality. Introduced species and competition, as well as habitat modification or destruction, are also identified as threats.

Its habitat has been severely affected by urbanisation and poor water quality. Introduced species and competition, as well as habitat modification or destruction, are also identified as threats.

Threats: Works risk

Works that modify or destroy rocky shallow habitat could affect the species, as could runoff that worsens water quality. The known habitat has been subject to urbanisation and poor water quality.

Survey methodology: 1. Species-specific methods

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

Targeted surveys in 1993 and 2010 failed to find the species. Intertidal searches have also failed to identify it.

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

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

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

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

Plan in-water works, vessel movements and lighting to avoid known habitat and sensitive periods, and set observer and shutdown procedures before works start.

During disturbance: 1. Controls

Keep works inside the approved footprint and conditions.

Use spotters and exclusion zones for in-water works and vessels, and pause works if the species is seen within the zone.

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.

Remove temporary structures, restore natural flow and substrate, and monitor water quality until it returns to baseline.

Sources