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Mitchell Gudgeon (Kimberleyeleotris hutchinsi)

The Mitchell gudgeon is a small freshwater fish known from the Mitchell River system in the Kimberley. Its habitat and ecology are poorly documented, so works near freshwater areas in its known range warrant careful assessment. It is listed as DBCA Priority 2 in Western Australia; no national listing is recorded.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 2.

Seasonal guidance

Seasonal information is not available for this species. Use the whole year as a planning window and obtain site-specific ecological advice before scheduling works.

Species-specific timing: Breeding, young, movement and seasonal activity periods have not been documented.

This seasonal guidance is precautionary planning advice, not a statement of the species' seasonal biology.

  • Precautionary planning: Planning window only. No species-specific seasonal activity or breeding period is known.

Identification: Appearance and size

Species information is limited. Where the species may be present, confirm identification with a suitably experienced fish ecologist.

The Mitchell gudgeon is reported to reach a maximum length of 4 cm. Its colour, body markings and other diagnostic features have not been described.

Identification: Similar species

Field characters for distinguishing the Mitchell gudgeon from similar fishes have not been documented. Do not rely on size or location alone for identification.

Identification: Field signs

Species-specific field signs and survey detectability have not been documented. Confirm fish records using appropriate identification methods.

Distribution: Known range

The Mitchell gudgeon is known from the Kimberley, with the Mitchell River system identified as its known range.

The species is endemic to the Kimberley region and known only from the Mitchell River system. Atlas of Living Australia records show 22 Western Australian records at three distinct 0.1-degree locations, matched under the name Hypseleotris hutchinsi.

Distribution: WA regions and records

Kimberley is the only WA region flagged on the DBCA priority list. Atlas of Living Australia records place the species between latitudes -15 and -14.8 and longitudes 125 and 125.7, but do not identify named sites for these coordinate clusters.

Habitat: Recorded habitat

The Mitchell gudgeon is among the freshwater fishes of the Kimberley, but its specific habitat requirements have not been documented.

Waterbody type, flow conditions, water depth, substrate and vegetation associations have not been documented.

Habitat: Works-site context

Treat freshwater areas within the known range as potential habitat until an appropriately designed assessment indicates otherwise. Do not assume that the species prefers any particular channel or waterbody feature.

Foraging habitat: Diet

The Mitchell gudgeon's diet and feeding habitat have not been documented.

Diet and feeding behaviour have not been documented. Information about other gudgeons or other species is not evidence of this taxon's feeding ecology.

Foraging habitat: Assessment

For project assessment, record relevant waterbody features and potential changes to water quality or flow without assuming which features the fish uses for feeding.

Breeding habitat: Breeding information

Species-specific breeding information is not available.

Breeding season, spawning habitat, egg characteristics and development of young have not been documented.

Breeding habitat: Precaution

Do not schedule works on the assumption that the species breeds in a particular season or habitat. Where works may affect freshwater areas in the known range, seek project-specific ecological advice to plan safeguards.

Sheltering habitat: Sheltering information

Shelter use and behaviour during disturbance have not been documented.

Shelter sites, resting behaviour and refuge use have not been documented.

Sheltering habitat: Precaution

Do not assume that any particular substrate, bank feature or vegetation type is a refuge. Where aquatic habitat may be affected, have an ecologist assess the site and disturbance footprint.

Threats: Known threats

No taxon-specific threats have been identified.

The Mitchell gudgeon is poorly known and known from few locations, as reflected in its DBCA Priority 2 category.

Threats: Potential project pressures

As a precaution for freshwater fauna, assess whether proposed works could disturb aquatic areas or affect water quality, flow or connected habitat. These are assessment considerations, not documented species-specific threats.

Survey methodology: 1. Desktop assessment

No species-specific survey or detectability method has been documented. A fish ecologist should lead survey design and tailor it to the site.

Check project locations against the known Mitchell River system range and Atlas of Living Australia records. Seek current records and advice from relevant agencies before finalising survey scope.

Survey methodology: 2. Site inspection

Map freshwater areas that could be affected and document their condition and connections to nearby waterbodies. The species' important habitat features are not known.

Survey methodology: 3. Fish survey

Use permitted, fish-appropriate survey methods selected by a qualified ecologist for the waterbody and project conditions. Record effort and conditions, and treat a non-detection as inconclusive unless the survey design supports a stronger conclusion.

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 habitat disturbance: 1. Confirm the footprint

Plan works conservatively where freshwater areas in the known range may be affected, given the limited information available about the species.

Identify all waterbodies and aquatic areas within or connected to the works footprint. Have a suitably qualified ecologist assess potential effects before clearing or other disturbance.

Before habitat disturbance: 2. Set safeguards

Define no-go areas, access routes and practical measures to prevent sediment, contaminants or other site materials entering freshwater areas. Confirm required permits and agency advice before works begin.

Before habitat disturbance: 3. Brief the crew

Explain the species' limited known range, uncertainty about its habitat requirements and the agreed stop-work and reporting process. Avoid presenting unverified habitat or seasonal assumptions as fact.

During habitat disturbance: 1. Control the work area

Keep disturbance within the assessed footprint and respond promptly if fish or previously unassessed aquatic habitat is encountered.

Follow the approved access limits and aquatic safeguards. Prevent avoidable discharge of sediment, fuels, chemicals or other materials into freshwater areas.

During habitat disturbance: 2. Respond to observations

If a fish suspected to be a Mitchell gudgeon is found, pause the relevant activity and contact the project ecologist for identification and instructions. Do not handle or relocate fish unless authorised and directed by a qualified person.

During habitat disturbance: 3. Record and report

Record the observation location, date, circumstances and photographs where appropriate, while avoiding additional disturbance. Follow project and agency reporting requirements.

After habitat disturbance: 1. Inspect affected areas

After works, check that agreed protections were maintained and document any effects or new records.

Have the ecologist inspect freshwater areas affected by the works for visible damage or unintended discharges. Follow the approved response plan if an impact is identified.

After habitat disturbance: 2. Close out records

Retain survey, observation and incident records and provide them to the project team and relevant agencies as required. Ensure any suspected species record is appropriately verified.

Rehabilitation actions: 1. Restore disturbed areas

Rehabilitation should address the aquatic areas actually affected, without assuming unrecorded species-specific requirements.

Use the approved site rehabilitation plan to stabilise disturbed ground and reduce the risk of sediment or other materials entering freshwater areas. Obtain ecological advice on suitable methods for the site.

Rehabilitation actions: 2. Monitor outcomes

Check that rehabilitation measures are functioning as intended and document any continuing impacts. No Mitchell gudgeon-specific rehabilitation method or monitoring period has been documented.

Sources