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Greenway's Grunter (Hannia greenwayi)

Greenway's grunter is a small freshwater fish endemic to Western Australia's Kimberley, recorded from the Fitzroy River system and the Isdell and Calder rivers. Its habitat and biology are poorly known, so works affecting freshwater streams in the region warrant careful checks. It is listed as DBCA Priority 1 in WA, with no national listing recorded.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Priority 1.

Seasonal considerations

Spawning is thought likely in the wet season, but calendar months have not been specified. Use year-round precautions when planning stream works.

Breeding: Male egg guarding and fanning are reported; wet-season spawning is considered likely, not confirmed.

Calendar months for breeding or other seasonal activity are unknown.

  • Possible breeding: Wet-season spawning is thought likely, but calendar months are unknown, so none are assigned here.
  • Works planning: Year-round planning window only. This does not indicate known seasonal activity.

Identification: Appearance and size

Use the combination of body shape, scale pattern and fin markings for identification. Take care with small fish and do not rely on colour alone.

A small, slender grunter, golden to silvery-grey, with large scales edged in dark colour and a dark blotch on the lower part of the caudal fin.

Juveniles have a dark spot at the base of the soft-rayed parts of the dorsal and anal fins. Larger adults may have thick, fleshy lips; individuals may show broad vertical bars when caught.

Reported maximum standard length is 14 cm, with about 8 cm more commonly reported.

Identification: Similar species and field signs

Hannia wintoni is the only other congener identified. Head profile, postorbital length, maximum length, preopercular spines and pectoral-fin rays help distinguish the species, but no field key or measurements for these characters are available.

No distinctive indirect field signs are recorded. Confirm identification from the fish itself where permitted, using appropriate expertise.

Distribution: Known range

The known range is in the Kimberley region of Western Australia. The species is endemic to the region, but its distribution is poorly documented.

Named records are from the Fitzroy River system, Isdell River and Calder River. The type locality is the Hann River at Moll Gorge.

Atlas of Living Australia records show 51 Western Australian records at 13 distinct 0.1-degree locations, between latitudes -17.6 and -15.7 and longitudes 124.9 and 126.1. These are aggregate coordinate bounds, not precise survey localities.

Distribution: WA status and regions

The DBCA list identifies Greenway's grunter as Priority 1, described as poorly known and known from few locations, with none on conservation lands. Kimberley is the WA region flagged on the list.

No national listing is recorded. The DBCA priority category is a priority-list designation and is not a threatened-species listing under the Biodiversity Conservation Act 2016.

Habitat: Stream conditions

Greenway's grunter is found in flowing freshwater streams. The full range of habitats it uses is poorly known.

Adults are reported from moderately to swiftly flowing streams in both clear and turbid water.

A historical collection of 100 specimens was associated with fast-flowing rapids, green-coloured water and visibility as low as 30 cm. This observation does not establish that all occupied sites have those conditions.

Habitat: Substrate and site context

The reported stream substrate is a mixture of sand and rock. Required depth, channel width, vegetation type and water-quality range are unknown.

Do not assume that an unrecorded stream type is unsuitable. The species is poorly known and survey records are sparse.

Foraging habitat: Recorded diet

The reported diet includes algae and small invertebrates. Particular feeding locations and times have not been documented.

Greenway's grunter is reported to eat algae and small invertebrates. Further dietary detail and changes in diet with age have not been documented.

Foraging habitat: Precautions near feeding habitat

Where works may affect occupied or potentially suitable streams, avoid unnecessary disturbance of the water, bed and banks. This is a precaution for stream habitat, not a documented species-specific threat.

Do not infer that visible algae or invertebrates confirm the fish's presence.

Breeding habitat: Known breeding behaviour

Breeding biology is poorly known. The male guards and fans the eggs, and spawning is thought likely to occur in the wet season.

The male is reported to guard and fan the eggs. Spawning is thought likely to occur in the wet season, but this timing is unconfirmed.

Breeding habitat: Planning around uncertainty

Specific spawning sites, nest form, egg numbers and calendar months have not been documented.

If works could affect a suitable stream, plan controls to protect the aquatic habitat throughout the works period rather than assuming that breeding is confined to a particular date range.

Sheltering habitat: What is known

Specific sheltering behaviour and shelter features have not been documented.

The species is reported from flowing streams with mixed sand and rock substrate, but its use of rocks, vegetation or other shelter features is unknown.

Sheltering habitat: Precaution

Treat stream-bed and bank features as potentially important until site surveys and suitable expert advice indicate otherwise. Avoid removing or rearranging substrate without an assessment of aquatic habitat and required approvals.

Threats: Evidence and uncertainty

No specific threats to Greenway's grunter have been identified. Its Priority 1 status reflects limited knowledge and few known locations.

No species-specific threats are recorded. Possible impacts from works are not confirmed threats to this species.

Threats: Works-related precautions

As a general precaution for freshwater stream works, prevent uncontrolled sediment, contaminants and debris from entering the water, and avoid unnecessary changes to flow or stream-bed structure.

These precautions protect aquatic habitat; they are not documented species-specific threat findings.

Survey methodology: 1. Desktop assessment

Detectability and the best survey conditions are unknown. Use qualified aquatic fauna personnel and methods suited to the site.

Check the proposed works footprint and connected waterways against known Kimberley records, including the named river systems and available occurrence information. Treat the range data as indicative rather than proof of presence or absence.

Review relevant approvals, access requirements and any applicable biosecurity procedures before entering waterways.

Survey methodology: 2. Aquatic field survey

Have suitably experienced fish ecologists assess potentially suitable flowing freshwater habitat and document water conditions, flow, substrate and survey effort. A species-specific survey season or detection rate has not been established.

Use only lawful, appropriate fish-survey methods selected by the qualified survey lead. A Fitzroy River study used a range of nets and visual methods for its broader fish survey, but no method has been established specifically for this species.

Record identification evidence and location details carefully. Do not handle or retain fish unless permitted and necessary under the approved survey method.

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.

Adults are reported from moderately to swiftly flowing streams in both clear and turbid water.

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: WA.

Habitat use: general

Attribution gap: No sentence-level reference is attached to the original profile block. Review the profile bibliography; this candidate is not source-verified.

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 aquatic footprint

Plan works around the possibility of Greenway's grunter occurring in suitable Kimberley streams, including where records are absent.

Map streams and connected aquatic areas that could be affected directly or through changes in water flow, sediment or water quality. Compare them with known records and the species' reported stream habitat.

Engage a suitably qualified aquatic ecologist to advise whether targeted surveys and approvals are required.

Before habitat disturbance: 2. Set controls and response steps

Before works, brief crews on avoiding unnecessary entry into streams, preventing materials from entering water, and reporting fish observations to the environmental lead.

Agree a response for unexpected fish observations, including pausing the relevant activity, recording the location and seeking advice from the project ecologist.

During habitat disturbance: 1. Protect water and habitat

Keep impacts to freshwater stream habitat as small and controlled as practicable. Follow the approved environmental controls and survey advice.

Keep sediment, fuels, chemicals, concrete washout and loose materials out of streams. Maintain the agreed controls for runoff and erosion.

Avoid unapproved changes to flow and unnecessary disturbance of the stream bed, banks and mixed sand-and-rock substrate.

During habitat disturbance: 2. Respond to observations

If a fish suspected to be Greenway's grunter is observed, pause nearby work where safe to do so and notify the environmental lead or aquatic ecologist.

Do not attempt to capture, move or release the fish unless this is directed by qualified personnel and authorised under the relevant approvals.

After habitat disturbance: 1. Inspect and record

Check that the works have not left avoidable impacts on stream habitat and water quality.

Inspect affected stream areas for visible sediment or debris, damaged banks, disturbed substrate and problems with agreed water-control measures. Record any fish observations and report them through the project process.

Escalate unexpected impacts or suspected fish injury to the environmental lead and follow the approved incident response.

After habitat disturbance: 2. Follow up

Complete any required corrective actions and monitoring set by the approvals or project environmental plan.

A species-specific post-works monitoring period or recovery threshold has not been established.

Rehabilitation actions: 1. Restore the site

Rehabilitation should restore affected stream areas in line with site requirements and expert advice. Species-specific rehabilitation methods have not been documented.

Stabilise disturbed banks and control erosion and runoff using methods suitable for the site and consistent with approvals. Avoid introducing materials or contaminants to the water.

Retain or reinstate stream-bed and bank features in accordance with the approved design and aquatic ecologist's advice.

Rehabilitation actions: 2. Verify outcomes

Inspect rehabilitation for stability and signs of ongoing sediment or debris entering the stream. Undertake any follow-up monitoring required by the project approvals.

Claim that rehabilitation has restored conditions for Greenway's grunter only when supported by appropriate monitoring.

Sources