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Fortescue Grunter (Leiopotherapon aheneus)

The Fortescue Grunter is a small freshwater fish endemic to the Pilbara of Western Australia. It uses permanent pools and streams, including isolated pools that may reconnect after rainfall, so clearing, creek crossings, dewatering and changes to surface water can affect local populations. It is listed as Priority 4 in Western Australia, a DBCA category for rare or near threatened species requiring monitoring.

Conservation status

Western Australia, WA Threatened and Priority Fauna List: Near threatened. Priority 4 (rare, near threatened) on the Western Australian priority fauna list. Priority species are not listed under the Biodiversity Conservation Act 2016 but should be considered in assessments.

Breeding season

Fortescue Grunter is a Pilbara endemic that uses permanent pools and streams in the Fortescue, Robe and Ashburton systems. Breeding is likely to occur during the wet season, but species-specific months are not established and timing may vary between river systems and years.

Breeding mode: Spawning is inferred for this freshwater fish. The spawning method and fertilisation details are not recorded.

Breeding timing: Breeding is likely during the wet season. Species-specific breeding months are not recorded.

Clutch or litter size: Not recorded.

Incubation period: Not recorded.

Age at maturity: Not recorded.

Breeding sites: Not recorded. Possible recent recruits have been found in pools, including MCR3, MCR4 and MCPE6.

Breeding frequency: Not recorded. Multiple spawning events are known generally for many Pilbara freshwater fish.

Timing may shift between years and river systems with rainfall, flooding, pool persistence and water availability, so surveys and works planning should be based on local hydrology rather than calendar months alone.

  • Wet-season breeding and spawning: Breeding is likely during the wet season, but the species-specific breeding window and peak months are uncertain.
  • Possible young fish and recruitment: Very small fish were recorded in May, indicating recruitment within the preceding year, but recruitment timing may extend beyond May.
  • Presence and activity in permanent pools: Adults and juveniles may remain active throughout the year in permanent pools and connected river habitats.
  • Movement through connected waterways after wet-season flows: Wet-season flows may connect pools and allow movement through river systems, although flood-driven movement is not required for reproduction.
  • Highest clearing risk: Treat permanent pools and adjacent stream habitat as high sensitivity year-round, with greater risk during the wet season when breeding, recruitment and movement may occur.

Identification: Appearance and size

The Fortescue Grunter is a small bronze to brownish freshwater fish in the Terapontidae family. It is not easy to confirm from a brief site observation, so records from suitable pools should be checked by an experienced aquatic ecologist where identification affects works.

Adults can grow to about 130 mm total length. Individuals are commonly around 70 to 80 mm, although survey catches have included smaller fish from 0 to 30 mm standard length and 31 to 50 mm standard length.

The species has been described as bronze to brownish in colour. Detailed diagnostic features are not established in the field information used for this profile.

Family: Terapontidae, the grunters

Maximum recorded size: About 130 mm total length

Typical survey size: About 70 to 80 mm total length

  • Look for a small-bodied grunter in permanent or semi-permanent freshwater pools.
  • Record the fish's total length or standard length, colour, pool location and a clear photograph where handling is permitted.

Identification: Calls and similar species

Fish calls or other acoustic features are not used for field identification. The Fortescue Grunter may occur with Spangled Perch, Barred Grunter, Western Rainbowfish, Bony Bream and Pilbara tandans, but a reliable comparison with these species requires an appropriate fish identification guide or expert confirmation.

Do not identify a fish from habitat alone. Spangled Perch is also a grunter and may be encountered in the same broad region.

  • Use photographs, measurements and, where necessary, an aquatic specialist for confirmation.
  • Keep fish handling to the minimum needed for identification and follow the project animal ethics, wildlife and biosecurity procedures.

Identification: Field signs

The most useful field sign is a live fish sighting or capture in a suitable pool. The species can display schooling behaviour when present in suitable numbers.

Droppings, nests, whitewash, odour and calls are not useful signs for this fish.

  • Check deeper sections, pool margins and areas with complex aquatic habitat.
  • Record schooling behaviour, numbers seen or captured, size classes and the condition of the pool.
  • Treat very small fish, including possible new recruits, as evidence that the pool may support recent local reproduction.

Distribution: Australian range

The Fortescue Grunter is endemic to the Pilbara region of Western Australia. Its known range is restricted to the Fortescue, Robe and Ashburton River systems, with records from several connected and isolated pool habitats.

The species is known only from Western Australia. Records include the Fortescue, Robe and Ashburton drainage systems, including the Fortescue River below the Fortescue Marsh, the Robe River, Mungarathoona Creek, Red Hill Creek and the Ashburton River.

It has also been recorded in Karijini National Park, including Hamersley Gorge. It may occur more broadly through suitable permanent water within each of the three river systems.

State: Western Australia only

Bioregion: Pilbara

Known river systems: Fortescue, Robe and Ashburton

  • Fortescue River system, including pools below the Fortescue Marsh.
  • Robe River system and tributary pools such as Mungarathoona Creek and Red Hill Creek.
  • Ashburton River system and suitable pools in the upper Ashburton region.

Distribution: Site scale and connectivity

Local populations may occupy isolated pools that are infrequently joined after major rainfall. During wet periods, fish may move through connected creeklines and river systems, then retreat to semi-permanent and permanent pools as conditions dry.

A site without fish records should not be assumed to be unsuitable if it contains permanent water or can be connected to occupied pools during flooding.

  • Review upstream and downstream pools, not just the proposed work footprint.
  • Map permanent, semi-permanent and potentially connected pools before creek crossings, earthworks or dewatering.
  • Consider recent rainfall and flooding when interpreting survey results.

Distribution: Works planning

For a Priority 4 species, the practical aim is to confirm whether suitable permanent water occurs in or near the works area and to avoid damaging occupied pools or their hydrological connections.

If a project may affect the Fortescue, Robe or Ashburton systems, engage an aquatic ecologist early. The level of survey effort should reflect the size of the works, the presence of water and the likelihood of direct or indirect hydrological change.

  • Check DBCA records and local project records before finalising access routes and crossing points.
  • Survey suitable pools when they contain water and fish detection is most likely.
  • Escalate confirmed records, dewatering proposals and major flow changes to the relevant environmental authority.

Habitat: Pools and watercourses

The Fortescue Grunter uses permanent water in streams and pools, from slow-flowing reaches to faster sections. It is associated with rocky or sandy substrates and may persist in isolated pools during dry conditions.

Look for the species in permanent pools, semi-permanent pools and flowing sections of the Fortescue, Robe and Ashburton systems. Suitable pools may occur in broad river channels, creek junctions, gorges and below waterfalls.

Records include large pools at creek junctions, narrow and shallow pools, deep pools and pools with receding water levels.

  • Permanent or semi-permanent pools.
  • Slow to fast-flowing stream sections.
  • Pools at creek junctions and the bases of waterfalls.
  • Rocky pools and pools over sand or mixed sand and rock.

Habitat: Habitat structure

Larger pools and more complex habitat generally support stronger Pilbara fish communities. Look for pools with varied depth, connected channel features, bankside cover, rock, gravel, debris or aquatic structure.

The species has been recorded in river systems with river stones and gravel, sections of topsoil, built-up debris and dense vegetation in places.

  • Deep sections that retain water as surrounding pools recede.
  • Rock, gravel, debris and irregular pool margins.
  • Vegetated sections that provide cover and reduce exposure.
  • Pool and channel features that could support movement after rainfall.

Habitat: Site assessment

Assess the whole aquatic feature, not only the area proposed for clearing. A small remnant pool may hold a large proportion of the local fish population when flows recede.

Record water permanence, pool dimensions, depth, flow, substrate, cover, adjacent vegetation, connection to other pools and signs of recent flooding.

  • Photograph the pool and its upstream and downstream connections.
  • Mark any proposed access, crossing, pump, discharge or dewatering locations.
  • Avoid placing spoil, sediment stockpiles or machinery in the pool or on its immediate banks.

Foraging habitat: Food and feeding areas

The Fortescue Grunter feeds on small crustaceans and juvenile fish and is mostly omnivorous. Feeding habitat is likely to be associated with the range of shallow and deeper features within permanent pools and streams.

The species has been recorded in pools and flowing water with sand, rock, gravel, debris and vegetation. These features can support small crustaceans and juvenile fish, which form part of its diet.

Specific feeding depths and preferred foraging structures are not well understood, so retain the full range of pool and margin habitats where possible.

Recorded food: Small crustaceans, including small prawns, and juvenile fish

Feeding type: Mostly omnivorous

  • Pool margins and shallow edges with cover.
  • Rocky, sandy or gravelly areas within permanent water.
  • Deeper pool sections that retain prey and fish during dry periods.
  • Vegetated or debris-rich margins, where these occur naturally.

Foraging habitat: Construction controls

Sediment, hydrocarbons, concrete washout, rubbish and other contaminants can reduce prey availability and degrade water quality. Prevent pollutants from entering occupied pools or connected waterways.

Avoid removing rock, gravel, woody debris or natural bank vegetation unless the work is authorised and the effect has been assessed.

  • Use sediment and erosion controls before ground disturbance starts.
  • Keep fuels, chemicals, spoil and concrete washout away from water.
  • Prevent turbid or contaminated water from entering pools.
  • Maintain natural flow paths and avoid creating stranded or isolated fish habitat.

Foraging habitat: Survey observations

During aquatic surveys, record fish size classes and habitat use as well as the number of fish. Small fish and mixed size classes can show that a pool supports more than one life stage.

Where safe and authorised, survey both pool margins and deeper water. Use consistent methods between visits so changes can be detected during construction and rehabilitation.

  • Record fish seen or captured by pool and habitat type.
  • Note schooling, refuge use and any fish concentrated near receding water.
  • Photograph representative habitat and any disturbance affecting water quality.

Breeding habitat: Likely breeding areas

Breeding details for the Fortescue Grunter are poorly understood. Very small fish recorded in several pools suggest that local spawning and recruitment can occur within pools, including where recent flooding is not evident.

Potential breeding habitat includes permanent and semi-permanent pools in the Fortescue, Robe and Ashburton systems, particularly pools that retain water through dry periods and provide varied depth and cover.

The exact spawning substrate, nest form and breeding place are not established. Treat occupied pools, connected pools and pool margins as potential breeding habitat.

  • Permanent pools and deep remnant pools.
  • Pools at creek junctions and within larger river channels.
  • Complex pool margins with rock, gravel, debris or vegetation.
  • Pools that retain water as nearby channels recede.

Breeding habitat: Timing and recruitment

Many Pilbara freshwater fish breed during the wet season, and more than one spawning event may occur. Fortescue Grunter specific spawning months are not established.

Fish from 0 to 30 mm standard length have been recorded in several pools. These may be new recruits from spawning within the preceding year.

Possible new recruits: 0 to 30 mm standard length

Breeding period: Likely associated with the wet season, but species specific months are not established

  • Plan aquatic disturbance outside periods of high flow and avoid disturbing occupied pools at any time where practicable.
  • Treat very small fish as a reason to pause, reassess and seek aquatic ecological advice before proceeding.
  • Repeat checks after rainfall or flooding where works could affect connected pools.

Breeding habitat: Protection during works

Do not drain, fill, isolate or substantially alter an occupied pool without an approved method and suitable aquatic fauna advice. Protect upstream and downstream flow paths so fish are not stranded or cut off from retained water.

If dewatering is unavoidable, prepare a site-specific fish management plan. It should cover aquatic fauna assessment, exclusion of additional inflow, fish rescue and release arrangements, water quality, disease prevention and post-work monitoring.

  • Inspect pools before dewatering, diversion or in-channel construction.
  • Maintain water quality and avoid sudden changes in depth or flow.
  • Use an experienced aquatic fauna team for any fish rescue or relocation.
  • Record the pool condition and fish observations before and after the work.

Sheltering habitat: Refuge habitat

The Fortescue Grunter has no well-defined species specific shelter structure. It uses pools and stream habitats, and larger pools with greater structural complexity are generally more suitable for Pilbara fish communities.

During dry conditions, fish retreat to semi-permanent and permanent pools. Deeper water, complex margins, rock, gravel, debris and vegetation may provide refuge from shallow water, heat and predators.

Reduced depth and volume in shallow pools can increase exposure of juvenile fish to teleost and bird predation.

  • Deep sections that retain water during recession.
  • Complex banks, rock and natural debris.
  • Vegetated margins and shaded sections where they occur naturally.
  • Pool areas protected from excessive disturbance and trampling.

Sheltering habitat: Schooling and cover

The species may school when present in suitable numbers, probably as a defence against predators. A school in a small remnant pool may represent a substantial part of the local population.

Avoid separating fish from cover or concentrating them in isolated shallow water through pumps, temporary bunds, access tracks or altered drainage.

  • Inspect pools for schooling fish before entering the water.
  • Keep machinery, vehicles and people out of occupied pools unless the method has been assessed and authorised.
  • Retain natural cover and avoid unnecessary removal of bank vegetation or debris.

Sheltering habitat: Dry season and temporary works

Waterholes can become the main refuge during dry conditions. Temporary works should not reduce pool volume, block movement between retained pools or leave fish stranded in shallow depressions.

After rain, check whether temporary drainage, culverts or bunds have changed fish passage or caused fish to collect in unsafe areas.

  • Inspect upstream and downstream of temporary crossings and diversions.
  • Remove temporary barriers when they are no longer needed, where safe and authorised.
  • Include aquatic habitat checks in daily environmental inspections near water.

Threats: Hydrology and water loss

The main development risks are changes to water, direct disturbance of pools and declining water quality. Because the Fortescue Grunter has a restricted range and is listed as Priority 4, manage confirmed habitat records conservatively and use monitoring to detect change.

Dewatering, diversion, drainage changes, excavation and altered runoff can reduce pool depth, disconnect habitats or change the timing and volume of flows. These effects may be most serious during dry conditions, when fish are concentrated in remnant pools.

Maintain natural inflows, outflows and overland drainage where possible. Assess both the work footprint and connected upstream and downstream pools.

  • Avoid draining or filling occupied pools.
  • Design crossings and temporary works to maintain fish passage and natural flow paths.
  • Monitor pool depth, connectivity and water quality during works and through dry periods.

Threats: Direct pool and bank disturbance

Vehicles, machinery, access tracks, sediment placement, bank clearing and in-channel works can kill fish, remove refuge habitat or damage pool margins.

Set out exclusion areas around water and keep machinery, spoil, fuels and waste away from occupied aquatic habitat. A fixed species specific buffer is not established, so use a risk-based exclusion area agreed with the aquatic ecologist and regulator.

  • Avoid driving through pools or wet channels.
  • Keep spoil and stockpiles outside drainage lines and pool margins.
  • Inspect for fish before any in-channel entry, pumping or bund construction.
  • Stop work if fish are stranded, exposed or unexpectedly concentrated.

Threats: Water quality and pollution

Sediment, saline or contaminated discharge, hydrocarbons, concrete washout and rubbish can reduce water quality and prey availability. Turbid water can also interfere with fish feeding and monitoring.

Use effective erosion, sediment, spill and wastewater controls before earthworks begin. Check discharge points and receiving pools after rainfall and during high-risk activities.

  • Install and maintain sediment controls.
  • Keep chemicals and refuelling areas away from water.
  • Do not discharge untreated or visibly contaminated water to pools or streams.
  • Use clean equipment between catchments to reduce disease and pest transfer.

Threats: Fragmentation and monitoring

Temporary or permanent barriers can isolate fish in small pools and prevent recolonisation after rainfall. Poorly planned rehabilitation can also leave channels disconnected or create shallow, unstable water.

Priority 4 status calls for monitoring rather than assuming that a single negative survey rules out the species. Confirm records, map habitat and compare conditions before, during and after construction.

  • Inspect culverts, crossings and temporary barriers for fish passage problems.
  • Survey suitable pools after disturbance and following major hydrological changes.
  • Report confirmed records and unexpected impacts through the project's environmental incident process.
  • Review controls if fish numbers, pool condition or connectivity decline.

Survey methodology: 1. Desktop assessment

Survey permanent and semi-permanent pools, slow to fast flowing streams and connected river channels. The Fortescue Grunter is small and poorly known, so use more than one aquatic survey method and sample across the range of water conditions likely to occur during the works.

Map permanent water, semi-permanent pools, rocky pools, stream channels, waterfall bases and areas that may connect after flooding.

Check DBCA records and previous aquatic fauna surveys for the Fortescue, Robe and Ashburton river systems.

Treat isolated pools as potential habitat where they are connected to larger pools during wet periods. Consider the species a potential occurrence in suitable permanent water, even where recent records are absent.

Survey methodology: 2. Field survey timing and conditions

Survey during the wet season or soon after rainfall where safe access allows. Also survey during dry conditions, when fish may be concentrated in permanent and semi-permanent pools.

Repeat surveys where water levels, connectivity or access conditions change. The species may move through connected waterways during wet periods and retreat to persistent pools during dry periods.

Avoid surveying during unsafe flood conditions. Record recent rainfall, flow, water level, pool connectivity and any restrictions on access.

Survey methodology: 3. Detection methods and effort

Use baited funnel traps, fyke nets, seine nets or other suitable fish sampling equipment, selected for the pool size, depth, substrate and fish community. Obtain any required collection approvals before deployment.

Sample shallow margins, deeper water, inflow and outflow areas, rocky edges and structurally complex habitat where safe and appropriate.

Use repeated sets across representative pools rather than relying on a single trap location. The species was detected previously using three funnel traps and 6.3 hours of trapping and searching, but this should not be treated as a minimum survey standard.

Consider environmental DNA or other specialist methods where trapping is unsuitable, subject to validation and approval. Engage an aquatic ecologist for site specific survey design.

Survey methodology: 4. Identification and records

Have an experienced freshwater fish ecologist confirm identifications. Record photographs, total length or standard length, colour, body form and distinguishing features used for the identification.

Record the number of fish by size class, including individuals less than 30 mm standard length where present. Very small fish may represent recent recruitment.

Record coordinates, pool dimensions, water depth, flow, substrate, cover, aquatic vegetation, water quality, habitat complexity and nearby disturbance.

Record all capture, release, mortality, injury and relocation details. Submit significant records to the relevant Western Australian database or land manager.

Before habitat disturbance: 1. Avoidance, approvals and permits

Avoid disturbance to permanent water and connected river habitat wherever practicable. Because the species is listed as Priority 4 in Western Australia, plan works conservatively and obtain advice before altering pools, stream channels or water flows.

Redesign clearing, access tracks, crossings, dewatering and spoil placement to retain permanent and semi-permanent pools, stream banks, inflow areas and outflow areas.

Confirm the current conservation status and all approvals with DBCA, the relevant water regulator and the project environmental authority.

The Western Australian Priority 4 category is a monitoring category rather than a statutory threatened species listing. It does not remove the need to obtain permits for fish collection, handling, relocation, translocation, fauna interference, clearing, water extraction or aquatic works.

An EPBC referral is not indicated for this species by its current profile, but assess the whole action for other listed matters and confirm the outcome with the Australian Government before work starts.

Queensland species management programs apply to relevant Queensland protected wildlife and breeding places. The Fortescue Grunter is a Western Australian species, so a Queensland SMP would not normally apply, but confirm this if the project or any proposed translocation involves Queensland.

Before habitat disturbance: 2. Pre-clearance aquatic survey

Complete a targeted fish survey before dewatering, infilling, isolating or disturbing suitable water. Survey every affected pool and connected habitat, including areas upstream and downstream of the work footprint.

Use a suitably experienced aquatic ecologist and approved methods. Allow enough time for trap checking, safe fish processing and release or authorised relocation.

Survey after recent flow changes as well as during low flow where fish may be concentrated. Search for small fish as well as larger individuals.

Do not begin aquatic disturbance until survey results, fauna handling arrangements and any required approvals have been reviewed by the environmental manager.

Before habitat disturbance: 3. Work timing and habitat protection

Avoid works that interrupt fish passage during wet season flows or shortly after flooding has connected pools, unless the work is specifically approved and managed by an aquatic ecologist.

Where practicable, schedule in-channel works during stable low flow while retaining enough water and habitat for fish. Do not allow pools to dry as a result of project activities.

Maintain natural flow paths and avoid rapid changes in water level, turbidity, temperature, dissolved oxygen and water quality.

Use site specific exclusion zones around pools and stream channels. No universal buffer is established for this species, so set distances through a hydrology, habitat and construction risk assessment.

Before habitat disturbance: 4. Exclusion and crew induction

Fence or mark aquatic exclusion zones before mobilisation. Keep vehicles, pumps, refuelling areas, chemicals, concrete washout, spoil and sediment controls outside those zones.

Install fish screens on pumps and prevent fish entry into pipes, sumps and dewatering systems.

Induct all workers on the species profile, aquatic exclusion zones, stop work authority, biosecurity, fish handling restrictions and incident reporting.

Provide contact details for the aquatic ecologist, fauna spotter catcher, environmental manager and relevant regulator at the work front.

During habitat disturbance: 1. Sequential clearing and dewatering

Use a staged, controlled approach to any work near water. Stop work if fish, suitable habitat, a breeding place or an unexpected aquatic impact is identified.

Clear vegetation and work from the margins towards the approved footprint, leaving aquatic refuge habitat intact until fish management is ready.

Isolate work areas with screened barriers where appropriate. Dewater slowly and under the direction of the aquatic ecologist.

Inspect pumps, hoses, sumps and isolated sections regularly for trapped fish. Maintain water quality and avoid stranding animals in shallow residual water.

Do not move fish between catchments or pools without written approval and an approved relocation or translocation plan.

During habitat disturbance: 2. Stop work and handling authority

Give the fauna spotter catcher or aquatic ecologist authority to stop work immediately where fish are found in the disturbance area or where controls fail.

Only authorised and trained personnel may capture, identify, hold, release or relocate fish. Do not allow general workers to handle the animals.

Use clean, fish safe equipment and minimise handling time, crowding, heat exposure and changes in water temperature.

Release animals into suitable retained habitat as directed by the aquatic ecologist. Record the release location and condition of every handled group.

During habitat disturbance: 3. Breeding places and aggregations

If eggs, larvae, very small recruits, spawning behaviour or a suspected active breeding place is found, stop work in the affected area and obtain advice before proceeding.

Protect the place from sediment, vibration, dewatering, light and changes in flow until its status and management requirements are confirmed.

Where a large aggregation or schooling group is found, treat it as a sensitive concentration area and revise the work method with the aquatic ecologist.

Do not disturb, collect or relocate eggs or larvae unless specifically authorised and covered by the approved fauna management procedure.

During habitat disturbance: 4. Injured or dead animals

Place injured fish in clean, aerated water of suitable temperature and contact the project aquatic ecologist or wildlife response contact immediately.

Do not release an injured animal or euthanise it unless directed by an authorised person under the approved procedure.

Record the cause, location, time, weather, water conditions, injury type and photographs where this can be done safely.

Report mortalities promptly to the environmental manager and relevant regulator where required by approval conditions.

During habitat disturbance: 5. Daily records

Record work areas opened and closed, pool and flow conditions, fish observations, captures, releases, relocations, injuries, mortalities, water quality events and control failures.

Record the names and approvals of people undertaking fish handling and the equipment used.

Keep maps, photographs, trap checks, release records and stop work events with the project environmental records.

Escalate any unexpected impact, fish kill, failed isolation or loss of aquatic habitat before work resumes.

After habitat disturbance: 1. Post-clearance checks

Check the work area after aquatic disturbance and confirm that retained habitat remains connected, clean and usable. Review the controls promptly if fish are missing, stranded or exposed to changed water conditions.

Inspect the full disturbance footprint, pool margins, drains, sumps, pump lines and downstream areas after dewatering and each major work stage.

Search for stranded fish, drying pools, damaged banks, blocked channels, sediment plumes, spills and fish passage barriers.

Remove temporary barriers, screens and equipment only after the aquatic ecologist confirms that no fish remain in the work area and that removal will not cause further harm.

Photograph retained pools and completed controls for the project record.

After habitat disturbance: 2. Relocated animals and retained habitat

Confirm that all authorised relocated fish were released into the approved habitat and that release water conditions were suitable.

Inspect release pools for adequate water, cover, flow and water quality. Report unusual mortality or repeated fish distress.

Do not conduct follow-up captures simply to prove survival unless this is included in the approved monitoring design.

Maintain fish passage through temporary and permanent crossings wherever the species could use connected habitat.

After habitat disturbance: 3. Monitoring and reporting

Undertake follow-up aquatic monitoring where pools were dewatered, stream flows were altered, fish were relocated, or water quality limits were exceeded.

Use the same methods and representative locations where possible so results can be compared with the pre-disturbance survey.

Report survey results, incidents, mortalities, relocations, water quality results, rehabilitation status and any approval non-compliance to the project manager and relevant regulators.

Share confirmed records with DBCA or the relevant land manager.

After habitat disturbance: 4. Incident review

Hold a review after any fish mortality, failed fish rescue, uncontrolled discharge, pool loss, barrier failure or unauthorised handling event.

Identify the cause and revise isolation, dewatering, sediment, lighting, access and inspection controls before similar work continues.

Update the induction and method statement where the review identifies a recurring risk.

Retain the review and corrective actions in the project environmental management system.

Rehabilitation actions: 1. Restore aquatic habitat

Rehabilitation should restore permanent and semi-permanent aquatic habitat, natural flow and water quality. For this fish, protecting functional pools and stream connections is more appropriate than installing terrestrial nesting or roosting structures.

Reinstate natural channel shape, pool depth variation, banks, riffles and connections between pools where these were altered by the project.

Use local rock, gravel, sand and woody or other natural cover where suitable for the waterway and approved by the aquatic ecologist.

Retain complex habitat and avoid leaving shallow, isolated depressions that can heat rapidly or trap fish during receding flows.

Remove temporary crossings, bunds, spoil and sediment barriers that obstruct fish passage once the area is stable and safe.

Rehabilitation actions: 2. Water quality and flow

Prevent sediment, hydrocarbons, concrete residues, saline water and other contaminants from entering pools or streams.

Restore natural drainage and avoid permanent changes to flow volume, timing, water level or pool persistence.

Stabilise banks with locally appropriate methods and inspect them after rainfall and flow events.

Do not fill or drain a permanent pool as a rehabilitation shortcut.

Rehabilitation actions: 3. Vegetation, weeds and lighting

Re-establish native riparian vegetation suited to the local waterway and protect it from grazing, vehicles and further disturbance.

Remove declared and environmental weeds using methods that prevent herbicide or sediment entry into water.

Limit night lighting near pools and stream margins. Use shielding, low spill lighting and lighting only where required for safety.

Control dust and runoff from rehabilitation areas until ground cover and bank stability are established.

Rehabilitation actions: 4. Replacement structures and habitat features

Do not install nest boxes, bat boxes, artificial nest sites or roost structures for the Fortescue Grunter. These structures do not match the known habitat or breeding information for this fish.

Where habitat replacement is required, create or restore suitable aquatic features instead, such as permanent water, complex pool margins, cover and fish passage.

Have the design reviewed by an aquatic ecologist and the relevant regulator before construction.

Rehabilitation actions: 5. Long term monitoring

Monitor rehabilitated pools and stream sections through wet and dry conditions, including after major rainfall or flooding where safe.

Track water permanence, pool connectivity, flow, water quality, bank stability, weeds, aquatic vegetation and fish presence.

Use repeat fish surveys where the project affected known habitat or where monitoring is required by approval conditions.

Continue monitoring until rehabilitation objectives are met and the site is stable. Escalate declining water permanence, loss of connectivity or fish mortality for corrective action.

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