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Barrow Cave Gudgeon (Milyeringa justitia)

The Barrow Cave Gudgeon is a small, blind, subterranean fish that lives in groundwater aquifers on Barrow Island, Western Australia. Its very restricted range makes groundwater, water quality and recharge areas important considerations during clearing and construction. It is listed as Endangered under the Commonwealth and Western Australian legislation.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Western Australia, Biodiversity Conservation Act 2016: Endangered.

Breeding season

The Barrow Cave Gudgeon is a poorly known subterranean fish restricted to aquifer systems on Barrow Island, Western Australia. Seasonal breeding and movement patterns have not been established, so groundwater habitat should be treated as occupied throughout the year.

Breeding mode: Not recorded.

Breeding timing: Not recorded by month or season.

Clutch size: Not recorded.

Incubation: Not recorded.

Age at maturity: Not recorded.

Breeding sites: Not recorded. Records are from subterranean freshwater habitat, including monitoring wells, but these are not confirmed breeding sites.

Breeding frequency: Not recorded.

Detection and activity may vary between years and sites, particularly because the species is rare in samples and much of Barrow Island remains poorly surveyed.

  • Aquifer presence and activity: Assume the species may be present and active in suitable freshwater aquifer habitat in every month.
  • Breeding activity: Breeding timing is unknown, so do not apply a seasonal breeding clearance window.
  • Young or eggs in subterranean habitat: The presence, timing and habitat of eggs or dependent young are unknown, so suitable aquifer habitat should be protected year-round.
  • Seasonal movement: No migration or seasonal movement has been recorded for this species.
  • Highest clearing risk: Treat all months as high risk because clearing, drilling or construction may affect the freshwater lens or water quality, and no lower risk season is known.

Identification: Appearance

The Barrow Cave Gudgeon is a troglobitic fish adapted to life in complete darkness. It is known from groundwater systems on Barrow Island and is rarely encountered during routine field work.

The body is pale and lacks normal pigmentation. The species has no functional eyes and is blind.

Sensory papillae on the head and body help it move and feed in darkness.

Identification: Size and calls

A reliable adult size range has not been established. No calls, echolocation or other audible field signal is known for this species.

Useful identification feature: Pale, eyeless fish from a suitable Barrow Island aquifer or groundwater bore.

Identification: Similar species

Blind Gudgeon, Milyeringa veritas, is the main potentially confused species. Cave eels, including Ophisternon species, may also occur in subterranean groundwater habitats but are readily distinguished by their eel-like body form.

Identification: Field signs and handling

There are no reliable surface signs such as droppings, nests, stains, odour or calls. A live capture from a suitable aquifer, or a validated environmental DNA detection, is the most useful evidence.

Treat any unusual pale or eyeless fish collected from a bore as a potential threatened species. Keep it in clean, aerated water and seek identification advice from a suitably qualified aquatic ecologist or the relevant Western Australian authority.

  • Record the bore or well identifier, coordinates, water level, depth if known, date and sampling method.
  • Photograph the fish in water where possible, using a scale only if this can be done without harm.
  • Do not release a specimen into a different bore or water body.

Distribution: Australian range

The Barrow Cave Gudgeon is endemic to Australia and has a highly restricted known range. For project planning, assume that suitable groundwater habitat on Barrow Island may support the species even where previous records are absent.

The species is restricted to Barrow Island in the Pilbara region of Western Australia. It has not been recorded from another Australian state or territory.

Known region: Pilbara, Western Australia

Known locality: Barrow Island

Distribution: Recorded locations

Records are concentrated in the central part of Barrow Island, where the freshwater lens is thickest. Most records have come from well L8, with records also reported from one other site.

Well L8 coordinates: 20°49’2.31”S, 115°23’41.98”E

Survey context: The species has been recorded only rarely during bore based subterranean fauna surveys.

Distribution: Site planning

Map all proposed clearing, excavation, road, laydown, drilling and dewatering areas against aquifer and freshwater lens information. Include recharge areas and connected groundwater where the project may alter infiltration or water quality.

The absence of a record should not be treated as evidence that the species is absent. Bore construction, casing and sampling methods can affect detection.

  • Refer potential impacts to the project aquatic ecologist early.
  • Use existing industry and consultant records when designing a survey program.
  • Protect the location details of records because the species has a very small known range.

Habitat: Aquifer habitat

The Barrow Cave Gudgeon lives below ground in the stygal environment, within interstitial spaces and voids in groundwater. On a works site, the relevant habitat is the aquifer and its physical and chemical connections, rather than surface vegetation alone.

The species is associated with the freshwater lens beneath Barrow Island. Most records are from central island groundwater where the lens is thickest.

Potential habitat includes saturated limestone voids, cavities and connected groundwater spaces that can be reached through suitable wells or bores.

Habitat: Surface features to consider

Surface features that may influence habitat include limestone landforms, recharge areas, drainage depressions and areas where rainfall can enter the groundwater system. The species may be affected even when construction does not directly enter a bore.

Vegetation type has not been established as a reliable indicator of occupancy. Assess the underlying geology, groundwater connection and proposed changes to infiltration or water levels.

  • Identify bores, wells and monitoring points before ground disturbance.
  • Map karstic limestone and groundwater recharge areas.
  • Check whether excavation or water abstraction could intersect or draw down the freshwater lens.

Habitat: Survey access points

Bores and wells can provide access for stygofauna sampling, but casing, slots and bore design influence which animals can be detected. Use methods suitable for small groundwater fauna and record the limitations of each access point.

  • Use appropriately designed plankton haul nets where bore access and safety arrangements allow.
  • Consider environmental DNA methods as part of a repeat monitoring program, supported by validated species reference material.
  • Consolidate sampling with industry monitoring and other authorised groundwater surveys.

Foraging habitat: Feeding environment

The Barrow Cave Gudgeon forages in total darkness within groundwater spaces. Its diet and detailed feeding ecology are poorly understood, so management should protect the quality and connectivity of the aquifer rather than focus on a particular prey habitat.

The species uses sensory papillae on its head and body to move and feed without sight. It is expected to search through saturated voids and interstitial spaces within the freshwater lens.

No species specific prey or diet has been established.

Foraging habitat: Water and food inputs

Groundwater food webs can depend on organic material entering from the surface or moving through connected groundwater. Avoid actions that introduce sediment, hydrocarbons, chemicals or other contaminants into recharge areas or bores.

Maintain natural groundwater flow and water quality wherever practicable. Sudden changes in water level, salinity or dissolved oxygen may affect subterranean fauna.

  • Use bunding and spill controls around fuels, chemicals and machinery.
  • Prevent dirty water from entering drainage features, recharge areas or uncapped bores.
  • Manage drilling fluids and bore development water so they cannot contaminate connected groundwater.

Foraging habitat: Survey interpretation

A single non detection is not enough to rule out occupancy. Detection can vary with bore design, sampling conditions, water levels and the distribution of animals within the aquifer.

  • Record water quality and sampling conditions with each survey.
  • Use repeat sampling where the project could affect suitable aquifer habitat.
  • Have unexpected fish captures checked by an aquatic subterranean fauna specialist.

Breeding habitat: What to protect

Breeding habitat and reproductive timing are not established for the Barrow Cave Gudgeon. Treat all connected freshwater lens habitat as potentially important throughout the year.

There are no confirmed nests, spawning sites, breeding chambers or seasonal breeding areas to target. Groundwater cavities and connected aquifer spaces should therefore be managed as potential breeding habitat.

Do not assume that a bore capture represents only a temporary occurrence. The animal may be using a connected subterranean system that extends beyond the work area.

Breeding habitat: Works planning

Avoid excavation, drilling, grouting, dewatering and discharge activities that could alter groundwater levels, flow paths or water chemistry. Where these activities cannot be avoided, assess the risk to the freshwater lens before works begin.

Plan high risk activities with the project ecologist, hydrogeologist and relevant regulators. Use staged works and monitoring where this can reduce uncertainty.

  • Check whether proposed works intersect the freshwater lens or its recharge area.
  • Maintain secure, clean and appropriately managed monitoring points.
  • Stop and seek advice if a pale, eyeless fish is captured or if groundwater conditions change unexpectedly.

Breeding habitat: Timing

No breeding season has been established. Apply protection measures year round rather than relying on a seasonal clearance window.

Sheltering habitat: Subterranean refuges

The species has no documented surface shelter, roost or refuge. Its likely shelter is provided by groundwater voids, interstitial spaces and cavities within the freshwater lens.

Potential shelter includes connected limestone openings and groundwater spaces that provide stable water conditions and protection from light. The species has been recorded from wells, but wells should not be treated as its natural shelter.

Avoid blocking, sealing or contaminating access to connected groundwater without assessing the consequences for subterranean fauna.

Sheltering habitat: Bores and wells

Bore casing and slot size can affect access by subterranean animals and can bias survey results. Keep bore records, construction details and maintenance history with the fauna survey data.

Only sample or modify bores under an approved method that protects workers, the bore and captured animals.

  • Use clean equipment between bores to reduce contamination and disease risks.
  • Prevent fuel, concrete, drilling additives and waste from entering open or poorly sealed bores.
  • Do not transfer animals, groundwater or sampling equipment between unrelated groundwater systems without appropriate controls.

Sheltering habitat: Site controls

Fence or otherwise protect monitoring points from vehicles, stock, sediment and construction materials. Maintain the integrity of recharge areas and avoid unnecessary compaction or sealing of ground surfaces.

  • Include groundwater protection zones in the site environmental plan.
  • Inspect controls after rainfall and following earthworks.
  • Record any damaged casing, spills, unusual odours or changes in water level and report them promptly.

Threats: Groundwater drawdown and altered flow

The Endangered status of the Barrow Cave Gudgeon calls for a precautionary approach. Development risks are most likely to arise through changes to groundwater quantity, quality or connectivity on Barrow Island.

Dewatering, groundwater abstraction, deep excavation and bore installation may lower water levels or change flow paths in the freshwater lens. These changes can reduce suitable habitat or isolate connected groundwater spaces.

Assess drawdown and recovery before works, and use monitoring to check whether predicted groundwater changes are occurring.

  • Minimise abstraction and dewatering volumes where practicable.
  • Use a staged approach for high risk groundwater works.
  • Define response actions before starting if water levels or quality move outside approved conditions.

Threats: Water quality impacts

Operations on Barrow Island may affect groundwater through spills, leaks, drilling fluids, contaminated runoff or poorly managed waste. Protect the freshwater lens from hydrocarbons, chemicals, sediment and other contaminants.

Use secondary containment, spill response equipment and strict chemical storage controls near bores and recharge areas.

  • Keep clean and dirty water separate.
  • Inspect fuel, chemical and waste storage areas regularly.
  • Report and contain spills immediately, then obtain aquatic fauna and groundwater advice.

Threats: Surface disturbance and recharge

Clearing, compaction, road construction and hardstand areas can change how rainfall enters the aquifer. Changes to recharge may affect groundwater levels, chemistry and the movement of subterranean fauna.

Limit the disturbed footprint and retain natural drainage and infiltration patterns where practicable.

  • Identify recharge areas before clearing.
  • Avoid unnecessary sealing or compaction over sensitive groundwater systems.
  • Rehabilitate temporary work areas to restore drainage and infiltration.

Threats: Detection and construction risks

The species is difficult to detect and may be missed because of bore design, sampling method or low encounter rates. A lack of captures does not remove the need for controls in suitable habitat.

For an Endangered species, stop work and seek specialist and regulatory advice if the species is captured, detected by validated environmental DNA, or if an unexpected groundwater connection is exposed.

  • Use a targeted subterranean fauna survey before high risk works.
  • Coordinate surveys with existing industry monitoring to improve coverage.
  • Keep accurate records of captures, non detections, water conditions and construction impacts.

Survey methodology: 1. Desktop assessment

The Barrow cave gudgeon is a poorly known, subterranean fish restricted to aquifer systems on Barrow Island. Surveys should focus on groundwater habitats and use methods suited to stygofauna, rather than surface fish sampling alone.

Confirm whether the project overlaps Barrow Island aquifers, groundwater infrastructure, monitoring bores or areas connected to the freshwater lens.

Review previous bore, stygofauna and water quality records. Most known records are from central Barrow Island, including well L8, where the freshwater lens is thickest. Treat areas without records as unsurveyed, not as absent habitat.

  • Map proposed clearing, excavation, dewatering, drilling and groundwater abstraction against aquifer information.
  • Identify bore construction details, casing, slot size, water levels and access constraints before selecting survey sites.
  • Engage the relevant Barrow Island land manager, industry environmental team and subterranean fauna specialists early.

Survey methodology: 2. Groundwater fauna survey

Use appropriately qualified stygofauna personnel to sample accessible bores and groundwater habitats. Plankton haul nets have been used for stygofauna surveys on Barrow Island.

Sample representative aquifer habitats across the project area, including locations hydraulically connected to proposed works. Small or tightly slotted casings may reduce detection, so interpret negative results cautiously.

  • Record the bore location, depth, casing and slot details, water level, water quality, sampling date, weather and recent pumping history.
  • Use consistent equipment, deployment and processing methods between survey rounds.
  • Avoid contaminating samples between bores by cleaning and decontaminating equipment according to the project hygiene procedure.
  • Use environmental DNA methods where validated for the species and combine results with physical sampling.

Survey methodology: 3. Timing and repeat effort

There is no established breeding or seasonal movement period for the Barrow cave gudgeon. Plan surveys when bores are safely accessible and groundwater conditions can be recorded consistently.

Repeat sampling where detection probability is low, where habitat is poorly represented, or where construction could alter groundwater levels or quality.

  • Allow enough time for consultation, bore access, laboratory processing and taxonomic confirmation before clearing or groundwater works begin.
  • Increase survey coverage in poorly sampled parts of Barrow Island, including northern and south-western areas.
  • Do not use one negative sample as evidence that the species is absent from a connected aquifer.

Survey methodology: 4. Identification and records

Have specimens checked by an experienced aquatic or subterranean fauna taxonomist. Distinguish the Barrow cave gudgeon from other subterranean fauna, including the blind gudgeon and cave eels.

Treat a suspected record as a significant finding until identification is confirmed.

  • Record photographs, specimen or tissue reference numbers, genetic sample details and chain of custody.
  • Map each detection and record the bore or habitat unit, depth, water quality and sampling method.
  • Submit records to the project database and relevant Western Australian biodiversity authorities in the required format.
  • Report detection limitations, including unsuitable casing, inaccessible bores and low sample volumes.

Before habitat disturbance: 1. Approvals and permits

The species is listed as Endangered under the Commonwealth EPBC Act and in Western Australia. Avoiding changes to aquifer habitat, groundwater levels and water quality is the primary management approach.

Confirm the project approval pathway before works begin. An EPBC Act referral may be required for an action that could significantly affect the species or its habitat.

Obtain all Western Australian approvals, licences and fauna authorisations that apply to the proposed clearing, drilling, dewatering, discharge and groundwater abstraction.

  • Use a suitably qualified environmental practitioner to check EPBC Act requirements and any approval conditions.
  • Confirm whether a scientific, fauna, collection or animal ethics permit is required for capture, handling, sampling or release.
  • A Queensland species management program is not a normal pathway for this Barrow Island species. If the project is in Queensland and the species is legally relevant, seek advice from the Queensland regulator before works and obtain an approved species management program where required.
  • Keep permits, approval conditions, maps and contact details at the site office and in the supervisor's vehicle.

Before habitat disturbance: 2. Avoidance and site planning

Keep works out of aquifers and groundwater-connected areas wherever practicable. Avoid excavation, drilling, dewatering, injection, discharge and spills that could alter the freshwater lens or introduce contaminants.

Design the project footprint around confirmed and potential subterranean fauna habitat, not only around known capture points.

  • Use existing cleared areas and existing infrastructure where feasible.
  • Maintain clean separation between fuels, chemicals, spoil, wastewater and groundwater infrastructure.
  • Prepare a groundwater management plan with trigger levels, response actions and named decision makers.
  • Do not seal, abandon, modify or replace a monitoring bore without assessing the effect on subterranean fauna access and groundwater flow.

Before habitat disturbance: 3. Pre-clearance checks and work timing

Complete a final environmental check before clearing, excavation or groundwater works. There are no confirmed breeding months or migration periods for this species, so timing alone cannot remove the risk.

Use current survey and groundwater information to confirm that planned works remain within approved limits.

  • Recheck the work boundary, bore locations, drainage, chemical storage and dewatering points before mobilisation.
  • Confirm that required surveys, permits, inductions and rescue arrangements are complete.
  • Stop and reassess if new groundwater, a previously unknown aquifer connection or a suspected Barrow cave gudgeon record is found.
  • Schedule repeat monitoring where the work could change groundwater levels or quality.

Before habitat disturbance: 4. Exclusion, induction and supervision

Set clear no-go areas around groundwater infrastructure, spill response equipment and sensitive aquifer access points. Use controls specified by the project approval and groundwater management plan.

Brief every worker and contractor before entering the site.

  • Mark approved work limits and exclusion areas on plans, vehicle navigation systems and the ground where practical.
  • Explain that the species is an Endangered subterranean fish and may not be visible during ordinary surface fauna searches.
  • Give spotter catchers and supervisors authority to stop work when an environmental trigger is reached.
  • Provide the incident phone number, isolation procedure, spill kit location and escalation contacts during induction.

During habitat disturbance: 1. Sequential clearing and work control

Work should proceed slowly and under the approved environmental controls. The Barrow cave gudgeon is not expected to be encountered during ordinary terrestrial clearing, but groundwater disturbance can affect habitat without producing a visible animal.

Clear in small, approved stages and inspect each stage before moving to the next. Keep machinery, spoil and runoff away from bores, drains and groundwater entry points.

Use the spotter catcher and environmental supervisor to check that controls remain effective as work fronts move.

  • Start with the lowest-risk, previously disturbed areas where practicable.
  • Install and maintain sediment, spill and runoff controls before breaking ground.
  • Keep dewatering, pumping and discharge within approved limits.
  • Stop work if water quality deteriorates, unexpected groundwater is encountered, a bore is damaged or monitoring triggers are exceeded.

During habitat disturbance: 2. Animal handling and suspected records

Do not handle a suspected Barrow cave gudgeon unless authorised under the relevant permit and directed by the aquatic fauna specialist. The species is a subterranean fish and should not be placed in an improvised container or released into an unapproved waterbody.

Use a qualified aquatic fauna handler for capture, identification, containment and release.

  • Photograph the animal in the water where safe to do so and protect it from heat, light and unnecessary handling.
  • Record the exact location, bore or waterbody, depth if known, time, condition and people present.
  • Keep samples or animals secure and transfer them only under the approved chain of custody.
  • Follow the permit and specialist instructions for release, voucher specimens and genetic samples.

During habitat disturbance: 3. Active habitat or significant discovery

No breeding place, colony or seasonal refuge has been described for this species. Treat a confirmed detection, a connected aquifer habitat or an unexpected concentration of subterranean fauna as a significant environmental discovery.

Do not assume that the absence of a visible breeding site removes the risk.

  • Stop work in the immediate area and prevent further pumping, discharge or contamination until the environmental lead assesses the risk.
  • Protect the bore, aquifer access point and surrounding ground from machinery, spoil, chemicals and unauthorised entry.
  • Contact the project environmental manager, aquatic fauna specialist and relevant regulator as required by approval conditions.
  • Resume work only after the risk assessment, revised controls and approvals are documented.

During habitat disturbance: 4. Injury, mortality and incident response

Treat an injured or dead animal as a reportable fauna incident under the project system. Do not attempt treatment or relocation without specialist direction.

For a live animal, keep it in clean, suitable water and in a shaded, secure container only for the shortest practical period while awaiting authorised advice.

  • Contact the nominated aquatic fauna specialist and wildlife veterinarian or rehabilitation provider if directed by the permit.
  • For a dead animal, avoid freezing or preserving it unless the taxonomist or permit holder gives instructions.
  • Isolate the source of harm, such as a spill, pump, contaminated discharge or damaged bore.
  • Record photographs, coordinates, cause or suspected cause, response actions and notifications.

During habitat disturbance: 5. Daily field records

Maintain records that allow the project team to link work activities with groundwater conditions and fauna findings. Good records are especially important because the species is rarely detected and survey limitations can be substantial.

  • Record the date, crew, work area, machinery, excavation or pumping activity and control measures.
  • Record water levels, water quality observations, discharges, spills, incidents, stoppages and corrective actions.
  • Record all searches, samples, detections, non-detections and identification decisions.
  • Submit daily records to the environmental manager before the next work shift where practicable.

After habitat disturbance: 1. Post-clearance and infrastructure checks

Post-work checks should confirm that groundwater controls remain effective and that any fauna response has been completed. Monitoring should be scaled to the level of risk and continued where works may affect aquifer conditions.

Inspect the completed work area, nearby bores, drainage and containment systems after each clearing or construction stage. Look for damaged casing, sediment entry, leaks, altered flow paths and unmanaged discharge.

Keep exclusion controls in place until the environmental manager confirms that the area is stable and compliant.

  • Check that spoil and waste have been removed from bore surrounds and drainage lines.
  • Confirm that temporary seals, caps and barriers are secure and do not block approved fauna sampling access.
  • Repair erosion, leaks and damaged groundwater infrastructure promptly.
  • Document the inspection with photographs, locations and outstanding actions.

After habitat disturbance: 2. Monitoring and reporting

Continue groundwater and subterranean fauna monitoring where required by approvals or where risk remains. Use the same methods and sites where possible so that results can be compared over time.

Review monitoring data for changes in water levels, quality, aquifer connectivity and fauna detections.

  • Use validated eDNA and physical sampling together where that is part of the approved program.
  • Compare results with baseline and previous monitoring, while allowing for imperfect detection.
  • Provide monitoring reports to the regulator, land manager and project approval holders as required.
  • Report confirmed detections, mortalities, exceedances and ineffective controls promptly rather than waiting for the next routine report.

After habitat disturbance: 3. Relocated or rescued animals

Release or transfer a rescued animal only under the direction of the authorised aquatic fauna specialist and in accordance with the permit. The correct release location must be confirmed from aquifer connectivity and water quality, not selected for convenience.

Keep a complete record of any temporary holding or relocation.

  • Record the animal's identification, condition, holding time, water source, destination and handler.
  • Do not release the species into surface pools, unrelated bores or an aquifer that has not been approved as suitable.
  • Monitor the release location when required by the permit or management plan.
  • Report unsuccessful releases, mortality or repeated rescues for management review.

After habitat disturbance: 4. Incident review and adaptive management

Review every detection, mortality, spill, groundwater exceedance and unplanned bore impact. Use the findings to improve the next work stage and the rehabilitation plan.

  • Identify the activity, pathway and control failure that caused or could have caused harm.
  • Update work methods, exclusion areas, induction content and monitoring triggers.
  • Share lessons with contractors, spotter catchers, consultants and industry monitoring teams.
  • Close corrective actions only after verification in the field.

Rehabilitation actions: 1. Restore groundwater protection

Rehabilitation should restore groundwater protection and prevent ongoing changes to aquifer quality or flow. Surface revegetation is useful for erosion and contamination control, but nest boxes, bat boxes and artificial roost structures are not appropriate substitutes for this subterranean fish's habitat.

Remove temporary infrastructure and restore the ground surface so that runoff, sediment, fuels and chemicals cannot enter bores or groundwater systems.

Repair disturbed drainage and compacted areas in a way that prevents ponding, erosion and uncontrolled infiltration of contaminants.

  • Decommission temporary bores in accordance with the approved hydrogeological method.
  • Use clean, compatible materials and prevent grout, drilling fluids and construction waste from entering the aquifer.
  • Stabilise exposed soil and spoil areas promptly.
  • Keep rehabilitation materials, fuel and chemicals outside groundwater protection areas.

Rehabilitation actions: 2. Revegetation and weed control

Reinstate native ground cover and surface drainage where clearing has disturbed the catchment around groundwater infrastructure. This supports erosion control and water quality, rather than providing direct breeding habitat for the fish.

Manage weeds so that bare ground, sediment movement and chemical use do not create new groundwater risks.

  • Use approved local native seed or plant material where available.
  • Control weeds with methods that avoid contaminating groundwater and comply with project chemical controls.
  • Inspect rehabilitated areas after rainfall and repair erosion or failed revegetation.
  • Keep cleared vegetation, mulch and imported soil out of bore heads and drainage pathways.

Rehabilitation actions: 3. Water quality and lighting controls

Maintain clean water inputs and stable groundwater conditions after construction. Artificial lighting has no established direct management role for this species, but unnecessary lighting around groundwater infrastructure should still be avoided.

Do not discharge untreated water, sediment, hydrocarbons or chemicals to the ground or aquifer.

  • Continue spill prevention, containment and inspection until the area is stable.
  • Use water quality triggers and response actions from the approved groundwater management plan.
  • Direct lights away from bore openings and sensitive aquatic infrastructure where practicable.
  • Avoid lighting that could attract surface fauna or increase activity around open water and work areas.

Rehabilitation actions: 4. Habitat replacement and long-term monitoring

Do not install nest boxes, bat boxes, artificial nests or roost structures for the Barrow cave gudgeon. Its known habitat is subterranean aquifer systems, so replacement measures should focus on protecting or restoring suitable groundwater conditions.

Retain access for approved monitoring and confirm that rehabilitation has not altered the aquifer or water quality.

  • Maintain suitable, secure monitoring bores where they are part of the approved program.
  • Monitor groundwater levels, water quality and subterranean fauna at a frequency proportionate to the project's residual risk.
  • Review monitoring results with the land manager and aquatic fauna specialists.
  • Continue monitoring until agreed completion criteria are met and trends are stable.

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