Bald Carp Gudgeon (Hypseleotris gymnocephala)

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Breeding season

The bald carp gudgeon’s breeding timing is poorly known. For planning in its two confirmed New South Wales creeks, use the general pattern for small freshwater gudgeons, with greatest sensitivity during spring and summer, and confirm conditions through site assessment.

Breeding mode: Not recorded for the bald carp gudgeon. Small gudgeons generally use external fertilisation, with eggs attached to a firm underwater surface.

Clutch size: Not recorded.

Incubation period: Not recorded.

Parental care: Not recorded for the bald carp gudgeon. Male guarding of attached eggs occurs in some related gudgeons.

Larval and juvenile habitat: Not recorded in detail. General carp gudgeon habitat includes slow-flowing or still water, macrophytes, woody debris, roots, rocks and other cover.

Breeding frequency: Not recorded.

Timing may shift between years and locations with water temperature, rainfall, flow, drought and local habitat conditions, so pre-clearance checks should be coordinated with an aquatic ecologist.

• Breeding and egg laying: Treat October to December as the likely start of breeding activity, subject to local water temperature and flow conditions.
• Eggs and early larvae: Eggs and early larvae may be present from late spring into summer where breeding has occurred.
• Adult presence and shelter use: Adults are expected to remain in suitable creek habitat throughout the year, using cover such as vegetation, woody debris, roots and rocks.
• Highest clearing risk: Plan the highest risk period as October to March, when works may affect breeding adults, eggs or early young, and apply controls year round because the species is critically endangered.

Identification: Appearance and size

Bald carp gudg​eons are small, laterally compressed freshwater fish. They can be difficult to identify in the field because carp gudgeons often hybridise and some lineages are morphologically similar.

Adults and juveniles are generally 20 to 60 mm total length. The body is laterally compressed, with two distinct dorsal fins, a rounded caudal fin and a small, upturned mouth.

Typical colouration is yellowish-grey to greenish-brown on the back, with a paler belly. Males may have an orange-red edge to the upper dorsal fin.

Bald carp gudgeon has a blunt head. Dorsal scales are absent as far posteriorly as the middle of the second dorsal fin, and scales are absent from the nape. Mature males have a pale orange band shading into a thin white band on the distal part of the median fin.

Body form: Small and laterally compressed

Key head feature: Blunt head with no scales on the nape

Key fin feature: No median fin tips

Identification: Similar species

Boofhead carp gudgeon, Hypseleotris bucephala, also lacks scales on the head but has scales on the nape and has median fin tips. Cryptic carp gudgeon, Hypseleotris acropinna, also has median fin tips.

Hemiclonal lineages involving bald carp gudgeon, boofhead carp gudgeon and cryptic carp gudgeon may show dorsal scales on the nape. Do not rely on one feature alone for a project decision.

• Photograph fish from both sides where possible.
• Record the capture location, waterbody, habitat and handling method.
• Seek specialist identification where bald carp gudgeon or a related carp gudgeon is suspected.
• Use genetic examination where a definitive result is required.

Identification: Calls and field signs

No useful call or echolocation feature is expected. Bald carp gudgeon is detected through direct capture, observation in clear shallow water or targeted aquatic surveys.

Fish may shelter among aquatic plants, woody debris, roots, rocks and other cover. Droppings, nests, whitewash and odour are not reliable field signs for this species.

Distribution: Confirmed Australian range

Bald carp gudgeon is currently confirmed only from the upper Lachlan River catchment in south-eastern New South Wales. The two natural creeks are treated as one assessment location because drought and alien fish can affect both populations.

The species is known from Meadow Creek near Gunning, at 560 m above sea level, and Urumwalla Creek, a tributary of Blakney Creek, at 605 m above sea level and 19 km northwest of Dalton.

The creeks are approximately 28.5 km apart and are separated by agricultural land and unsuitable stream habitat.

• State: New South Wales only, based on confirmed records.
• Region: upper Lachlan River catchment, south-eastern New South Wales.
• Natural subpopulations: two.
• Extent of occurrence: 39.5 km².
• Area of occupancy: 16 km², based on a 2 by 2 km grid.

Distribution: Translocated populations

Between 2017 and 2019, bald carp gudgeons were translocated to two small dams immediately west of Gunning and to one dam adjacent to Urumwalla Creek. The Gunning dams are within the Gunning golf course and the Meadow Creek catchment.

These dams provide insurance populations, but their long-term persistence and self-sustainability remain to be established. Treat any nearby dam population as significant and avoid unnecessary disturbance.

Distribution: Site survey implications

The species was first found in Meadow Creek in 2011 and in Urumwalla Creek in 2015. Extensive sampling and genetic examination found bald carp gudgeon at only those two creek sites.

A negative result from a single visit should not be treated as proof that a suitable creek or dam is unoccupied. Engage an aquatic fauna ecologist for survey design, identification and any salvage or relocation work.

• Check mapped watercourses, farm dams and connected drainage features before works begin.
• Use current threatened species and approval requirements for the site and proposed activity.
• Protect both known catchments from avoidable sediment, chemical and aquatic pest impacts.

Habitat: Creek and waterbody features

The species uses slow-flowing or still freshwater at low to mid elevations. Both confirmed natural habitats are low-gradient creeks with cover and shallow margin features that can be affected by clearing, crossings and bank works.

Look for low-gradient creek sections, pools, slow runs, backwaters and still margins. Carp gudgeons generally occur below 625 m above sea level and are associated with areas that provide cover.

Potential habitat can occur in small creeks as well as connected dams or other still-water features. Treat apparently minor drainage lines with aquatic habitat as potentially relevant until assessed.

Typical elevation: Low to mid elevations, normally below 625 m above sea level

Flow conditions: Slow-flowing or still water

Known natural setting: Low-gradient creeks

Habitat: Cover and structure

Inspect macrophyte beds, woody debris, fringing vegetation, plant roots and rocks. These features provide shelter and feeding surfaces and may be concentrated around pools and shallow margins.

Retain in-stream and bank cover wherever practicable. Keep machinery, spoil, concrete washout and stockpiled materials away from the waterbody and its immediate margins.

• Map aquatic plants and woody debris before clearing.
• Avoid unnecessary removal of snags, roots, rocks and fringing vegetation.
• Maintain clean water and natural low-flow connections during works.

Foraging habitat: Features to inspect

Detailed feeding information for bald carp gudgeon is limited. For field planning, protect the shallow, slow-water areas and cover used by carp gudgeons generally, particularly where aquatic plants and organic structure are present.

Survey shallow margins, macrophyte beds, woody debris, plant roots, rocks and areas of fringing vegetation. These features can provide feeding surfaces and refuge for small fish.

Give particular attention to slow-flowing pools and still edges that may be overlooked during a general creek inspection.

• Record water depth and flow conditions in a site-specific way.
• Map aquatic vegetation and structural cover within the work footprint.
• Inspect connected dams and off-channel waterbodies, not only the main channel.

Foraging habitat: Works controls

Prevent sediment, fuel, chemicals and concrete products from entering occupied or potential habitat. Maintain downstream water quality during bank, crossing, earthmoving and dewatering works.

Use aquatic fauna specialists for fish capture, handling and relocation where works will isolate or dewater habitat. Do not move fish, water, mud or aquatic plants between catchments without appropriate biosecurity controls.

Breeding habitat: Potential breeding features

Specific breeding sites and breeding timing for bald carp gudgeon are poorly known. Until local information is available, manage suitable slow-water habitat and vegetated margins as potential breeding habitat.

Inspect sheltered shallow water around macrophytes, roots, woody debris, rocks and fringing vegetation. These features may provide cover for adults, eggs or young fish, although a breeding site should not be assumed from habitat alone.

Record fish size classes, numbers, water conditions and any evidence of repeated use during surveys.

• Avoid clearing aquatic plants and bank cover during works in suitable habitat.
• Retain low-gradient pools and slow margins where practicable.
• Do not isolate or rapidly drain habitat without a planned aquatic fauna response.

Breeding habitat: Survey and management approach

Use a suitably qualified aquatic ecologist to determine survey timing and methods for the site. Confirm the identity of captured carp gudgeons before making decisions about clearance or relocation.

Because the species is Critically Endangered and has a very restricted confirmed distribution, apply a precautionary approach to any occupied or potentially occupied habitat.

• Plan works to avoid direct disturbance to known populations.
• Stage dewatering and salvage under an approved method statement.
• Maintain records of captures, releases, mortality, water conditions and habitat affected.

Sheltering habitat: Shelter features

Bald carp gudgeon shelters in aquatic and bank-edge structure rather than in terrestrial nests or roosts. Small changes to cover, flow and water quality can reduce habitat value in a narrow creek system.

Search among macrophytes, woody debris, fringing vegetation, plant roots and rocks. Also inspect quiet margins, pools and other areas where flow is slow or absent.

Hemiclonal carp gudgeon lineages may use the same structural habitat, so mixed or uncertain captures should be handled as conservation-sensitive fish until identified.

• Retain submerged and emergent cover where safe to do so.
• Avoid removing snags or roots solely for convenience.
• Keep disturbed banks stable and revegetate with suitable local species where required.

Sheltering habitat: Dewatering and capture

Dewatering, channel isolation and sediment removal can trap or expose small fish. Use staged drawdown, fish exclusion and aquatic fauna salvage where required by the site assessment and approvals.

Keep captured fish in clean, oxygenated water for the shortest practical time. Release or relocate them only under the direction of the aquatic fauna ecologist and relevant approvals.

Threats: Habitat clearing and construction

Bald carp gudgeon is listed as Critically Endangered under the Commonwealth EPBC Act. Its confirmed natural range is very small, so impacts at either known creek can affect the species at a national scale.

Bank clearing, creek realignment, crossing construction, dam works and removal of aquatic or fringing vegetation can destroy shelter and feeding habitat.

Keep the work footprint out of the channel and water margins where practicable. Clearly mark exclusion zones and brief all operators before works start.

• Use existing access points and crossings where possible.
• Retain macrophytes, roots, woody debris and rocks unless removal is authorised and necessary.
• Use erosion and sediment controls before ground disturbance begins.

Threats: Water quality and altered flow

Sediment, pollutants, dewatering and altered drainage can reduce habitat quality or kill fish directly. Low-gradient pools and slow margins may be especially vulnerable during dry conditions and construction drawdown.

Maintain clean inflows, stable low flows and downstream connectivity where practicable. Inspect controls after rainfall and during each construction stage.

• Separate clean and dirty water.
• Prevent fuel, chemicals and concrete products from entering water.
• Stop work and seek ecological advice if fish are exposed, stranded or found in unexpected areas.

Threats: Drought and alien fish

Drought can affect both natural subpopulations because the two creeks are assessed as one location. Introduction or expansion of alien fish species is also a recognised risk.

Do not release aquarium fish, bait or captured fish. Apply aquatic pest controls to machinery, equipment, water and sediment moved between sites.

• Use clean, drain and dry procedures for aquatic equipment.
• Report suspected alien fish or unusual mortality through the project environmental system.
• Protect refuge pools and avoid unnecessary water extraction during dry periods.

Threats: Identification and approval risk

Carp gudgeon taxonomy is complex, and bald carp gudgeon can be missed or confused with related forms. A poor identification can lead to unsuitable clearance or salvage decisions.

The species is Critically Endangered under Commonwealth law. Obtain project-specific ecological and approvals advice before disturbing known or potential habitat, and retain survey and management records.

• Use an aquatic fauna ecologist familiar with Hypseleotris identification.
• Escalate uncertain captures for specialist or genetic identification.
• Treat occupied habitat as high sensitivity and apply the strongest practicable avoidance measures.

Survey methodology: 1. Desktop assessment

Bald carp gudgeon is a small, cryptic fish that can be confused with other carp gudgeons. Use aquatic survey methods suited to shallow, slow-flowing water, and arrange genetic confirmation where identification affects a project decision.

Map all creeks, drains, farm dams and connected wet areas within and downstream of the work area. Give particular attention to low-gradient reaches with slow or still water.

Check for macrophytes, woody debris, fringing vegetation, plant roots, rocks and other cover. Include the upper Lachlan River catchment and nearby translocated dams in the search area where relevant.

Review recent records, drought conditions, alien fish records, proposed dewatering and barriers to fish movement. Treat the two known natural creeks and any established translocated populations as highly sensitive habitat.

• Obtain current threatened species records and confirm the state or territory status before fieldwork.
• Identify all proposed access tracks, crossings, pump points, discharge points, stockpile areas and sediment control structures that could affect aquatic habitat.
• Plan surveys with a suitably experienced freshwater fish ecologist and confirm animal ethics, biosecurity and collection requirements.

Survey methodology: 2. Aquatic field survey

Survey suitable habitat using a combination of methods selected for site conditions. Suitable methods can include seine nets, dip nets, bait traps, fyke nets, electrofishing and visual searches in clear shallow water.

Search around macrophytes, woody debris, roots, rocks and shaded margins. Check backwaters and still edges as well as the main flow path.

Repeat surveys when water is accessible and conditions are suitable. Avoid relying on one visit after heavy rain, extreme drought, high turbidity or sudden changes in water level.

• Use the least disturbing method that can answer the survey question.
• Decontaminate nets, traps, waders, boats and other equipment between waterways to prevent movement of pathogens, weeds and fish.
• Follow all conditions applying to electrofishing, trapping, handling and release.

Survey methodology: 3. Identification and confirmation

Record the blunt head and the point to which dorsal scales extend. Bald carp gudgeon has no scales on the nape and lacks median fin tips, although hemiclonal fish can show variable features.

Do not rely on appearance alone where carp gudgeons are present together. Bald carp gudgeon can be morphologically similar to boofhead carp gudgeon, cryptic carp gudgeon and their hemiclonal lineages.

Arrange genetic identification for uncertain specimens, unusual records and any record that may affect clearing, referral or management decisions.

• Photograph live fish in water or in a suitable container, including the side of the body, head and dorsal fins.
• Record the capture location, date, time, method, waterbody, water depth where measured, habitat features and number of fish observed or captured.
• Keep voucher material only when authorised and when it is necessary for reliable identification. Release other fish promptly at the capture site.

Survey methodology: 4. Survey records and reporting

Record both positive and negative survey results. A negative result does not by itself demonstrate that suitable habitat is unoccupied.

Map the survey footprint and all sampled habitat. Record barriers, connected waterways, water quality concerns, alien fish and evidence of recent disturbance.

Separate natural records from fish found in translocated dams. Record whether translocated populations appear self-sustaining, without assuming that presence confirms establishment.

• Submit significant records to the relevant state database and the Australian Government species profile or records system where required.
• Retain field sheets, photographs, genetic results, permits, chain of custody records and release details.
• Escalate any suspected new population or range extension to the project ecologist and relevant conservation agency before works continue.

Before habitat disturbance: 1. Confirm approvals and permits

Plan the work around the narrow known distribution and the uncertainty caused by similar carp gudgeon lineages. Avoid aquatic habitat wherever practicable, and obtain approvals before fish are disturbed, captured, relocated or killed.

Assess whether the action is likely to have a significant impact on this Critically Endangered species or its habitat under the EPBC Act. Refer the action to the Australian Government where required.

Obtain all relevant New South Wales threatened species, fisheries, animal ethics, scientific collection, fish rescue and waterway work approvals before starting.

Queensland projects must check whether a near threatened animal listing applies and whether a species management program is required for tampering with a breeding place. Do not assume a Queensland approval pathway applies to this New South Wales species without advice from the relevant agency.

• Include aquatic habitat removal, dewatering, sediment release, barriers, altered flows and indirect downstream effects in the impact assessment.
• Check local council, water authority, fisheries, biosecurity and Aboriginal cultural heritage requirements.
• Keep approval conditions on site and brief the supervisor, spotter catcher and aquatic fauna team before mobilisation.

Before habitat disturbance: 2. Avoid and design out impacts

Keep machinery, refuelling, spoil, concrete washout and access routes out of the waterway and its riparian edge wherever practicable.

Retain slow-flowing pools, backwaters, macrophyte beds, woody debris, roots, rocks and fringing vegetation. Maintain fish passage and avoid creating isolated pools.

Use a site-specific aquatic habitat buffer based on the waterway, ground conditions, project risk and approval conditions. Mark the exclusion area clearly before works begin.

• Locate crossings at the least sensitive point and use existing disturbed access where possible.
• Stage works to minimise the duration of dewatering and isolate only the smallest practicable work area.
• Install sediment, erosion and pollution controls before soil disturbance and inspect them after rainfall and during works.

Before habitat disturbance: 3. Pre-clearance and timing

Complete a pre-clearance aquatic inspection immediately before isolation, dewatering or in-stream work. Confirm whether fish are present and whether the area provides shelter or a likely spawning or breeding place.

There is limited information on the breeding season of bald carp gudgeon. Obtain local advice and avoid in-stream disturbance during locally recognised breeding periods where practicable.

Do not describe a waterbody as clear solely because fish were not seen. Use an approved capture and rescue plan where suitable habitat will be disturbed.

• Survey connected pools, refuge areas, pump intakes, discharge points and downstream margins.
• Check dams and other artificial waters near known records, including translocation sites where relevant.
• Stop and seek advice if survey results indicate bald carp gudgeon, a new population or an active spawning area.

Before habitat disturbance: 4. Induct the work crew

Explain that bald carp gudgeon is a Critically Endangered freshwater fish and that small fish may be difficult to distinguish from other carp gudgeons.

Show photographs and the site map to machinery operators, supervisors, aquatic fauna handlers and erosion control crews.

Give the spotter catcher or aquatic fauna specialist clear authority to stop work when a fish, breeding place, pollution event or unapproved impact is identified.

• Mark no-go areas, fish rescue zones, clean equipment points and emergency contacts.
• Prohibit unauthorised netting, collecting, moving, releasing or killing of fish.
• Brief the crew on the injured animal pathway and the requirement to record all incidents.

During habitat disturbance: 1. Isolate and clear sequentially

Use a staged, supervised approach whenever water or aquatic habitat will be disturbed. Keep the aquatic fauna specialist involved from isolation through to release, and stop work whenever the approved method is no longer safe or effective.

Complete works from the least disturbed area towards the isolated section where practicable. Use fish-friendly exclusion and dewatering methods approved for the site.

Inspect the isolated area before pumping, during drawdown and after dewatering. Check shallow margins, vegetation, debris, roots, rocks, pump sumps and damp depressions.

Maintain suitable water quality and prevent sediment, fuel, chemicals, concrete or untreated water from entering the waterway.

• Use screened pump intakes and check screens regularly.
• Move rescued fish only under the approved method and release them into suitable water at the authorised release location.
• Keep rescue equipment clean and use separate equipment for separate waterways unless it has been decontaminated.

During habitat disturbance: 2. Handle fish lawfully and carefully

Only authorised and trained personnel may capture, identify, hold, sample, transport or release fish. Treat every small carp gudgeon as potentially significant until identification is resolved.

Minimise handling time. Keep fish cool, shaded and in clean, aerated water suitable for the species. Do not mix fish from different waterways unless the approved method allows it.

Do not retain bald carp gudgeon for display, photography or teaching. Follow the permit and animal ethics conditions for any genetic sample.

• Use clean, smooth, wet equipment and avoid contact with dry surfaces.
• Record capture and release locations separately and maintain a clear chain of custody for samples.
• Report mortality immediately to the project ecologist and relevant authority.

During habitat disturbance: 3. Respond to breeding places and other discoveries

If an active spawning or breeding place is found, stop the affected work area and protect it from entry, vibration, sediment and changes in water level. Obtain ecological and agency advice before restarting.

A colony or roost is not an expected feature for this fish. If another protected fauna feature is found, apply the relevant species procedure and keep the area undisturbed until advice is received.

If bald carp gudgeon or a suspected new population is found outside the approved survey area, stop nearby disturbance and arrange confirmation.

• Mark the exclusion area without entering the habitat unnecessarily.
• Do not remove eggs, larvae, adults, vegetation or shelter unless the approved rescue method specifically allows it.
• Document the location, habitat, photographs, actions taken and the name of the person who authorised the response.

During habitat disturbance: 4. Manage injured or dead animals

Stop work around an injured fish and have an authorised aquatic fauna handler assess it. Do not return a visibly injured fish to unsuitable or contaminated water.

Contact the project ecologist, wildlife or fisheries authority, or the nominated aquatic fauna veterinarian or rehabilitation service, according to the project response plan.

Treat dead fish as evidence where the cause may be project related. Preserve the specimen only as authorised and prevent scavenging or further damage.

• Record the exact location, time, apparent injury, water conditions, equipment involved and photographs.
• Report threatened species injury or mortality under the approval conditions and to the relevant agency.
• Review pumping, isolation, traffic, sediment and handling controls before work resumes.

After habitat disturbance: 1. Complete post-clearance checks

Close out aquatic works with a documented inspection and a clear record of fish outcomes. Monitoring should focus on whether habitat remains connected, suitable and free of project-related stress.

Inspect the work area, isolated pools, pump sumps, banks, downstream margins and access points after clearing or construction. Look for stranded fish, damaged habitat, barriers and pollution.

Confirm that the approved waterway profile, flow path and fish passage have been restored or maintained.

Remove temporary screens, barriers, pumps, hoses and materials only when the aquatic fauna specialist confirms that doing so will not strand fish or release sediment.

• Check for fish after water levels stabilise and before demobilising from the aquatic work area.
• Repair failed erosion or sediment controls immediately.
• Record any residual impact and refer it to the environmental manager.

After habitat disturbance: 2. Report outcomes

Prepare a fauna report covering survey methods, effort, conditions, captures, identifications, genetic samples, releases, mortalities, incidents and approval conditions.

Map all bald carp gudgeon records and distinguish natural creeks from translocated dams. State whether the result is confirmed, suspected or unresolved.

Report any breach, unexpected impact, new record or failure of a mitigation measure within the timeframe required by the approval.

• Provide records to the relevant conservation, fisheries and project authorities.
• Retain photographs, field sheets, laboratory results, permits and release records with the project environmental file.
• Update the risk assessment and method statement before similar work occurs elsewhere on the project.

After habitat disturbance: 3. Monitor relocated and retained habitat

Where fish were relocated, inspect the release habitat for survival, connectivity, water quality, cover and signs of alien fish. Do not assume that a translocated population is established or self-sustaining.

Use monitoring methods that can detect small, cryptic fish and that are consistent between visits. Include genetic confirmation where carp gudgeon identity is uncertain.

Continue monitoring for the period required by approvals and the project risk assessment, with extra checks after drought, fish kills, pollution or major flow changes.

• Record effort as well as results so changes in detection can be interpreted.
• Compare relocated sites with nearby retained habitat where a suitable reference site is available.
• Escalate declining detections, loss of cover, isolation or alien fish expansion to the relevant ecologist and agency.

After habitat disturbance: 4. Review the incident and controls

Hold a short review after aquatic disturbance, especially after a fish rescue, mortality, unplanned dewatering or pollution event.

Identify whether the cause was design, timing, equipment, supervision, induction, water quality or communication.

Update exclusion zones, sequencing, rescue methods and crew training before the next work stage.

• Share the review with supervisors, fauna handlers, machinery operators and subcontractors.
• Track corrective actions to completion and retain evidence of close out.
• Use lessons from each work area to improve controls at the next waterway.

Rehabilitation actions: 1. Restore aquatic habitat

Rehabilitate aquatic habitat for the fish community rather than installing generic fauna structures. Bald carp gudgeon uses aquatic cover and shallow, slow or still water, so restoration should focus on water quality, shelter, connectivity and stable banks.

Reinstate a natural-looking flow path, shallow margins and low-gradient habitat where these features have been disturbed. Retain or replace suitable macrophytes, woody debris, roots, rocks and fringing vegetation.

Reconnect isolated pools and maintain fish passage where the project has altered a crossing, bank or channel. Remove temporary barriers when safe and authorised.

Use clean, local materials and avoid introducing plants, soil, water or fish from another catchment.

• Stabilise banks with vegetation and low-impact erosion controls rather than hardening the channel unnecessarily.
• Stage revegetation so bare soil is not left exposed to rainfall or flowing water.
• Inspect restored habitat after rainfall and during the first suitable low-flow period.

Rehabilitation actions: 2. Restore water quality and weeds

Prevent sediment, nutrients, chemicals, concrete washout and contaminated runoff from entering the waterway. Maintain controls until vegetation is established and the site is stable.

Remove invasive weeds using methods that protect fish, aquatic plants and water quality. Avoid herbicide entry to water and follow label, approval and riparian restrictions.

Manage stock access, vehicle access and trampling around restored margins.

• Use locally appropriate native riparian plants and protect them from browsing where needed.
• Keep shade, cover and natural debris where they support aquatic habitat.
• Record weed treatment, chemical use, water quality incidents and follow-up inspections.

Rehabilitation actions: 3. Consider replacement features carefully

Nest boxes, bat boxes, artificial nest sites and roost structures are not appropriate substitutes for bald carp gudgeon habitat. Do not install them as a standard response for this species.

Where a project affects fish shelter or spawning habitat, replace the lost aquatic function with suitable shallow water, cover, vegetation, woody material and stable banks, subject to ecological and agency advice.

Use artificial aquatic structures only where a qualified fish ecologist has shown that they suit the local waterway and will not trap fish, obstruct passage or create poor water quality.

• Do not place structures in the channel without approval and a maintenance plan.
• Inspect any installed aquatic feature for blockage, entrapment, scour, weeds and alien fish.
• Remove or modify a feature if monitoring shows that it causes harm or provides no habitat benefit.

Rehabilitation actions: 4. Monitor rehabilitation

Set monitoring objectives for habitat condition, water quality, fish passage, cover, weeds and bald carp gudgeon detection where the species may occur.

Use repeatable survey methods and record effort, flow conditions and detection results. Include genetic confirmation when carp gudgeon identity is uncertain.

Continue monitoring for the period required by approval conditions and until rehabilitation is stable. Increase monitoring after drought, flood, pollution or major maintenance.

• Compare results with the pre-work survey and a suitable reference reach where available.
• Inspect restored banks, macrophytes, woody debris and exclusion fencing at planned intervals.
• Treat loss of cover, sediment deposition, barriers, alien fish or declining detections as triggers for corrective action.

Rehabilitation actions: 5. Manage lighting and long-term disturbance

Keep artificial lighting away from creek margins and shallow water where practicable. Use the lowest effective intensity, direct lights away from the water and switch off unnecessary lights.

Control night access, vehicle crossings, noise, vibration and maintenance activities near retained habitat.

Include aquatic habitat protection in the long-term site environmental management plan.

• Use physical screening or shielding where lighting cannot be avoided.
• Schedule maintenance to avoid unnecessary disturbance to water and riparian vegetation.
• Review controls when land use, water extraction, drainage or nearby development changes.

Sources

• Department of Climate Change, Energy, the Environment and Water, Australian Government DCCEEW: http://www.environment.gov.au/biodiversity/threatened/species/pubs/92610-conservation-advice-07092023.pdf
• Occurrence records for the distribution map, Atlas of Living Australia: https://biocache.ala.org.au/