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Kosciuszko Galaxias (Galaxias supremus)

The Kosciuszko Galaxias is a small, non-migratory freshwater fish known only from cold alpine streams and Blue Lake in Kosciuszko National Park, New South Wales. It is Critically Endangered, with a very small range and isolated subpopulations that are highly sensitive to trout invasion, sediment, altered flows and damage to stream banks or lake margins during project works.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Breeding season

The species is non-migratory and remains in alpine freshwater habitat throughout the year. Breeding timing is inferred rather than confirmed, and the timing of juvenile development is not documented.

Month values are January to December: 0 means not typical, 1 means occurs or risk is present, and 2 means the likely peak. Breeding and young-season timing is inferred because detailed reproductive studies have not been completed.

  • Breeding: Spawning probably occurs from very late spring to early summer, with November and December shown as the likely peak period. Exact timing is unknown.
  • Young: The timing of eggs, larvae, juveniles and dependent young is not documented. This row shows the period immediately following the probable spawning season only as an indication, not a confirmed life-cycle schedule.
  • Winter snow and ice: Known sites are covered by snow and ice for an extended period during winter. Water temperature can fall below 2 degrees Celsius.
  • Highest clearing risk: Occupied habitat is sensitive to disturbance in every month because the species is restricted to a few permanent waterways. Risk is highest in November and December because spawning probably occurs from very late spring to early summer. Sediment, flow alteration, barrier damage and trout access can harm fish at any time.

Identification

The Kosciuszko Galaxias is a small, slender galaxiid that is difficult to distinguish from other members of the Galaxias olidus complex without close examination. Identification should be confirmed by an appropriately qualified freshwater fish ecologist, particularly because the species can hybridise with G. olidus.

Adults average 80 to 85 mm in length and have been recorded to 96 mm. The body has a distinctive mottled pattern and lacks the black, ovoid bars commonly used to recognise some related upland galaxiids.

Diagnostic features include eight pelvic fin rays, a short lower jaw, relatively shallow body depth, a short and shallow caudal peduncle, a long snout and small eyes. The dorsal and anal fins are short, and the anal fin is set well back, at about 85 percent of the distance from the front of the dorsal fin.

Average recorded length: 80 to 85 mm

Maximum recorded length: 96 mm

Maximum published weight: 8.00 g

Identification: Distinguishing it from similar fish

The species is morphologically very similar to other members of the Galaxias olidus complex. A mottled body without black lateral bars, eight pelvic fin rays, the long snout, small eyes and the far-back position of the anal fin should be assessed together rather than used as isolated characters.

Kosciuszko Galaxias is known to hybridise with G. olidus. Fish from the upper Snowy catchment that do not match the diagnostic combination should be treated as requiring specialist confirmation.

  • Do not rely on colour pattern alone when distinguishing this species from other upland galaxiids.
  • Record the location, waterbody, photographs and handling details for any suspected individual and submit the record to the relevant NSW threatened species authority.
  • Do not retain, relocate or release fish during project works unless this is authorised under the relevant approval and undertaken under an approved translocation or salvage procedure.

Identification: Field signs and sex

There are no documented species-specific tracks, scats, calls, nests, burrows, sloughs or eyeshine signs. Detection depends on observing or sampling fish in suitable permanent, cold and clear water.

The supplied documents do not provide reliable external features for separating males and females in the field. Sex-specific size, behaviour and habitat information are not established.

  • Treat permanent alpine creeks, pools, lake margins and inflowing tributaries as potential habitat where the species may occur, even when fish are not immediately observed.
  • Use aquatic fauna survey methods approved for the site and threatened species status, with appropriate hygiene and disinfection controls between waterways.

Distribution: National range

The Kosciuszko Galaxias has an extremely restricted distribution in the Australian alpine region. All confirmed sites are in New South Wales, within Kosciuszko National Park.

In Australia, the species is known only from a small number of sites in the upper Snowy River catchment near Mount Kosciuszko and from an unnamed drainage line on the upper slopes of Mount Kosciuszko near Rawson's Pass.

The documented range falls within the alpine Australian Alps and Snowy Mountains area of NSW. No confirmed records are provided from Victoria, the Australian Capital Territory, Queensland, South Australia, Western Australia, Tasmania or the Northern Territory.

Known state range: New South Wales only

Elevation: 1900 to 2150 m above sea level

Area of occupancy: 20 km2

Extent of occurrence: Measured as 10 km2, but treated as 20 km2 because it was smaller than the area of occupancy

Distribution: Strongholds and subpopulations

Four small subpopulations are recognised. They are considered isolated by trout in connecting and downstream waterways, which restrict the species to very upper reaches of tributary streams.

Confirmed habitat includes upper Snowy River tributaries, Carruthers Creek, Blue Lake Creek and Blue Lake. Hybrids between Kosciuszko Galaxias and G. olidus were recorded at Sawpit Creek, a tributary of the Thredbo River, indicating that the species or its genetic material may occur more widely than confirmed records show.

Known subpopulations: Four small, isolated subpopulations

Additional site: Hybrids were recorded at Sawpit Creek in 2002

Population size: No reliable estimate of total abundance or mature individuals is available

Population trend: Not quantified, but continuing decline in distribution and habitat quality is projected

Habitat: Waterways and lake margins

Kosciuszko Galaxias occupies permanent, cold and clear alpine freshwater. Its known habitat includes small flowing creeks and the shoreline of a deep cirque lake, with no documented requirement for aquatic vegetation or overhead canopy.

The species has been collected from small flowing creeks with an average width of 0.6 to 1.1 m, an average depth of 0.1 to 0.2 m and a maximum depth of 0.5 to 0.6 m.

It has also been recorded in Blue Lake, a 16 ha, 28 m deep cirque lake. Fish have been collected among small cobbles and within 2 m of the shoreline, but habitat use in deeper water is unknown.

Creek width: 0.6 to 1.1 m average

Creek depth: 0.1 to 0.2 m average; 0.5 to 0.6 m maximum

Blue Lake: 16 ha surface area and 28 m depth

  • Protect permanent stream pools, shallow runs, undercut banks, rocky margins and the first 2 m of lake shoreline from direct disturbance.
  • Maintain clear, cold water and natural flow paths during clearing, construction, track works and infrastructure maintenance.
  • Prevent sediment, ash, fuel, concrete washout and other pollutants from entering occupied or potential habitat.

Habitat: Substrate and climate

Creek substrates include bedrock, boulder, cobble, gravel and sand. Fish have been found among rocks, in pools, undercut banks and beneath overhanging grasses.

All known sites are covered by snow and ice for an extended period during winter. The species can tolerate water colder than 2 degrees Celsius. Its upper thermal tolerance is expected to be below 33 degrees Celsius and may be reduced when dissolved oxygen falls or ash and sediment enter the water.

  • Avoid removing or rearranging bedrock, boulders, cobbles and gravel in occupied stream habitat.
  • Keep machinery, spoil, access tracks and stockpiles out of stream beds, banks, lake margins and overhanging grass cover.
  • Design erosion and drainage controls for high-intensity rainfall and post-fire runoff, not only normal flows.

Foraging habitat

The diet and detailed feeding behaviour of Kosciuszko Galaxias have not been studied in detail. Project planning should therefore protect the shallow rocky and edge habitats used by the species and the water quality that supports its aquatic prey.

The supplied documents do not identify particular prey, food plants or feeding rates for Kosciuszko Galaxias. Fish are collected mainly from pools, among rocks and cobbles, near undercut banks, beneath overhanging grasses and within 2 m of the Blue Lake shoreline.

As a small benthopelagic freshwater fish, it is likely to feed within the water column and near the bed, but the documents do not provide sufficient species-specific evidence to describe its diet or foraging range.

Diet: Not documented for this species

Known feeding areas: Pools, rocky stream margins, undercut banks, overhanging grasses and within 2 m of the Blue Lake shoreline

Foraging range: Not documented; the species is non-migratory

  • Retain natural bed material, shallow pools, undercut banks, overhanging grass and lake-edge cobble where works occur near potential habitat.
  • Prevent fine sediment and ash from smothering the stream bed, reducing water quality or altering aquatic prey communities.
  • Do not infer absence from a lack of visible fish during a single inspection, because the species may shelter among substrate or in shallow pools.

Breeding habitat

Breeding biology is poorly known and is inferred mainly from related members of the Galaxias olidus complex. Breeding habitat requirements for eggs, larvae and juveniles have not been defined.

Spawning probably occurs from very late spring to early summer. The species is not considered to undertake migration as part of its life cycle, so breeding is expected to occur within or near its resident creek and lake habitats.

Known habitat features that should be retained during the breeding period include permanent flow, cold clear water, rocky and gravel substrates, pools, undercut banks, overhanging grasses and cobbled lake margins.

Breeding season: Probably very late spring to early summer, approximately November to December; exact timing is unknown

Clutch or litter size: Unknown

Gestation or incubation: Unknown

Age at maturity: Unknown

Lifespan: Unknown

Generation length: Estimated at 3 or 4 years

  • Avoid in-water works, bank disturbance, dewatering and sediment-producing activities in occupied habitat during the likely late spring to early summer spawning period.
  • Maintain connection between shallow pools and flowing water, while retaining natural barriers that currently limit trout access.
  • Obtain specialist advice before any fish salvage, relocation, barrier modification or works that could alter flow through known habitat.

Sheltering habitat: Known refuges

The species has no known terrestrial refuge, den or nest. Shelter is provided by aquatic substrate and stream-edge structure, especially in shallow pools and along rocky margins.

In creeks, fish have been collected among rock, in pools, beneath undercut banks and beneath overhanging grasses. In Blue Lake, fish have been collected among small cobbles and within 2 m of the shoreline.

The documents do not provide refuge dimensions, minimum cover sizes or life-stage-specific shelter requirements. They also do not record the use of aquatic vegetation, emergent vegetation or overhead canopy, and known sites generally lack these features.

Creek refuges: Rock, pools, undercut banks and overhanging grasses

Lake refuges: Small cobbles and shoreline habitat within 2 m of the margin

Known refuge size: Not specified

Winter conditions: Known sites are covered by snow and ice for an extended period

  • Retain undercut banks, stable banks, rocky cover, cobbles, pools and overhanging grasses within and beside occupied waterways.
  • Do not place temporary crossings, pumps, hoses, sediment fences or construction materials where they block shallow refuge areas or fish passage.
  • Keep disturbance and vibration away from stream beds and lake margins wherever practicable, particularly during the likely breeding period.

Threats: Introduced fish

The species has a very small, fragmented range, so disturbance at one site can affect a substantial part of the global population. Project risks include direct damage to stream and lake habitat, sediment and pollutant entry, altered flows and accidental movement of trout or other aquatic organisms.

Brown Trout and Rainbow Trout are the major and most imminent threat. Trout prey on galaxiids, compete with them and isolate subpopulations by occupying connecting waterways.

Trout are abundant through much of the upper Snowy River catchment. If they pass existing waterfall barriers or are illegally stocked above them, affected Kosciuszko Galaxias subpopulations could decline rapidly or become extinct.

Principal threat: Introduction and spread of trout into occupied waterways

Documented risk: Galaxiid subpopulations can be rapidly reduced or extirpated after salmonid invasion

  • Do not move water, fish, aquatic plants, mud or equipment between catchments without following approved aquatic hygiene and fish movement controls.
  • Do not alter natural waterfalls, fish barriers or flow paths without assessing the risk of creating trout access.
  • Report suspected illegal stocking or trout incursions to the relevant NSW authority.

Threats: Habitat damage and hydrology

Feral horses damage stream banks, wetlands and riparian areas through trampling, pugging, crossings and sedimentation. These impacts overlap much of the species' known distribution.

Clearing, earthworks, road crossings, drainage works and construction near occupied waterways can remove bank cover, destabilise substrates, increase sediment delivery or change the depth and flow of small streams. The species is dependent on permanent cold and clear water, so dewatering and changes to catchment runoff are direct risks.

  • Keep clearing limits, access routes, spoil and machinery outside stream beds, banks, pools and lake margins.
  • Use site-specific erosion and sediment controls before ground disturbance starts, and inspect them after rainfall.
  • Avoid concentrating runoff into small alpine creeks or allowing untreated water from excavations, roads or compounds to enter habitat.
  • Do not remove rock, cobble, gravel, undercut banks or overhanging grass from occupied habitat unless specifically approved and mitigated.

Threats: Fire, drought and extreme weather

More intense or frequent bushfires can heat small streams, cause fish mortality and deliver ash and sediment during post-fire rainfall. Ash and sediment can smother substrates and alter water chemistry, dissolved oxygen, riparian cover and organic inputs.

Drought and higher temperatures can reduce surface water, remove refuge habitat and increase thermal stress. Severe storms and floods can increase erosion, sedimentation and the chance that trout pass or damage existing barriers.

Post-fire sediment risk: Sedimentation can affect waterways 50 to 80 km downstream of burned areas

Thermal tolerance: The upper thermal tolerance is expected to be below 33 degrees Celsius and may decline with reduced dissolved oxygen

  • After fire, inspect catchments upstream of known habitat and implement measures that reduce ash and sediment delivery before forecast rainfall.
  • Treat post-fire runoff, intense rainfall and barrier damage as triggers for ecological inspection and consultation with the relevant threatened fish authority.
  • Maintain natural cold-water refuges and avoid activities that further reduce flow or dissolved oxygen during hot, dry conditions.

Threats: Fragmentation, genetics and other risks

Four small, isolated subpopulations are vulnerable to inbreeding, loss of genetic diversity and reduced capacity to adapt. The species has little opportunity for natural recolonisation if a local subpopulation is lost.

Potential illegal collection or harvest is also identified as a threat. The supplied documents do not identify a species-specific disease threat, but handling, salvage and translocation can spread aquatic pathogens if hygiene controls are not followed.

Known isolation: Four subpopulations are considered isolated from one another

Genetic risk: Small population size and isolation may cause inbreeding and loss of evolutionary potential

  • Treat every known or potential population as significant because population abundance is not known and the total range is very small.
  • Do not collect or handle fish without the required approvals, permits and qualified personnel.
  • Use clean, disinfected equipment between waterways and follow the project's approved aquatic fauna hygiene procedure.

Survey methodology: 1. Define the survey area and habitat

Kosciuszko Galaxias is a small, non-migratory freshwater fish known from permanent, cold, clear creeks and Blue Lake in Kosciuszko National Park. The supplied documents do not provide a species-specific survey guideline or prescribed survey effort, so survey design should be set by a qualified aquatic ecologist and approved by the relevant authority.

Known range: Upper Snowy River catchment and an unnamed drainage line near Rawson’s Pass, all within Kosciuszko National Park, New South Wales.

Known locations: Four small, isolated subpopulations are used in the assessment, with a fifth site producing hybrids with Galaxias olidus.

Recorded range metrics: Area of Occupancy 20 km2 and Extent of Occurrence 20 km2 for assessment purposes.

  • Map all permanent and potentially perennial streams, pools, lake margins, tributaries, drainage lines and downstream habitat that could receive sediment or altered flows from the project.
  • Inspect habitat from 1900 to 2150 metres above sea level where the project overlaps the upper Snowy River catchment near Mount Kosciuszko or the upper slopes near Rawson’s Pass.
  • Record creek width, depth, flow, substrate, bank condition, water temperature, dissolved oxygen, turbidity and evidence of trout or other introduced fish.
  • Give particular attention to small flowing creeks about 0.6 to 1.1 metres wide, 0.1 to 0.2 metres average depth and up to 0.5 to 0.6 metres maximum depth.
  • Search amongst bedrock, boulder, cobble, gravel, sand, undercut banks and overhanging grasses, and within 2 metres of the Blue Lake shoreline.
  • Treat all connected downstream and upstream habitat as relevant because trout, sediment and altered flows can affect isolated subpopulations.

Survey methodology: 2. Aquatic fish survey

Body size: Average recorded length is 80 to 85 mm, with a maximum recorded length of 96 mm.

Activity and life cycle: The species is non-migratory, with an estimated generation length of 3 or 4 years.

Spawning period: The spawning period is unknown but is inferred to probably occur from very late spring to early summer.

  • Use an aquatic fish survey method suitable for cold, clear, shallow streams, such as backpack electrofishing, seine or dip-net sampling, visual searches and environmental DNA, only where the method is authorised and safe for the site.
  • Set sampling reaches to cover representative pools, runs, undercut banks, cobble margins, tributary junctions and any habitat that could be affected by the works.
  • Survey both the proposed disturbance area and suitable retained habitat upstream and downstream, including areas that could receive sediment or provide relocation habitat.
  • Record survey date, start and finish time, weather, water level, flow, water temperature, dissolved oxygen, turbidity, method, equipment settings, reach length, area searched, operator names and all fish captured or observed.
  • Identify captured fish using the diagnostic combination of eight pelvic fin rays, a mottled pattern without black ovoid side bars, a short lower jaw, shallow body, long snout and small eyes, while recognising that the species is morphologically similar to other upland galaxiids.
  • Photograph representative fish where this can be done without prolonged handling, and retain voucher material only under the relevant approval.

Survey methodology: 3. Timing, conditions and detection limits

Cold tolerance: The species can withstand water below 2 degrees Celsius in winter.

Expected upper thermal tolerance: Less than 33 degrees Celsius, with tolerance reduced by low dissolved oxygen and ash or sediment exposure.

Survey guideline supplied: No species-specific nights, hours, trap nights, transect lengths or area-based effort is prescribed in the supplied documents.

  • Complete surveys when the waterway is flowing and accessible, and include the period from very late spring to early summer if the project could affect spawning habitat.
  • Avoid sampling during unsafe high flows, severe storms, heavy sediment movement or conditions that could damage the habitat or increase fish stress.
  • Record whether snow, ice, drought, low flow, elevated temperature, ash or sediment could have reduced detectability or affected fish distribution.
  • Do not treat a negative survey as proof of absence because the species has a very small range, small isolated populations, unknown life-stage habitat requirements and limited ecological study.
  • Use repeat sampling or additional methods where habitat is suitable but the first survey produces no fish, with the effort determined and documented by the aquatic ecologist.
  • Survey for trout and other introduced fish at barriers, downstream reaches and connecting waterways because trout can isolate subpopulations and cause rapid local declines.

Survey methodology: Minimum effort and reporting

  • Prepare a written survey plan that states the aquatic methods, reach lengths or areas, repeat visits, seasonal timing, site conditions, detection limitations and approvals before fieldwork starts.
  • Use experienced aquatic fauna personnel who can distinguish Kosciuszko Galaxias from other members of the Galaxias olidus complex and who hold any required electrofishing or animal ethics authority.
  • Submit verified records, including negative survey results where relevant, to the relevant state wildlife or biodiversity database and provide records to the project approval authority.
  • Report any suspected Kosciuszko Galaxias record promptly to the relevant state fisheries or threatened species agency, particularly where the record is outside the known range.
  • Keep georeferenced photographs, field sheets, water-quality data, capture records, tissue or voucher approvals and chain-of-custody information with the project environmental records.

Before habitat disturbance: 1. Avoid and minimise habitat impacts

Treat any suitable cold, clear aquatic habitat as potentially occupied until an approved assessment shows otherwise. The species is nationally listed as Critically Endangered and has a very restricted distribution, so avoid direct disturbance and prevent trout, sediment and altered flows from reaching occupied or suitable habitat.

Primary threat: Introduction, spread and establishment of trout, particularly Brown Trout and Rainbow Trout.

Known trout risk: Trout are abundant through much of the Snowy River and restrict Kosciuszko Galaxias to upper reaches.

Fire and sediment risk: Ash and sediment can smother substrates, alter water chemistry and severely affect aquatic fauna.

  • Redesign the project to avoid permanent creeks, Blue Lake shoreline habitat, tributaries, undercut banks, cobble margins, pools and other suitable habitat wherever practicable.
  • Keep machinery, storage areas, access tracks, spoil, fuels, concrete washout and drainage outlets out of the waterway and its contributing drainage lines.
  • Maintain natural flow paths, cold clear water, bedrock, boulder, cobble, gravel and sand substrates, overhanging grasses and undercut banks.
  • Maintain connectivity between retained reaches while recognising that existing trout populations already isolate the four known subpopulations.
  • Prevent any new fish passage pathway that could allow trout to move upstream, including temporary bypass channels, damaged barriers or high-flow scour around works.
  • Do not stock, release, move or use live trout or other fish near the project, and control fishing access and equipment hygiene where unauthorised fish movement is a risk.

Before habitat disturbance: 2. Approvals and project planning

EPBC status: Critically Endangered, effective from 25 March 2023.

Recovery plan: The Australian Government advice does not recommend an EPBC Act recovery plan because the approved conservation advice is considered sufficient direction for priority actions.

  • Check whether the action is likely to significantly affect this nationally listed species or its habitat and refer the action under the EPBC Act where required.
  • Obtain all relevant state fisheries, threatened species, national park, animal ethics, electrofishing, handling, translocation and release approvals before survey, capture or relocation work.
  • Confirm the current listing and approval requirements with the relevant state agency because the supplied NSW documents identify the species as Critically Endangered in NSW.
  • Prepare a species-specific fauna management plan covering survey, exclusion, rescue, handling, relocation, injury response, stop-work triggers, water-quality controls and reporting.
  • Stage works outside the inferred late spring to early summer spawning period where practicable, and obtain agency advice if works cannot be avoided during that period.
  • Include emergency responses for fire, ash, sediment pulses, drought, high temperatures, severe storms, flooding and trout incursions.

Before habitat disturbance: 3. Pre-clearance and site preparation

  • Complete the approved aquatic survey before ground disturbance, including any upstream, downstream or off-site habitat that could receive project runoff.
  • Mark no-go aquatic habitat, retained banks, pools, undercut banks, cobble margins, lake shoreline habitat, drainage lines and exclusion zones on plans and in the field.
  • Install exclusion fencing or equivalent controls where they can prevent machinery, people, spoil and sediment from entering the retained habitat without diverting natural flow.
  • Stabilise access points, stockpiles, batters and drainage controls before clearing, and design sediment controls for intense rainfall and post-fire conditions.
  • Inspect all machinery, pumps, hoses, nets, footwear and containers to prevent transfer of trout, fish pathogens, mud, ash or sediment between waterways.
  • Brief all workers and spotter catchers on the species’ appearance, restricted distribution, legal status, no-go areas, reporting requirements and stop-work triggers.

During habitat disturbance: 1. Daily controls and machinery coordination

Use a low-impact work system that keeps machinery and sediment away from aquatic habitat. The fauna spotter catcher must have authority to stop work and must work with the aquatic ecologist and machine operators, not after the disturbance has occurred.

  • Hold a daily pre-start briefing covering the work area, retained habitat, weather, water levels, sediment controls, fauna personnel and emergency contacts.
  • Inspect exclusion fencing, silt controls, diversion structures, pumps, crossings, fuel storage and drainage before work starts and after rain or high flows.
  • Keep machinery outside marked aquatic exclusion areas unless the approved method specifically permits entry and an aquatic fauna supervisor is present.
  • Use a spotter catcher to check the immediate work area and any dewatered or isolated pool before machinery enters, shifts substrate or removes bank material.
  • Stop machinery immediately on the fauna spotter catcher’s instruction, and do not restart until the animal, habitat feature or hazard has been assessed and cleared.
  • Prevent concrete, hydrocarbons, chemicals, wash water, sediment, ash and turbid water from entering the waterway.

During habitat disturbance: 2. Handling fish and aquatic habitat

Relocation planning: The conservation advice recommends surveys for suitable translocation sites, trout removal where required, genetic analysis and a detailed translocation plan.

Known habitat: Fish have been collected among rock, undercut banks and overhanging grasses, and within 2 metres of the Blue Lake shoreline.

  • Do not handle Kosciuszko Galaxias unless the person is authorised under the project approvals and is competent in threatened fish capture and handling.
  • If fish must be captured, use the least stressful approved method, minimise air exposure and handling time, keep fish in suitable clean water, and record capture location and condition.
  • Do not move fish between catchments or release them into unapproved habitat, and do not relocate them across trout barriers without written approval and an approved translocation plan.
  • Relocate animals only to nearby, retained, suitable habitat approved by the aquatic ecologist and relevant agency, with water temperature and chemistry considered.
  • Stop work if dewatering, isolation, turbidity, temperature change, low dissolved oxygen, ash or sediment threatens fish or prevents safe capture.
  • Return bedrock, boulders, cobbles, gravel, sand, undercut bank material and overhanging grass habitat only under an approved aquatic rehabilitation method.

During habitat disturbance: 3. Fauna response and stop-work triggers

  • If a Kosciuszko Galaxias is found, stop the relevant work, protect the location from vibration, sediment and machinery, photograph the fish if safe, and contact the authorised aquatic fauna supervisor.
  • Use only the approved project response for capture, temporary holding and relocation, and keep unauthorised workers from handling or collecting the fish.
  • Send injured fish to the nominated aquatic veterinarian, wildlife carer or agency contact under the approved emergency procedure, and record the transfer and outcome.
  • Stop work for any fish mortality, fish distress, unexpected Kosciuszko Galaxias record, trout upstream of a recognised barrier, major sediment discharge, dewatering failure, chemical spill, ash pulse, fish passage blockage or barrier damage.
  • Stop work when weather, fire, drought, high temperature, severe storm or flooding creates a material risk to water quality, fish survival or safe fauna handling.
  • Resume only after the aquatic ecologist and the relevant approval holder have documented the cause, controls, clearance decision and any required agency notification.

During habitat disturbance: 4. Records and incident reporting

  • Record every fauna inspection, capture, observation, mortality, relocation, injury, trout detection, water-quality exceedance, stop-work event and control failure.
  • For each record, include date, time, location, coordinates, habitat, weather, water level, method, personnel, photographs, fish condition, action taken and approval reference.
  • Record the number and condition of all fish handled, even where the species identification is uncertain and the animal is released.
  • Report suspected illegal stocking, fish collection, habitat damage or unauthorised release to the relevant NSW fisheries or threatened species authority.
  • Provide daily environmental records and a final fauna report to the project manager, ecologist, approval authority and relevant wildlife database.

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

Completion of construction does not end the risk. Check that the waterway remains connected, cold and clear, that retained habitat has not been buried or altered, and that sediment, trout and flow controls remain effective through the first high-flow events.

  • Inspect the full work area and adjacent upstream and downstream habitat for stranded fish, mortality, sediment deposition, altered banks, damaged barriers, blocked flow paths and turbid discharges.
  • Complete a post-clearance aquatic fauna check of isolated pools, dewatered areas, temporary channels, culverts, crossings and disturbed shoreline habitat before demobilisation.
  • Remove temporary barriers, pipes, pumps, spoil and construction materials without releasing trapped sediment or fish and without creating a trout passage pathway.
  • Confirm that retained creek substrate, undercut banks, overhanging grasses, cobble margins, pools and lake shoreline habitat remain available.
  • Repair erosion, scour, bank damage, drainage failures and sediment controls before the site is signed off.

After habitat disturbance: 2. Monitoring and maintenance

Post-fire sediment reach: The assessment reports that post-fire sedimentation can affect waterways 50 to 80 km downstream of burnt areas.

  • Monitor water quality, flow, sediment deposition, bank stability, fish passage and trout presence at a frequency set by the approval and risk assessment.
  • Inspect after intense rainfall, flooding, wildfire, ash runoff or other events that could move sediment, damage barriers or open a pathway for trout.
  • Repeat targeted fish surveys where the project affected occupied or suitable habitat, with the method, timing and effort approved by the aquatic ecologist.
  • Compare monitoring results with pre-work records for habitat condition, water quality, fish detections and trout detections.
  • Maintain exclusion fencing, sediment controls, drainage structures, crossings and fish passage controls until the site is stable and the approval authority accepts their removal.

After habitat disturbance: 3. Reporting and offsets

  • Submit the completion report and monitoring results to the relevant approval authority and state biodiversity or fisheries database.
  • Report any new population, suspected hybrid, fish mortality, trout incursion or range extension promptly to the relevant agency.
  • Where residual impacts cannot be avoided or mitigated, obtain advice on EPBC Act offsets, state biodiversity requirements and any approval-specific compensatory actions before finalising the project.
  • Do not use an offset as a substitute for avoiding direct impacts to occupied habitat or preventing trout, sediment and altered flows from reaching the species.

Rehabilitation actions: 1. Restore aquatic and riparian habitat

Rehabilitation should restore cold, clear, permanent aquatic habitat and reduce the pathways by which trout, sediment, heat and altered flows affect isolated subpopulations. Use local reference sites and an aquatic ecologist to set the design and success criteria.

  • Re-establish natural creek banks, shallow pools, runs, undercut margins and flow paths rather than creating uniform, deep or artificial channels.
  • Use locally sourced native riparian plants suited to the high-elevation Snowy Mountains environment, and avoid species or materials that shade, smother or alter the cold clear-water habitat.
  • Reinstate suitable bedrock, boulder, cobble, gravel and sand where construction removed or buried those substrates.
  • Retain or replace overhanging grasses and bank structure that provide cover, while recognising that the known sites lack emergent and submerged aquatic vegetation and overhead shading.
  • Restore Blue Lake shoreline habitat within 2 metres of the water’s edge where it has been disturbed, using natural cobble, pebble, gravel and silt conditions as reference features.
  • Do not add logs, woody debris, nest boxes or artificial hollows unless an aquatic ecologist confirms that they are appropriate for the site and will not obstruct fish passage or increase sediment retention.

Rehabilitation actions: 2. Control sediment, weeds and predators

Feral horse pressure: Feral horse distribution in Kosciuszko National Park overlaps much of the species’ distribution.

Horse impacts: Documented risks include stream-bank damage, pugging, crossings, sedimentation and alteration of riparian vegetation.

  • Stabilise bare ground, drainage lines and banks to prevent sediment from entering occupied or suitable streams after rain.
  • Control weeds using methods approved for aquatic and high-elevation environments, and prevent herbicide, mulch and soil from entering the waterway.
  • Manage feral horse access and damage across the project area because horses can pug stream banks, increase erosion and sedimentation, alter riparian vegetation and damage wetlands and drainage lines.
  • Inspect and maintain fish barriers where approved, and remove trout from suitable conservation or translocation sites only under an authorised management plan.
  • Do not release or stock salmonids, and include equipment hygiene and public access controls where they reduce the risk of fish transfer.

Rehabilitation actions: 3. Fire and climate resilience

Climate risks identified: Increasing wildfire intensity, drought, elevated temperatures, severe storms and flooding are identified as threats.

Fire effect: A single bushfire could affect a large part of the species’ range and cause rapid decline or local extirpation.

  • Design drainage, erosion and sediment controls to limit ash and sediment entry after wildfire and intense rainfall.
  • Protect cold-water refuges and maintain adequate flow during drought and elevated temperatures where this is within the project’s control.
  • Inspect the site after fire, drought, severe storms and flooding for fish mortality, water-temperature change, low dissolved oxygen, sediment deposition and barrier damage.
  • Use emergency extraction or relocation only where the approved response identifies unsafe post-fire temperature, oxygen, ash or sediment conditions and authorised personnel are available.
  • Avoid creating temporary or permanent pathways that allow trout to pass upstream when high flows drown out or damage existing barriers.

Rehabilitation actions: 4. Success measures and monitoring

Recommended conservation actions: The assessment recommends monitoring known populations, surveys for new populations, ecological studies, captive management, genetic analysis and authorised translocations to spread extinction risk.

  • Set measurable rehabilitation targets for stable banks, functioning flow paths, low turbidity, retained cold-water conditions, restored substrate, effective fish passage controls and absence of trout in protected reaches.
  • Monitor rehabilitated habitat against pre-work photographs, water-quality data, substrate descriptions and fish survey results.
  • Undertake follow-up surveys for Kosciuszko Galaxias and other galaxiids using approved methods, and investigate any decline or failure to detect fish in previously occupied habitat.
  • Record survival of plantings, erosion, weed cover, horse damage, sediment movement, barrier condition and trout detections after rainfall and at other approval-specified intervals.
  • Continue monitoring until the aquatic ecologist and approval authority agree that the habitat is stable and the agreed success measures have been met.

Sources