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Short-tail Galaxias (Galaxias brevissimus)

The Short-tail Galaxias is a small, non-migratory freshwater fish known only from four patchily distributed localities in the upper Tuross River system of southern coastal New South Wales, above 900 m elevation. It is Critically Endangered and is highly sensitive to stream disturbance, sedimentation, altered flows, fire impacts and introduced trout, so works near suitable creeks require careful aquatic habitat assessment and controls on sediment and fish passage.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Breeding season

The species is non-migratory and remains in freshwater streams throughout the year. Breeding timing is inferred from related species and late winter observations of spent individuals, so the seasonal pattern should be treated as a field planning guide rather than a complete description of the life cycle.

Seasonal information is limited. Avoid in-stream disturbance during the inferred August to September spawning peak where practicable, and obtain project-specific advice for known or potentially suitable habitat.

  • Breeding: Spawning is thought to occur in late winter or early spring, with spent individuals observed during late winter. August and September are shown as peak months for planning.
  • Young: The timing and duration of egg, larval and juvenile stages are not documented. The September to November period is a cautious planning indication following the inferred spawning period, not a confirmed young-of-year period.
  • Fire and low-flow risk: Fire weather, drought, high temperatures and low flows are identified risks, particularly under climate change. The supplied documents do not define a fixed annual risk window for individual sites.
  • Highest clearing risk: Late winter and early spring are the highest planning risk period because spawning is inferred during this time and eggs may be attached beneath riffle rocks. Clearing and stream disturbance can damage habitat in any month, so sediment and flow controls are required year-round.

Identification

The Short-tail Galaxias is a small brown freshwater fish with irregular dark blotches and spots. It is difficult to identify reliably in the field because it is morphologically similar to other members of the Galaxias olidus complex.

The back and upper sides are predominantly brown, with abundant small to moderately large, irregular dark brown to black blotches and spots. The species has the shortest caudal peduncle and caudal fin among members of the Galaxias olidus complex.

It is usually found in shallow freshwater streams and pools. Fish may be concentrated in shaded water or near inflowing riffles, particularly where dissolved oxygen is higher.

Typical length: 70 to 75 mm length to caudal fork.

Maximum recorded length: 97 mm.

Maximum recorded weight: 7.0 g.

Colour: Brown back and upper sides with irregular dark brown to black blotches and spots.

Identification: Features separating similar species

Reliable separation from other Galaxias olidus complex species may require close examination or genetic confirmation. Diagnostic features include a very short caudal peduncle and caudal fin, short dorsal, anal and pectoral fins, a relatively narrow head, a relatively large eye and the absence of black bars along the lateral line.

The species has 9 to 10 dorsal soft rays, 10 to 12 anal soft rays and usually 51 to 52 vertebrae. These characters are not generally suitable for an untrained field identification from a brief observation.

Caudal peduncle: Short, approximately 10.3 to 12.0 percent of standard length.

Caudal fin: Short, approximately 10.1 to 12.2 percent of standard length.

Lateral line pattern: Black bars along the lateral line are absent.

Fin rays: Dorsal soft rays 9 to 10; anal soft rays 10 to 12.

  • Do not assume that a small brown galaxiid in a Tuross River tributary is a Short-tail Galaxias without expert confirmation.
  • Photograph the whole fish, head, fins and lateral body pattern where handling is authorised.
  • Record the creek, pool or riffle location, water depth, substrate, flow, cover and capture method.

Identification: Sexes and field signs

The supplied documents do not describe reliable external differences between males and females. No species-specific tracks, scats, calls, nests, sloughs or eyeshine are relevant because this is a fish.

The most useful field signs are the fish themselves and their association with narrow pools, short riffles, shallow flowing water, rock or coarse substrate and available shade. Spent individuals were observed at one locality in late winter 2021, but spent fish cannot be identified by a simple external sign alone.

  • Treat any suspected individual as a protected threatened fish and avoid unnecessary capture, handling or relocation.
  • Use an appropriately qualified aquatic ecologist or fisheries specialist for confirmation and authorised survey handling.

Distribution: National range and strongholds

The Short-tail Galaxias has an extremely restricted Australian range. All known records are from the upper Tuross River system in southern coastal NSW, and the supplied documents do not identify records from any other state or territory.

The species is known only from the upper reaches of the Tuross River system above 900 m elevation in southern coastal New South Wales. Known localities include Jibolaro, Guinea and Lantooley creeks, and Bumberry Creek in or near Wadbilliga National Park.

The four known localities are patchily distributed and represent two isolated subpopulations. The historic range is unknown, although the species is considered to have formerly extended further downstream before predatory trout reduced and fragmented its distribution.

A formal bioregion name is not provided in the supplied documents. The national range should therefore be mapped using current locality records rather than inferred from a broader NSW bioregion.

States recorded: New South Wales only in the supplied records.

Elevation: Upper Tuross River system above 900 m ASL.

Known localities: Four localities.

Extent of occurrence: 29 km².

Area of occupancy: 24 km², calculated using a 2 by 2 km grid method.

Number of subpopulations: Two isolated subpopulations, treated as one location for the assessment.

Distribution: Population size and trend

The total number of mature individuals is unknown. The assessment found insufficient information to assess the species under the small population size criteria.

Available observations indicate decline at some sites. At the Tuross Road Bridge site on Jibolaro Creek, relative abundance fell from 50 individuals per seine haul in 2015 to zero in 2021. Relative abundance also declined over time in Guinea Creek, although further survey effort is needed to confirm the trend.

A structured expert elicitation estimated a possible 41 percent decline over the next three generations, with an estimated range of 21 to 76 percent. This estimate has high uncertainty.

Mature population size: Unknown.

Jibolaro Creek index: 50 individuals per seine haul in 2015 and zero in 2021 at one site.

Projected decline: 41 percent over three generations, with an estimated range of 21 to 76 percent.

Trend confidence: Decline is indicated at some sites, but the overall population trend remains uncertain.

Habitat: Stream types

Short-tail Galaxias habitat consists of narrow, shallow freshwater streams with pools connected by short riffles. The species occurs in both modified pastoral catchments and forested, steeper streams.

Jibolaro, Guinea and Lantooley creeks are generally 0.5 to 3 m wide, occasionally reaching 5 to 6 m in Guinea Creek pools. They are gently flowing, moderately turbid streams with depths of approximately 0.3 to 1.5 m.

Bumberry Creek is a narrow, moderately flowing stream in a deeply incised valley with a steep gradient and native Eucalypt forest. It is generally 1 to 3.5 m wide and 0.15 to 0.75 m deep.

Pastoral creek width: Usually 0.5 to 3 m, occasionally 5 to 6 m in Guinea Creek pools.

Pastoral creek depth: Approximately 0.3 to 1.5 m.

Forested creek width: Approximately 1 to 3.5 m.

Forested creek depth: Approximately 0.15 to 0.75 m.

Elevation: Known range is above 900 m ASL in the upper Tuross River system.

  • Look for pools connected by short sections of shallow riffle.
  • Record both flowing and still-water habitat because the species uses a connected pool and riffle system.
  • Retain natural flow paths, riffles, pools, stream banks, shade and instream cover during works.

Habitat: Substrate and vegetation

In the three more modified creeks, the substrate is generally clay overlain by fine and coarse sand and sediment. Riparian vegetation is largely pasture and tussock grass, with occasional patches of native Eucalypt forest.

In Bumberry Creek, the substrate is dominated by bedrock, boulder and cobble, with fine and coarse sand in shallow pools. Native Eucalypt forest provides a more intact riparian setting.

Clearing can reduce stream shading and increase erosion, sediment delivery and loss of riparian and overhanging vegetation. These changes can reduce habitat quality even where the channel remains physically connected.

  • Prevent soil, spoil, ash, concrete washout and other material from entering occupied or potentially suitable streams.
  • Keep machinery, access tracks, stockpiles and refuelling areas away from stream banks and drainage lines.
  • Maintain riparian shade, overhanging grasses, aquatic vegetation, rocks and coarse substrate wherever practicable.

Foraging habitat: Diet and feeding areas

The diet of the Short-tail Galaxias has not been studied directly. Based on closely related species in the Galaxias olidus complex, it is expected to feed mainly on aquatic and terrestrial macroinvertebrates in shallow stream habitat.

The species is considered a macro-invertivore. Insect fall from riparian vegetation is an important food source for the closely related Galaxias olidus and may also contribute to the Short-tail Galaxias diet.

Suitable feeding habitat includes shallow pools, short riffles, rocky margins, aquatic vegetation, overhanging grasses and areas where riparian vegetation can supply insects. Fish have also been observed concentrated in shade near the head of a pool, where inflowing water may provide higher dissolved oxygen.

Diet: Macroinvertebrates, inferred from related Galaxias olidus complex species.

Potential terrestrial food: Insects falling from riparian vegetation.

Recorded habitat depth: FishBase describes habitat at 0 to 1 m depth; site descriptions record shallow pools and streams up to 1.5 m deep.

Foraging range: Not known; the species is non-migratory and no home range has been established.

  • Protect the connection between pools and riffles so fish can access feeding areas and refuge habitat.
  • Avoid sediment plumes that can smother benthic prey habitat and reduce water quality.
  • Retain riparian vegetation and overhanging grasses that may supply terrestrial insects.

Breeding habitat: Breeding facts

Breeding ecology is poorly known and is inferred partly from other members of the Galaxias olidus complex. Spawning is thought to occur in late winter or early spring in flowing riffle habitat.

Spawning is suspected to occur on the underside of rocks in riffles, where flowing water helps keep eggs free of sediment and supplies oxygen. Spent individuals were recorded at one locality in late winter 2021.

The supplied documents do not provide confirmed clutch size, incubation period, age at maturity, or lifespan. Generation length is estimated at approximately 3 to 4 years.

Breeding season: Late winter to early spring, probably August to September in the known NSW range.

Spawning site: Suspected underside of rocks in riffles.

Clutch size: Unknown.

Egg incubation: Unknown.

Age at maturity: Unknown.

Lifespan: Unknown.

Generation length: Approximately 3 to 4 years.

Breeding habitat: Features needed for spawning

Potential breeding habitat includes shallow riffles with clean, oxygenated flow and stable rocks or coarse substrate. Fine sediment, ash and excessive suspended material may cover spawning surfaces or alter oxygen conditions.

Works near occupied streams should avoid disturbing riffles, rocks, banks and flow paths, particularly during late winter and early spring. The preferred spawning habitat has not been confirmed for this species.

  • Schedule in-stream disturbance outside the likely late winter to early spring spawning period where practicable.
  • Use sediment and turbidity controls before starting earthworks near drainage lines.
  • Do not remove or reposition rocks in riffles without approval and species-specific aquatic advice.

Sheltering habitat: Known refuge features

The species uses physical cover and localised areas of better water quality within shallow streams. No dens, burrows, hollows or roosts are relevant to this fish.

Recorded cover includes rocks, aquatic vegetation and overhanging grasses. Fish were collected in shade beneath a bridge at the head of a pool, where water flowing over a short riffle was thought to have higher dissolved oxygen.

Shallow pools connected by short riffles provide the main described refuge arrangement. In forested streams, bedrock, boulders and cobbles occur around shallow pools; in modified streams, clay, sand and sediment form much of the bed.

Recorded instream cover: Rock, aquatic vegetation and overhanging grasses.

Pool depth: A FishBase source record describes a maximum pool depth of 0.9 m at one site.

Water quality refuge: Shade and inflow near the head of a pool were associated with presumed higher dissolved oxygen.

Thermal tolerance: Upper thermal tolerance is anticipated to be approximately 33 °C, with tolerance reduced when dissolved oxygen declines.

  • Retain pools, riffles, rocks, aquatic vegetation, overhanging grasses and stream shade.
  • Avoid isolating pools, blocking fish passage or creating sudden changes in depth and flow.
  • Keep sediment and organic debris from filling shallow pools or covering coarse refuge and spawning surfaces.

Threats: Fire, drought and hydrology

The Short-tail Galaxias has a very small, fragmented range, so a single major event could affect much or all of the known population. Project risks are greatest where works alter stream flow, riparian cover, substrate, water quality or fish passage.

More frequent or severe bushfires can heat small streams and produce ash and sediment runoff after rain. Ash and sediment may smother stream substrates, alter water chemistry, reduce dissolved oxygen and change riparian shading and organic inputs.

Drought and higher temperatures can reduce water availability, remove refuge pools and increase water temperature. The species has an anticipated upper thermal tolerance of approximately 33 °C, with reduced tolerance when dissolved oxygen is lower.

Extreme weather can also produce high flows, erosion and rapid sediment delivery. The 2019 to 2020 bushfires were predicted to increase sedimentation across almost half of the known range.

Post-fire sediment reach: Post-fire sedimentation can affect waterways 50 to 80 km downstream of burnt areas.

Upper thermal tolerance: Approximately 33 °C, declining with reduced dissolved oxygen.

2019 to 2020 fire impact: Increased sedimentation was predicted over almost half of the known range.

  • Stop work and review controls after intense rainfall, fire or rapid changes in turbidity and flow.
  • Prevent post-fire ash, exposed soil and construction sediment from entering streams.
  • Maintain low-flow channels, pools and fish refuges when designing crossings, diversions and temporary works.

Threats: Clearing, construction and sediment

Land clearing for agriculture has removed riparian vegetation and modified stream habitat at several known localities. Soil disturbance and loss of ground cover can increase erosion, sedimentation and runoff into occupied streams.

Construction activities that disturb beds, banks or drainage lines may produce similar effects. Barriers, dredging, bed disturbance, removal of woody or rocky habitat and altered flows can directly damage habitat or prevent movement between pools.

The supplied documents do not identify a road-specific impact threshold or a road mortality pattern for this species. Road and crossing works should nevertheless be treated as potential risks where they affect known or suitable upper Tuross tributaries.

  • Keep clearing to the minimum area authorised and retain riparian and overhanging vegetation beside streams.
  • Install and maintain erosion and sediment controls before soil disturbance begins.
  • Design crossings to avoid bed and bank disturbance, maintain fish passage and prevent isolation of pools.
  • Do not place spoil, mulch, stockpiles, fuels or concrete washout where runoff can reach a creek.
  • Obtain species-specific aquatic advice before dewatering, relocating fish or disturbing a known locality.

Threats: Introduced trout and fragmentation

Brown Trout and Rainbow Trout are serious threats because they prey on galaxiids and may rapidly eliminate local populations. Trout are recorded downstream of at least one known locality and continue to be stocked within the same catchment.

Partial barriers may limit upstream trout movement, but trout behaviour during high flows is uncertain. Historic trout impacts are believed to have reduced and fragmented the Short-tail Galaxias range.

The species' four localities and two isolated subpopulations increase the risk that a single incursion or stochastic event will affect a substantial proportion of the population.

Main introduced predators: Brown Trout, Salmo trutta, and Rainbow Trout, Oncorhynchus mykiss.

Recorded response in a related galaxiid: Complete extirpation of Galaxias olidus occurred within three years of salmonid invasion at a documented site.

  • Do not create new barriers that prevent Short-tail Galaxias movement between pools and riffles.
  • Report suspected trout incursions or illegal fish stocking through the appropriate NSW fisheries authority.
  • Assess proposed waterway structures for both trout exclusion and continued passage of native galaxiids.

Threats: Disease and other risks

One fish was reported with small white cysts, possibly trematode metacercariae, embedded in tissue on the inside of both gill covers. The supplied documents do not establish this as a population-level disease threat.

Small isolated populations may also be susceptible to genetic deterioration. The number of mature individuals is unknown, and the species' restricted range leaves little capacity for recolonisation after local loss.

Documented disease observation: One individual had cysts that were possibly trematode metacercariae.

Disease status: No confirmed population-level disease threat is identified in the supplied documents.

  • Use clean equipment between streams and follow aquatic hygiene procedures to avoid transferring pathogens or aquatic pests.
  • Record abnormal lesions, mortalities and unusual fish behaviour during surveys and report them to the relevant fisheries authority.
  • Treat any activity that could affect one of the four known localities as potentially significant because the entire known distribution is restricted.

Survey methodology: 1. Targeted aquatic habitat inspection

Short-tail Galaxias is a small, non-migratory freshwater fish known from four patchily distributed localities in the upper Tuross River system, above 900 m elevation. Surveys must focus on shallow pools, short riffles and connected refuge habitat, and should be designed and led by a qualified freshwater fish ecologist.

Map all narrow streams, pools, shallow riffles, crossings, drainage lines and wet areas that could connect to occupied habitat before selecting survey sites.

Prioritise streams 0.5 to 3 m wide, with occasional pools up to 5 to 6 m wide, and depths commonly between 0.15 and 1.5 m.

Record substrate, flow, water depth, turbidity, dissolved oxygen where practicable, riparian condition, barriers and potential trout access.

Inspect both modified stream reaches, including clay, sand and sediment substrates, and forested reaches with bedrock, boulders, cobbles and shallow pools.

Survey methodology: 2. Targeted fish detection

Use methods approved by the relevant state fisheries authority and selected by a qualified fish ecologist for the stream size, depth, conductivity and animal welfare risks.

Use a combination of appropriate active fish sampling methods, such as seine-based sampling where safe and permitted, and other approved methods suited to shallow pools and short riffles.

The assessment records a relative abundance result from seine sampling at Tuross Road Bridge, where 50 fish per seine haul in 2015 fell to zero in 2021; record the exact gear, haul length, area sampled, number of hauls and conditions so results can be compared over time.

Search pool margins, shallow riffles, undercut banks, instream cover, overhanging grass, aquatic vegetation and shaded inflows, because fish may concentrate where water quality and dissolved oxygen are better.

Do not assume that a negative result proves absence, because the species is patchily distributed and known from only a limited number of sites.

Survey methodology: 3. Timing and survey conditions

Survey when streams are flowing and access is safe, while recording recent rainfall, drought, fire, water level, turbidity, temperature and dissolved oxygen.

Include late winter to early spring surveys where the project may affect spawning habitat, because spawning is suspected during this period and spent individuals were observed in late winter 2021.

Avoid undertaking only one survey after a major fire, drought or high-flow event, because ash, sediment and altered water quality can change detectability and fish distribution.

Treat shallow pools connected by short riffles as potential habitat throughout the year, including during low-flow periods when refuge habitat may be limited.

Obtain all required animal ethics, fisheries and threatened-species approvals before capture, handling or relocation.

Survey methodology: Minimum effort and reporting

  • Prepare a species-specific survey plan signed off by a qualified freshwater fish ecologist before works start.
  • Define survey reaches, sampled area, number of passes or hauls, search time, crew, equipment, weather, water conditions and detection limitations before fieldwork.
  • Survey all suitable habitat within and downstream of the disturbance area, including connected pools and riffles that could receive sediment or polluted runoff.
  • Record every Short-tail Galaxias observation with date, coordinates, reach, count or estimate, life stage if known, method and photographs where this can be done without harm.
  • Submit confirmed records and negative survey results, with survey effort and location details, to the relevant state wildlife or fisheries database and notify the relevant threatened-species authority where required.
  • Report suspected trout, fish kills, fire impacts, major sediment movement and new populations to the relevant NSW fisheries or environmental authority.

Before habitat disturbance: Avoid and minimise

Treat any suitable upper-catchment stream habitat as potential Short-tail Galaxias habitat until a qualified fish ecologist has assessed it. The species has a very restricted range, with an estimated extent of occurrence of 29 km2 and area of occupancy of 24 km2.

  • Avoid direct works in pools, shallow riffles, stream beds, banks and riparian areas wherever practicable.
  • Retain connected pools and short riffles, natural bedrock, boulder, cobble, sand and gravel features, undercut margins, aquatic vegetation and overhanging vegetation.
  • Maintain fish passage and do not create barriers that prevent movement between pools or allow introduced trout to enter occupied or potential habitat.
  • Keep clearing, excavation, vehicle access, stockpiling, refuelling and concrete washout away from streams and drainage lines.
  • Prevent sediment, ash, nutrients, chemicals and turbid runoff from entering the stream, because sediment can smother substrates and alter water chemistry and dissolved oxygen.
  • Retain shaded inflows and riparian vegetation where present, while recognising that some known sites have cleared pasture and tussock grass riparian cover.

Before habitat disturbance: Approvals and project planning

  • Check whether the project is likely to have a significant impact on this EPBC Act listed Critically Endangered species or its habitat, and obtain an EPBC Act referral or approval where required.
  • Obtain relevant state fisheries, threatened-species, animal ethics, scientific collection and waterway work approvals before disturbing habitat or handling fish.
  • Confirm the current state listing and permit requirements with the relevant state authority before works begin, because the supplied NSW documents list the species as Critically Endangered in NSW.
  • Schedule instream works outside late winter and early spring where practicable, when spawning is suspected, and avoid works during drought, fire recovery and high-flow conditions where impacts may be greater.
  • Stage works so that retained pools and connected refuge habitat remain available throughout the project.
  • Include a Short-tail Galaxias response procedure in the fauna management plan, including contact details, stop-work authority, equipment, approved holding arrangements and release locations.

Before habitat disturbance: Pre-clearance preparation

  • Complete a pre-clearance aquatic habitat inspection and targeted fish survey before finalising the construction footprint.
  • Mark no-go stream sections, retained riparian vegetation, pools, riffles, banks, refuge areas and access routes on plans and on the ground.
  • Install exclusion fencing or equivalent controls where they can prevent machinery, sediment, spoil and personnel entering retained habitat without diverting flow or blocking fish passage.
  • Prepare sediment and erosion controls before soil is disturbed, and inspect them after rainfall and high-flow events.
  • Set up clean equipment procedures to reduce transfer of sediment, pathogens and aquatic weeds between waterways.
  • Confirm an emergency response for fire, ash, sediment pulses, chemical spills, fish stranding, trout detection and sudden loss of flow.

During habitat disturbance: Daily work controls

A fauna spotter catcher must work as part of the aquatic environmental team, not as a substitute for a qualified fish ecologist. Works must stop when the approved controls cannot prevent harm to fish or their habitat.

  • Inspect exclusion fencing, sediment controls, stream crossings, flow controls and retained habitat before work starts each day.
  • Keep machinery, fuels, spoil, concrete, wash water and chemicals out of streams, pools, riffles and drainage lines.
  • Maintain environmental flows and fish passage during temporary diversions, pumping, dewatering and crossings.
  • Use clean, inspected equipment and prevent dirty water from moving between reaches or entering retained habitat.
  • Reduce noise, vibration, lighting and bank disturbance near retained pools and riffles where practicable.
  • Recheck controls after rainfall, high flows, fire-related runoff or any event that causes visible turbidity or sediment movement.

During habitat disturbance: Spotter catcher and machinery interface

  • The spotter catcher must brief the supervisor and machine operators on no-go areas, access routes, stop-work triggers and the approved response before each work stage.
  • Keep a qualified fish ecologist or appropriately authorised aquatic fauna professional available when works may disturb water, stream bed, banks, pools or riffles.
  • Do not enter or sample the water without the required approvals, safe access, hygiene controls and animal welfare procedures.
  • Stop machinery before anyone enters the exclusion zone, handles equipment near water or responds to a fish observation.
  • Do not attempt to identify, catch, hold or relocate a Short-tail Galaxias unless the person is authorised and the action is covered by the approved permit and fauna management plan.
  • Use a permitted, nearby release site only when relocation has been approved by the relevant authority and fish can be returned safely to suitable retained habitat.

During habitat disturbance: Finds, incidents and stop-work triggers

  • Stop work immediately if a Short-tail Galaxias is observed in the disturbance area, if fish become stranded, or if water diversion, pumping or excavation could injure fish.
  • Stop work if sediment, ash, concrete, fuel, chemicals or other pollutants enter or are likely to enter a stream or connected pool.
  • Stop work if a trout is detected in or near occupied or potential Short-tail Galaxias habitat, and notify the relevant fisheries authority promptly.
  • Keep handling to the minimum needed for authorised identification, rescue or release, and never retain a fish as a specimen unless specifically permitted.
  • Place injured fish in an approved temporary holding system and arrange transfer to an authorised aquatic wildlife rehabilitator or veterinarian where available.
  • Record the date, time, location, observer, activity, habitat condition, fish details, photographs, action taken, release location, injury or mortality and authority notifications.
  • Report any mortality, unapproved take, failed control, major sediment event or suspected population impact to the project environmental officer and relevant regulator.

After habitat disturbance: Completion checks

Post-work checks must confirm that retained stream habitat remains connected, fish passage is available and water quality has not been degraded. The restricted distribution of this species means that a local incident can affect a substantial part of its known range.

  • Inspect the work area, upstream and downstream reaches, pools, riffles, banks and temporary access points immediately after clearance and again after the first substantial rainfall or flow event.
  • Remove temporary barriers, spoil, sediment, waste, pumps and construction materials that could obstruct fish passage or enter the stream.
  • Confirm that flow has returned through all retained channels and that no fish are stranded in isolated pools, drains, sumps or dewatering areas.
  • Check for visible ash, sediment, erosion, altered shading, bank collapse, chemical contamination and loss of instream cover.
  • Undertake an authorised post-work fish inspection or survey where the approval, risk assessment or environmental management plan requires it.

After habitat disturbance: Monitoring and reporting

  • Monitor known or potentially occupied reaches for fish presence, water quality, sediment deposition, pool persistence, riparian recovery and trout incursion at the frequency specified in the approval or management plan.
  • Use the same reach boundaries, method and effort on repeat surveys where the purpose is to detect change.
  • Compare results with baseline records and investigate any decline, including a zero detection where survey conditions or effort were suitable.
  • Maintain records of all incidents, corrective actions, inspections, monitoring results, photographs, approvals and regulator notifications.
  • Submit new records, mortality reports and relevant monitoring data to the responsible state fisheries or wildlife database and authority.

After habitat disturbance: Residual impacts and offsets

  • Reassess the project if monitoring shows loss of habitat quality, reduced connectivity, fish mortality or continuing sediment impacts.
  • Apply additional avoidance, rehabilitation and threat reduction before considering any residual impact measure.
  • Obtain regulator advice on offsets or other compensatory measures where an approval identifies a residual significant impact.
  • Do not treat an offset as permission to damage occupied stream habitat or as a substitute for preventing trout access, sedimentation and water-quality decline.

Rehabilitation actions: Stream and riparian restoration

Rehabilitation should restore cool, connected, clean stream habitat rather than only treating the disturbed footprint. Priorities are refuge pools, shallow riffles, stable substrates, riparian cover, fish passage and protection from trout and post-fire sediment.

  • Re-establish stable banks and natural channel form without filling pools or short riffles used to connect refuge habitat.
  • Use locally appropriate native riparian vegetation and retain or replace overhanging grasses, shrubs and trees that provide shade, bank stability, organic inputs and cover.
  • Restore a mix of shallow riffles and pools with clean bedrock, boulder, cobble, sand and stable fine substrate that reflects the local reference reach.
  • Keep sediment out of spawning and refuge areas, because spawning is suspected on the underside of rocks in riffles and eggs require flowing, oxygenated water.
  • Do not introduce fish, crayfish, aquatic plants or water from another catchment during rehabilitation.
  • Remove weeds and prevent livestock, vehicles and future earthworks from damaging restored banks and riparian cover.

Rehabilitation actions: Connectivity, predators and disturbance risk

  • Remove temporary construction barriers and design permanent crossings to maintain fish passage under normal and high-flow conditions.
  • Inspect restored habitat for trout access and work with the fisheries authority on approved trout detection, removal, stocking controls or barrier measures.
  • Protect restored reaches from sediment pulses after fire, drought-breaking rain and high-flow events.
  • Use fire and erosion planning that reduces ash and sediment delivery into streams across the species' restricted range.
  • Consider restored or predator-free sites for future approved translocation only after habitat suitability, genetics, disease risk and trout security have been assessed.

Rehabilitation actions: Monitoring and success measures

  • Monitor restored reaches for at least the period required by the approval, with additional checks after major rainfall, drought, fire or high-flow events.
  • Measure survival and establishment of riparian vegetation, bank stability, pool and riffle persistence, substrate condition, water clarity, dissolved oxygen where practicable and fish passage.
  • Use repeat authorised fish surveys to assess Short-tail Galaxias presence, relative abundance and recruitment, while recording effort and detection conditions.
  • Treat successful rehabilitation as retention or recovery of connected shallow pools and riffles with stable banks, suitable cover, no new trout incursion and no harmful sediment or pollution inputs.
  • Escalate corrective works if monitoring detects erosion, sediment deposition, loss of flow, fish stranding, trout presence, fish mortality or continuing habitat degradation.
  • Share monitoring results and confirmed records with the relevant state fisheries authority and wildlife database.

Sources