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Barred Galaxias (Galaxias fuscus)

Barred galaxias is a small, scaleless freshwater fish restricted to cool upland streams in the upper Goulburn River catchment of central Victoria. It is endangered nationally and critically endangered in Victoria, with very few isolated populations remaining, so stream crossings, riparian clearing, sediment movement, altered flows and trout access need specific controls on development sites.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Victoria, Flora and Fauna Guarantee Act 1988: Critically endangered.

Breeding season

Timing varies between catchments and may be affected by water temperature, flow and canopy condition. The following pattern is based on documented Victorian populations and should guide, not replace, site-specific survey planning.

Construction near suitable headwater streams should be planned around current fish survey results, water conditions and permit requirements. The species can be affected by habitat disturbance outside the immediate occupied reach through sediment and flow changes.

  • Breeding and egg laying: Spawning generally occurs from mid-August to late September, in shallow moderate to fast flowing riffles immediately upstream of pools.
  • Egg incubation and young: Eggs may take about 30 to 48 days to hatch. Larvae have been observed from late September to November, and are usually noted in wild populations by December.
  • Juvenile growth: The species is non-migratory and relatively sedentary. Juveniles remain in the headwater stream habitat and are particularly vulnerable to trout predation.
  • Local movement: No regular migration is documented. Movement is expected to be local within connected pools, riffles and glides, and recolonisation after trout removal can be slow.
  • Highest clearing risk: Clearing or instream disturbance from August to October can directly affect spawning adults, eggs and newly hatched larvae. Sediment released during this period can smother demersal eggs and spawning cobbles.

Identification

Barred galaxias is a small, strikingly coloured galaxiid found in shallow upland streams. It is most likely to be encountered during targeted electrofishing or fine-mesh netting rather than by casual observation.

The body is yellow-orange, red-orange or orange, paling to light yellow-orange or cream on the belly. It has one to 10 complete or partial vertical black bars on the sides between the rear of the gill cover and the pelvic fin bases.

The species is scaleless. The head is large and long, distinctly wider than deep, with a wide gape. The tail is weakly forked and may occasionally be truncate. The anal fin begins at about 0.7 of the distance along the dorsal fin base.

Common adult length: 80 to 105 mm

Maximum length: About 160 to 165 mm

Weight: Up to about 40 g

Identification: Distinguishing features

Mountain galaxias, Galaxias olidus, is the main similar species in the upper Goulburn catchment. In barred galaxias, the bars usually stop around the pelvic fin bases, whereas stripes or bars in mountain galaxias usually continue well behind the pelvic fin bases.

Barred galaxias is the only fish species recorded in some surveyed headwater reaches, but mountain galaxias may occur in the wider catchment. Identification should be confirmed by an experienced freshwater fish ecologist where the two species may overlap.

  • Check that the fish is scaleless and has a yellow-orange to orange body.
  • Check the number and position of the black lateral bars, particularly whether they extend behind the pelvic fin bases.
  • Record the full location, stream reach and habitat because populations are small and isolated.

Identification: Field detection and handling

There are no useful tracks, scats, calls, nests or other terrestrial field signs. Fish are usually detected by electrofishing, fine-mesh seines or scoop nets in suitable stream habitat.

In small streams with low electrical conductivity, backpack electrofishing has been used at about 1000 volts and 110 Hertz. December to April is the recommended Victorian sampling period because flows are generally lower, but all capture and handling must be undertaken under the relevant permits, ethics approvals and fish handling procedures.

  • Search pools, riffles, glides and under-rock habitats systematically, including shallow margins and deeper pool sections.
  • Use a fine-mesh seine downstream of electrofishing in rapids and riffles where appropriate.
  • Minimise electrofishing passes, handling time and disturbance to spawning substrates.

Distribution: National range

Barred galaxias is endemic to Victoria and occurs in the southern Murray-Darling Basin. Its current range is a small remnant of a much wider historical distribution.

The species is known only from Victoria, in the upper Goulburn River catchment north of the Great Dividing Range. It occurs in upland headwaters of the Goulburn, Big and Acheron River systems and associated tributary streams in the central Victorian highlands.

Known populations occur above about 400 m altitude. The species formerly occurred in larger streams at lower elevations, around 300 m, but is now largely confined to headwaters.

  • State: Victoria only.
  • Bioregional setting: central Victorian highlands and the southern Murray-Darling Basin.
  • Catchment setting: upper Goulburn River system, including tributaries of the Goulburn, Big and Acheron Rivers.

Distribution: Strongholds and subpopulations

The remaining populations are in small, isolated headwater streams, often upstream of natural barriers that exclude trout and other fish. Examples of streams containing or supporting populations include Luke Creek, Kalatha Creek, S Creek, Rubicon River, Little Rubicon River, upper Taggerty River, Robertson Gully, Keppel Hut Creek and Torbreck River South Branch.

The full list of currently occupied streams should not be assumed from historical records. Targeted pre-clearance surveys and current Victorian biodiversity data are needed before works near suitable headwater habitat.

Distribution: Population size and trend

The species has declined catastrophically in range and abundance. Remaining populations are small, fragmented and genetically isolated, with very limited gene flow between many populations.

A low count from broad fish survey programs should not be treated as proof of absence. The species is difficult to detect, and suitable headwater reaches need targeted survey effort.

Known extant populations: 12 populations in seven small streams

Former populations presumed extinct: At least five

Total stream length occupied: Less than 20 km across all known populations

Historical decline: More than 95% of likely historical distribution and abundance

Sustainable Rivers Audit record: 79 individuals recorded from 2004 to 2013; none recorded in the MDB Fish Survey from 2014/15 to 2021/22

Habitat: Stream habitat

Barred galaxias uses cool, clear, flowing headwater streams with good oxygenation and a mosaic of pools, riffles and glides. Habitat is usually protected from trout by a natural or constructed barrier.

Typical habitat is in small to medium-sized, shallow, cool and clear upland streams with moderate to fast flows. Substrates are usually cobble, boulder, pebble, gravel and some sand.

Known study reaches were narrow, about 1 to 4 m wide, heavily shaded, well oxygenated and above 400 m altitude. They had alternating pool and riffle sequences and were generally 1 to 2 km upstream of major instream barriers.

  • Protect the entire stream channel, not only occupied pools, because riffles and glides provide feeding and spawning habitat.
  • Retain stable cobbles and boulders and prevent soil, ash, sand and construction sediment entering the channel.
  • Maintain riparian shade and vegetation to limit warming, erosion and changes in flow conditions.

Habitat: Catchment and barriers

The most secure sites are remote headwater reaches with reliable surface water, little disturbance and an effective downstream barrier to upstream trout movement. Natural barriers are commonly waterfalls or steep drops that prevent trout from entering the occupied reach.

Catchment disturbance, bushfire, timber harvesting, roads and altered drainage can increase sediment delivery, change stream topography or reduce water security. A barrier can be weakened when debris, flood flows or channel changes create a route for trout to move upstream.

  • Map all upstream and downstream drainage connections, culverts, crossings and barriers before works begin.
  • Avoid works that remove, bypass or drown natural barriers without a species-specific assessment.
  • Keep construction compounds, spoil, fuels and sediment controls outside the riparian zone where practicable.

Habitat: Water conditions

Spawning reaches have been recorded with water temperatures of 8.4 to 10 degrees Celsius, dissolved oxygen of 10.8 to 12.4 mg/L and turbidity of 1.2 to 6.3 NTU. These values describe documented spawning sites, not universal thresholds for occupancy.

Drought and reduced runoff can remove surface water from small isolated streams. Water regime changes, dewatering and increased temperature after riparian clearing can reduce habitat suitability.

Foraging habitat: Diet

Barred galaxias feeds within pools, riffles and glides in the stream channel. It takes aquatic and terrestrial invertebrates from the bottom and the water column.

The diet consists mainly of drifting and benthic aquatic invertebrates, with terrestrial invertebrates also taken. Fish forage off the bottom and in mid-water in pools, and along the bottom of riffle and glide sections.

  • Retain riffle, glide and pool sequences that provide both drifting prey and benthic feeding surfaces.
  • Avoid sediment inputs that cover coarse substrates and reduce aquatic invertebrate habitat.
  • Avoid removing overhanging riparian vegetation where it supplies shade, bank stability and terrestrial invertebrate inputs.

Foraging habitat: Foraging area

The species is thought to be non-migratory and relatively sedentary. There is no documented long-distance feeding range, so occupied reaches and connected pool, riffle and glide habitat should be treated as a single local foraging area.

Movement pattern: Thought to be non-migratory and relatively sedentary

Foraging locations: Pools, riffles and glides, using bottom and mid-water habitats

Breeding habitat: Breeding biology

Breeding occurs in late winter and early spring in shallow, fast-flowing riffles immediately upstream of pools. Eggs are laid on the downstream side of stable cobbles or boulders close to the stream bed.

Spawning is likely triggered by increasing day length and possibly rising water temperature. Females may spawn at multiple sites, depositing several small egg clusters rather than one large mass.

Eggs are large, adhesive, demersal and spherical. Hatching has been recorded after about 30 to 48 days, with most eggs in one study hatching within 44 days and the last by day 48.

Breeding season: Usually mid-August to late September

Fecundity: About 500 eggs per female on average

Egg cluster size: Usually fewer than 80 eggs, with up to 218 recorded

Egg size: About 3 to 4 mm diameter

Incubation: About 30 to 48 days in documented conditions

Newly hatched larva: About 8.5 to 9 mm long

Age at maturity: Not stated in the supplied documents

Lifespan: Up to 15 years recorded

Breeding habitat: Spawning sites

Thirteen spawning sites were recorded in moderate to fast flowing water, with flows of 0.4 to 2.0 m/s and depths of 70 to 310 mm. All were in riffles immediately upstream of pools.

Egg clusters were attached close to the stream bed on the downstream side of cobbles measuring about 115 to 280 mm across, with a mean diameter of about 180 mm. Fine sediment can smother these eggs and remove suitable spawning surfaces.

  • Treat shallow riffles immediately upstream of pools as potential breeding habitat, even if adult fish are not seen during a brief inspection.
  • Do not disturb, remove or cover cobbles and boulders during the breeding and egg incubation period.
  • Prevent sediment, ash, concrete washout and turbid runoff entering spawning reaches.

Sheltering habitat: Aquatic cover

The species has no den, hollow, burrow or roost requirement. Shelter and cover are provided by the stream channel, pools, coarse substrate, banks and riparian shade.

Preferred habitat is thought to include slow-flowing, deeper pools next to riffles and cascades. Coarse substrates, undercut margins and the alternating pool and riffle structure provide local cover and resting areas.

Barred galaxias may climb over wet rocks using specialised paired-fin structures, but it is generally regarded as sedentary and has limited ability to recolonise streams after local loss.

  • Retain pools, undercut banks, cobbles, boulders and natural channel complexity.
  • Do not place machinery, temporary crossings or instream structures over pool and riffle sequences without a site-specific aquatic assessment.
  • Maintain flow through occupied reaches and avoid isolating pools during construction.

Sheltering habitat: Riparian cover

Heavily shaded riparian habitat helps maintain cool water and stable stream conditions. Loss of canopy can increase water temperature, erosion and sediment delivery, particularly after fire or earthworks.

  • Retain streamside trees, shrubs and ground vegetation wherever practicable.
  • Stage clearing away from the channel and use erosion and sediment controls before soil is exposed.
  • Inspect occupied reaches after storms, fire or earthworks for sediment slugs, debris dams and newly opened routes for trout.

Threats: Introduced trout

Barred galaxias remains at high risk because its populations are small, isolated and restricted to short lengths of headwater stream. Threats that may appear local, such as one crossing, sediment discharge or a new trout access point, can affect an entire population.

Predation by introduced brown trout and rainbow trout is the main documented threat. Trout prey on adults and juveniles, with juveniles particularly affected, and can rapidly eliminate barred galaxias from a stream within one to two years after invasion or introduction.

Trout may also compete for food and habitat. Roads, construction access, fish stocking, illegal fish movement and altered barriers can increase the risk of upstream trout entry.

  • Do not move live fish, contaminated water, bait or wet equipment between catchments.
  • Keep machinery and equipment clean, drained and dry before entering another waterway.
  • Protect natural barriers and report any trout detected within or immediately downstream of occupied habitat.

Threats: Clearing, roads and sediment

Riparian clearing can remove shade and instream cover, increase water temperature and destabilise banks. Roads, crossings, earthworks, forestry and post-fire salvage activities can deliver sediment and ash to the channel.

Sedimentation can fill pools, smother cobbles, reduce aquatic invertebrate habitat and bury demersal eggs. Construction crossings can also alter channel form, block movement or create a route around a trout barrier.

  • Avoid direct disturbance to the channel and spawning riffles.
  • Use crossings that do not create perched outlets, fish passage barriers or sediment release points.
  • Install and maintain sediment controls before clearing or earthworks, and inspect them after rainfall.
  • Keep spoil, concrete washout, fuels and fine sediment away from drainage lines.

Threats: Fire, drought and hydrology

Bushfire can remove riparian shade, raise stream temperature and wash ash and sediment into occupied reaches. About 45% of the known range was affected by the 2009 fires, and other populations had also been affected by fires in 2006 and 2007.

Drought, reduced runoff, dewatering and altered flow regimes can remove surface water from small streams. Small isolated populations have limited capacity to recolonise after these events.

  • Do not extract or divert water from occupied headwater reaches without assessing low-flow effects.
  • Maintain riparian vegetation and stabilise disturbed soils to reduce post-fire and post-clearing sediment delivery.
  • Consider downstream effects of drainage, culverts, stormwater outlets and water storage infrastructure.

Threats: Genetic and stochastic risk

Genetic variation within some populations is extremely low, while variation between populations is high. Limited gene flow, small population size and fragmentation increase the risk from drought, bushfire, landslides and other local disturbances.

No specific disease is identified in the supplied documents. Disease risk should nevertheless be managed when handling fish or moving equipment between isolated populations.

  • Do not collect, relocate or mix fish without an approved conservation translocation plan.
  • Treat each occupied stream as a separate conservation unit unless current genetic and management advice supports movement.
  • Use clean equipment and separate holding water between sites.

Survey methodology: 1. Confirm habitat and survey scope

Barred galaxias is a small, non-migratory fish of cool, clear, shallow upland streams in the upper Goulburn River catchment of central Victoria. Surveys must focus on suitable stream habitat and use authorised aquatic fauna methods, rather than terrestrial fauna techniques.

Map all streams, tributaries, pools, riffles, cascades, wetlands and drainage lines that could receive direct or indirect project impacts.

Treat shallow, cool, clear streams above 400 m altitude with moderate to fast flows, stony or sandy substrates, pools beside riffles and natural downstream barriers as potential habitat.

Extend the survey area downstream where sediment, altered flows, ash, pollutants or construction water could affect habitat.

Use the current state species database, Victorian Biodiversity Atlas records and the EPBC protected matters search when defining the survey area.

Known range: Upper headwaters of the Goulburn River catchment in central Victoria, generally above 400 m altitude

Known remaining populations: 12 geographically isolated populations in seven small streams

Known stream length occupied: Less than 20 km in total

Survey methodology: 2. Backpack electrofishing

Use a trained and authorised electrofishing operator with a suitable backpack unit, following the Australian Code of Practice, animal ethics requirements and Victorian fisheries requirements.

In small streams with low electrical conductivity, the survey guideline identifies 1000 volts and 110 Hertz as an effective setting for barred galaxias, subject to equipment, safety and permit requirements.

Fish all accessible habitat in an upstream direction, with an assistant collecting stunned fish downstream, as described for headwater surveys.

A single pass may provide a representative sample where barred galaxias are present, but record the length of stream surveyed and the basis for stopping.

Record the stream reach, date, time, water level, flow, water temperature, conductivity, turbidity, dissolved oxygen, pH, habitat type and all fish captured.

Identify, measure and examine captured fish promptly, then release them at the capture location unless an approved translocation or rescue plan authorises another action.

Preferred Victorian survey period: December to April, when flows are generally lower

Typical survey reach in site assessments: 25 to 150 m, with 100 m sampled where no fish were detected

Suggested low conductivity setting in the survey guideline: 1000 volts and 110 Hertz

Survey methodology: 3. Rapids, riffles and spawning habitat

Survey rapids and riffles with a combination of fine mesh seine netting and electrofishing.

Secure the fine mesh seine downstream of the electrofishing area so stunned fish are carried into the net by the flow.

Inspect shallow, moderate to fast flowing riffles immediately upstream of pools for spawning habitat, particularly where cobbles or boulders are present.

During late winter and early spring, avoid disturbing suspected nest sites because eggs are adhesive, demersal and attached to the downstream side of cobbles close to the stream bed.

If spawning habitat must be inspected, record substrate size, flow, depth, water quality and evidence of eggs, and use the least disturbing method available.

Spawning period: Late winter to early spring, generally mid-August to late September

Typical spawning water: Moderate to fast flow of 0.4 to 2.0 m/s, depth of 70 to 310 mm, temperature of 8.4 to 10 degrees Celsius

Typical spawning substrate: Cobbles or rocks, with a mean recorded diameter of about 180 mm

Egg incubation: Up to 48 days in the reported captive observations

Survey methodology: Minimum effort and reporting

Use the survey period, method and effort specified by the relevant Victorian regulator or project approval where those requirements exceed this profile.

Record a negative result as well as a capture, including the surveyed reach length, pass number, equipment settings, habitat conditions and access limitations.

Repeat surveys where high flows, turbid water, dewatering, inaccessible habitat or equipment limitations reduce detection confidence.

Do not infer absence from a short visual inspection because the species is small, fragmented and restricted to isolated headwater reaches.

Submit confirmed records, including date, coordinates, observer, method, effort, photographs and voucher or identification details where required, to the relevant Victorian wildlife or biodiversity database and the project regulator.

Report any detection immediately through the project fauna management system so works can be reviewed before the next disturbance activity.

Before habitat disturbance: Avoid and minimise habitat damage

Plan the project around the stream and its catchment, not only the work footprint. Barred galaxias populations are small and isolated, and sediment, altered flows, fire, drought and introduced trout can affect them beyond the immediate clearing area.

Retain the full stream channel, riparian shading, pools, riffles, cascades, coarse substrates and natural downstream barriers wherever practicable.

Set no-go areas around occupied or potential habitat and keep construction access, spoil, fuels, concrete washout and stockpiles outside those areas.

Maintain surface water, baseflows and the natural connection between pools and riffles; do not divert, drain, dam or dewater habitat without an approved aquatic fauna plan.

Prevent sediment and ash from entering the stream because sediment can smother spawning substrates, eggs and other instream habitat.

Protect natural barriers that exclude trout, and do not create temporary channels, roads or drainage paths that allow introduced fish to move upstream.

Before habitat disturbance: Approvals, timing and work planning

Check whether the action requires an EPBC Act assessment or referral because barred galaxias is listed as Endangered nationally.

Obtain Victorian fisheries, wildlife, animal ethics and translocation approvals before electrofishing, rescue, captive holding, release or movement of fish.

Schedule instream disturbance outside the late winter to early spring spawning period where practicable.

Use staged works so an occupied reach is not isolated, dewatered or disturbed at the same time as all nearby refuge habitat.

Prepare a fauna management plan that identifies survey methods, aquatic rescue arrangements, stop-work triggers, sediment controls, emergency contacts and reporting requirements.

National status: Endangered under the EPBC Act

Victorian status in the supplied profile: Critically Endangered

Victorian aquatic translocation requirement: Movement of live aquatic organisms into or within inland public waters requires approval under the Fisheries Act 1995

Before habitat disturbance: Pre-clearance preparation

Complete targeted aquatic surveys before finalising the work footprint, including any reach that may receive sediment, changed runoff or altered flow.

Mark retained streams, riparian vegetation, pools, riffles, spawning substrates and natural barriers on construction drawings and in the field.

Install exclusion fencing or other clearly visible controls where they can keep machinery, vehicles, people and materials out of the stream and riparian protection area.

Brief machinery operators and the fauna spotter catcher on the species appearance, habitat, rescue limits, stop-work triggers and incident contacts.

Check that clean water diversion, sediment basins, pump screens, fish rescue equipment, aerated holding containers and approved release sites are ready before works begin.

Adult size: Maximum about 160 to 165 mm, commonly 80 to 105 mm

Appearance: Scaleless yellow-orange to orange fish with up to 10 black vertical bars on the sides

Preferred habitat: Cool, clear, shallow upland streams with moderate to fast flows and stony or sandy substrates

During habitat disturbance: Daily controls and machinery coordination

The fauna spotter catcher should work as part of the construction team, with authority to pause activities when aquatic habitat or fish are at risk. Barred galaxias must not be handled, moved or released outside an approved procedure.

Inspect exclusion fencing, stream crossings, pump screens, sediment controls and clean water diversions before work starts each day.

Keep machinery, spoil, fuels, concrete, wash water and disturbed soil out of the channel and riparian protection area.

Use low-impact access routes and cross streams only at approved locations designed to avoid isolating pools or damaging riffles.

Stop or modify work if rainfall, rising water, a failed sediment control or a pump discharge creates a risk of sediment or polluted water entering habitat.

The fauna spotter catcher should remain in communication with the supervisor and give a clear stop signal before machinery enters a sensitive reach or a fish rescue begins.

During habitat disturbance: Fish rescue and handling

If fish are found, stop the activity that could affect them and keep machinery and people clear of the occupied water.

Do not catch, hold, transport or release barred galaxias unless the person, equipment, destination and procedure are covered by the relevant approval and fauna management plan.

Use an authorised aquatic fauna specialist for electrofishing, netting, temporary holding and any relocation decision.

Keep captured fish in clean, aerated stream water, minimise handling and exposure, maintain suitable temperature, and release them only to the approved nearby habitat or rescue location.

Do not move fish across catchments, past barriers or into water containing other fish without a specific approved translocation plan.

Send injured, distressed or moribund fish to the nominated aquatic wildlife veterinarian or authorised wildlife carer, following the project response procedure.

During habitat disturbance: Habitat feature protection and stop-work triggers

Do not remove or reposition cobbles, boulders, logs or woody debris in occupied habitat unless the aquatic specialist confirms that the action is authorised and necessary.

Treat cobbles and boulders in shallow riffles immediately upstream of pools as potential spawning substrates during late winter and early spring.

Stop work for a confirmed barred galaxias detection, fish kill, stranded fish, exposed eggs, unexpected dewatering, barrier damage, trout detection upstream of a protected reach or uncontrolled sediment discharge.

Stop work if a fire, flood, landslide or road failure changes stream condition and threatens the occupied reach.

Record the trigger, location, time, weather, water condition, activity, people involved, fish numbers, actions taken and whether the regulator or approval holder was notified.

Typical egg cluster: Average about 78 eggs, with reported clusters ranging up to 218 eggs

Egg location: Attached close to the stream bed on the downstream side of cobbles

Main introduced fish threat: Predation and competition from Brown Trout and Rainbow Trout

After habitat disturbance: Post-clearance checks

Completion of construction does not end the risk. Check that the stream has retained suitable habitat, that controls are working and that any rescued or translocated fish are accounted for.

Inspect the full affected reach and downstream receiving waters for stranded fish, turbidity, sediment deposits, damaged spawning substrates, altered flow paths and barrier damage.

Carry out an authorised post-work fish survey where the project caused dewatering, channel disturbance, a spill, a fish rescue, a barrier change or a substantial sediment event.

Remove temporary crossings, pipes, bunds, diversion structures and debris that obstruct fish passage or alter pool and riffle structure, unless they form part of an approved permanent design.

Confirm that riparian shading, stable banks, coarse substrates and natural barriers remain intact or have been restored.

After habitat disturbance: Monitoring and reporting

Monitor rescued, released or translocated fish according to the approval and fauna management plan, including survival, condition, breeding, recruitment and range expansion where applicable.

For a translocation, use the documented monitoring approach from the Victorian trial as a guide, which included checks at three and six months after release and later genetic monitoring recommendations.

Report captures, mortalities, injuries, failed controls, trout detections, sediment events and corrective actions to the regulator and relevant state database where required.

Retain survey sheets, electrofishing settings, GPS tracks, photographs, water quality results, chain of custody records and release details with the project environmental records.

Victorian trial monitoring: Source and translocated populations were monitored at three and six months after release

Recommended longer-term translocation checks: Genetic analysis at one, five and ten years after establishment was recommended in the supplied study

After habitat disturbance: Maintain controls and offsets

Keep stream exclusion fencing, sediment controls, clean water diversions and access restrictions in place until exposed soil is stable and water quality has returned to the approved condition.

Repair controls after rainfall, flooding, fire, vehicle damage or construction changes.

Where residual impacts remain, apply the approved offset or conservation measure and make sure it addresses aquatic habitat, catchment condition and the species' documented threats.

Do not treat an offset as a substitute for avoiding disturbance to occupied habitat or maintaining trout exclusion barriers.

Rehabilitation actions: Restore stream and riparian habitat

Rehabilitation should restore cool, clear, connected headwater stream habitat and reduce the threats that limit recovery. Designs should be checked by an aquatic ecologist because the species depends on specific flow, substrate and barrier conditions.

Re-establish native riparian vegetation to restore shade, bank stability, lower water temperatures and reduce sediment delivery.

Reinstate a varied channel with pools, riffles, cascades, stable cobbles and boulders, while avoiding barriers that could isolate occupied habitat or allow trout to bypass existing barriers.

Where spawning substrates have been buried by sand or silt, place appropriately sized clean rock in suitable moderate to fast flowing riffles immediately upstream of pools, subject to approval and hydraulic design.

Use rocks of about 180 mm diameter as an evidence-based starting point for spawning habitat augmentation, then monitor whether fish use them.

Do not place rock, logs or other material where it blocks flow, buries existing nests or creates a route for trout movement.

Suitable spawning rock reported in the Victorian study: About 180 mm diameter, with recorded spawning substrates ranging from 115 to 280 mm

Reported spawning flow: 0.4 to 2.0 m/s

Reported spawning depth: 70 to 310 mm

Rehabilitation actions: Control sediment, weeds, predators and fire risk

Stabilise exposed soil, revegetate disturbed banks and maintain sediment controls until ground cover and channel stability are established.

Prevent weed establishment in the riparian zone and remove invasive plants using methods that do not introduce chemicals or sediment into the stream.

Maintain or install approved physical barriers that prevent Brown Trout and Rainbow Trout from entering restored habitat.

Do not stock, release, transfer or encourage non-native fish in the catchment, and report suspected illegal fish introductions.

Manage fire risk and post-fire runoff in the supporting catchment, including protection of riparian cover and rapid treatment of ash and sediment sources after fire.

Rehabilitation actions: Monitor rehabilitation success

Inspect restored reaches after the first significant rainfall, at the end of the first dry period and during the following spawning season.

Measure bank stability, riparian cover, water temperature, turbidity, dissolved oxygen, flow, pool and riffle condition, substrate availability and barrier integrity.

Use authorised electrofishing surveys to assess barred galaxias presence, abundance, size classes, recruitment and condition, and survey for trout upstream and downstream of barriers.

Treat rehabilitation as successful only when the reach is stable, water quality is suitable, spawning substrates remain available, trout exclusion is effective and monitoring shows persistence or recovery of barred galaxias.

Continue monitoring small and isolated populations during drought, fire recovery, major floods and other events that could reduce surface water or deposit sediment.

Key population risk: Small, isolated populations have limited recolonisation potential after disturbance

Species life span reported in the supplied account: Individuals up to 15 years old have been recorded

Sources