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Golden Galaxias (Galaxias auratus)

The golden galaxias is a small to medium freshwater fish endemic to two shallow lakes and associated wetlands and streams on Tasmania's Central Plateau. It is listed as Endangered under the EPBC Act, and works affecting lake levels, rocky shorelines, wetlands or connecting waterways may affect spawning, juvenile shelter and population connectivity.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Breeding season

The timing below reflects the documented late autumn to winter breeding period and the movement of juveniles from open water to inshore habitat. Local water levels and inundation can shift the timing and availability of habitat.

The documents describe breeding as late autumn to winter, while one general database records early spring. The late autumn to winter timing is used here because it is supported by the species conservation advice and Tasmanian survey guidance.

  • Breeding and spawning: Spawning occurs in late autumn to winter. Eggs are attached to rocky substrate or aquatic vegetation in shallow water, with seasonal water level rises between May and September supporting recruitment.
  • Eggs and larvae: Eggs incubate for approximately 30 to 45 days and hatch at about 5 to 6 mm long. Larvae feed in the water column.
  • Young fish in open water: Juveniles remain in open water until about 4 to 5 months old and 40 mm long, then move towards the shore for shelter and larger prey. Exact calendar timing will vary with spawning date.
  • Inshore movement and feeding: Juveniles between about 60 and 70 mm feed on larger benthic prey inshore. Adults use rocky margins, aquatic vegetation and marsh habitat. Fish may move into shallow shoreline water at night and deeper water during the day.
  • Highest clearing risk: Clearing, shoreline disturbance, dewatering and sediment release are most likely to harm the species from May to September, when spawning habitat needs to be inundated and recruitment is occurring. Risk is highest from June to August.

Identification

The golden galaxias is a thickset, scaleless freshwater fish with a long head and slender snout. Identification should be completed by an experienced freshwater fish ecologist, particularly where other galaxias or introduced fish occur.

Adults are golden to olive on the back and sides, with dark elliptical or oval spots. The underside is silvery grey. The fins are amber to light orange, with black posterior edges on the dorsal, anal and pelvic fins, and the tail is forked.

Juveniles have dark bands on the back and sides. These bands gradually break up into the spotted adult pattern. The species has no scales.

Adult size: Usually up to about 140 to 150 mm, with occasional fish reaching 240 mm

Body: Stout or thickset, with a long head and slender snout

Weight: Not reported in the supplied documents

Sex differences: No reliable external sex differences are described in the supplied documents

Identification: Similar species and confirmation

The species may occur in the same broad wetland system as introduced common galaxias, Galaxias maculatus. The supplied documents do not provide a full diagnostic comparison, so uncertain records should be retained, photographed where possible and referred to a suitably experienced freshwater fish specialist.

Golden galaxias can be distinguished from many small fish in the area by its golden to olive colour, dark elliptical spots, orange to amber fins with black posterior edges, forked tail and absence of scales. Juveniles may be harder to identify because they have dark bands rather than the adult spot pattern.

Identification: Field detection

There are no useful terrestrial field signs such as tracks, scats, nests, hollows or calls. Detection relies on observing or capturing fish in suitable freshwater habitat.

The species is primarily nocturnal in survey samples. Fish move into shallow water near shore at night and use deeper water during the day. Night fyke netting has produced the best overall results for numbers and size range in survey work, while night snorkelling, electrofishing and small dip nets may also be used under appropriate permits and animal ethics requirements.

General stream or lake shore effort: At least 30 minutes of backpack electrofishing is given as general effort for Tasmanian galaxiids, where suitable and authorised

Lake sampling: Fine soft mesh fyke nets are commonly left overnight; about 10 nets for one or two nights is described as generally adequate for some lake galaxiid surveys

  • Treat shallow rocky shorelines, vegetated margins, marsh edges and gently flowing connecting waters as potential habitat.
  • Use experienced personnel and approved methods for any capture, handling, electrofishing or netting.
  • For project surveys, consider night sampling because detection rates may be higher near the shore at night.
  • Prevent transfer of water, fish, equipment or aquatic organisms between catchments to reduce the risk of spreading introduced fish and aquatic diseases.

Distribution: National range

The golden galaxias is endemic to Tasmania and has one of the most restricted distributions of Australia's threatened freshwater fish. Its natural range is confined to the Lake Sorell and Lake Crescent system and nearby connected waters.

The species is known naturally only from Tasmania. Records are from Lake Crescent, Lake Sorell, associated streams and wetlands, a tributary of Lake Crescent at Interlaken, and the Clyde River outflow from Lake Crescent.

The species occurs in the Tasmanian Central Highlands Interim Biogeographic Regionalisation for Australia bioregion and the South Natural Resource Management Region.

States and territories: Tasmania only

Estimated extent of occurrence: Approximately 76 km², and less than 100 km²

Elevation: The lakes are at approximately 800 m above mean sea level

Distribution: Strongholds and subpopulations

The two natural populations are in Lake Crescent and Lake Sorell. Carp containment screens installed in the connecting canal have fragmented the populations by restricting movement of all but the smallest, larval fish.

Lake Crescent is the main stronghold. The species is reported to occur at about ten times the density found in Lake Sorell. A Ramsar site assessment estimated that Lake Crescent may contain up to 80 per cent of the total population, although there are no quantitative data for total abundance.

Natural locations: Two, Lake Crescent and Lake Sorell

Relative density: Approximately ten times higher in Lake Crescent than in Lake Sorell

Population size: No quantitative estimate is available

Population trend: Abundance declined during the prolonged dry period from the late 1990s to early 2009, particularly in Lake Crescent; current total abundance is not quantified

  • Treat both lakes as occupied habitat, even where fish are not detected during a particular survey.
  • Include associated wetlands, tributaries, outflows and connecting channels in the assessment of potential project impacts.
  • Do not assume that a small or isolated wetland is unimportant, because adjacent marshes may provide nursery, refuge, feeding or spawning habitat.

Distribution: Translocated populations

Two small translocated populations have been reported from isolated farm dams outside the natural range. The supplied assessment did not consider them in the listing because the basis for translocation and evidence of successful breeding were unavailable.

Habitat: Overall habitat

Golden galaxias are primarily lake dwelling and use still or gently flowing freshwater. Habitat quality depends on water levels, shoreline structure, aquatic vegetation, wetland connectivity and water quality.

Adults occur in shallow lake margins, rocky shorelines, rocky lake beds, aquatic macrophyte beds and marsh habitats. The species also uses associated tributaries, outflows and wetlands.

Juveniles remain in open water during their first 4 to 5 months, until they are about 40 mm long, before moving inshore for shelter and larger prey.

Water type: Freshwater, primarily lacustrine, in still or gently flowing water

Typical lake setting: Shallow, high elevation lakes at approximately 800 m above mean sea level

Important wetland type: Intermittently inundated freshwater marshes adjacent to the lakes

  • Map permanent and intermittent freshwater lakes, marshes, tributaries, outflows and connecting channels within and downstream of a project area.
  • Identify rocky substrates, submerged or emergent aquatic vegetation, macrophyte beds and shallow sheltered margins.
  • Assess whether construction or clearing could alter water levels, inundation timing, sediment movement, turbidity or connectivity.

Habitat: Structural features

Complex shoreline habitat provides shelter and supports feeding and spawning. Rocky substrate and aquatic vegetation are especially important in shallow water.

Intermittent marshes can provide nursery habitat for juveniles, refuge from introduced fish predators, feeding habitat and possible spawning habitat when inundated.

  • Retain rocky shorelines, submerged vegetation, emergent vegetation and wetland margins wherever practicable.
  • Avoid isolating wetlands or shallow margins from the main lake during works or through altered drainage.
  • Maintain suitable water levels and seasonal inundation so spawning areas are covered during the breeding period.

Foraging habitat: Diet

Golden galaxias feed in the water column when young and shift towards inshore and benthic feeding as they grow. They use open water, rocky margins, aquatic vegetation and adjacent wetlands.

Larvae feed on zooplankton and small insect larvae in the water column. Juveniles and adults eat aquatic and terrestrial insects, insect larvae, small crustaceans and molluscs.

Terrestrial invertebrates that fall onto the water form a significant part of the diet during summer and autumn. Fish of this species may also consume eggs and juvenile fish, including through cannibalism.

Larval prey: Zooplankton and small insect larvae

Juvenile and adult prey: Aquatic and terrestrial insects, insect larvae, small crustaceans and molluscs

Seasonal food input: Terrestrial invertebrates falling onto the water are important in summer and autumn

Foraging habitat: Where and how it feeds

Young fish shoal and feed in open water. At about 60 to 70 mm long, juveniles move inshore and take larger benthic prey. Adults use rocky areas, vegetated margins and marsh habitat.

Feeding habitat can be reduced when low lake levels expose rocky shores, dry marshes and remove aquatic structure. Increased turbidity may also alter the availability of habitat and prey, even though laboratory trials did not show a direct feeding effect from turbidity alone.

Inshore movement threshold: Juveniles move inshore at approximately 60 to 70 mm, after first moving from open water at about 40 mm and 4 to 5 months of age

Foraging range: No quantified home range is provided; fish use open water, lake margins, wetlands and associated streams

  • Treat shallow margins, rocky substrate, macrophyte beds, marsh edges and open water as foraging habitat for different life stages.
  • Prevent sediment inputs, pollution and hydrological changes that reduce aquatic vegetation or increase turbidity.
  • Retain terrestrial vegetation adjacent to water where it contributes falling invertebrates and protects the shoreline from erosion.

Breeding habitat: Breeding biology

The golden galaxias breeds in shallow water among rocky substrate or aquatic vegetation. Successful recruitment depends on suitable lake levels and seasonal inundation of shoreline and wetland habitat.

Spawning occurs in late autumn to winter. Eggs adhere to rocky substrate or aquatic vegetation in shallow water. Eggs hatch after about 30 to 45 days.

Seasonal rises in water level between May and September help cover spawning habitat and support recruitment, particularly in Lake Crescent.

Breeding season: Late autumn to winter, generally May to August, with water level management relevant from May to September

Eggs per female: Approximately 1,000 to 15,000 small eggs, depending on female size

Egg size: Approximately 1.5 mm diameter

Egg attachment: Eggs adhere to rocky substrate or aquatic vegetation

Spawning depth: Approximately 300 to 600 mm of water

Incubation: Approximately 30 to 45 days

Larval size at hatching: Approximately 5 to 6 mm long

Age at maturity: Not reported in the supplied documents

Lifespan: Most fish live for 3 to 4 years, with some reaching more than 6 years

Breeding habitat: Breeding habitat features

Important breeding habitat includes inundated rocky lake margins, shallow aquatic vegetation and adjacent intermittent marshes. Wetlands may also provide nursery habitat for juveniles and refuge from predation.

Low lake levels reduce the area of available spawning habitat. Loss of connectivity between marshes and the lake can isolate fish from spawning sites and reduce access to shelter and food.

  • Avoid works that disturb or remove shallow rocky shoreline and aquatic vegetation, especially between May and September.
  • Maintain water over known or potential spawning substrates at approximately 300 to 600 mm during spawning.
  • Prevent sedimentation, pollution and abrupt water level changes near spawning and nursery habitat.
  • Survey connected wetlands and marshes as well as the open lake, because their use may vary with inundation.

Sheltering habitat: Shelter by life stage

Shelter is provided by rocky shorelines, complex submerged habitat, aquatic vegetation and intermittently inundated marshes. Shelter needs change with age and time of day.

Larvae and small juveniles occupy the water column. At about 40 mm long and 4 to 5 months old, juveniles move towards the shore and seek shelter and larger prey.

Adults prefer complex rocky habitat, particularly along the shore of Lake Crescent and across the rocky substrate of Lake Sorell. Macrophyte beds and marshes also provide shelter.

Juvenile shift to shelter: At approximately 4 to 5 months of age and 40 mm long

Known shelter features: Rocky shorelines, rocky lake beds, macrophyte beds, vegetated margins and inundated marshes

Shelter dimensions: No den, refuge or home range dimensions are reported

  • Retain rocky margins, submerged rocks, aquatic macrophytes and emergent vegetation.
  • Protect inundated marshes that may provide cover for juveniles and refuge from trout.
  • Do not treat exposed shoreline as permanent non habitat, because habitat value can return when water levels rise.

Sheltering habitat: Daily habitat shifts

Survey evidence indicates that fish move into shallow water near shore at night and occupy deeper water during the day. This pattern should be considered when planning construction exclusion zones and fish salvage or monitoring.

  • Do not rely on daytime shoreline observations alone to determine whether habitat is occupied.
  • Schedule detection surveys across suitable times, including night sampling where safe, authorised and appropriate.
  • Keep works, dewatering and temporary barriers away from connected shallow and deeper-water habitat until occupancy has been assessed.

Threats: Hydrology and habitat loss

The main risks to golden galaxias are loss and degradation of shallow lake and wetland habitat, low water levels, introduced fish and fragmentation between the two natural populations. Development activities can worsen these risks through hydrological change, sedimentation, shoreline disturbance and barriers to movement.

Low lake levels caused by drought, evaporation and water extraction are the primary threat. They reduce spawning habitat, dry shallow marshes, expose rocky shores, reduce aquatic vegetation and can increase turbidity.

Long periods of high or low water can also disrupt wetland reproduction, water quality and the seasonal inundation trigger for spawning. Climate scenarios for the region indicate that lower inflows and higher evaporation may produce lower lake levels and longer periods between spill events.

  • Assess direct and downstream effects on lake levels, wetland inundation, groundwater and connecting flows before works begin.
  • Avoid drainage, dewatering or water extraction that lowers shallow habitat during the breeding period.
  • Maintain water levels above the applicable critical minimum level under the Lakes Sorell and Crescent Water Management Plan.
  • Avoid sedimentation and pollution that could reduce water quality or increase turbidity.

Threats: Clearing, construction and fragmentation

Clearing or partial harvesting near wetlands may increase sediment deposition, turbidity, nutrient inputs, altered drainage and weed establishment. These effects can reduce fish habitat even where the lake shoreline is not directly disturbed.

Screens in the canal between Lake Sorell and Lake Crescent restrict movement of golden galaxias and have fragmented the two natural populations. New culverts, weirs, temporary dams, screens or poorly designed crossings could create similar barriers in associated streams and channels.

  • Avoid clearing native vegetation adjacent to tributaries, wetlands, lake margins and outflows where it protects water quality and shoreline structure.
  • Design crossings and temporary works to maintain fish passage and natural wetting and drying patterns.
  • Inspect barriers and screens for unintended exclusion of golden galaxias, not only for their intended target species.
  • Keep machinery, spoil, concrete washout, fuels and sediment controls out of connected freshwater habitat.

Threats: Predators and introduced species

Brown trout occur in both lakes and feed on golden galaxias. Trout can also cause indirect effects by changing golden galaxias habitat use, potentially reducing feeding, growth and reproduction.

European carp have been present in the lake system and can affect water quality and turbidity. Common galaxias has also been introduced to the system. The containment screens installed to restrict carp movement have also restricted golden galaxias movement.

  • Do not stock or translocate trout or other non native fish into connected waters.
  • Prevent fish transfer between water bodies and follow approved aquatic hygiene procedures.
  • Do not use golden galaxias as live or dead bait.
  • Report suspected introduced fish and avoid moving water, plants, mud or equipment between catchments.

Threats: Fire, disease and other risks

The supplied documents do not identify fire as a direct species specific threat. Fire planning should nevertheless consider indirect effects from loss of riparian cover, ash, sediment and altered runoff into occupied freshwater habitat.

The Ramsar assessment identifies potential risks from didymo, Didymosphenia geminata, and other exotic aquatic organisms. Disease and aquatic pest controls should be applied to equipment and personnel working between wetlands and lakes.

Ramsar recruitment trigger: Loss of two successive golden galaxias cohorts was identified as a limit of acceptable change for the Interlaken Lakeside Reserve

  • Prevent ash, sediment and contaminated runoff from entering occupied streams, wetlands and lake margins after fire or vegetation clearing.
  • Clean and dry boats, nets, waders, pumps and other aquatic equipment before moving between water bodies.
  • Include aquatic weeds, didymo and introduced fish in environmental inductions for project staff and contractors.
  • Treat any prolonged loss of recruitment as a warning sign, noting that the Ramsar assessment used loss of two successive cohorts as a limit requiring investigation.

Survey methodology: 1. Define the survey area and habitat

Golden galaxias occur only in freshwater habitats associated with Lake Sorell, Lake Crescent, nearby streams and wetlands in central Tasmania. Surveys for projects affecting these habitats should target shallow rocky margins, vegetated lake edges, intermittent marshes and gently flowing water, with extra attention to night activity and the autumn to early winter spawning period.

Map the project footprint and all areas that could be affected indirectly, including upstream and downstream waterbodies, drainage lines, wetlands, lake margins and areas where sediment, altered flows or water extraction could affect habitat.

Record rocky shorelines, submerged or emergent vegetation, macrophyte beds, intermittent marshes, shallow water and connections between lakes, streams and wetlands.

Treat any freshwater habitat within the species’ known natural range as potentially relevant, because the species is known naturally only from Lake Sorell, Lake Crescent and associated streams and wetlands.

Known natural distribution: Lake Sorell, Lake Crescent, associated streams and wetlands on Tasmania’s Central Plateau

Extent of occurrence: Approximately 76 km², and less than 100 km²

Adult habitat: Rocky lake margins, rocky lake substrate, macrophyte beds and marsh habitat

Juvenile habitat: Open water until approximately 4 to 5 months of age, then shallow inshore habitat with shelter

Survey methodology: 2. Night fyke netting

Use fine soft mesh fyke nets in lakes and other suitable still-water habitat, because night fyke netting produced the best overall results for numbers and size range in the survey guidance.

Set nets overnight and construct and operate them to prevent platypus drowning, restrict access by large trout, and keep cod ends out of the water or buoyed.

Use approximately 10 nets for one or two nights where lake conditions and access allow, and record the number, location and duration of every set.

Give particular attention to shallow margins at night, when golden galaxias move closer to shore; they may be in deeper water during the day.

Typical effort: Approximately 10 fine-mesh fyke nets for 1 to 2 nights

Best period of activity: Night, when fish move into shallow water near shore

Detection note: Fyke netting at night gave the best overall results for numbers and size range in the cited comparison

Survey methodology: 3. Electrofishing and dip-netting

Use backpack electrofishing for streams and lake shores where the method is safe, permitted and suitable for the waterbody, and use a flat dip net to slide fish into a holding bucket.

Complete at least 30 minutes of backpack electrofishing at each monitoring site for streams and lake shores, using standardised effort between sites.

Use the lowest effective electrofishing settings and follow the Australian Code of Practice, with settings selected for local conductivity and site conditions by an appropriately trained operator.

Use small scoop or dip nets in shallow margins, aquatic vegetation and other areas where electrofishing is unsuitable or likely to harm fish.

Minimum electrofishing effort: At least 30 minutes at each stream or lake-shore site

General electrofishing guidance: Use 60 Hz and 2 or 4 mS as the general galaxiid settings cited, with voltage commonly 200 to 700 V, adjusted to conductivity and used only by trained operators

Handling equipment: Flat dip net and partly filled water bucket for temporary holding

Survey methodology: 4. Snorkelling, visual searches and larval sampling

Use night snorkelling and small hand nets for visual searches or capture where water clarity, depth, safety and approvals permit.

Inspect shallow rocky margins and vegetated edges at night, when the species is more active and closer to shore than during the day.

Use a fine-mesh larval tow net behind a boat only where larvae need to be assessed and the activity is authorised; preserve collected larvae for later sorting because larvae are generally difficult to identify in the field.

Increase sampling during autumn and early winter where practicable, because higher numbers have been recorded during the spawning season in Tasmania.

Spawning period: Late autumn to winter in the conservation advice, with higher survey numbers reported in autumn and early winter

Egg habitat: Rocky substrate or aquatic vegetation in shallow water approximately 300 to 600 mm deep

Larval method: Fine-mesh net towed behind a boat, with samples preserved for later sorting

Survey methodology: Minimum effort and reporting

  • Use a combination of suitable methods rather than relying on a single negative survey result, particularly where the project may affect lake margins, marshes or connected streams.
  • Record survey dates, times, water levels, weather, water clarity, water depth, habitat sampled, method, effort, equipment settings, net locations, captures and identification confidence.
  • Photograph representative habitat and any captured fish where this can be done without delaying release or increasing handling stress.
  • Have an experienced galaxiid identifier or relevant aquatic ecologist confirm uncertain records, because larvae and small fish can be difficult to identify.
  • Submit confirmed records and survey results to the relevant Tasmanian wildlife or biodiversity database and provide records to the project approval authority where required.
  • Report negative results as well as detections, including the area and habitat types actually surveyed.

Before habitat disturbance: Avoid and minimise habitat loss

Avoid disturbance to the shallow freshwater margins and wetland connections used by golden galaxias for shelter, feeding, spawning and juvenile development. A project that may affect these habitats should be assessed as an EPBC Act matter and managed with aquatic survey, timing, water-quality and fish-handling controls.

  • Retain rocky shorelines, shallow vegetated margins, macrophyte beds, intermittent marshes and connected streams wherever practicable.
  • Keep works, access tracks, stockpiles and machinery out of shallow margins and wetlands, and avoid filling, draining, dewatering or isolating habitat.
  • Maintain connections between lakes, wetlands and streams, because low water levels and containment structures can isolate fish from spawning and nursery habitat and reduce movement between populations.
  • Avoid changes to hydrology, sediment delivery, pollution and turbidity that could reduce spawning habitat or water quality.
  • Do not introduce, move or stock alien fish, including brown trout, European carp or other non-native species, through project activities.

Before habitat disturbance: Approvals and project planning

  • Check whether the action is likely to have a significant impact on this EPBC Act endangered species and refer the action under the EPBC Act where required.
  • Confirm Tasmanian permits, Inland Fisheries Service requirements, animal ethics approvals, scientific permits and any waterway, wetland or threatened-species approvals before aquatic survey, capture, relocation, dewatering or construction.
  • Prepare a fauna and aquatic habitat management plan that identifies survey methods, authorised handlers, exclusion areas, water-quality controls, fish rescue procedures, release sites, stop-work triggers and reporting responsibilities.
  • Schedule unavoidable works to avoid the late autumn to winter spawning period where practicable, and avoid periods when low lake levels have exposed or disconnected spawning margins.
  • Stage works so retained habitat remains connected and fish can be moved only under an approved procedure if temporary isolation cannot be avoided.

Before habitat disturbance: Pre-clearance preparation

Typical size: Common length approximately 150 mm, with a maximum recorded length of approximately 240 mm

Identification features: Golden to olive upper body with dark elliptical or ovoid spots, silvery-grey underside, amber to light orange fins and no scales

Key spawning depth: Approximately 300 to 600 mm of water over rocky substrate or aquatic vegetation

  • Complete the targeted aquatic survey before disturbance, including suitable lake-margin, wetland and stream habitat within and downstream of the work area.
  • Mark no-go areas around retained rocky margins, aquatic vegetation, marshes, wetlands, waterways and fish movement connections before machinery arrives.
  • Install exclusion fencing or clearly marked aquatic buffers where these controls can keep machinery, sediment, fuels and personnel away from retained habitat.
  • Inspect culverts, temporary crossings, cofferdams, pumps and dewatering points for fish passage, entrapment and escape risks before installation.
  • Brief all operators and spotter catchers on the species’ appearance, its endangered status, its shallow-margin habitat and the requirement to stop if fish or suitable habitat is found.

During habitat disturbance: Daily controls and machinery coordination

Treat works in or near freshwater habitat as an aquatic fauna operation, not as ordinary terrestrial clearing. The fauna spotter catcher must work within the approved method, keep machinery away from retained habitat and stop work when fish, connected habitat or an uncontrolled water-quality risk is encountered.

  • Hold a daily pre-start briefing covering exclusion areas, water levels, weather, approved work limits, fish rescue arrangements, emergency contacts and stop-work triggers.
  • Inspect exclusion fencing, sediment controls, pumps, screens, temporary crossings and dewatering systems before work starts and after heavy rain or equipment movement.
  • Keep fuels, chemicals, concrete washout, spoil and sediment away from water, wetlands and drainage lines, and prevent dirty water from entering retained habitat.
  • Use a fauna spotter catcher or aquatic fauna specialist to inspect the active work area immediately before machinery enters or changes the bed, bank, water level or flow path.
  • Require operators to stop immediately on the spotter catcher’s instruction, keep the machine stationary and await direction before restarting.

During habitat disturbance: Aquatic habitat and fish handling

  • Do not disturb rocky spawning substrate, aquatic vegetation, macrophyte beds or marsh habitat unless the approved impact cannot be avoided.
  • Where dewatering or isolation is approved, use a documented fish rescue procedure with trained and authorised personnel, suitable nets, aerated holding containers, shade and water-quality checks.
  • Keep captured fish in site water for the shortest practicable time, avoid crowding and temperature shock, and release them to nearby retained habitat only where the approved plan identifies a safe, connected release location.
  • Do not transfer fish between Lake Sorell, Lake Crescent or other catchments unless specifically authorised, because containment structures have fragmented the two natural populations and unapproved movement can spread fish and disease.
  • Do not use live or dead golden galaxias as bait, and prevent workers, boats, nets and equipment from moving alien fish or aquatic pests between waterbodies.

During habitat disturbance: Finds, injury and stop-work response

  • If a golden galaxias is found, stop the activity affecting its habitat, protect the fish from machinery and notify the project ecologist and the person responsible for the approval.
  • Only personnel authorised under the project plan and relevant permits may capture, handle, identify, transport or release the fish.
  • Do not handle a fish unnecessarily; record its location and habitat, photograph it where safe, and use the approved rescue and release procedure if the work cannot be avoided.
  • Take injured fish to an appropriately qualified aquatic wildlife veterinarian or authorised wildlife carer, or follow the approved government contact procedure.
  • Stop work if fish are detected in an unapproved impact area, fish are trapped or stressed, water becomes visibly turbid or contaminated, dewatering threatens fish passage, or exclusion and sediment controls fail.
  • Obtain approval from the project ecologist and relevant regulator before restarting work after a stop-work event.

During habitat disturbance: Records and incident reporting

  • Record every detection, capture, relocation, injury, mortality, release location, water-quality incident, stop-work event and corrective action on the same day.
  • Record fish length where this can be done without harmful handling, together with photographs, GPS location, habitat type, water depth, water level and project activity.
  • Report deaths, injuries, unapproved captures, pollution events, loss of connectivity and damage to spawning or nursery habitat to the approval holder and relevant authorities within the timeframes in the approval or management plan.
  • Retain survey and incident records with the project environmental file and submit confirmed species records to the relevant state wildlife database.

After habitat disturbance: Immediate post-work checks

Post-work checks should confirm that fish were not left isolated, spawning and nursery habitat remains functional, and water quality and connectivity have been restored. Monitoring should continue long enough to detect delayed effects on recruitment, not only immediate mortality.

  • Inspect the work area, downstream reaches, retained lake margins and nearby wetlands for stranded, injured or dead fish after machinery leaves and after temporary water-control structures are removed.
  • Check that rocky margins, aquatic vegetation, marshes and shallow-water connections have not been buried, dewatered, isolated or contaminated.
  • Remove temporary pumps, screens, barriers, spoil and access materials that could obstruct fish movement or create entrapment, unless they are part of an approved permanent design.
  • Confirm that sediment controls are stable and that released water is suitable for the receiving habitat before reconnecting isolated areas.

After habitat disturbance: Monitoring and success checks

Interlaken Lakeside Reserve fish limit of acceptable change: Loss of two successive cohorts of golden galaxias

Monitoring context: The golden galaxias is a critical component of the Interlaken Lakeside Reserve and its wetlands provide spawning, foraging, refuge and nursery habitat

  • Monitor retained and restored habitat for water level, turbidity, aquatic vegetation, rocky substrate, fish passage and evidence of spawning or juvenile use.
  • Repeat targeted fish surveys where the approval, risk assessment or project ecologist identifies a risk of delayed mortality, recruitment failure or loss of connectivity.
  • Use the wetland Ramsar ecological character reference point where relevant, including the stated limit of acceptable change of loss of two successive golden galaxias cohorts at Interlaken Lakeside Reserve.
  • Investigate any decline in detections, loss of spawning habitat, prolonged disconnection, fish mortality or deterioration in water quality, and adapt controls before further works proceed.

After habitat disturbance: Close-out and ongoing controls

  • Maintain exclusion fencing, sediment controls, weed hygiene and fish-passage controls until the site is stable and the project ecologist confirms that they are no longer needed.
  • Provide the regulator and approval holder with a close-out report containing methods, effort, detections, handling, injuries, mortalities, water-quality incidents, habitat impacts, rehabilitation results and any corrective actions.
  • Submit confirmed records to the relevant state wildlife database and update the project’s EPBC and state approval records.
  • Implement any approved offset, compensatory habitat or long-term management measure where residual impacts cannot be avoided or mitigated.

Rehabilitation actions: Restore physical habitat and hydrology

Rehabilitation should restore the shallow-water structure and hydrological connections that golden galaxias use during feeding, shelter, spawning and juvenile development. Design and monitoring should reflect the species’ dependence on rocky margins, aquatic vegetation, intermittent marshes and suitable water levels.

Spawning habitat: Rocky substrate or aquatic vegetation in shallow water approximately 300 to 600 mm deep

Important wetland function: Adjacent wetlands are thought to provide feeding, shelter and possibly spawning habitat, and are important nursery areas for juveniles

Management reference: Maintain lake levels above the Critical Minimum Level specified in the Lakes Sorell and Crescent Water Management Plan where that plan applies

  • Reinstate shallow rocky margins and stable rocky substrate where construction has removed or covered spawning habitat.
  • Re-establish native aquatic and wetland vegetation in areas that previously supported macrophytes, emergent vegetation or marsh habitat, using locally appropriate species and a design suited to periodic inundation and drying.
  • Restore wetland to lake connectivity and avoid drainage, barriers or culverts that prevent fish movement between open water, shallow margins, marshes and streams.
  • Design water levels and environmental flows to retain suitable spawning habitat, with particular attention to seasonal rises between May and September where this is consistent with the applicable water-management plan.
  • Do not create permanent deep, bare or isolated water in place of the shallow, structurally complex habitat used by adults and juveniles.

Rehabilitation actions: Control weeds, predators and aquatic pests

  • Control weeds and exotic plants that displace native wetland vegetation or reduce the structure available for fish shelter and feeding.
  • Prevent introduction or spread of European carp, brown trout and other alien fish during rehabilitation, equipment movement, water transfer and stocking activities.
  • Maintain weed and aquatic-pest hygiene for boats, nets, pumps, boots and machinery before they enter another waterbody.
  • Do not stock alien salmonids in Lake Sorell or Lake Crescent, and support approved carp eradication and monitoring programs where relevant.
  • Manage sediment and nutrient runoff so turbidity, algal growth and loss of aquatic vegetation do not reduce habitat quality.

Rehabilitation actions: Monitoring and success measures

Suggested fish monitoring reference: At least 30 minutes of electrofishing per stream or lake-shore site, or approximately 10 fyke nets for 1 to 2 nights in suitable lake habitat, where those methods are approved and safe

Wetland vegetation reference: At Interlaken Lakeside Reserve, a 50 per cent change in wetland vegetation area for more than six months is identified as a limit of acceptable change

  • Monitor restored areas through at least the first spawning periods and continue for the period required by the approval or rehabilitation plan.
  • Measure survival and cover of native aquatic and wetland vegetation, area and continuity of shallow-water habitat, condition of rocky substrate, water level, turbidity and fish passage.
  • Use repeat night fyke netting, electrofishing or other approved methods to assess golden galaxias presence, size classes and recruitment, applying consistent effort between monitoring events.
  • Treat restoration as successful only when the approved habitat, water-quality and connectivity targets are met and monitoring shows continued use by golden galaxias without unacceptable injury or mortality.
  • Investigate failure to achieve habitat or recruitment targets and repair water-level, sediment, weed, predator or connectivity problems.

Sources