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Pedder Galaxias (Galaxias pedderensis)

The Pedder galaxias is a small to medium sized, non migratory freshwater fish endemic to south-western Tasmania. It is extinct in its natural Lake Pedder range and survives in translocated populations at Lake Oberon and Strathgordon water supply dam, so works affecting suitable high altitude lakes, feeder streams or fish-free refuge waters require specialist advice and controls.

Conservation status

Tasmania, Threatened Species Protection Act 1995: Endangered.

Breeding season

The species lives in freshwater year round and is not known to migrate between freshwater and the sea. Spring spawning and the presence of eggs and larvae make late spring and summer the most sensitive period for in-stream or lake margin disturbance.

Month values represent January to December: 0 means not typical, 1 means occurs, and 2 means peak or highest risk. The species remains present in freshwater throughout the year.

  • Breeding: Spawning occurs in spring as water temperatures rise, generally in October. Eggs are placed under rocks, aquatic vegetation or submerged wood.
  • Eggs and larvae: Eggs take about 22 to 30 days to hatch at 15 to 16 degrees Celsius. Larvae are about 10 mm long at hatching.
  • Young fish: Juveniles are reported in large numbers during summer and may school in open water near lake margins. They also use shallow vegetated margins.
  • Movement and habitat use: The species is non migratory and spends its whole life in freshwater. Adults use streams and pools, while larvae and juveniles may use lake margins and open water.
  • Highest clearing risk: Risk is highest from September to February because spawning, eggs, larvae and young fish may be present in stream beds, lake margins, vegetation, rocks and submerged wood. Any aquatic disturbance can also harm adults outside this period.

Identification

The Pedder galaxias is a slender, medium sized galaxiid with no scales. Identification in the field should be undertaken by an experienced freshwater fish ecologist, particularly where climbing galaxias are present.

Adults have a slender elongated body, light grey-brown upper body and sides, irregular dark blotches and spots, gold flecks or gold iridescence on the back and sides, and a grey-white underside. The blotching can extend onto the head and the fleshy bases of the dorsal, caudal and anal fins.

The mouth faces slightly downwards because the lower jaw is distinctly undercut. The species has no scales, a single dorsal fin set well back on the body, and yellow-brown fins.

Typical adult length: 75 to 120 mm

Maximum recorded length: About 156 to 170 mm

Weight: No reliable weight information is provided in the supplied sources.

Identification: Distinguishing it from climbing galaxias

The climbing galaxias is the main similar species identified in the supplied sources. The Pedder galaxias has a more bullet-shaped head and jaws of more nearly equal length, whereas the climbing galaxias has a dorsally compressed, wedge-shaped head and a distinctly undercut lower jaw.

Pedder galaxias generally lack the chevron shaped side markings often seen on climbing galaxias and have relatively small pectoral fins. Climbing galaxias have larger, rounded pectoral fins and are associated with leaping and climbing behaviour, which is not characteristic of the Pedder galaxias.

Identification: Field detection

There are no documented tracks, scats, calls, nests, burrows, sloughs or eyeshine for this fish. The practical field signs are live fish, larvae, juveniles or eggs in suitable freshwater habitat.

Adults and juveniles can occur in mid-water pools. Juveniles may form schools in open water near lake margins. Night snorkelling has been used to observe Pedder galaxias, while electrofishing, fyke nets and small hand nets are used by trained specialists for targeted surveys.

Survey effort guidance: General Tasmanian galaxiid guidance specifies at least 30 minutes of backpack electrofishing for streams and lake shores; the Pedder galaxias may require substantially longer stream searches because of its rarity.

  • Use a trained freshwater fish survey team for any targeted assessment.
  • Use electrofishing in streams and along lake shores only with the required permits, animal ethics controls and equipment.
  • Treat any suspected record as significant and photograph, measure and release fish according to the approved survey method.

Distribution: State and bioregion

The species is endemic to south-western Tasmania and has never had a natural mainland Australian distribution. Its natural range was centred on the original Lake Pedder and nearby streams, swamps and pools, while current records are from translocated populations outside the former range.

The Pedder galaxias is known only from Tasmania. Its historical distribution was in south-western Tasmania, within the Tasmanian West IBRA Bioregion and the South Natural Resource Management region.

The current translocated populations occur in the same broad south-west Tasmanian region, including the Western Arthur Range and Strathgordon.

Australian states: Tasmania only

IBRA bioregion: Tasmanian West

Natural Resource Management region: South

Distribution: Known populations and strongholds

The natural population occupied the original Lake Pedder, inflowing streams and tributaries of the Serpentine and Wedge rivers, and nearby swampy pools. The species was last recorded in its natural range in 1996, and intensive surveys through 2002 found no further fish.

A population was established at Lake Oberon in the Western Arthur Range using 34 fish released between 1991 and 1997. A second population was established at the Strathgordon water supply dam using fish transferred from Lake Oberon. The Tasmanian listing statement reports both translocated populations as abundant and self sustaining through natural recruitment.

Distance of Lake Oberon from Lake Pedder: About 10 to 12 km south-west

Lake Oberon establishment: 34 fish released between 1991 and 1997

Strathgordon transfers: 353 fish transferred from Lake Oberon between 2001 and 2007

Natural range trend: No records from the natural range after 1996 despite intensive surveys

  • Lake Oberon, within the Tasmanian Wilderness World Heritage Area.
  • Strathgordon water supply dam, managed for conservation and monitored by the Inland Fisheries Service.

Distribution: Population status

The original population declined rapidly after Lake Pedder was inundated and after alien fish became established. The species is now considered extinct in its natural habitat.

The translocated Lake Oberon population has shown successful breeding. The Strathgordon population is described in the latest Tasmanian listing statement as self sustaining, although earlier assessments recorded uncertainty about breeding success.

Habitat: Waterbodies and stream habitat

The Pedder galaxias is a non migratory freshwater fish that uses lakes, feeder streams, swamps and pools. It is associated with cool, high altitude Tasmanian waters and requires sites without predatory or competing introduced fish.

The species uses both lacustrine and stream habitats. The original Lake Pedder was shallow, generally less than 3 m deep, with a predominantly sandy substrate, extensive beaches, surrounding swamps and meandering inflowing streams.

Adults in streams preferred forested sections with deep pools, relatively slow flow, sandy bottoms and abundant cover. Steeper streams above the inundation level were among the natural habitats that remained after the lake was flooded.

Original Lake Pedder depth: Less than 3 m

Post inundation Lake Pedder depth: More than 20 m in much of the impoundment, with a maximum reported depth of 43 m

Known elevation example: Lake Oberon is about 851 m above sea level

  • Look for deep, slow flowing pools in forested feeder streams.
  • Map lake margins, inflowing streams, swampy pools, submerged vegetation and woody debris where aquatic works are proposed.
  • Treat isolated, fish free lakes and streams as potential conservation habitat where the species or a translocated population is known or proposed.

Habitat: Vegetation and physical structure

The supplied sources do not assign the species to a named vegetation community. They describe forested stream sections, overhanging terrestrial vegetation, aquatic vegetation, submerged driftwood, rocks, boulders and sandy margins.

The species is associated with temperate, darkly tannin stained freshwater and rocky lake margins. Juveniles use open water near lake margins as well as vegetated shallow areas.

Habitat: Development screening

For projects in south-west Tasmania, include the full aquatic footprint in habitat screening. This includes upstream feeder streams, lake shorelines, temporary work areas, access crossings and downstream waters that could receive sediment, altered flows or fish.

The absence of a recent record from natural Lake Pedder does not remove the need to protect the two translocated populations. Confirm current records and management requirements with the Tasmanian Inland Fisheries Service before works near Lake Oberon or Strathgordon.

  • Prevent sediment, concrete washout, fuels and other pollutants from entering occupied or connected waters.
  • Do not move water, equipment or live fish between catchments without approved washdown and biosecurity controls.
  • Avoid creating fish passage for trout, climbing galaxias or redfin perch into refuge waters.

Foraging habitat: Diet and feeding sites

The Pedder galaxias is an opportunistic carnivore that feeds in freshwater pools, lake margins and stream habitats. It takes both aquatic and terrestrial prey.

The diet includes terrestrial insects, aquatic insect larvae, aquatic beetles and crustaceans. Larvae feed on small aquatic crustaceans.

Adults and juveniles are active mid-water swimmers and can be observed in pools. Lake juveniles may school in open water near the margins, while adults also use rocky margins, submerged vegetation and log snags.

Foraging range: No home range or regular foraging distance has been reported in the supplied sources.

Feeding mode: Opportunistic carnivory in lake and stream habitats

  • Retain pool structure, stable banks, overhanging vegetation, aquatic vegetation, rocks and submerged woody debris where works occur near occupied water.
  • Control sediment and turbidity because they can reduce the quality of shallow margins and affect aquatic prey.
  • Do not assume that open water is unused habitat, as juveniles may school away from the immediate shoreline.

Breeding habitat: Breeding biology

Breeding is linked to spring warming and appears to require sheltered surfaces in shallow stream or lake margin habitat. The original Lake Pedder may have provided nursery habitat for pelagic larvae and juveniles, while adults used streams for spawning.

Eggs are deposited under flat rocks, among aquatic vegetation or on submerged driftwood. Captive eggs hatched after 22 to 30 days at 15 to 16 degrees Celsius, and larvae were about 10 mm long at hatching.

The species is non migratory within its freshwater range, but adults may use feeder streams for spawning and lakes or lake margins as nursery habitat.

Breeding season: Spring, generally October

Eggs per female: About 200 to 1,200

Egg diameter: 2.2 to 2.5 mm

Incubation: 22 to 30 days at 15 to 16 degrees Celsius

Larval length at hatching: About 10 mm

Age at maturity: About two years; most fish breed at three to four years

Lifespan: Up to about six years

Breeding habitat: Breeding features to retain

Potential spawning habitat includes shallow or slow flowing stream margins, flat rocks, aquatic vegetation, submerged woody debris and sheltered lake edge structure. Works that remove these features or alter water temperature, flow or water quality may affect eggs and larvae.

The supplied sources do not define a breeding territory, nest size or minimum spawning flow. Apply a site specific aquatic habitat assessment rather than a fixed terrestrial buffer.

  • Avoid bed disturbance and removal of rocks, aquatic plants and submerged wood during spring spawning and egg incubation.
  • Maintain clean inflows and stable water levels around known spawning and nursery habitat.
  • Inspect dewatered work areas for eggs, larvae and small fish before isolation, with any rescue or relocation undertaken only under an approved fish management plan.

Sheltering habitat: Documented cover

The species uses physical cover in streams and along lake margins. Specific refuge dimensions have not been reported, but the documented cover types should be retained in occupied and potential refuge waters.

Adults in streams use deep pools with relatively slow flow, sandy bottoms and abundant cover. Lake habitats include rocks and boulders, submerged vegetation and log snags.

Eggs are sheltered under flat rocks, aquatic vegetation and submerged driftwood. Juveniles use shallow vegetated margins and open water near lake edges.

Known refuge size: No den, refuge or cover dimensions are provided in the supplied sources.

  • Retain deep pools, undercut or covered margins where present, rocky edges, boulders, aquatic vegetation and submerged logs.
  • Keep refuge waters free from brown trout, rainbow trout, redfin perch and climbing galaxias where required by the approved conservation programme.
  • Do not place temporary cofferdams, pumps or access tracks across pools or spawning structures without a fish passage and salvage plan.

Sheltering habitat: Biosecurity refuge requirements

The two translocated populations depend on waterbodies that are free from trout and other harmful fish. The more accessible Strathgordon site is particularly exposed to illegal or accidental fish introduction.

Climbing galaxias have been detected at Strathgordon during monitoring, and redfin perch in nearby Lake Gordon are a potential future threat to connected waters.

  • Use clean, dry or appropriately disinfected boats, nets, waders, pumps and other aquatic equipment before entering refuge waters.
  • Do not release, transfer or use live bait fish near occupied or potential refuge waters.
  • Report suspected introduced fish immediately to the relevant Tasmanian fisheries authority.

Threats: Introduced fish

The main historical decline followed inundation of Lake Pedder and the establishment of brown trout and climbing galaxias. For current project work, the main risks are disturbance of occupied refuge waters, altered hydrology, pollution, sediment and accidental introduction or spread of other fish.

Brown trout are the primary documented threat through predation and competition. Climbing galaxias may also compete for space and food and may prey on smaller galaxiids. Redfin perch are a potential additional threat because they occur in nearby Lake Gordon.

The two translocated populations were established in waters without trout. Introduction of any other fish species could threaten their persistence.

  • Prevent fish passage and fish transfer between occupied waters and waters containing trout, climbing galaxias or redfin perch.
  • Include aquatic equipment hygiene, bait controls and fish exclusion in construction environmental management plans.
  • Treat any proposed connection, culvert, channel modification or water transfer as a potential biosecurity risk.

Threats: Hydrology and habitat change

Inundation of the original Lake Pedder removed shallow lake margins, swampy pools, sandy shorelines and tributary habitat. The enlarged impoundment had very different depth and physical conditions.

Further changes to water levels, stream flow, flow velocity, lake margins or spawning cover could affect breeding and nursery habitat. The species is also sensitive to the loss of fish free refuge waters.

  • Avoid unnecessary dewatering, diversion, rapid drawdown or alteration of feeder stream flows.
  • Maintain connection between suitable pools and spawning areas where that connection is part of the approved habitat design.
  • Assess downstream effects from sediment release, altered discharge and changes to water temperature.

Threats: Clearing, roads and construction disturbance

The supplied sources do not identify terrestrial clearing, roads or fire as direct population threats. They do identify stream banks, forested stream sections, overhanging vegetation, aquatic vegetation, sandy substrates, rocks and woody debris as habitat features.

Clearing or access works beside occupied waters may remove cover, increase sediment delivery, destabilise banks or allow contaminated runoff to enter the water. Crossings and temporary works may also block or injure fish.

  • Keep riparian clearing to the minimum approved footprint and retain overhanging and aquatic vegetation where it contributes to cover or spawning habitat.
  • Use sediment and erosion controls before ground disturbance and maintain them until banks and access areas are stabilised.
  • Keep fuels, concrete washout, herbicides and other pollutants away from drainage lines, lake margins and feeder streams.
  • Use fish friendly crossings and avoid placing temporary infrastructure across deep pools, slow flowing margins or known spawning areas.

Threats: Fire, disease and fragmentation

The supplied sources do not identify fire or disease as established threats to the Pedder galaxias. They also provide no species specific fragmentation thresholds or road mortality data.

Fragmentation remains relevant where works isolate pools, remove fish passage or connect refuge waters to waters containing introduced fish. Disease and pathogen transfer should be managed through aquatic equipment hygiene and clean water practices.

  • Do not infer that a site is suitable for works solely because the species has not been recorded there recently.
  • Use a project specific aquatic connectivity and biosecurity assessment for any work near the two translocated populations.
  • Follow current Tasmanian fisheries and animal health requirements for fish handling, release and equipment disinfection.

Survey methodology: 1. Confirm the project area and potential habitat

The Pedder galaxias is a freshwater fish confined to two translocated populations in south-western Tasmania: Lake Oberon and the Strathgordon water supply dam. Survey work must be led by suitably experienced freshwater fish ecologists, with methods selected for lake margins, streams and other connected freshwater habitat.

First check whether the project could affect Lake Oberon, the Strathgordon water supply dam, or connected freshwater habitat in south-western Tasmania.

The species originally occupied Lake Pedder, its inflowing streams and tributaries, and swampy pools, but it has not been recorded in its natural range since 1996 despite intensive surveys.

Treat any freshwater lake margin, feeder stream, pool, swamp or wetland within or near a known translocation site as potential habitat until an experienced fish ecologist has assessed it.

Known current locations: Lake Oberon and the Strathgordon water supply dam

Original range: Lake Pedder, inflowing streams and tributaries, and swampy pools in south-western Tasmania

Typical habitat: Freshwater lakes and streams, including lake margins, pools and forested stream sections

Survey methodology: 2. Electrofishing streams and lake shores

Use backpack electrofishing for streams and lake shores where access and water conditions allow.

Use a flat dip net and place captured fish into a bucket containing water for identification and measurement before release.

Use the lowest effective electrical setting and equipment operated in accordance with the Australian Code of Practice by trained personnel.

Minimum effort: At least 30 minutes of backpack electrofishing for streams and lake shores

General settings reported for Tasmanian galaxiids: 60 Hz and 2 or 4 mS, with voltage generally 200 to 700 V, adjusted to water conductivity and fish response

Operator requirement: Trained specialists using approved fish-handling and animal-care procedures

  • Allow at least 30 minutes of backpack electrofishing at each stream or lake-shore monitoring site.
  • Survey slowly through pools and slower-flowing sections, including sandy-bottomed areas with cover, submerged vegetation and woody debris.
  • Record the length of each survey, the area or reach covered, water conditions, equipment settings, catch results and the precise location.

Survey methodology: 3. Fyke nets and night snorkelling

Use fine, soft-mesh fyke nets in lakes where authorised and where the method can be deployed without drowning platypuses or exposing fish to unnecessary harm.

Set nets according to Inland Fisheries Service requirements, with screens to exclude large trout and platypuses and cod ends out of the water or buoyed.

Use night-time snorkelling with small hand nets for visual detection or capture, particularly where fish are active near lake margins or in clear pools.

Fyke effort described for Tasmanian galaxiids: About 10 nets for one or two nights in lakes

Night observation method: Night snorkelling with small hand nets

  • Set fine-mesh fyke nets overnight in suitable lake habitat and check them as required by the approved method and animal ethics conditions.
  • As a general Tasmanian galaxiid approach, use about 10 fyke nets for one or two nights where lake access and approvals allow.
  • Conduct night snorkelling only with appropriately trained personnel, safe access, suitable visibility and a method that avoids disturbance to the bed, banks and aquatic vegetation.
  • Record the number of nets, net locations, soak time, snorkelling time, visibility, water level, weather and all detections or non-detections.

Survey methodology: Minimum effort and reporting

  • Use more than one method where the site contains both stream and lake-margin habitat, because electrofishing, fyke nets and night snorkelling detect fish in different settings.
  • Repeat surveys where water levels, visibility, access or other conditions could have reduced detection, and explain the reason for any reduced effort.
  • Do not treat a non-detection as proof that the species is absent from a known or suitable translocation site.
  • Have all capture, handling and translocation work undertaken by people authorised under the relevant Tasmanian approvals and animal-care arrangements.
  • Submit confirmed records, survey effort and spatial data to the relevant Tasmanian wildlife or threatened-species database and provide records to the Inland Fisheries Service or relevant land manager.
  • Report any Pedder galaxias detection, suspected capture, injury, mortality or introduced fish detection immediately to the project environmental manager and relevant Tasmanian authority.
  • Retain field sheets, photographs, specimen measurements, water-quality observations, equipment settings, net checks, GPS locations and chain-of-custody details for all records.

Before habitat disturbance: Avoid and minimise habitat disturbance

The species is nationally listed as Extinct in the Wild and is endangered under Tasmanian legislation. Project planning must therefore focus on avoiding disturbance to the two translocated populations and preventing the entry or spread of other fish.

Avoid works in Lake Oberon, the Strathgordon water supply dam, their feeder streams and associated freshwater margins wherever a practicable alternative exists.

Retain lake margins, pools, stream cover, aquatic vegetation, woody debris and stable banks used for feeding, shelter or spawning.

Prevent changes to water quality, flow, water level, sediment movement and connectivity that could affect the two translocated populations.

Do not move, release or stock trout, climbing galaxias, redfin perch or any other fish into the known translocation sites.

  • Maintain a clearly mapped no-go area around each known population and all aquatic habitat that could be connected to it.
  • Keep sediment, concrete washout, fuels, chemicals, rubbish and contaminated water out of streams, pools and lakes.
  • Use clean equipment and water-control measures between catchments to prevent transfer of fish, eggs, pathogens or contaminated sediment.
  • Do not assume that a site is low risk because it is outside the original Lake Pedder range, since both known populations are translocated and outside that range.

Before habitat disturbance: Check approvals and plan the works

Confirm the current EPBC Act status before works proceed, because the conservation documents identify the species as Extinct in the Wild, not as an unlisted species.

Obtain project-specific advice on whether an EPBC Act referral is required for an action that may have a significant impact on the species or its habitat.

Obtain Tasmanian approvals for taking, catching, keeping, handling or moving the species, noting that a permit is required under the Tasmanian Threatened Species Protection Act 1995 for listed-species activities.

Consult the Inland Fisheries Service, the land manager and the relevant Tasmanian threatened-species authority before designing works at either translocation site.

Spawning period: Spring, generally around October

Tasmanian status: Endangered

EPBC status in the supplied conservation documents: Extinct in the Wild

  • Prepare a fauna management plan that identifies the two known populations, aquatic exclusion zones, survey methods, authorised personnel, stop-work triggers, fish rescue arrangements and reporting contacts.
  • Stage works so that aquatic disturbance is limited to the smallest practicable area and shortest practicable period.
  • Schedule in-water works outside periods of spring spawning where the approving authority and fish ecologist identify that timing as a risk, noting that spawning occurs in spring, usually around October as water temperatures rise.
  • Include a method for stopping or isolating works if a Pedder galaxias or an unapproved fish species is detected.

Before habitat disturbance: Prepare the site

  • Complete the approved pre-clearance aquatic survey before machinery enters the water, banks, lake margins or connected drainage lines.
  • Mark aquatic exclusion zones, retained habitat, access routes, refuelling areas, washdown points and sediment controls on site plans and in the field.
  • Install exclusion fencing or other barriers where they can keep machinery, vehicles, people, sediment and pollutants away from retained aquatic habitat.
  • Brief all workers that they must not handle fish, alter watercourses, release bait or fish, or enter exclusion zones without authorisation.
  • Ensure the fauna spotter catcher and fish ecologist have suitable nets, holding containers, aeration equipment, personal safety equipment, identification material, permits and emergency contacts before works begin.

During habitat disturbance: Daily work controls

Active works must prevent fish entry, water pollution and accidental harm. A suitably authorised aquatic fauna specialist should direct any search, capture, handling or relocation response.

  • Inspect exclusion fencing, sediment controls, pumps, diversion structures, nets and access points before work starts each day and after heavy rain or other events that could damage them.
  • Keep machinery, fuels, chemicals, concrete, spoil and washdown water outside aquatic exclusion zones unless the approved method specifically allows entry.
  • Use clean, disinfected equipment and do not transfer water, sediment, plants or fish between Lake Oberon, Strathgordon and other waterways.
  • Prevent fish passage into dewatered work areas and inspect isolated pools before pumping, draining, filling or recommencing work.
  • Have the fauna spotter catcher maintain direct communication with the machinery operator and give clear instructions before any bucket, auger, pump, vehicle or person enters the work area.

During habitat disturbance: Fish rescue and handling

Handling advice: Use trained and authorised personnel, temporary holding in water and low-stress handling

Known conservation populations: Lake Oberon and Strathgordon water supply dam

  • Stop the relevant activity and notify the fauna spotter catcher and environmental manager immediately if a Pedder galaxias is seen, captured, injured or found in an isolated work area.
  • Only an appropriately authorised fish ecologist or other approved person may capture, identify, measure, hold or relocate the fish.
  • Keep captured fish in clean, temperature-appropriate water with adequate oxygen and minimise handling time, crowding, noise and exposure.
  • Do not relocate a Pedder galaxias unless the approved management plan and relevant authority authorise it; if relocation is approved, use nearby retained habitat identified by the fish ecologist.
  • Do not release the fish into Lake Pedder or another waterbody as an unplanned action, because the natural Lake Pedder habitat is affected by introduced fish and the known populations are managed translocations.
  • Transfer injured fish to an appropriately authorised aquatic wildlife veterinarian, wildlife carer or government fish-rehabilitation contact, as directed by the approval conditions.
  • Photograph the fish only where this can be done without delaying release or causing additional stress, and record the location, time, condition, measurements, handler and outcome.

During habitat disturbance: Stop-work triggers and records

  • Stop work in the affected area if a Pedder galaxias is detected until the fish ecologist confirms the response and the environmental manager confirms that the approval conditions are being met.
  • Stop work if a fish barrier, exclusion fence, pump screen, sediment control or water diversion fails and fish could enter, leave or be harmed by the work area.
  • Stop work and notify the relevant authority if trout, climbing galaxias, redfin perch or another non-target fish is detected in a translocation site or work area.
  • Record daily weather, rainfall, water level, turbidity, flow, works undertaken, machinery locations, control inspections, fish observations, captures, injuries, mortalities, responses and notifications.
  • Report any mortality, unauthorised take, fish release, pollution incident or barrier failure in accordance with the approval and fauna management plan.

After habitat disturbance: Post-clearance checks

Completion of works does not end the risk. The project team must confirm that aquatic habitat is functioning, controls remain effective and all incidents and records have been closed out with the relevant authorities.

  • Inspect the full work footprint and downstream and connected aquatic habitat for stranded, injured or dead fish after each work stage and before removing isolation, pumping or sediment controls.
  • Have the fish ecologist check retained pools, lake margins, feeder streams, aquatic vegetation, woody cover and spawning substrates where these were exposed to disturbance.
  • Remove temporary barriers, pumps, nets and equipment only after the fauna specialist confirms that no fish remain isolated and that release will not create a fish-passage or contamination risk.
  • Repair eroded banks, sediment controls, fencing and water diversions before demobilisation.

After habitat disturbance: Monitoring and reporting

  • Monitor the affected site and any retained translocation habitat at the frequency and for the duration required by the approval, fauna management plan and relevant authority.
  • Use repeat electrofishing, fyke-net or night-snorkelling methods only where approved and where they will not add unacceptable risk to the populations.
  • Compare post-work observations with pre-work survey effort and results, including detections, non-detections, water conditions and habitat changes.
  • Submit the final survey, incident, capture, mortality, rehabilitation and monitoring records to the relevant Tasmanian wildlife database, Inland Fisheries Service and other authorities specified in the approvals.
  • Keep the site contact list and emergency response arrangements active until monitoring and rehabilitation obligations are complete.

After habitat disturbance: Offsets and ongoing controls

  • Confirm with the approval authority whether an offset, conservation payment, habitat action or additional monitoring is required for residual impacts.
  • Do not use an offset as a substitute for avoiding disturbance to Lake Oberon, the Strathgordon water supply dam or connected freshwater habitat.
  • Maintain fish-exclusion, biosecurity, sediment and pollution controls for as long as the project risk assessment requires.
  • Include any new climbing galaxias, trout, redfin perch or other fish detection in the project close-out report and notify the relevant authority promptly.

Rehabilitation actions: Restore aquatic habitat

Rehabilitation should restore clean, connected freshwater habitat while protecting the two translocated populations from introduced fish. Actions must be designed with the Inland Fisheries Service and the relevant land manager because the species uses lakes, streams, pools and spawning cover.

Spawning substrates recorded for the species: Flat rocks, aquatic vegetation and submerged woody debris

Habitat features recorded for adults: Deep pools, relatively slow flow, sandy bottom and abundant cover in forested stream sections

  • Reinstate stable, natural stream banks and pool margins without filling pools, simplifying channels or removing retained cover.
  • Restore suitable shallow lake-margin and stream habitat with native aquatic and riparian vegetation appropriate to the local Tasmanian site.
  • Retain or replace naturally occurring flat rocks, submerged woody debris and aquatic vegetation that can provide shelter and spawning surfaces.
  • Replace disturbed woody cover and rocks only where the fish ecologist confirms that placement will not block fish passage, increase sediment or introduce material from another catchment.
  • Prevent weed establishment and remove weeds using methods that do not contaminate water or harm fish.

Rehabilitation actions: Protect populations and water quality

  • Maintain or improve barriers and exclusion measures that prevent brown trout, rainbow trout, redfin perch, climbing galaxias and other non-target fish from entering translocation habitat.
  • Do not stock or release fish, bait or live aquatic organisms into rehabilitated water.
  • Maintain sediment, erosion, nutrient and chemical controls until water quality and bed and bank stability have returned to the approved condition.
  • Coordinate any change to water levels, flow controls, canals, dams or fish barriers with the Inland Fisheries Service and relevant water manager.

Rehabilitation actions: Monitor rehabilitation success

Maturity: About two years

Typical breeding age: Three to four years

Adult lifespan: Up to about six years

Egg hatching period: 22 to 30 days at 15 to 16 degrees Celsius

  • Set success measures before works begin, including survival of planted native vegetation, stable banks, functioning pools, retained spawning cover, acceptable water quality and no entry of non-target fish.
  • Inspect rehabilitated areas after rainfall and at agreed seasonal intervals, with additional checks during spring spawning and following any barrier or water-level change.
  • Use approved fish surveys to check for Pedder galaxias recruitment and persistence at affected sites, noting that the species reaches maturity at about two years and most fish breed at three to four years.
  • Investigate declining detections, failed recruitment, loss of cover, excessive sediment or new fish incursions and implement corrective action with the relevant authority.
  • Report rehabilitation results, photographs, mapped habitat changes, survey effort, fish detections and corrective actions to the project regulator, land manager and relevant Tasmanian wildlife database.

Sources