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Arthurs Paragalaxias (Paragalaxias mesotes)

Arthurs paragalaxias is a small, endemic freshwater fish found only in central Tasmania, mainly in Arthurs Lake and Woods Lake, with records from the Lake River below Woods Lake dam and an artificial canal. It is listed as Endangered under the EPBC Act and Tasmanian legislation, and development risks include disturbance to lake margins, water level change, turbidity, habitat dewatering and the spread or presence of introduced predatory fish.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Tasmania, Threatened Species Protection Act 1995: Endangered.

Breeding season

The annual pattern below is based on the limited breeding observations and the species' non-diadromous freshwater life cycle. Exact timing of spawning, recruitment and seasonal movement remains incompletely known.

Months are indicative rather than a substitute for site-specific aquatic fauna assessment. Water level management and introduced fish risks can operate throughout the year.

  • Breeding: Ripening females were observed in September, and ripe eggs and milt were obtained in early November. The broader natural spawning period is not established.
  • Young: Several captive eggs hatched 25 days after stripping, and larvae were about 9 mm soon after hatching. The timing and duration of dependent young in the wild are not known.
  • Movement: The species is non-diadromous and completes its life cycle in freshwater. It has no documented seasonal migration, although it may move between rocky cover and aquatic weeds to feed.
  • Highest clearing risk: Risk is highest from September to November because breeding and shallow egg habitat are indicated during this period. Drawdown, dewatering, sediment release and disturbance to rocky lake margins can harm fish or eggs at other times as well.

Identification

Arthurs paragalaxias is a small, stout, scaleless fish with bold dark markings. Identification in the field should be based on body shape, fin position, colour pattern and locality, with specimens handled under the appropriate permit and released where required.

The body is small and stout, with a rounded trunk that is somewhat flattened underneath. The head slopes to a blunt, long snout, and the mouth is large with jaws of about equal length. The back is dark greenish brown or dark greenish grey, with irregular bands and patches extending down the sides over a paler yellowish, grey or olive background. The belly is silvery grey.

The dorsal fin is large for the body and begins above, or slightly behind, the pelvic fins. The tail is slightly forked to almost straight. The fins are generally clear or amber, with darker pigmentation along some fin rays.

Adult size: Around 80 mm according to the recovery plan; known museum material reached 73 mm total length and commonly exceeded 60 mm.

Weight: Not reported in the supplied documents.

Identification: Distinguishing features

The species can be separated from other paragalaxias by its bullet-shaped form, bold colour pattern and smallish dorsal fin positioned above the pelvic fins. The scientific revision records differences from Shannon paragalaxias, Great Lake paragalaxias and western paragalaxias in fin, gill-raker and head-pore characters, but these features are not practical for untrained field identification.

The known locality is a strong identification aid. Arthurs paragalaxias is associated with the Arthurs Lake and Woods Lake drainage, whereas Shannon paragalaxias and Great Lake paragalaxias are associated with the Great Lake, Shannon Lagoon and Penstock Lagoon system.

  • Do not identify a small galaxiid from colour alone where other paragalaxias may occur.
  • Use locality, body shape, dorsal fin position and an authorised fish identification key together.
  • Seek confirmation from the Tasmanian Inland Fisheries Service or an experienced freshwater fish specialist when a threatened galaxiid is captured.

Identification: Field signs

There are no reported tracks, scats, calls, nests, sloughs or eyeshine for this species. It is an aquatic fish and is usually detected by targeted netting, trapping or electrofishing rather than by passive signs.

The fish has been collected around rocky lake margins, among aquatic weeds and at depths of 4 to 5 m in Arthurs Lake. It may move into weed beds to feed, potentially at night, and has also been collected from man-made rock piles.

  • Treat rocky shorelines, macrophyte beds, submerged rock piles and connected lake margins as potential fish habitat.
  • Do not disturb or remove rocks, aquatic vegetation or shallow shoreline substrate before the required aquatic fauna assessment and approvals are in place.
  • Use low-impact, permitted survey methods and follow handling, release and biosecurity procedures for threatened freshwater fish.

Distribution: Range and strongholds

Arthurs paragalaxias is endemic to Tasmania and has a very restricted range on the Central Plateau. Its known distribution is concentrated in the Arthurs Lake and Woods Lake system, with an additional record from the connected Lake River below Woods Lake dam.

The species is known from Arthurs Lake and Woods Lake in central Tasmania. The recovery plan also records it from the artificial canal carrying water from Arthurs Lake to Great Lake, while the survey guidelines list Woods Lake, Arthurs Lake and the Lake River as its known freshwater range.

The habitat considered critical to survival includes Arthurs Lake and its upstream catchment, Woods Lake and its upstream catchment, and the connected waters identified in the recovery plan. Arthurs Lake is the principal known stronghold in the supplied material.

Australian states: Tasmania only.

Biogeographic setting: Tasmanian Central Plateau, including the Arthurs Lake and Woods Lake drainage.

Known waterbodies: Arthurs Lake, Woods Lake, the Lake River below Woods Lake dam and an artificial canal between Arthurs Lake and Great Lake.

Distribution: Subpopulations and trend

The species has been treated as having populations in Arthurs Lake and Woods Lake. It was common in Arthurs Lake at the time of the recovery plan, but it had not been collected from Woods Lake despite several years of intensive sampling after about 1995.

A release of 174 individuals into Woods Lake occurred in August and November 2002. Later surveys did not establish whether a breeding population had formed there. The supplied documents do not provide a current total population estimate.

Individuals released into Woods Lake: 174 in 2002.

Population estimate: Not reported.

Known trend: Woods Lake records declined or became undetectable after about 1995; the current status of that population is unresolved.

Distribution: Project area screening

For projects anywhere in Australia, the species should only be considered a realistic potential species where the project can affect the Arthurs Lake, Woods Lake or Lake River system in central Tasmania. The survey guidelines advise assessing the project area and any downstream or indirectly affected aquatic habitat, including lakes, rivers, wetlands and connected waterbodies.

  • Map all lake margins, inflowing and outflowing channels, canals and downstream reaches that could be affected by the project.
  • Check current state records, Australian Government species information and Tasmanian threatened species databases before finalising survey scope.
  • Refer any suspected record to the Tasmanian Inland Fisheries Service and the relevant threatened species authority.

Habitat: Lake habitat

Arthurs paragalaxias is a lacustrine fish of highland Tasmanian waters. It uses a mixture of rocky lake margins, aquatic vegetation and deeper lake habitat, with habitat condition closely linked to water level and turbidity.

The species inhabits rocky and macrophyte-covered areas around lake shores. It has also been caught in fyke nets at depths of 4 to 5 m in Arthurs Lake, indicating that it may occur throughout the lake rather than only in shallow water.

Records from man-made rock piles and aquatic weeds indicate that submerged hard structure and aquatic vegetation provide cover. The species was not collected from streams entering the lakes in the historical survey, although two small fish were taken from the upper Lake River when it was not flowing.

Recorded depth: 4 to 5 m in Arthurs Lake.

Elevation: Not reported for the fish in the supplied documents.

  • Rocky and cobble lake margins.
  • Submerged macrophyte beds and aquatic weeds.
  • Submerged rock piles and other stable hard structure.
  • Deeper lake water, including recorded habitat at 4 to 5 m.

Habitat: Catchment and water quality

The recovery plan defines critical habitat as the occupied lakes and their upstream catchments. Habitat quality can be reduced by low water levels, wind-driven sediment suspension and high nutrient or turbidity conditions.

Turbidity may damage gills, alter feeding behaviour, affect the algal food chain and reduce macrophyte habitat. Gently sloping shorelines are especially sensitive because a small fall in water level can expose a wide band of lake margin.

  • Prevent sediment and nutrient runoff from entering occupied lakes or connected channels.
  • Avoid works that expose or compact rocky shallows, macrophyte beds or submerged rock habitat.
  • Assess changes to water level, flow, turbidity and shoreline exposure before construction or infrastructure works.
  • Maintain aquatic connectivity where it is part of the occupied drainage, while preventing transfer of introduced fish.

Foraging habitat: Food

Arthurs paragalaxias feeds on small aquatic animals in lake habitat. The available information indicates feeding among rocky margins, aquatic weeds and other submerged cover, with possible increased activity in aquatic vegetation at night.

The diet consists of aquatic insect larvae and crustaceans. The supplied documents do not identify particular prey species or quantify feeding rates.

Recorded prey: Aquatic insect larvae and crustaceans.

  • Protect shallow rocky margins and aquatic vegetation that support aquatic invertebrates.
  • Prevent sedimentation and turbidity that can reduce benthic prey habitat and interfere with feeding.
  • Avoid introducing fish, bait or aquatic organisms into occupied or connected waters.

Foraging habitat: Foraging areas and behaviour

Historical collections were made mostly from cover provided by man-made rock piles and occasionally from aquatic weeds bordering rocky areas. The species is likely to move into weed beds to feed, perhaps at night, although the documents do not establish a fixed foraging range.

It has also been recorded at 4 to 5 m depth in Arthurs Lake, so works confined to the immediate shoreline may not encompass all occupied habitat.

Known foraging range: No measured range is reported.

Recorded depth: 4 to 5 m in Arthurs Lake.

  • Survey both shallow littoral habitat and deeper water where the project could affect the lake.
  • Include rocky margins, aquatic vegetation and submerged artificial structure in habitat mapping.
  • Use additional night sampling where daytime surveys do not adequately assess fish activity or habitat use, following the survey guidelines and permit conditions.

Breeding habitat: Breeding biology

Breeding information is limited. The available records indicate spawning in shallow, sheltered lake habitat, with eggs vulnerable to exposure when water levels fall.

Ripening females have been observed in September. Eggs and milt were stripped from ripe fish in early November, and several eggs hatched after 25 days in captivity. The recovery plan notes that other paragalaxias lay eggs under rocks in shallow water, and identifies this as a likely vulnerability for Arthurs paragalaxias.

The supplied documents do not establish the complete natural spawning period, clutch size, age at maturity, lifespan or a confirmed natural incubation period.

Breeding season: Ripening females recorded in September; ripe eggs and milt obtained in early November.

Egg size or clutch size: Not reported for Arthurs paragalaxias.

Incubation: Several captive eggs hatched 25 days after stripping.

Larval size: Approximately 9 mm soon after hatching.

Age at maturity: Not reported.

Lifespan: Not reported.

Breeding habitat: Spawning habitat

Likely spawning habitat is shallow water under or beside rocks in occupied lake margins. Eggs may be exposed if water levels fall during the spawning or incubation period, particularly where the lake bed slopes gently.

Low water levels can also remove rocky refuge habitat, reduce macrophyte cover and increase the risk of predation by brown trout. Large or rapid drawdowns may therefore affect both spawning habitat and recruitment.

  • Protect shallow rocky margins during September to November, when breeding activity is indicated.
  • Avoid drawdown, pumping, dewatering or rapid water level change near likely spawning habitat.
  • Keep sediment, spoil and construction runoff out of shallow spawning areas.
  • Inspect proposed works for submerged rocks, macrophyte beds and other potential egg-laying habitat before disturbance.

Sheltering habitat: Known refuges

The species uses submerged physical cover rather than terrestrial refuges. Important shelter includes rocky lake margins, submerged rock piles, aquatic weeds and macrophyte beds.

Arthurs paragalaxias has been collected mostly from the cover of man-made rock piles and occasionally among aquatic weeds bordering rocky areas. Rocky shorelines and macrophyte-covered margins provide refuge for adults and may also provide cover for eggs and young fish.

The species has no known nest, burrow, hollow, den, roost or terrestrial shelter. A specific refuge size is not reported.

Shelter size: Not reported.

Recorded deeper habitat: Individuals have been collected at 4 to 5 m in Arthurs Lake.

  • Retain submerged rock piles and stable rocky margins where they occur in occupied waters.
  • Retain aquatic weeds and macrophyte beds unless an approved ecological assessment demonstrates that removal is permitted and unavoidable.
  • Do not strand or expose submerged cover through unplanned pumping or water level change.
  • Treat temporary construction access across shallow lake margins as a potential loss of fish shelter.

Sheltering habitat: Refuge populations

The recovery plan proposed surveying artificial waterbodies in the catchment for refuge or translocation sites free of introduced fish. This reflects the species' restricted range and the risk posed by predatory or competing introduced fish.

  • Do not transfer water, fish, equipment or aquatic plants between catchments without effective decontamination and authorisation.
  • Keep temporary work sites, pumps and machinery free of fish and aquatic organisms before entering occupied waters.
  • Report any suspected introduced fish or unusual decline promptly to the Tasmanian Inland Fisheries Service.

Threats: Hydrology and habitat change

The main threats are introduced predatory fish, altered water levels, habitat dewatering, turbidity and loss of shallow lake habitat. Because the species is restricted to a few connected waterbodies, a local impact can affect a substantial part of its known range.

Arthurs and Woods lakes have been modified for water storage and irrigation, and water level management can expose shoreline habitat, eggs and aquatic vegetation. The large drawdown at Woods Lake in 1995 is identified as a possible contributor to the species' subsequent absence from surveys.

Low water levels can increase turbidity in Woods Lake because wind suspends sediment from the lake bed. Turbidity may affect gills, feeding, the algal food chain and macrophytes. Loss of rocky refuge and shallow spawning habitat can also increase exposure to trout predation.

Woods Lake minimum level agreement noted in the recovery plan: 735.40 m above sea level, intended to reduce the risk of high turbidity events.

  • Avoid unplanned drawdown, pumping or rapid changes in water level.
  • Keep construction spoil, sediment and nutrient runoff out of the lake and connected drainage.
  • Use erosion and sediment controls that remain effective during wet weather and high wind exposure.
  • Assess indirect hydrological effects on upstream catchments, lake margins and downstream reaches.

Threats: Introduced fish and predation

Brown trout have probably been present in Woods and Arthurs lakes for more than 100 years. They are likely to prey on Arthurs paragalaxias and may limit abundance. The recovery plan also identifies the risk of further introduced fish species, including illegal or accidental introductions.

Changes that remove shallow rocky cover or macrophytes may increase the fish's exposure to trout. Equipment, boats and water transfers can spread aquatic organisms between catchments if biosecurity is poor.

  • Apply aquatic biosecurity controls to boats, nets, pumps, vehicles and other equipment.
  • Do not release bait, aquarium fish, live fish or water into natural or artificial waterbodies.
  • Report introduced fish sightings and suspected illegal stocking immediately.
  • Design works to retain submerged cover and avoid concentrating native fish in exposed or isolated pools.

Threats: Development and clearing risks

The species is not a terrestrial clearing species, but clearing or construction in its catchment can affect it through sediment runoff, altered drainage, shoreline disturbance, water extraction and changes to water quality. Works on lake margins can directly remove rocky habitat, macrophytes and likely spawning substrate.

Roads, crossings, pipelines, dams, pumping infrastructure and access tracks can create indirect impacts by changing flow paths, increasing sediment delivery or allowing machinery and water to move invasive fish or other aquatic organisms.

  • Screen any project that can affect the Arthurs Lake, Woods Lake or Lake River system, even where the works footprint is outside the waterbody.
  • Map direct and indirect aquatic impact pathways before clearing or construction begins.
  • Keep cleared soil, spoil, fuels and concrete products away from drainage lines and lake margins.
  • Use fish salvage, exclusion and relocation procedures only under advice, permit and supervision from the relevant Tasmanian authority.
  • Stop work and seek advice if an unrecorded paragalaxias is captured or observed.

Threats: Fire and disease

The supplied documents do not identify a disease specific to Arthurs paragalaxias. Fire is not described as a direct species threat, but fire-related erosion and ash or sediment entering the lakes would be relevant project risks because turbidity and sediment can degrade fish habitat.

Use catchment erosion controls after fire or vegetation clearing, particularly before rainfall, and maintain aquatic hygiene between waterbodies.

  • Inspect and maintain sediment controls after fire, flood or heavy rainfall.
  • Prevent ash, soil and debris from entering occupied lakes and connected channels.
  • Clean and dry aquatic equipment between sites to reduce transfer of pathogens and invasive organisms.

Survey methodology: 1. Confirm habitat and the survey area

Arthurs paragalaxias is a small, non-diadromous freshwater fish found only in Woods Lake, Arthurs Lake and the Lake River below Woods Lake dam in central Tasmania. Survey planning must focus on rocky lake margins, macrophyte beds, shallow spawning habitat and deeper lake habitat, including areas affected indirectly by changed water levels or sediment movement.

Map the proposed works, access tracks, dewatering areas, drainage lines and downstream receiving waters before selecting survey methods.

Treat Woods Lake, Arthurs Lake, the catchment upstream of the Woods Lake dam and Arthurs Lake dam, and the Lake River below Woods Lake dam as potential species habitat where the project could affect water quality, water levels, shoreline habitat or fish movement.

Inspect rocky shorelines, macrophyte-covered margins, shallow water, artificial waterbodies and deeper lake areas. The species has been collected at depths of 4 to 5 metres in Arthurs Lake and may occur throughout the lake.

Include the canal carrying water from Arthurs Lake to Great Lake in the assessment where works could affect fish passage or water quality.

Survey methodology: 2. Sample lake margins and shallow habitat

Use a combination of electrofishing and small scoop nets for lake shores and other suitable shallow-water habitat, applying methods that minimise harm and allow fish to be released.

Sample rocky margins and macrophyte beds separately because both are recorded habitat types for Arthurs paragalaxias.

Use a flat dip net to receive fish during electrofishing, place captured fish in a suitable water-filled bucket for identification, and release them promptly at the capture location unless an approved relocation is required.

Undertake daylight sampling where identification and release are priorities, and consider night sampling where quantitative assessment is required because many galaxiids are more active at night and may move closer to shore.

Survey methodology: 3. Sample deeper lake habitat and time the work

Where the project affects open water, sample beyond the immediate shoreline because Arthurs paragalaxias has been collected in fyke nets at 4 to 5 metres and may occur throughout Arthurs Lake.

Use fyke nets or another approved method only under the relevant fish collection permit and animal ethics requirements, with regular checking and safe fish release procedures.

Arthurs paragalaxias is not known to migrate within freshwater, so survey timing is generally less constrained than for migratory fish. Do not treat this as a reason to survey during unsafe conditions or when turbidity, water levels or access prevent reliable detection.

Give additional attention to late winter and spring through summer when planning around reproduction. Ripening females have been observed in September, ripe fish have been stripped in early November, and other paragalaxias may breed in summer.

Recorded adult size: Around 80 mm in the recovery plan, with a known length of 73 mm in the taxonomic account.

Recorded deeper-water capture: 4 to 5 metres in Arthurs Lake.

Known distribution: Woods Lake, Arthurs Lake and the Lake River below Woods Lake dam.

Survey methodology: Minimum effort and reporting

  • Prepare a site-specific survey design that states the area sampled, shoreline and open-water coverage, number and length of electrofishing runs, net type and checking interval, weather and water conditions, water levels, turbidity, macrophyte condition, and all detection and non-detection results.
  • Repeat surveys where a single visit cannot represent the affected habitat, where water levels or turbidity reduce detection, or where the project may affect more than one season or lake habitat type.
  • Use experienced fish ecologists and obtain all required Commonwealth and Tasmanian permits before capture, handling, tissue sampling, translocation or release.
  • Record each capture with date, time, location, waterbody, habitat, depth, method, fish measurements, photographs where appropriate, condition on release and any voucher or genetic sample details.
  • Submit confirmed records, including reliable non-detections where requested, to the relevant Tasmanian wildlife or threatened-species database and provide records to the project approval authority.

Before habitat disturbance: Avoid and minimise

Avoiding disturbance to occupied lake habitat is the first control. This species has a very restricted range, and all areas where it occurs are identified as habitat critical to survival in the recovery plan.

  • Avoid direct works in Woods Lake, Arthurs Lake, the associated upstream catchments and the Lake River below Woods Lake dam where the same outcome can be achieved outside the waterbody or shoreline.
  • Retain rocky shorelines, macrophyte beds, shallow spawning areas, submerged cover and connected inflows and outflows.
  • Prevent drawdown, dewatering, rapid water-level change, sediment release and physical damage to the lake bed or shoreline.
  • Maintain connectivity between retained aquatic habitat and avoid blocking the canal or other waterways used by fish.

Before habitat disturbance: Approvals and project planning

  • Refer the proposal under the EPBC Act where the action may significantly affect Arthurs paragalaxias, which is listed as endangered nationally.
  • Obtain Tasmanian approvals and permits before disturbing habitat or collecting, handling, moving or releasing fish. The Tasmanian Inland Fisheries Act 1995 prohibits collecting freshwater species without a permit.
  • Prepare a fauna and aquatic habitat management plan covering survey results, exclusion zones, erosion and sediment controls, water-level controls, fish rescue, incident response, authorised personnel and reporting.
  • Stage works to keep one continuous area of suitable aquatic refuge available at all times, and schedule in-water works outside identified spawning activity where the approval authority and fish ecologist advise that this will reduce risk.

Before habitat disturbance: Prepare the site

  • Complete a pre-clearance aquatic survey before machinery enters the shoreline, lake bed, canal or connecting drainage.
  • Mark no-go aquatic habitat, rocky margins, macrophyte beds, spawning areas, retained shoreline and access routes on site plans and on the ground or water where practicable.
  • Install exclusion fencing or floating turbidity barriers where they can be secured without damaging fish habitat, and inspect them after rain, wind and changes in water level.
  • Brief the fauna spotter catcher, operators, supervisors and waterway crew on the species' appearance, the stop-work trigger and the approved fish rescue procedure.

During habitat disturbance: Daily controls and machinery interface

Works near occupied water must be controlled as an aquatic fauna operation, not treated as ordinary terrestrial clearing. The fauna spotter catcher should work with the aquatic ecologist and machine operator to prevent fish injury, habitat isolation and water-quality impacts.

  • Inspect exclusion fencing, turbidity controls, pumps, screens, access routes and retained habitat before starting work each day and after rain or water-level change.
  • Keep machinery, fuels, spoil, concrete washout and stockpiles out of the lake, shoreline and drainage paths unless the approved method specifically requires access.
  • Use screened pump intakes and prevent fish being drawn into pumps, hoses, culverts or diversion channels.
  • The fauna spotter catcher must have authority to call an immediate stop when fish, fish eggs, unexpected aquatic habitat or a failed control is observed, and the operator must stop until the aquatic ecologist clears the work area.

During habitat disturbance: Fish, eggs and habitat handling

  • Do not handle Arthurs paragalaxias unless the person is authorised under the relevant permit and the approved fauna management plan.
  • Do not remove rocks, macrophytes, submerged cover or shallow substrate from occupied habitat until the aquatic ecologist has assessed the feature and approved the method.
  • If fish must be rescued from an isolated work area, use the permitted capture method, minimise air exposure and crowding, keep fish in clean, appropriately oxygenated water, and release them into nearby retained habitat approved by the aquatic ecologist.
  • Do not move fish between Woods Lake, Arthurs Lake, the canal, the Lake River or other waterbodies without a specific approved translocation decision, because the species has a restricted distribution and genetic management is required.

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

  • Stop work immediately if Arthurs paragalaxias, fish eggs, a distressed fish, unexpected occupied habitat, substantial turbidity or an uncontrolled water-level change is detected in the work area.
  • Keep the fish in water and avoid unnecessary handling, photographs, measurements or relocation until the authorised aquatic ecologist gives instructions.
  • Transfer injured fish to an approved aquatic wildlife rehabilitator, veterinarian or other authorised facility, and record the transfer and condition of the fish.
  • Notify the project environmental officer, approval authority and relevant threatened-species contact of a confirmed find, mortality, injury, fish kill, habitat isolation or permit breach.
  • Record the date, time, coordinates, waterbody, habitat, water depth, method of detection, photographs, people involved, machinery status, action taken and final disposition.

After habitat disturbance: Post-work checks

Completion of construction does not end the risk. The project team must confirm that retained habitat remains connected, water quality has recovered and controls have not caused delayed fish mortality or habitat loss.

  • Inspect the work area, downstream waterway, shoreline and any temporary diversion or dewatering area for stranded fish, fish mortality, damaged macrophytes, exposed spawning substrate, sediment deposits and blocked fish passage.
  • Remove temporary barriers, pumps, hoses, spoil and access structures only after the aquatic ecologist confirms that fish can move safely and water quality is acceptable.
  • Complete a follow-up fish survey where habitat was isolated, water was discharged, turbidity increased, water levels changed, or fish were rescued or found during works.
  • Keep erosion, sediment and water-level controls in place until the site is stable and the approval conditions have been met.

After habitat disturbance: Monitoring and reporting

  • Monitor retained rocky margins, macrophyte beds, water clarity, water levels and fish passage at the frequency specified in the fauna management plan or approval.
  • Compare post-work observations with the pre-work survey, including habitat area, depth, substrate, macrophyte cover, fish detections and any mortality.
  • Report all confirmed records, incidents, rescue outcomes, injuries, deaths, permit breaches and corrective actions to the relevant approval authority and Tasmanian wildlife database.
  • Retain survey data, photographs, permit details, chain-of-custody information for samples and evidence that controls were inspected and maintained.

After habitat disturbance: Offsets and residual impacts

  • Demonstrate that avoidance, minimisation, rehabilitation and monitoring have been applied before considering an offset.
  • Where an approval requires an offset, design it for the species' restricted Tasmanian range and the specific lost or degraded habitat, rather than treating it as a generic aquatic offset.
  • Include protection or improvement of occupied habitat, control of introduced fish and management of water levels where those measures address the approved residual impact.

Rehabilitation actions: Restore aquatic habitat

Rehabilitation should restore the lake-edge and shallow-water features used by Arthurs paragalaxias, while protecting water quality and avoiding new barriers or introduced species. Do not assume that revegetation alone will replace rocky or macrophyte habitat.

  • Reinstate stable rocky margins and shallow shoreline habitat where these features were removed, using clean material and a design approved by the aquatic ecologist.
  • Restore or re-establish native macrophyte beds where they were damaged, using locally appropriate material and methods that do not introduce fish, weeds, pathogens or contaminated sediment.
  • Grade disturbed shorelines to avoid abrupt dewatering and retain wetted refuge as water levels change.
  • Reconnect isolated inflows, outflows and the canal only where the approved design maintains safe fish passage and does not create a pathway for introduced species.

Rehabilitation actions: Manage threats during recovery

  • Control sediment and nutrient runoff so wind-driven turbidity, suspended sediment and loss of macrophytes do not reduce habitat quality.
  • Manage water levels to avoid rapid drawdown, exposure of shallow spawning habitat and prolonged loss of rocky or macrophyte-covered margins.
  • Prevent the introduction of brown trout, redfin perch or other non-native fish through equipment hygiene, screening, signage and approved fish-transfer procedures.
  • Use aquatic weed and predator controls only where they are approved, targeted and shown not to harm Arthurs paragalaxias or its food resources.

Rehabilitation actions: Monitor success

  • Set success measures for restored shoreline length, rocky habitat, macrophyte cover, water clarity, stable water levels, fish passage and confirmed Arthurs paragalaxias use.
  • Survey restored areas with the permitted combination of electrofishing, scoop nets and, where appropriate, fyke nets, using comparable methods before and after the works.
  • Monitor for at least the period required by the approval and continue longer where the species' short life cycle, recruitment or water-level effects cannot be assessed in one season.
  • Investigate failed recruitment, repeated fish absence, stranded eggs, declining macrophytes, increased turbidity or introduced fish immediately and revise the rehabilitation controls.

Sources