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Shannon Paragalaxias (Paragalaxias dissimilis)

The Shannon Paragalaxias is a small, endemic freshwater fish found only on Tasmania’s Central Plateau, in Great Lake, Shannon Lagoon and Penstock Lagoon. Works that disturb lake margins, shallow rocky spawning areas, macrophyte or algal beds, water levels, or catchment water quality may affect this nationally and state listed species.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Tasmania, Threatened Species Protection Act 1995: Vulnerable.

Breeding season

The species completes its life cycle in freshwater and is not known to undertake a marine migration. Timing below is based on the documented summer breeding period, egg development and prolonged pelagic larval phase.

The seasonal risk pattern is a planning guide based on the documented breeding and larval periods. Site-specific timing should be checked against water temperature, recent survey results and the proposed work method.

  • Breeding and spawning: Breeding occurs in summer, mainly December and January. Eggs are deposited in masses on sheltered rocks in shallow shore waters.
  • Breeding and spawning: January is included because the documented breeding period is December to January.
  • Eggs and early larvae: Eggs hatch after at least 14 days. The exact duration of the egg stage in the wild is not given, so the timing is shown as occurring across the breeding period and early February.
  • Pelagic larvae and juvenile transition: Larvae are apparently pelagic for about 6 months. Juveniles feed in midwater before colonising bottom habitat after about six months.
  • Local movement: The species is non-diadromous and completes its life cycle in freshwater. No regular seasonal migration is documented, but juveniles change from pelagic to bottom-associated habitat.
  • Highest clearing risk: Risk is highest from December to January when eggs are laid in shallow rocky habitat, and remains elevated through June while larvae and juveniles occupy the water column and transition to bottom habitat.

Identification

The Shannon Paragalaxias is a small, stout, scaleless fish with variable dark colouring. It is usually associated with rocky lake margins, aquatic vegetation and submerged algal beds.

Adults grow to approximately 75 mm, although most are about 55 mm long. The snout is tapered, the dorsal fin is long and begins above the pelvic fins, and the tail is forked.

Colour varies from olive brown to almost black. The back and sides have indistinct dark bands or elliptical spots, the belly is greyish white, and the fins are olive and generally clear.

Body length: Up to approximately 75 mm; commonly about 55 mm.

Weight: Not reported in the supplied sources.

Activity: Often nocturnally active and seldom seen.

Identification: Distinguishing features

The species has very large laterosensory pores on the head, long gill rakers, a large dorsal fin positioned above the pelvic fins, and two well separated pores below each side of the lower jaw.

It can be distinguished from the Great Lake Paragalaxias by its more forked tail, shorter-based dorsal fin, broader interorbital area, larger number of gill rakers and vertebrae, and presence of submandibular pores. It differs from Arthurs Paragalaxias in having a longer dorsal fin base, larger pectoral fins and more dorsal fin rays, gill rakers and vertebrae.

The Great Lake Paragalaxias has a more steeply profiled snout, a less forked or emarginate tail and black specks on the fin rays. Field identification should be confirmed by an appropriately authorised fish ecologist because colour and size vary.

Identification: Field signs and survey handling

There are no terrestrial signs such as tracks, scats, nests, hollows or calls. The useful field sign is the presence of small fish in rocky shallows, among macrophytes, beneath rocks or within submerged algal beds.

The species may also occur in deeper lake water. It can be difficult to detect during daylight because it is often nocturnally active and may occupy deeper water during the day.

Survey guidance for Tasmanian galaxiids identifies electrofishing and small scoop nets as suitable methods, with fine soft mesh fyke nets used in lakes and left overnight. Any capture, handling or release must be undertaken by suitably authorised personnel.

Distribution: National range

The Shannon Paragalaxias is endemic to Tasmania and has a highly restricted distribution on the Central Plateau. No occurrence outside Tasmania is given in the supplied sources.

The species is known only from Tasmania, within the Central Plateau area. Its known localities are Great Lake, Shannon Lagoon and Penstock Lagoon.

Shannon Lagoon and Penstock Lagoon are artificial impoundments downstream from Great Lake. Their populations are considered likely to have been derived from Great Lake.

  • Great Lake, including rocky margins and submerged charophyte beds.
  • Shannon Lagoon and its upstream catchment.
  • Penstock Lagoon and its upstream catchment.

Distribution: Strongholds and subpopulations

Great Lake is the largest known population area identified in the supplied sources. The species is also recorded in Shannon Lagoon and Penstock Lagoon, which are separated localities connected through the regulated water system.

The known localities are treated as habitat critical to survival in the recovery plan. The species has a limited distribution and a small number of fragmented localities.

Known localities: Three main localities: Great Lake, Shannon Lagoon and Penstock Lagoon.

Distribution in the Tasmanian Temperate Rainforests and Highland Forests conservation management zone: The zone contains 100 percent of the reported national distribution, with an estimated occurrence across 0.74 percent of the zone.

Population size: No total population estimate is provided.

Trend: A quantitative population trend is not provided. The species is considered at risk of future decline from habitat deterioration and introduced fish.

Distribution: Project area assessment

For a project assessment, include the works footprint, connected shorelines and catchments, inflowing and outflowing waters, and any downstream areas that could receive sediment, altered flows or introduced fish.

The absence of a record at a particular shoreline does not exclude the species because it may use deeper lake water and some habitat has not been fully surveyed.

Habitat: Waterbodies and shorelines

This is primarily a lacustrine species of highland Tasmanian waters. It uses a combination of shallow rocky margins, aquatic vegetation and submerged algal beds, with some records from deeper lake habitat.

The species occurs in Great Lake, Shannon Lagoon and Penstock Lagoon. It is generally found around rocky lake margins, often in shallow water, and in macrophyte beds.

In Great Lake it has been recorded in submerged charophyte beds to the maximum sampled depth of 7 m. It may occur deeper than 7 m, but the full depth distribution has not been established.

Waterbody type: Lacustrine, including artificial impoundments.

Recorded depth: Submerged charophyte beds sampled to 7 m.

Flowing water use: Not generally known from inflowing streams, although fish have been taken at the edge of a short connecting stream section.

Habitat: Structural habitat features

Important features include sheltered rocky shallows, crevices beneath rocks, submerged macrophytes, charophyte beds, woody debris and other submerged cover.

The known habitat critical to survival includes the three waterbodies and their catchments upstream of the relevant dams. Avoid treating only the wetted work area as habitat because catchment activities can affect turbidity, sediment loads and water levels.

  • Rocky lake margins and shallow shore waters.
  • Submerged algal or charophyte beds.
  • Macrophyte beds in Penstock Lagoon.
  • Sheltered rocks used for spawning.
  • Connected catchments that influence lake water quality and levels.

Habitat: Elevation and climate limits

The supplied sources identify the species as a Central Plateau Tasmanian fish but do not provide a numerical elevation range or a defined thermal tolerance. Do not infer an elevation limit from general highland habitat descriptions.

Foraging habitat: Diet

The Shannon Paragalaxias feeds within lake margins, aquatic vegetation and submerged algal beds. Adults use both benthic and midwater food resources.

The main food items are small aquatic insect larvae and planktonic crustaceans. Other reported food includes algae and eggs of other galaxiid fishes.

Juveniles are pelagic and feed on plankton in midwater before moving to bottom-associated habitat after about six months.

Primary prey: Small aquatic insect larvae and planktonic crustaceans.

Additional food: Algae and eggs of other galaxiids have also been reported.

Foraging habitat: Foraging places and behaviour

Adults forage around rocky lake margins, among macrophytes and within submerged charophyte beds. The species swims in midwater in aquaria but is also associated with bottom habitat in lake shallows.

No home range or routine foraging distance has been established. For project assessments, map and protect connected shallow margins, vegetation beds and deeper aquatic habitat rather than assuming that fish are confined to the immediate shoreline.

Breeding habitat: Breeding biology

Breeding occurs in summer in shallow, sheltered lake margins. Spawning habitat is closely linked to stable rocks and suitable water levels.

Breeding season: Summer, mainly December to January.

Egg number: Up to approximately 300 eggs per female.

Egg size: Approximately 2 mm in diameter.

Egg placement: Eggs are deposited in masses on sheltered rocks in shallow shore waters.

Hatching time: At least 14 days.

Larval period: Larvae are apparently pelagic for about 6 months.

Age at maturity: Approximately 1 year.

Lifespan: Probably about 3 years.

Gestation or incubation: No gestation; eggs hatch after at least 14 days.

Breeding habitat: Spawning habitat

Spawning sites are in sheltered shallow water around Great Lake, where rocks provide a firm surface for egg masses. Similar sheltered rocky habitat should be treated as potential breeding habitat in the other occupied lagoons.

Rapid or extensive water level changes can expose spawning rocks, dewater egg masses, reduce shallow habitat and damage algal or macrophyte beds. Sediment and turbidity can also alter the condition of shallow breeding habitat.

  • Retain sheltered rocks in shallow water during the breeding season.
  • Prevent drawdown, wave wash, sediment deposition and direct disturbance at rocky shallow margins.
  • Manage upstream runoff so that construction sediment does not enter spawning or larval habitat.
  • Consider connected downstream habitat because larvae and juveniles use the water column for an extended period.

Sheltering habitat: Known refuges

The species shelters in shallow rocky lake habitat and among submerged vegetation and debris. It has no known terrestrial refuge stage.

Adults are found among rocks around lake margins and may shelter in crevices beneath rocks, among woody debris or within aquatic plants. Penstock Lagoon supports habitat in macrophyte beds, while Great Lake supports rocky margin and charophyte bed habitat.

The supplied sources do not provide a minimum refuge size, home range or critical crevice dimensions.

  • Rock crevices and spaces beneath submerged rocks.
  • Submerged macrophytes and charophyte beds.
  • Woody debris and other submerged cover.
  • Rocky shallow margins that remain wetted during normal water level fluctuations.

Sheltering habitat: Implications for works

Avoid removing or isolating submerged cover and avoid leaving shallow rocky habitat dry during works. Where dewatering is proposed, fish rescue, exclusion and relocation methods should be designed and supervised by appropriately authorised freshwater fauna personnel.

Fine soft mesh fyke nets, scoop nets and carefully controlled electrofishing are described for threatened Tasmanian galaxiid surveys. Equipment and methods must be selected to minimise injury and comply with relevant approvals.

Threats: Hydrology and habitat loss

The main risks are alteration of lake levels and shallow habitat, predation by introduced fish, sediment and turbidity, and the possible movement of non-native or non-local fish through connected infrastructure.

Hydro-electricity operations can cause water level fluctuations that reduce habitat quality and availability. Drawdown can dewater rocky spawning margins, remove shallow refuge habitat and damage submerged algal beds through erosion, exposure or reduced light.

Historical raising of Great Lake reduced dense shallow macrophyte habitat. Extremely dry conditions in 2002 caused a substantial reduction in algal bed area.

  • Avoid rapid or extensive changes in water level during works.
  • Keep spawning rocks and shallow refuge habitat wetted where practicable.
  • Assess indirect effects from dams, canals, outlets and altered operating levels.
  • Protect charophyte and macrophyte beds from physical damage, dewatering and sediment burial.

Threats: Introduced fish

Brown and rainbow trout occur in all known localities and prey on Shannon Paragalaxias. Trout may limit its abundance, although the species has remained common in some areas.

Redfin perch have been considered a serious potential threat because they are aggressive piscivores and could move through connected water infrastructure. The presence of redfin in Great Lake was not confirmed in the supplied recovery plan.

Other paragalaxias or galaxias species may also move through hydro-electric canals, creating a risk of competition, predation or hybridisation if they establish in new waterbodies.

  • Prevent the release or transfer of live fish, bait or contaminated water between catchments.
  • Inspect and manage pumps, canals, valves, vessels and equipment that could transport fish.
  • Maintain contingency arrangements for detection of redfin or other undesirable introduced fish.

Threats: Construction runoff and fire related sediment

Clearing, earthworks, roads and drainage changes in the catchment can increase sediment and turbidity entering occupied lagoons and lakes. Sediment can degrade rocky margins, macrophytes and algal beds and can affect feeding habitat.

The supplied research on threatened freshwater fauna identifies ash and sediment exposure as a potential stressor for freshwater fish. For this species, post-fire or post-clearing runoff should therefore be managed as a water quality risk, particularly where runoff reaches occupied lake margins.

  • Stabilise exposed soil before rainfall and keep sediment out of inflows and shorelines.
  • Use sediment controls that remain effective during large rainfall events.
  • Inspect downstream lake margins and aquatic vegetation after fires, clearing or major storm runoff.
  • Prevent concrete washout, fuels, chemicals and other pollutants from entering freshwater habitat.

Threats: Fragmentation and direct disturbance

The known localities are fragmented and connected through regulated water infrastructure. New barriers, altered flows or works that isolate lagoons and lake margins may reduce access to habitat and complicate population management.

Direct disturbance of shallow rocky margins during the December to January breeding period may damage egg masses. Disturbance can also affect pelagic larvae and juveniles during the following months.

  • Map all connected aquatic habitat before construction begins.
  • Keep machinery, temporary crossings and stockpiles away from occupied shorelines and inflows.
  • Schedule unavoidable in-water works outside the main breeding period where practicable.
  • Maintain fish passage and water quality through temporary and permanent structures.

Threats: Other threats

The supplied sources do not identify a species-specific disease, road mortality pattern or fire mortality mechanism for Shannon Paragalaxias. Roads and fire remain relevant where they alter catchment runoff, sediment loads or water levels rather than through direct terrestrial contact.

Survey methodology: 1. Habitat assessment and site selection

Survey the Shannon paragalaxias in permanent freshwater habitats on Tasmania's Central Plateau, particularly Great Lake, Shannon Lagoon and Penstock Lagoon. Focus on rocky lake margins, shallow spawning areas, macrophyte beds and submerged algal beds.

Map all lakes, lagoons, connecting canals, inlet and outlet areas, rocky margins, macrophyte beds, submerged algal beds and other aquatic habitat within the project area and downstream of it.

Treat Great Lake, Shannon Lagoon and Penstock Lagoon, including their catchments upstream of the dams, as potential habitat where the project could affect water quality, water levels or aquatic connectivity.

Record substrate, depth, aquatic vegetation, shelter under rocks or debris, turbidity, flow, water level and evidence of introduced fish.

Include areas that could receive indirect impacts from sediment, ash, altered drainage, dewatering, changes in water levels or fish movement through artificial waterways.

Known distribution: Great Lake, Shannon Lagoon and Penstock Lagoon on Tasmania's Central Plateau.

Typical size: Up to approximately 75 mm, with common lengths around 55 mm.

Habitat: Rocky lake margins, macrophyte beds and submerged algal beds, including habitat sampled to 7 m in Great Lake.

Survey methodology: 2. Lake-shore and shallow-water sampling

Use a combination of small scoop nets, standardised backpack electrofishing and fine, soft-mesh fyke nets selected for the habitat and water depth.

Use electrofishing around lake shores and in suitable shallow connecting-water habitat, with at least 30 minutes of backpack electrofishing at each monitoring site.

Use a flat dip net to slide stunned fish into a bucket, and use the lowest effective electrofishing settings and effort needed to detect the species.

Set fine, soft-mesh fyke nets in lakes overnight, construct and set them to Inland Fisheries Service requirements, and fit screens that prevent platypus drowning.

Sample rocky margins, macrophyte beds and submerged algal beds, and include deeper lacustrine water where the project could affect habitat because the species may occur below the shallows.

Release captured fish promptly at the capture location after identification and recording, unless an authorised wildlife or fisheries officer directs otherwise.

Electrofishing effort: At least 30 minutes of backpack electrofishing per stream or lake-shore monitoring site.

Fyke-net effort: Set fine, soft-mesh fyke nets overnight in lakes.

Typical settings described for Tasmanian galaxiids: Generally 60 Hz and 2 or 4 mS, with voltage commonly between 200 and 700 V, adjusted to conductivity and used at the lowest effective setting.

Survey methodology: 3. Timing, visibility and detection

Plan surveys across suitable freshwater conditions and repeat them where water levels, turbidity or access could reduce detection.

Survey during daylight when reliable identification and release are needed, and add night sampling where quantitative assessment is required or where increased nocturnal activity may improve detection.

Give particular attention to summer, from December to January, when Shannon paragalaxias breeds and adults deposit eggs on sheltered rocks in shallow shore water.

Do not assume that absence from a single shallow-water survey proves absence, because the species may occur in deeper lake water and is seldom seen.

Record water level, recent drawdown, turbidity, weather, sampling time, net soak time, electrofishing duration, habitat sampled, depth and all fish captured.

Breeding period: Summer, December to January.

Egg development: Eggs hatch in at least 14 days.

Early life history: Larvae are apparently pelagic for about 6 months, and fish mature at 1 year of age.

Maximum recorded age: Approximately 3 years.

Survey methodology: Minimum effort and reporting

  • Use habitat mapping followed by at least 30 minutes of backpack electrofishing at each suitable lake-shore monitoring site, supplemented by overnight fine, soft-mesh fyke nets and small scoop nets where safe and appropriate.
  • Include night sampling where the assessment requires quantitative data or where daytime sampling is unlikely to detect fish using deeper or sheltered habitat.
  • Survey all suitable aquatic habitat within the project area and all connected habitat that could receive downstream effects, rather than limiting the survey to the proposed disturbance footprint.
  • Have electrofishing and netting undertaken by appropriately trained and authorised personnel using approved animal ethics, fisheries and platypus protection procedures.
  • Report locations, survey dates, effort, methods, conditions, captures, photographs and habitat observations in the project fauna report.
  • Submit confirmed records and negative survey results, where requested, to the relevant Tasmanian wildlife or threatened-species database and provide records to the Inland Fisheries Service or other responsible state agency.

Before habitat disturbance: Avoid and minimise

Avoid physical disturbance to occupied lake and lagoon habitat wherever practicable. This species has a very small known range and depends on shallow rocky margins, aquatic vegetation and algal beds that can be affected by water-level changes, sediment and introduced fish.

  • Redesign works to retain rocky shore habitat, macrophyte beds, submerged algal beds, sheltered spawning areas and connecting waterways.
  • Keep machinery, spoil, access tracks, stockpiles, fuels and concrete washout areas out of the drainage area leading to Great Lake, Shannon Lagoon, Penstock Lagoon and their connected waters.
  • Maintain aquatic connectivity unless an approved isolation, salvage and reinstatement method has been prepared by a suitably qualified aquatic ecologist.
  • Avoid rapid drawdown, dewatering, bank armouring, sediment release and changes to the water level or flow regime that could expose spawning rocks, macrophyte beds or algal beds.
  • Use project-specific no-go areas and buffers around mapped aquatic habitat, with their distances set through the impact assessment and approval conditions rather than applying an unverified generic distance.
  • Prevent the movement of fish, water, mud, plants and equipment between catchments unless the equipment has been cleaned and disinfected under the relevant biosecurity procedure.

Before habitat disturbance: Approvals and work planning

National status: Vulnerable under the EPBC Act.

Tasmanian status: Vulnerable under the Tasmanian Threatened Species Protection Act.

Collection restriction: The Tasmanian Inland Fisheries Act 1995 prohibits collecting freshwater species without a permit.

  • Check whether the action is likely to have a significant impact on this EPBC Act listed species or its habitat, and refer the action under the EPBC Act where required.
  • Obtain Tasmanian approvals and permits before disturbing threatened fish, collecting or handling fish, electrofishing, netting, dewatering, relocating fish or altering aquatic habitat.
  • Consult the Tasmanian Inland Fisheries Service, the relevant threatened-species authority and the land or water manager before finalising the method statement.
  • Prepare a fauna management plan covering aquatic habitat protection, pre-clearance surveys, fish salvage, water-quality controls, stop-work triggers, incident response and reinstatement.
  • Stage works so that the smallest practicable area is exposed at one time and aquatic habitat remains connected and protected during each stage.
  • Schedule in-water works outside the December to January breeding period where practicable, and avoid disturbance of shallow sheltered spawning habitat during that period.

Before habitat disturbance: Pre-clearance preparation

  • Complete a targeted aquatic pre-clearance survey before works begin and immediately before any isolation, dewatering, excavation or bank removal.
  • Mark retained rocky margins, macrophyte beds, submerged algal beds, spawning habitat, exclusion zones, clean-water entry points and fish salvage areas on the ground and in the construction plans.
  • Install sediment, erosion and turbidity controls before earthworks, and inspect them after rain and during each shift.
  • Use exclusion fencing, floating booms or other physical controls where they can prevent machinery or sediment from entering retained aquatic habitat without blocking required fish movement.
  • Prepare clean water, aerated holding containers, dip nets, measuring equipment, approved disinfectant and transport equipment before any authorised fish salvage.
  • Brief all workers that the species is a small, dark galaxiid that may shelter among rocks, vegetation and debris and may be overlooked during visual inspections.

During habitat disturbance: Daily controls and machinery coordination

Treat any fish found during works as protected fauna. Keep the fauna spotter catcher in direct contact with the supervisor and plant operators, and stop work before habitat or animals are placed at risk.

  • Hold a daily pre-start inspection of aquatic exclusion zones, sediment controls, water levels, turbidity, dewatering points, access routes and weather conditions.
  • Keep machinery outside marked aquatic exclusion zones unless the approved method specifically allows entry and the fauna spotter catcher is present.
  • Use a spotter catcher with authority to stop the operator before excavation, pumping, rock removal or bank disturbance proceeds near water.
  • Move plant slowly and in short stages near aquatic habitat so the spotter catcher can inspect the next work area before disturbance.
  • Prevent fuel, hydraulic fluid, concrete slurry, wash water, spoil and sediment from entering the waterway, and stop pumping if fish could be drawn into the pump or discharge line.
  • Maintain water-quality controls throughout the shift and stop or modify work if visible sediment plumes, sudden turbidity, fish distress or unexpected water-level changes occur.

During habitat disturbance: Aquatic habitat and fish salvage

  • Before dewatering or isolating habitat, obtain approval for the fish salvage method and have suitably trained and authorised personnel inspect and sample the affected area.
  • Search shallow rocky margins, aquatic vegetation, debris, algal beds and connecting channels before removing rocks, vegetation, sediment or structures.
  • Use soft dip nets and aerated containers, keep handling time short, maintain suitable water temperature and water quality, and avoid crowding or rough handling.
  • Do not release a captured fish into another waterbody unless the approved relocation plan identifies nearby retained habitat and the relevant authority has authorised the action.
  • Do not move water, fish, aquatic plants, sediment or equipment between Great Lake, Shannon Lagoon, Penstock Lagoon or other catchments without applying the approved biosecurity controls.
  • Treat eggs or larvae, if found on sheltered rocks or in shallow water, as a stop-work matter and obtain direction from the responsible threatened-species and fisheries authorities before proceeding.

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

  • Stop work immediately if a Shannon paragalaxias is found in the disturbance area, if fish are stranded, or if eggs or larvae are suspected.
  • Keep machinery, people and sediment away from the animal and maintain water around it until the authorised handler gives direction.
  • Only an appropriately trained and authorised person may capture, identify, handle, relocate or release the fish.
  • Record the location, date, time, habitat, water level, water quality, photographs, handling details, release location and names of the people involved.
  • Transfer injured fish to an approved aquatic wildlife veterinarian, fisheries officer or wildlife carer as directed, and record the incident and outcome.
  • Notify the site supervisor, environmental manager, project ecologist and relevant state authority of a capture, injury, mortality, pollution event, unapproved fish movement or breach of an approval condition.
  • Resume work only after the fauna spotter catcher and environmental manager confirm that the animal is clear, the habitat risk is controlled and any required authority has provided direction.

After habitat disturbance: Post-work inspection and monitoring

Do not close out aquatic works when machinery leaves the site. Confirm that retained habitat is intact, water quality has recovered and any relocated or salvaged fish have been accounted for.

  • Inspect the work area, downstream habitat, exclusion zones, lake margins, macrophyte beds, algal beds and connecting channels after completion and after the first substantial rainfall or flow event.
  • Remove temporary barriers, pumps, hoses, spoil and waste without disturbing retained fish habitat or creating a new sediment pulse.
  • Check for stranded fish, altered banks, exposed spawning rocks, damaged vegetation, sediment deposition, turbidity, fish passage barriers and changes in water level.
  • Undertake follow-up fish surveys where habitat was dewatered, isolated, disturbed, exposed to a pollution event or subject to an unplanned change in water level.
  • Continue monitoring during the period specified in the fauna management plan or approval, with extra monitoring where the project affected the December to January breeding period.

After habitat disturbance: Records, controls and offsets

  • Maintain sediment, erosion, pollution and biosecurity controls until the site is stable and the responsible environmental officer approves their removal.
  • Report survey results, captures, mortalities, injuries, relocations, water-quality incidents, permit breaches and rehabilitation outcomes to the relevant approval agencies.
  • Update the project threatened-species register and submit confirmed records to the relevant Tasmanian wildlife database or responsible state agency.
  • Review monitoring results against the approved performance criteria, including no unapproved loss of habitat, no unapproved decline in fish passage and no unaddressed mortality.
  • Apply any approved offset or compensatory conservation measure where residual impacts remain after avoidance and mitigation, and document how it benefits Shannon paragalaxias habitat.

Rehabilitation actions: Restore habitat structure and water quality

Rehabilitation should restore the aquatic features used by Shannon paragalaxias, not only stabilise the construction footprint. The priority is to restore clean, connected lake and lagoon habitat with rocky shelter, aquatic vegetation and suitable shallow spawning areas.

  • Reinstate natural or approved rocky margins with stable rock sizes and sheltered crevices that provide fish refuge and potential spawning surfaces.
  • Re-establish locally appropriate native macrophytes and submerged aquatic vegetation in areas where construction removed them, using clean material and methods approved by the water and fisheries managers.
  • Protect and, where practicable, restore submerged algal beds and avoid covering them with spoil, fine sediment or rock armour.
  • Regrade disturbed banks to stable profiles that retain shallow-water habitat without creating rapid erosion or excessive exposure during normal water-level changes.
  • Remove contaminated sediment and construction material only under an approved method that prevents downstream release and avoids further disturbance to retained habitat.
  • Restore fish passage through temporary crossings, culverts, channels and isolation structures, and confirm that the completed works do not create a barrier between occupied or potentially occupied waters.

Rehabilitation actions: Control weeds, predators and introduced fish

  • Prevent the introduction and spread of non-native aquatic plants and fish through clean equipment, controlled water movement and inspection of imported materials.
  • Maintain controls against brown trout, rainbow trout, redfin perch and other introduced fish where the approved management programme identifies a risk to Shannon paragalaxias.
  • Treat any confirmed redfin occurrence as a contingency matter and notify the Inland Fisheries Service because the recovery plan identifies redfin as an aggressive piscivore with potential to move through connected canals.
  • Control weeds and stabilise bare soil with methods that do not increase turbidity or remove retained aquatic vegetation.
  • Manage fire-related ash and sediment risks in the catchment by stabilising exposed soil, protecting drainage lines and inspecting controls after rainfall.

Rehabilitation actions: Success measures and follow-up

  • Set measurable rehabilitation targets for retained and restored rocky margin area, macrophyte and algal-bed recovery, stable banks, water clarity, fish passage and absence of new introduced fish.
  • Repeat standardised surveys using comparable lake-shore electrofishing, scoop-net and overnight fyke-net methods, with at least 30 minutes of electrofishing at each monitoring site where that method is suitable.
  • Include surveys during or near the December to January breeding period where the approval requires evidence that shallow spawning habitat remains available and functional.
  • Compare post-work results with pre-work habitat maps, survey effort and catch records rather than relying only on visual inspection.
  • Continue weed, sediment, water-level and introduced-fish controls until the success measures are met for the period required by the approval or fauna management plan.
  • Use monitoring results to adjust water-level management, habitat works, fish passage measures and contingency actions in consultation with the Inland Fisheries Service and the relevant threatened-species authority.

Sources