Flinders Pygmy Perch (Nannoperca sp. 1)

Conservation status

Victoria, Flora and Fauna Guarantee Act 1988: Vulnerable.

Breeding season

Breeding timing is poorly documented for Flinders Pygmy Perch. For planning, use the general spring to summer pattern of freshwater pygmy perch, with local variation between waterways and years.

Breeding mode: Egg laying with external fertilisation, as expected for freshwater pygmy perch. Species specific details are not recorded.

Clutch size: Not recorded.

Incubation period: Not recorded.

Fledging or weaning: Not applicable. Fish hatch from eggs and juveniles become free swimming.

Age at maturity: Not recorded.

Breeding place: Not recorded. Freshwater pygmy perch generally use sheltered aquatic habitat, often including aquatic vegetation or submerged structure.

Breeding frequency: Not recorded.

Timing may shift between years and regions, so local observations, recent records and suitable habitat conditions should guide site specific survey and management decisions.

• Breeding activity: Use September to January as the likely general breeding window for freshwater pygmy perch.
• Eggs and young fish: Young fish may be present from spring into early autumn where spawning occurs.
• Freshwater habitat occupancy: Plan for the species to occupy suitable dams and other freshwater habitat throughout the year.
• Highest clearing risk: The highest risk period is September to March, when breeding, eggs and young fish may be present and aquatic habitat works can affect refuge areas.

Identification: Appearance and size

The Flinders Pygmy Perch is a small, patterned freshwater fish. It is currently recognised as a subspecies or form of Southern Pygmy Perch, so field identification should be confirmed by an experienced aquatic ecologist.

Specimens have reached 100 mm. The larger size is a useful field clue when separating it from Southern Pygmy Perch, which is recorded to 85 mm.

The fish has attractive patterning and colour, but appearance can vary with water quality, habitat and condition.

Identification: Similar species

Southern Pygmy Perch is the main identification issue. Flinders Pygmy Perch is currently recognised as a subspecies or form of Southern Pygmy Perch, and DELWP has been working towards recognition as its own species.

• Do not rely on size alone where identification affects clearing or construction decisions.
• Retain photographs and voucher information, and seek confirmation from a suitably experienced fish ecologist.

Identification: Calls and field signs

This fish does not have a useful call for site detection. It leaves no distinctive nest, droppings, whitewash, odour or other terrestrial field sign.

Presence is best assessed from fish captured or observed in suitable waterbodies.

• Record the waterbody type, water depth and shade.
• Photograph live fish where practical and minimise handling time.
• Use an appropriately permitted aquatic survey method.

Distribution: Australian range

The species is associated with south eastern Australia. Records include the Warragul area of Victoria, and the species is mapped in Victoria and New South Wales.

In Victoria, the species has been recorded in the vicinity of Warragul. The supplied distribution information also maps it in New South Wales, although a more specific New South Wales region is not given.

• Treat suitable freshwater habitat in mapped areas as potential habitat until a targeted assessment is completed.
• Check current state databases and local records during project planning.

Distribution: Overseas range

The Flinders Pygmy Perch is an Australian freshwater fish. No overseas range is recognised here.

Distribution: Works site screening

Screen farm dams, connected wetlands, slow water and other permanent or semi-permanent freshwater habitats within or downstream of the works area.

Include habitats that may be affected indirectly by sediment, dewatering, altered drainage or contaminated runoff.

Habitat: Waterbodies to inspect

Known habitat includes farm dams, including dams about 20 years old. Larger fish were found in a shaded, deep and dark dam, so shaded water with depth and cover should receive particular attention during site inspections.

Inspect farm dams and other freshwater impoundments, especially where water is retained through dry periods. Consider both the dam itself and any inlet, outlet or drainage line that could provide aquatic connection.

• Dams with shaded margins.
• Deep, dark water with submerged cover.
• Waterbodies connected to other freshwater habitat.
• Sites with limited disturbance and stable water levels.

Habitat: Site features

Look for overhanging vegetation, submerged branches, aquatic plants, leaf litter and protected margins. These features can provide cover for small fish and aquatic prey.

Record water clarity, shade, depth, aquatic vegetation, bank condition and signs of inflow or outflow.

Habitat: Habitat assessment for works

Map all suitable waterbodies before clearing, access track construction, trenching or dam modification. Include areas that may receive pumped water, sediment or runoff.

Avoid entering or disturbing the waterbody during initial inspection where a visual assessment from the bank is sufficient.

Foraging habitat: Likely feeding areas

The diet of the Flinders Pygmy Perch is poorly documented. As a small freshwater fish, it is likely to feed among aquatic vegetation, woody cover and shallow margins on small aquatic prey, but local conditions should be confirmed during assessment.

Inspect vegetated margins, submerged cover, leaf litter and the edges of deeper water. These areas can support small aquatic invertebrates and provide cover while fish feed.

• Aquatic plant beds.
• Overhanging or submerged vegetation.
• Woody debris and sheltered margins.
• Transitions between shallow margins and deeper water.

Foraging habitat: Observations to record

Record fish activity, water clarity, aquatic vegetation and visible invertebrate abundance where this can be done without disturbing the habitat.

Avoid assuming that an apparently bare or turbid dam is unsuitable. Fish may be present below the visible surface or in deeper water.

Foraging habitat: Survey approach

Use a qualified aquatic ecologist to select a survey method suited to the waterbody and project risk. Any capture, handling or relocation should be carried out by authorised personnel under the relevant permits.

• Survey more than one habitat zone where safe and practical.
• Record effort, method, weather, water conditions and exact survey locations.
• Release captured fish promptly at the capture location unless an approved translocation procedure applies.

Breeding habitat: Potential breeding features

Detailed breeding information for the Flinders Pygmy Perch is limited. Until local breeding areas are known, treat sheltered margins and vegetated shallow water as potential breeding habitat.

Inspect shallow margins with aquatic plants, fine cover, leaf litter and stable water levels. Connected backwaters, dam edges and protected coves may also provide suitable conditions.

• Dense or patchy aquatic vegetation.
• Sheltered shallow water.
• Stable margins with cover.
• Inlet and outlet areas that retain aquatic connection.

Breeding habitat: Protection during works

Avoid draining, infilling or isolating potential habitat. Keep machinery, spoil and construction materials away from the water's edge and prevent sediment from entering the waterbody.

Where work near water cannot be avoided, prepare a site-specific aquatic fauna and sediment control plan before works begin.

Breeding habitat: Breeding surveys

Do not rely on a single visual inspection to rule out breeding use. Seek advice from an aquatic ecologist about timing, water levels and suitable survey techniques for the local population.

• Inspect before clearing or dewatering.
• Record aquatic vegetation and sheltered margins.
• Escalate suspected breeding habitat to the project ecologist and relevant regulator.

Sheltering habitat: Shelter features

Shelter is likely to be important because the species is small and can share waterbodies with larger fish and other predators. The shaded, deep and dark dam where larger individuals were found is a useful habitat reference for site inspections.

Look for deeper water, shade, submerged vegetation, woody debris, undercut edges and dense aquatic plants. Retain a range of depths and cover types where the species may be present.

• Shaded dam margins.
• Deep water with low light.
• Submerged branches and leaf litter.
• Dense aquatic vegetation and protected coves.

Sheltering habitat: Refuge during works

Avoid rapid drawdown, dam dewatering and sudden changes in flow. If water must be removed, stop work and obtain aquatic fauna advice before proceeding.

Maintain water quality and prevent sediment plumes from reaching retained habitat.

Sheltering habitat: Handling and relocation

Fish handling, salvage or relocation should only be undertaken by appropriately authorised personnel using a method approved for the project and the relevant jurisdiction.

Keep handling brief, protect fish from heat and direct sun, and document all captures and releases.

Threats: Habitat loss and alteration

Development can affect this species through direct loss of waterbody habitat and through changes to water quality, water levels and aquatic connectivity. The Vulnerable listing in Victoria warrants early assessment and conservative controls where suitable habitat is present.

Dam removal, infilling, drainage, bank reshaping and clearing of aquatic or overhanging vegetation can remove shelter and feeding habitat.

Avoid placing access tracks, laydown areas or spoil within or beside suitable waterbodies.

• Map and retain suitable dams where practicable.
• Use exclusion fencing around retained aquatic habitat.
• Keep stockpiles and fuels away from drainage paths and water margins.

Threats: Water quality impacts

Sediment, concrete washout, chemicals, hydrocarbons and nutrient-rich runoff can harm fish and their aquatic prey. Turbid runoff can also reduce the quality of deeper and sheltered habitat.

• Install and maintain sediment and erosion controls before earthworks.
• Prevent dirty water from entering dams or connected drainage lines.
• Stop work and investigate any fish distress or unexpected fish deaths.

Threats: Hydrology and connectivity

Dewatering, altered inflows, blocked outlets and rapid changes in water level can strand fish or isolate habitat. Maintain suitable aquatic connections where they are part of the local habitat.

• Plan pumping and discharge with an aquatic ecologist.
• Use screened pumps where fish could be drawn into equipment.
• Check downstream and receiving waters before releasing water.

Threats: Introduced fish and cumulative pressure

Introduced fish, repeated disturbance, loss of aquatic vegetation and declining water availability can add pressure to small native fish populations.

Report suspected Flinders Pygmy Perch records promptly and consider cumulative effects where several dams or connected habitats are affected.

• Do not release fish, bait or aquarium species into project waterbodies.
• Clean and dry aquatic equipment between waterbodies.
• Apply survey and management controls appropriate to the Vulnerable listing in Victoria.

Survey methodology: 1. Desktop assessment

Flinders Pygmy Perch is a poorly known freshwater fish. Use targeted surveys wherever works may affect farm dams, wetlands, streams, drains or connected waterbodies, with extra care at shaded, deep and dark dams and other areas with cover.

Map all waterbodies and drainage lines within and downstream of the work area. Include farm dams, even where they appear isolated.

Review recent records, aerial imagery, hydrology, aquatic vegetation, water permanence, shade, connectivity and planned changes to inflows, water levels or water quality.

Treat the Victorian Vulnerable listing as a trigger for early ecological assessment and strong avoidance measures. Confirm the current taxonomic and legal status before works start.

• Contact the relevant state environment agency and local fish experts for records and survey advice.
• Check whether the proposed action may require an EPBC Act referral or approval.
• Check state wildlife, fisheries, waterway and threatened species permit requirements before handling or sampling fish.

Survey methodology: 2. Targeted fish survey

Use a suitably qualified freshwater fish ecologist. Select methods that suit the waterbody and avoid injury to small fish.

Use a combination of visual searches and permitted sampling methods, such as seine nets, fyke nets, bait traps or electrofishing, where safe and authorised. Sample shallow margins, aquatic vegetation, woody cover, inflow areas and deeper shaded water.

The species has been recorded at about 100 mm in farm dams. Record all pygmy perch carefully because Southern Pygmy Perch can be similar and has been recorded to about 85 mm.

• Survey under suitable water levels and visibility. Avoid relying on a single visit where water is highly turbid, recently disturbed or unusually cold, flooded or dewatered.
• Have an experienced fish ecologist confirm identification from photographs, measurements and, where lawful, voucher material.
• Do not move fish, water, plants, sediment or equipment between waterbodies without suitable hygiene controls.

Survey methodology: 3. Timing, effort and records

There is no reliable species specific breeding or migration calendar for Flinders Pygmy Perch. Plan surveys before design and before any dewatering, excavation, bank disturbance or removal of aquatic habitat.

Repeat or extend surveys when the first assessment is inconclusive, when suitable habitat is present, or when a previous record occurs nearby. Set the effort according to waterbody size, habitat complexity, access and the risk of impact, and document the basis for that decision.

• Record date, start and finish time, weather, recent rainfall, water level, water clarity, temperature if measured, flow, depth, shade, aquatic vegetation, woody debris and bank condition.
• Record each sampling method, gear dimensions, soak or search time, locations, habitat sampled and the number of people involved.
• Record every fish captured or observed, including identification confidence, length, photographs, condition, release location and any signs of breeding, such as eggs, larvae or spawning activity.
• Map occupied habitat and potential habitat separately, and provide the records to the project ecologist and relevant authority.

Before habitat disturbance: 1. Avoidance and approvals

Avoiding occupied habitat is the safest approach for this Vulnerable fish. Complete approvals, surveys and a site specific aquatic fauna plan before clearing, construction, dewatering or changes to water levels begin.

Redesign works to retain occupied waterbodies, their aquatic vegetation, shaded margins, inflows, outflows and links to other habitat. Avoid draining, filling, isolating or heavily shading suitable habitat.

Obtain the permits and written approvals that apply to the site, survey methods, fish handling, waterway works, water extraction and relocation. Confirm whether an EPBC Act referral is required or whether approval is needed because of a significant impact on a listed matter.

For work in Queensland, check the protected wildlife provisions and whether tampering with a breeding place requires a species management program, or SMP. Obtain the SMP before relevant work starts. Apply the equivalent state requirements in Victoria and New South Wales.

• Use the Vulnerable listing to set a high avoidance standard, not merely a salvage response.
• Have the project ecologist document the impact assessment, approvals, exclusion areas, contingency actions and contact details for regulators and wildlife carers.
• Do not assume that a private farm dam is exempt from threatened species or waterway controls.

Before habitat disturbance: 2. Pre clearance survey and exclusion

Complete a final pre clearance inspection of all waterbodies and drainage features that could be affected. Check for fish, eggs, larvae, shallow nursery areas, refuge pools and recent connections to other water.

Mark no go areas on plans and on the ground. Use clear fencing, signs and physical barriers where plant, vehicles, sediment or workers could enter retained habitat.

Set buffers through the approval and aquatic ecology plan. Make them wide enough to protect the waterbody, banks, shade, inflows, outflows and water quality, rather than protecting only the open water.

• Inspect barriers before each shift and after rain or flooding.
• Keep stockpiles, fuels, concrete washout, chemicals and spoil outside exclusion areas and away from drainage paths.
• Install sediment and erosion controls before soil disturbance, and maintain them until the site is stable.
• Prevent dirty water, sudden discharge, dewatering or altered flows from entering retained habitat.

Before habitat disturbance: 3. Work timing and crew induction

Avoid works that alter water levels, water quality or aquatic cover when fish are present in isolated pools or when breeding evidence has been found. Species specific breeding and movement periods are not well established, so use the survey results and regulator advice rather than an assumed seasonal window.

Sequence construction to keep suitable aquatic habitat connected and wet for as long as possible. Schedule dewatering only after an approved fish rescue plan is in place.

• Induct all workers, operators and subcontractors before entering the site.
• Show the species, likely habitat, exclusion areas, hygiene procedures and stop work signals.
• Give the fauna spotter catcher or aquatic ecologist authority to stop work immediately if fish, eggs, larvae or occupied habitat are found.
• Keep clean water separate from dirty water and use dedicated or disinfected equipment for each waterbody.

During habitat disturbance: 1. Sequential clearing and dewatering

Use a controlled, staged approach whenever work may affect water or aquatic habitat. Stop work early if conditions differ from the approved plan or if Flinders Pygmy Perch or evidence of breeding is found.

Clear vegetation and remove obstructions in stages, working from retained habitat towards the disturbance area. Keep escape routes and wet refuge areas available until the final stage.

Use gradual, supervised dewatering where it is approved. Inspect shallow margins, residual pools, wet vegetation, pumps, screens and sediment traps for stranded fish.

Do not discharge captured water, sediment or fish into another waterbody without approval and a suitable biosecurity assessment.

• Use screened pumps and low flow rates where practicable.
• Keep rescued fish in clean, aerated water and out of direct sun while an authorised fish handler directs the response.
• Stop pumping if fish are stranded, injured, distressed or concentrated near the intake.
• Release or relocate fish only under the approved plan and into an authorised, suitable location.

During habitat disturbance: 2. Handling, breeding places and unexpected finds

Only authorised and competent personnel may capture, identify, hold, transport or release fish. The fauna spotter catcher must not improvise a relocation outside the approval or fish rescue plan.

If an active breeding place, eggs, larvae, a spawning aggregation or a previously unknown occupied waterbody is found, stop the affected work area. Protect the location from people, plant, sediment and changed flows until the project ecologist and relevant authority provide direction.

• Mark the location without entering the habitat unnecessarily.
• Notify the site supervisor, project ecologist and approval holder immediately.
• Check whether the discovery triggers a change to an EPBC approval, state permit or Queensland SMP.
• Resume work only after the revised controls are documented and communicated to the crew.

During habitat disturbance: 3. Injured fish and incident response

If a fish is injured, keep it in suitable clean water, minimise handling and contact the approved aquatic fauna specialist or wildlife authority. Do not euthanise or release an injured fish without direction from an appropriately authorised person.

Contain spills, turbid water and unplanned discharges immediately. Prevent further entry to retained habitat and implement the incident response plan.

• Record the time, location, cause, condition, photographs, person handling the fish and advice received.
• Report mortalities, escapes, failed exclusion controls, unauthorised handling and water quality incidents under the approval conditions.
• Make the stop work decision explicit in the daily site record and notify all relevant supervisors.

After habitat disturbance: 1. Post clearance inspection

Post works checks should confirm that no fish remain stranded and that retained habitat still functions. Treat any mortality, unexpected record or water quality failure as an incident requiring review.

Inspect the disturbance footprint, residual pools, pump locations, drains, sediment controls and downstream areas after clearing and dewatering. Search wet vegetation and damp depressions where fish may have been stranded.

Check that exclusion fencing remains secure and that no altered flow, sediment, chemical spill or construction debris is entering retained habitat.

• Complete a final fish rescue inspection before declaring the area clear.
• Record live fish, mortalities, eggs, larvae, habitat condition and any corrective action.
• Photograph and map all significant findings.

After habitat disturbance: 2. Monitoring and relocated animals

Monitor retained and receiving habitat under the approved plan. Focus on water levels, connectivity, shade, aquatic vegetation, turbidity, bank stability and signs of fish persistence.

Where animals were relocated, confirm that the release site remains suitable and that the relocation was completed by authorised personnel. Do not infer success from release alone.

• Use the same core locations and methods where repeat surveys are required so results can be compared.
• Report survey results, relocations, mortalities and habitat changes to the approval holder and relevant authority.
• Continue monitoring if water quality, habitat condition or fish detections do not meet the performance criteria.

After habitat disturbance: 3. Close out and incident review

Compare actual works with the approved method and environmental controls. Review any stop work event, fish handling, mortality, breach or unexpected habitat connection.

Update the site environmental plan before similar works continue elsewhere in the project.

• Record the cause, immediate response, notification pathway and final outcome for each incident.
• Revise inductions, exclusion controls, dewatering methods and survey effort where the controls were ineffective.
• Retain survey and monitoring data in the project fauna and threatened species register.

Rehabilitation actions: 1. Restore aquatic habitat

Rehabilitation should restore functioning freshwater habitat, not just the appearance of a bank or dam. For this species, protect water quality, aquatic cover, shade and connectivity over the long term.

Reinstate natural or approved water levels and flows without sudden changes that strand fish or scour habitat. Stabilise banks with suitable local methods and retain shallow margins, deeper refuge areas, shade and aquatic vegetation.

Reconnect isolated habitat only after checking for water quality, fish passage, disease and the risk of introducing non native species. Preserve farm dams or other waterbodies that support the species unless removal is approved and unavoidable.

• Use clean local materials and uncontaminated water.
• Replace lost aquatic vegetation with locally appropriate species after confirming that planting will not spread weeds or obstruct fish passage.
• Keep livestock, vehicles, fuels and construction materials out of rehabilitated waterbodies.
• Control erosion and sediment until banks and disturbed ground are stable.

Rehabilitation actions: 2. Weeds, water and lighting

Remove aquatic and riparian weeds using methods that do not cause sudden oxygen loss, toxic runoff, excessive turbidity or wholesale removal of fish cover.

Maintain water quality and natural shade. Avoid unnecessary night lighting over dams, stream margins and wetland habitat, and direct essential lights away from the water.

• Use an approved weed management plan with staged treatment where fish are present.
• Prevent herbicide, fertiliser, concrete washout and contaminated runoff from entering water.
• Inspect drains, culverts, basins and sediment controls after rain and maintain them through the establishment period.
• Monitor water levels and avoid unnecessary drawdown or rapid filling.

Rehabilitation actions: 3. Replacement structures and long term monitoring

Nest boxes, bat boxes, artificial nest sites and roost structures do not replace the aquatic habitat used by Flinders Pygmy Perch and should not be installed as mitigation for this fish.

Where habitat has been lost, prioritise waterbody retention or approved aquatic habitat restoration. Consider fish friendly refuge features only where they are designed by a freshwater ecologist for the site and will not trap fish, obstruct movement or worsen water quality.

• Set monitoring objectives around fish presence, habitat condition, water quality, connectivity and weed cover.
• Monitor restored habitat for the period required by approvals and continue checks after major floods, droughts or maintenance works.
• Use survey results to adapt vegetation management, water level controls, lighting and access restrictions.
• Keep long term habitat protection measures, maps and maintenance responsibilities in the project handover documents.

Sources

• Giant Sized Pygmy Perch, aquaticaenvironmental.com.au: https://aquaticaenvironmental.com.au/giant-sized-pygmy-perch/
• Occurrence records for the distribution map, Atlas of Living Australia: https://biocache.ala.org.au/