Australian Mudfish (Neochanna cleaveri)

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Victoria, Flora and Fauna Guarantee Act 1988: Endangered.

Breeding season

The timing below represents the best-supported seasonal pattern for Australian populations. Exact timing varies between catchments and remains poorly known, especially for spawning and local movements.

Month values are ordered January to December. A value of 0 means not typical, 1 means occurs, and 2 means the period is likely to be a peak or higher-risk period.

• Breeding: Spawning is thought to occur in winter, possibly extending from late autumn into early spring. Suitable high flows may inundate low-lying coastal margins and drainage lines.
• Young: Larvae or juveniles are thought to spend about two to three months in estuarine or marine water before returning to freshwater. The exact timing is not established.
• Movement and migration: Juvenile upstream movement is reported mainly in spring and summer. Connection between coastal wetlands, lower streams and the estuary is needed for movement and recolonisation.
• Dry-period refuge: Where wetlands dry in summer, fish may burrow into damp mud or shelter beneath logs and rocks. Local timing depends on rainfall and wetland persistence.
• Highest clearing risk: Risk is highest during summer drying, when fish may be hidden in substrate, and during winter to spring breeding and juvenile movement. Clearing, excavation or drainage works can harm fish even when no fish are visible.

Identification

The Australian Mudfish is a small, eel-like or tubular fish that is usually found among dense aquatic vegetation in shallow, still water. It is difficult to detect because it is secretive, largely nocturnal and able to survive for periods in damp mud or under cover when wetlands dry.

Adults are generally greenish brown, brown or blackish above and grey to greyish green below, with irregular darker mottling or patches.

The body is scaleless and elongate. The head is short, broad and rounded, with very small eyes and conspicuous, long tubular nostrils.

The dorsal fin is positioned well back and above the anal fin. The fins have fleshy bases and are generally rounded, while the caudal peduncle has prominent flanges.

Typical adult length: About 80 mm

Maximum length: About 140 mm

Scales: Absent

Identification: Distinguishing features

In Victoria, check the combination of a scaleless tubular body, very small eyes, large tubular nostrils, small pelvic fins and large caudal-peduncle flanges.

These features distinguish it from other galaxiids likely to occur in the same coastal streams and wetlands. Identification should be confirmed by an experienced native fish ecologist where the record may affect clearing or construction.

• Do not rely on colour alone, because the fish may be brown, greenish brown, blackish or heavily mottled.
• Record photographs of the whole fish, head, nostrils, fins and caudal peduncle before release where handling is authorised.
• Use approved electrofishing, dip-netting, bait trapping or fyke-net methods under the relevant permits and animal welfare procedures.

Identification: Field signs and detection

There are no documented tracks, scats, calls, nests, sloughs or eyeshine signs for this fish. The most useful field evidence is a live capture, a verified specimen record or a confirmed environmental assessment record from suitable habitat.

During daylight, individuals may be inactive on the substrate or concealed within dense aquatic vegetation. Activity and detection are expected to increase at night.

When wetlands dry, inspect damp mud beneath logs, rocks and dense vegetation for potential aestivating fish, while avoiding disturbance of the substrate unless an approved survey requires it.

• Treat shallow, vegetated, mud-bottomed drains, swamps, billabongs and coastal backwaters as potential habitat even when fish are not seen.
• A negative survey does not demonstrate absence, particularly after drought, low flows or loss of connection with the estuary.
• The supplied Victorian surveys used electrofishing, dip nets and fyke nets, with targeted surveys recommended after shallow coastal wetlands were re-inundated.

Distribution: National range

The species has a patchy coastal distribution in Tasmania and southern Australia. Victorian populations are sparse and mainly associated with coastal wetlands and lower reaches of streams that retain a connection with estuarine or marine habitat.

In Tasmania, the species occurs around low-lying coastal areas in the north, west, south and south-east, including the Henty, Pieman, Huon and Lune river areas, and on Flinders Island.

In Victoria, records include Wilsons Promontory, the Yarra River near Dights Falls, the Aire, Calder and Wye river systems in the Otway Ranges, the Barwon River near Geelong and Belmont Common.

The supplied records also identify southern and far eastern South Australia, including the Naracoorte area.

States and territories with records: Tasmania, Victoria and South Australia

Mainland Australian setting: Southern coastal wetlands, lower coastal streams, estuarine margins and swampy tributaries

Victorian bioregional areas identified: Wilsons Promontory, the Otway Ranges, the Yarra and lower Barwon areas, and the Geelong to Melbourne region

Distribution: Known Victorian strongholds and records

The Glen Aire area, including the Aire and Calder river valleys, has been an important Victorian record area. Eleven specimens were collected from three sites on private land there in 1990.

Other Victorian records include two sites at Wilsons Promontory, the Yarra River, Belmont Common and four locations in the Otway Ranges. The Wye River and lower Aire tributaries were recognised as areas requiring targeted survey.

The species has also been recorded from drainage channels and swampy tributaries, so records may occur outside the main river channel.

Victorian sites reported in the Action Statement: Seven sites

Adult specimens reported in the Action Statement: 29

Glen Aire record from 1990: 11 specimens from three private-land sites

Distribution: Population status and survey limitations

A reliable national population estimate is not provided. Victorian populations are considered highly restricted, and the supplied documents describe the species as cryptic and difficult to survey.

The absence of Australian Mudfish from 2007 surveys in the lower Aire tributaries and the Wye River did not establish local extinction. Low flows, drying of backwaters and insufficient recent connection with the ocean may have prevented detection or recolonisation.

Mainland records remain scarce, partly because the preferred coastal swamp habitat is difficult to access and survey.

Habitat: Habitat types

Australian Mudfish occupy low-lying coastal freshwater and mildly estuarine habitats, especially where water is still or slow moving and aquatic or inundated terrestrial vegetation is dense. Habitat may occur in small drains and swampy tributaries as well as in larger river systems.

Documented habitats include coastal swamps, marshes, drains, ditches, riverside billabongs, shallow swampy tributaries and the lower reaches of coastal streams.

The species has been recorded in tannin-stained, acidic Tasmanian waters, including waters with pH of 6.0 or lower, and in Victorian coastal wetland systems with estuarine influence.

The species can use temporary or seasonally drying wetlands, provided damp substrate, cover and suitable hydrological connections remain.

Typical waterbody: Still or slow-flowing, shallow and heavily vegetated water

Substrate: Mud or silt

Documented Tasmanian water chemistry: Tannin-stained, acidic water, commonly pH 6.0 or lower in some west coast systems

Habitat: Key habitat structure

Preferred sites contain dense aquatic vegetation or inundated terrestrial vegetation, a soft mud or silt substrate, shallow backwaters and refuge cover such as logs, rocks and vegetated margins.

Coastal tea-tree vegetation, drainage lines and streamside vegetation are identified as important habitat features in the Otways.

The wider riverine habitat should be retained because the species occurs with other native fish and depends on connectivity between wetland, stream and estuarine environments.

• Retain dense aquatic vegetation and avoid unnecessary removal of plants from small wetland patches.
• Maintain streamside vegetation and prevent stock access to muddy, vegetated margins.
• Protect connections between coastal swamps, drains, tributaries, the main stream and the estuary.
• Avoid filling, deepening, straightening or clearing small drainage channels without a species-specific assessment.

Habitat: Climate and elevation

The supplied documents place records in low-lying coastal areas and lower coastal streams. They do not provide a reliable elevation limit or a national climatic envelope.

For project screening, treat low-elevation coastal wetlands and swampy tributaries as potential habitat wherever they occur within the recorded range, including Tasmania, southern Victoria and southern South Australia.

Foraging habitat: Diet

The diet has not been studied in detail. Available observations indicate nocturnal feeding in or around dense aquatic vegetation, with the species presumed to take small aquatic and terrestrial animals.

The species is presumed to feed on aquatic and terrestrial insects and other small animals. No confirmed list of prey species is provided in the supplied documents.

In captivity, individuals readily accepted freeze-dried food, including tubifex worms, but this does not establish the full wild diet.

Confirmed wild diet: Not well studied

Presumed prey: Aquatic and terrestrial insects and other small animals

Captive food accepted: Freeze-dried food, particularly tubifex worms

Foraging habitat: Foraging behaviour and habitat

Aquarium observations indicate that individuals are relatively inactive during the day, resting on the substrate or among dense aquatic vegetation. They become more active at night and move through more open areas, presumably while browsing for food.

Retain a mix of dense vegetation for daytime cover and nearby open shallow water for nocturnal movement and feeding.

• Avoid removing all aquatic vegetation from potential habitat during clearing or channel works.
• Keep water quality suitable for aquatic invertebrates by controlling sediment, herbicide, fertiliser and other contaminant inputs.
• Inspect and survey at night where safe and authorised, because daytime searches may under-record the species.

Foraging habitat: Foraging range

A foraging range, home range or movement distance has not been established in the supplied documents. The species is small and associated with local wetland and stream cover, but the full area used by an individual should not be assumed from the capture point alone.

Breeding habitat: Breeding biology

Breeding biology remains poorly known. The species appears to need seasonal connection between freshwater habitat and the estuary or sea, with suitable winter flows and access to shallow coastal margins.

Spawning sites in Victoria are unknown. The available evidence indicates winter spawning, with larvae or juveniles using estuarine or marine habitat before returning to freshwater.

High flow events in autumn and winter may inundate low-lying coastal margins and drainage lines and provide the conditions needed for spawning and downstream movement.

Spawning season: Thought to occur in winter, possibly winter to early spring

Egg number: Not established in the supplied documents; one source states that several thousand small eggs may be produced

Egg size: Not reported

Larval or juvenile marine phase: Thought to last about two to three months

Age at maturity: Not reported

Lifespan: Not reported

Breeding habitat: Breeding habitat features

Potential breeding habitat includes shallow, vegetated coastal swamps, drains, billabongs and lower tributaries that connect to an estuary or coastal stream during suitable flows.

Maintain natural seasonal water levels and avoid artificial opening or drainage of estuaries and wetlands during the breeding and recruitment period.

Barriers that restrict movement between freshwater, estuarine and marine areas may prevent access to breeding or juvenile habitat.

• Do not block, fill or isolate drainage lines that connect known or potential habitat to the lower river and estuary.
• Keep muddy, vegetated shallow margins intact through winter and spring.
• Plan unavoidable works outside periods of inundation, spawning and juvenile movement where practicable, following a site-specific fish survey and approval process.

Sheltering habitat: Wet-period shelter

The species shelters in dense vegetation, soft substrate and woody or rocky cover. It can also survive some drying by entering a semi-torpid state in damp refuges.

During the day, individuals rest on the substrate or among dense aquatic vegetation. They may also shelter beneath logs, rocks and inundated terrestrial vegetation.

Suitable shelter is generally in shallow, still or slow-flowing water with a mud or silt bottom.

• Retain submerged and partly submerged logs, rocks, dense aquatic plants and vegetated wetland margins unless their removal is authorised and supported by a species-specific plan.
• Avoid driving machinery through shallow vegetated wetlands, drains and billabongs.
• Use temporary exclusion fencing where stock could trample shallow wetland margins.

Sheltering habitat: Dry-period refuge

When habitat dries, Australian Mudfish can burrow into mud or shelter beneath logs and rocks and survive for extended periods. It does not form the protective mucous cocoon associated with some true aestivating animals.

Drying habitat can therefore still contain live fish. Excavation, grading, scraping, desilting and removal of woody cover may kill fish that are not visible at the surface.

Known refuge dimensions: No burrow depth, shelter size or refuge area has been reported

Dry-period state: Semi-torpid or aestivation-like state, with survival in damp mud or beneath logs and rocks

• Treat damp mud beneath cover in recently dried wetlands as occupied potential habitat.
• Do not stockpile spoil, slash or construction materials on wetland margins or in drainage lines.
• If dry-season works cannot be avoided, obtain advice from the relevant aquatic fauna specialist before disturbing substrate or cover.

Threats: Clearing, drainage and hydrology

The main project risks are loss and degradation of low-lying coastal wetlands, altered drainage and estuarine flows, barriers to movement, stock trampling, contamination and predation by introduced fish.

Drainage, wetland reclamation, clearing of swamps and development have removed or degraded large areas of suitable habitat. In South Gippsland, wetlands of the type used by the species were reported to have declined by 99 percent.

Artificial opening of estuary mouths, altered water levels, prolonged low flows and loss of seasonal high flows can interrupt spawning, larval transport and juvenile return.

Channelisation, excavation and clearing of drainage lines can remove dense vegetation, soft substrate and dry-period refuges.

• Map and protect all connected wetlands, drains, tributaries, billabongs and estuarine margins, not only the main channel.
• Maintain natural flow timing and avoid works that isolate coastal wetlands from the estuary.
• Avoid unnecessary removal of aquatic vegetation or mud from small drains and swamp margins.
• Treat prolonged drought and low flow as a survey and management issue because fish may be absent from the water column or unable to recolonise.

Threats: Fragmentation and barriers

Road culverts, weirs and other instream barriers can restrict upstream migration. Low flows can make existing barriers less passable and can isolate wetland populations.

The species appears to require access between freshwater, estuarine and marine environments, so small barriers may have effects beyond the footprint of the structure.

• Inspect culverts, crossings, weirs and temporary bunds for fish passage during normal and low flows.
• Do not install temporary crossings or sediment barriers across connected drainage lines without an approved fish passage design.
• Retain or restore connection between lower tributaries, coastal swamps and the estuary.

Threats: Stock, contaminants and introduced fish

Unrestricted cattle access can trample fish, damage wetland vegetation and disturb mud refuges. Herbicides, fertilisers and other contaminants may reduce habitat quality.

Introduced Brown Trout and Redfin may prey on Australian Mudfish or reduce population viability. Eastern Gambusia and other exotic fish can also affect native fish communities.

• Fence stock from occupied and potential habitat, using temporary electric fencing where permanent fencing is impractical.
• Prevent sediment, fuel, concrete washout, herbicides, fertilisers and other pollutants from entering wetlands and drainage lines.
• Do not stock or release exotic fish into catchments containing Australian Mudfish habitat.

Threats: Fire, roads and construction disturbance

The supplied documents do not identify fire as a quantified direct threat, but heavy machinery used for fire protection works was identified as a risk at the Wilsons Promontory site. Similar disturbance can damage shallow wetland vegetation, substrate and dry-period refuges.

Road construction and drainage changes can remove habitat, interrupt fish passage and alter the timing and volume of water entering coastal wetlands.

• Keep firebreaks, access tracks, machinery and material storage outside wetland margins and connected drainage lines wherever possible.
• Use low-impact access methods and wet-weather exclusion controls to prevent rutting and substrate disturbance.
• Survey potential habitat before clearing, road upgrades, culvert replacement, drainage works or fire protection works.

Threats: Survey and detection risk

The species is cryptic, nocturnal and difficult to survey in dense vegetation. A survey during drought or after loss of estuarine connection may fail to detect fish that remain in damp substrate or are temporarily absent from the site.

The absence of captures from a limited survey should not be treated as proof that a wetland or drain is unoccupied.

• Use experienced aquatic fauna personnel and the required permits for electrofishing, dip-netting, bait trapping or fyke-netting.
• Time follow-up surveys after re-inundation or suitable flow events where the first survey was conducted during severe low flow.
• Record habitat condition, water level, connectivity, vegetation cover and recent drying alongside all survey results.

Survey methodology: 1. Define and inspect potential habitat

Australian Mudfish are small, cryptic fish of densely vegetated, still or slow-flowing coastal wetlands, drains, billabongs and lower coastal streams. Surveys should target shallow, vegetated backwaters and drainage channels, particularly after re-inundation or high-flow events when fish may recolonise or become active.

Map coastal swamps, wetland margins, vegetated drains, ditches, billabongs, lower stream reaches and estuarine-connected channels before selecting survey sites.

Record dense aquatic or inundated terrestrial vegetation, soft mud or silt substrates, shallow backwaters, logs, rocks and connections to the main channel or estuary.

Give particular attention to habitat near known Victorian records, including the Aire, Calder and Wye River systems, Glen Aire, Wilsons Promontory, the Yarra River, Belmont Common and the Barwon catchment.

Survey methodology: 2. Electrofishing

Use electrofishing as the primary targeted method where conditions, approvals and operator qualifications allow. The Victorian Action Statement identifies electrofishing as the best available survey technique because captured fish can be released after identification.

Sample shallow, densely vegetated backwaters and drainage channels rather than relying only on the main channel. Include areas that may have dried recently but have since refilled.

A regional Victorian fish survey used a measured 100 metre reach, two consecutive electrofishing runs of 30 to 45 minutes, with the second run made 30 minutes after the first. Treat this as a documented regional method, not as a species-specific minimum effort.

Do not remove more aquatic vegetation than is needed for safe sampling. The species uses dense vegetation and unnecessary clearance can damage the habitat being surveyed.

Survey methodology: 3. Dip nets, bait traps and fyke nets

Use fine-mesh dip nets, small bait traps and fyke nets as supplementary methods in shallow, vegetated habitat, especially where water is too shallow, too deep or too conductive for electrofishing.

Set fyke nets overnight where approvals allow, and use the species' mainly nocturnal activity to improve detection.

Keep fyke-net cod ends above the water so captured animals can breathe, and check nets promptly in accordance with the approved animal ethics and fisheries procedures.

Use methods that allow live release and minimise disturbance to mud, aquatic vegetation and aestivating fish.

Survey methodology: 4. Timing and detection conditions

Prioritise surveys after shallow coastal wetlands have re-inundated and after suitable autumn or winter flow events have reconnected drains and backwaters with the main stream or estuary.

Repeat surveys across suitable flow conditions where the species is not detected. A single negative survey does not demonstrate absence because the fish is cryptic, difficult to sample and may remain buried during drying.

Include winter to early spring conditions when spawning is thought to occur, and spring and summer when juvenile fish may move upstream from estuarine or marine areas.

Record recent drying, inundation, connectivity, water depth, flow, water quality, aquatic vegetation, substrate, stock access, barriers and any exotic fish captured.

Survey methodology: Minimum effort and reporting

• Use a habitat-based survey design that covers all suitable coastal wetland, drain and lower-stream habitat within the impact area and any connected retained habitat.
• Use electrofishing where authorised and safe, supported by dip nets, bait traps or overnight fyke nets where those methods are suitable.
• Record the exact location, date, start and finish times, method, reach length or trap effort, weather, recent flow and inundation conditions, habitat features, effort limitations, captured species, measurements and photographs.
• Identify captured fish before release where possible, and retain voucher material only under the relevant approval and collection requirements.
• Treat non-detection cautiously and explain whether drying, low connectivity, unsuitable water levels, high conductivity, access limitations or limited sampling effort affected detection.
• Submit verified records, including reliable non-detections where required, to the relevant Victorian wildlife or aquatic fauna database and to the relevant state or territory biodiversity database for projects elsewhere in Australia.
• Report any new Australian Mudfish location promptly to the relevant state environment and fisheries authority.

Before habitat disturbance: Avoid and minimise

Treat any suitable coastal wetland, vegetated drain, billabong or lower coastal stream as potential habitat until an ecologist has assessed it. The species is listed as endangered under the EPBC Act in the project brief and as endangered in Victoria, so the project must address both Commonwealth and state requirements.

• Redesign works to retain coastal swamps, wetland margins, vegetated drains, billabongs, lower-stream backwaters and their connections to estuaries.
• Retain dense aquatic and inundated terrestrial vegetation, soft mud or silt substrates, logs, rocks and shallow refuge pools.
• Avoid draining, filling, deepening, widening or straightening potential habitat unless the relevant approval expressly permits the activity.
• Maintain upstream and downstream passage between wetland habitat, lower streams and estuarine areas, and remove or avoid new barriers to fish movement.
• Keep stock, machinery, sediment and contaminated water out of retained wetlands and drainage lines.
• Do not assume that a dry channel is unused habitat, because Australian Mudfish can survive drying by burrowing into mud or sheltering under logs and rocks.

Before habitat disturbance: Approvals and project planning

• Check whether the proposed action may significantly affect this EPBC Act listed species or its habitat, and refer the action under the EPBC Act where required.
• Obtain the relevant state or territory threatened-species, fisheries, collection, animal ethics and wildlife handling approvals before surveying, trapping, electrofishing, clearing or relocating fish.
• Engage the state environment and fisheries authorities early where works affect coastal wetlands, estuarine connections, fish passage or known Victorian records.
• Prepare a species-specific fauna management plan that identifies habitat, exclusion areas, survey methods, authorised handlers, stop-work triggers, wetland protection measures, incident response and reporting requirements.
• Stage works to keep connected habitat, water quality and refuge pools available throughout construction.
• Schedule ground disturbance outside periods when works would interrupt likely winter spawning, autumn and winter flow connections, or spring and summer juvenile movement, unless the approved management plan demonstrates that impacts can be controlled.

Before habitat disturbance: Pre-clearance preparation

• Complete targeted pre-clearance surveys in all suitable habitat within and downstream of the impact area, with additional surveys in connected retained habitat where disturbance could affect fish movement.
• Mark no-go areas around wetlands, drains, backwaters, dense aquatic vegetation, soft substrates, logs, rocks and known or suspected aestivation sites.
• Install exclusion fencing where it can keep machinery, vehicles, stock, sediment and personnel out without blocking fish passage or changing wetland flows.
• Fence or otherwise protect retained habitat before machinery arrives, and clearly mark access routes, refuelling areas, spoil areas and water discharge points.
• Plan a fish-safe method for isolating and dewatering work areas, including live capture and release procedures approved by the relevant authority.

During habitat disturbance: Daily controls and machinery coordination

The fauna spotter catcher should work as part of the construction team, not as a final check after habitat has already been disturbed. Work must stop or change when an animal, occupied habitat or an uncontrolled impact is identified.

• Inspect exclusion fencing, wetland boundaries, access tracks, pumps, silt controls and water levels before work starts each day.
• Brief operators on the marked habitat limits, no-go areas, low-ground-pressure access routes and the requirement to stop on the spotter catcher's instruction.
• Keep machinery, spoil, fuels, concrete washout, sediment and dirty water away from wetlands, drains and connected waterways.
• Prevent dewatering, pumping or diversion from stranding fish, isolating wetland habitat or changing the connection between backwaters and the estuary.
• Use a staged clearance method in which the spotter catcher checks each work area immediately before machinery enters and remains present during habitat disturbance.

During habitat disturbance: Handling habitat features

• Treat logs, rocks, mud banks, dense aquatic vegetation and wet depressions as potential shelter or aestivation habitat until inspected by the authorised aquatic fauna specialist.
• Do not remove logs, rocks or aquatic vegetation from retained habitat unless the approved method requires it and the feature has been checked.
• If a wetland or drain must be isolated, use an approved fish rescue method before water levels fall and maintain suitable water quality and shade in temporary holding containers.
• Do not excavate, compact or traffic mud and silt in potential habitat without a documented inspection and clearance decision.
• Keep any temporary fish passage, bypass channel or holding area connected, shaded and free of sediment and contaminants.

During habitat disturbance: If an Australian Mudfish is found

• Stop the affected activity and keep machinery, people and vehicles clear of the animal and its immediate habitat.
• Do not handle the fish unless you are authorised, trained and acting under the approved fauna management, fisheries and animal welfare procedures.
• Have the authorised aquatic fauna specialist identify, photograph, measure and record the fish, location, habitat, water conditions and likely source of disturbance.
• Release the fish as soon as practicable into nearby retained habitat with suitable water, dense vegetation, mud or silt substrate and a connection to the local stream or wetland system, unless the relevant authority directs another action.
• Do not move the fish to a different catchment or release it into an unapproved waterway.
• Send injured fish to an approved aquatic wildlife rehabilitator, veterinarian or other facility nominated in the project fauna management plan.
• Keep the work area stopped until the ecologist and relevant project environmental officer have confirmed the revised controls and any required authority notification.

During habitat disturbance: Stop-work triggers and records

• Stop work if an Australian Mudfish is found, if fish are stranded or injured, if dewatering is uncontrolled, if exclusion fencing fails, or if sediment or contaminated water enters potential habitat.
• Stop work if machinery reaches a marked wetland, drain, backwater, log, rock shelter or mud refuge that has not been cleared by the authorised specialist.
• Record all sightings, captures, relocations, injuries, mortalities, non-target fauna, water releases, habitat damage, stop-work events and corrective actions.
• Notify the project environmental officer and the relevant authority within the time required by the approval, incident plan or fauna management plan.

After habitat disturbance: Immediate completion checks

Post-work checks should confirm that no fish have been stranded and that retained and restored habitat remains connected, vegetated and free from construction impacts. Monitoring should be matched to the project's approval conditions and the sensitivity of the affected wetland or stream.

• Inspect the work area, wetland margins, drains, culverts, temporary dams and downstream refuge pools for stranded, injured or dead fish after each dewatering, flood, rainfall event or major construction stage.
• Remove temporary barriers and reinstate fish passage only when the aquatic fauna specialist confirms that doing so will not strand fish or release contaminated water.
• Check that retained habitat has not been filled, compacted, drained, shaded by spoil, contaminated or disconnected from the local stream and estuary.
• Repair failed fencing, sediment controls, flow bypasses and wetland protection measures before demobilisation.

After habitat disturbance: Monitoring and reporting

• Monitor water levels, connectivity, aquatic vegetation, mud or silt substrate, water quality, stock access, barriers and signs of fish use at retained and rehabilitated habitat.
• Repeat targeted fish surveys after re-inundation and during suitable flow conditions where habitat was disturbed, connectivity was interrupted or a population was recorded.
• Use the same locations, methods and effort where possible so that post-work results can be compared with pre-work observations.
• Report all sightings, survey results, injuries, mortalities, habitat loss, incidents, corrective actions and unresolved risks to the approval holder and relevant government databases.
• Implement any approved offset, restoration or compensatory action required for unavoidable residual impacts, and do not treat an offset as a substitute for avoiding or minimising habitat disturbance.

Rehabilitation actions: Wetland and stream restoration

Rehabilitation should recreate the features used by Australian Mudfish: shallow, still or slow-flowing water, dense aquatic or inundated terrestrial vegetation, soft mud or silt substrate, shelter features and safe connection to lower coastal streams and estuaries.

• Reinstate shallow wetland depressions, vegetated drainage lines, backwaters and billabongs rather than replacing them with unvegetated, fast-flowing channels.
• Use locally appropriate native aquatic and wetland plants to restore dense cover along wetland margins and in shallow water.
• Retain or reinstate soft mud or silt substrate where it is compatible with water quality and erosion controls.
• Reconnect restored habitat to the local lower stream and estuary without creating barriers, uncontrolled drainage or abrupt changes in water level.
• Design culverts, crossings and temporary works to maintain fish passage during the seasonal flow conditions used by migrating juveniles and adults.
• Do not stock restored habitat with exotic fish, and prevent colonisation by brown trout, rainbow trout, redfin and other introduced predators where management authority permits control.

Rehabilitation actions: Shelter, stock and weeds

• Reinstate suitable logs and rocks in or beside restored wetland habitat where they will not block fish passage or create an erosion risk.
• Use fencing or temporary electric fencing to exclude stock from wetlands, drains and shallow refuge areas, particularly during summer drying when fish may be buried in mud or sheltering under cover.
• Control weeds without herbicide drift or runoff into aquatic habitat, and use methods approved for threatened fish habitat.
• Maintain riparian and coastal tea tree vegetation where it forms part of the wetland or drainage-line cover.
• Manage sediment, nutrients and contaminated runoff so that restored water remains suitable for fish and aquatic vegetation.

Rehabilitation actions: Fire, predators and success measures

• Plan fire protection works so that heavy machinery does not enter known or restored Australian Mudfish habitat without ecological assessment and approval.
• Maintain refuge pools, wetland vegetation and habitat connectivity through fire planning, drought planning and water management.
• Monitor restored sites for at least the period required by the approval, including after re-inundation, drying, high-flow events and major fire or earthworks.
• Measure success by retained or increasing wetland area, dense native aquatic and inundated vegetation, suitable mud or silt substrate, maintained stream and estuary connectivity, absence of new barriers, effective stock exclusion and stable water quality.
• Use targeted electrofishing, dip-netting, bait traps or fyke nets under approval to test for recolonisation, and interpret non-detection in light of flow, inundation, connectivity and sampling conditions.
• Record and submit all monitoring results and any new Australian Mudfish records to the relevant state or territory biodiversity and fisheries databases.

Sources

• [DOC] NORTH EAST, Australian Government DCCEEW: https://www.agriculture.gov.au/sites/default/files/sitecollectiondocuments/rfa/regions/vic-west/rfa/vic_west_rfa.doc
• Neochanna cleaveri, Home of the Rainbowfish, rainbowfish.angfa.org.au: https://rainbowfish.angfa.org.au/galaxiids/neochanna_cleaveri.html
• Microsoft Word - P109021_R01V02b.docx, Victorian Government: https://www.ccmaknowledgebase.vic.gov.au/resources/P109021_R01V02.pdf
• Status of fish communities in streams of the Otways, Victorian Government: https://www.ccmaknowledgebase.vic.gov.au/resources/fish_communities.pdf