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Clarence River Cod (Maccullochella ikei)

The Clarence River Cod is a large, predatory freshwater fish endemic to the Clarence River system in northern New South Wales, with stocked populations in parts of the Richmond River system. It depends on clear flowing streams, deep pools, rocky beds, large boulders, woody debris and intact riparian vegetation, so works that disturb channels, banks, flows or water quality can affect occupied habitat and breeding sites.

Conservation status

Commonwealth, EPBC Act 1999: Endangered.

Breeding season

The timing below represents a typical year for the Clarence River population. Local temperature and flow conditions can shift breeding and movement timing, so project scheduling should use local records and current agency advice.

Survey guidelines advise avoiding the breeding season where possible so breeding is not affected. An all-inclusive fishing closure in the Mann and Nymboida rivers and tributaries was reported for 1 August to 31 October in the cited guidance.

  • Breeding: Breeding occurs in spring, with spawning generally from September to November. Spawning begins when water temperature rises above 16 degrees Celsius, and the observed breeding season lasted 8 to 10 weeks.
  • Eggs and larvae under male care: The male cleans the nest before spawning and guards eggs and larvae for up to 24 days. Hatching begins about 8 days after fertilisation and is complete by 12 days at 17 to 20 degrees Celsius.
  • Movement to spawning habitat: Males increase activity during breeding and may move up to 30 km to locate suitable spawning sites. Inter-pool movement is associated with increases in flow.
  • Larval dispersal and early feeding: Larvae disperse after the period of paternal care. They begin feeding on zooplankton about 12 days after hatching, and the day 10 to day 20 period was identified as especially sensitive in laboratory studies.
  • Highest clearing risk: Avoid clearing, in-channel works, dewatering, vibration and sediment release near occupied habitat from August to November, with highest risk during the September to November breeding and early development period.

Identification

Clarence River Cod are large, deep-bodied freshwater fish with a broad head and a large mouth. Identification in the field should be confirmed carefully because the species can resemble Murray Cod and Mary River Cod.

The species has an elongate, deep body, relatively small eyes, a short rounded and depressed snout with a distinctly concave profile, a protruding lower jaw and a large mouth extending to below the rear margin of the eye. The tail is rounded and the caudal peduncle is short. Colour is generally yellow-green to golden, with black or very dark green reticulated mottling over the back and sides, sometimes extending onto the underside.

Typical length and mass: Most records since the 1960s are of fish less than 660 mm and 5 kg.

Largest recorded fish: 41 kg.

Body colour: Yellow-green to golden with dark reticulated mottling.

Identification: Similar species

Clarence River Cod are often confused with Murray Cod and can also resemble Mary River Cod. The species is distinguished from Murray Cod and Mary River Cod by its combination of head, snout, eye, caudal peduncle, fin and colour features, but reliable identification may require an experienced fish ecologist or specialist examination. Do not rely on colour alone.

  • Record clear photographs of the whole fish, head profile, fins and body pattern where this can be done without increasing handling time.
  • Use approved, low-impact survey methods and obtain specialist confirmation where identification affects development approvals or threatened species reporting.

Identification: Field signs and detection

There are no terrestrial tracks, scats, calls, nests or other above-water signs that can be used to confirm presence. The main field evidence is a live observation or capture during an authorised aquatic survey, supported by location, habitat photographs and survey method. Adults generally occupy deep pools and cover, and may be concealed during daylight in clear water.

Most effective survey period reported: April to June for electrofishing; November to January, after spawning, for combinations of fyke nets, angling and electrofishing.

  • Search deep pools, slow-flowing reaches and areas beside boulders, rocky islands, large woody debris and undercut banks.
  • Use a combination of appropriate methods, such as fyke nets, boat-based electrofishing and barbless lure fishing, selected to suit site conditions and authorised by the relevant agency.
  • Handle captured fish for the shortest practical period, retain them in aerated flow-through water when necessary, and release them at the capture location unless an approved protocol requires otherwise.

Distribution: National range

The species is restricted to coastal river systems in northern New South Wales. The remaining natural population is centred on tributaries of the Clarence River, while the Richmond River population disappeared naturally and has been subject to conservation stocking.

Clarence River Cod are endemic to New South Wales. Historically, they occurred in the Clarence and Richmond River systems downstream of tablelands waterfalls. The current natural range is concentrated in the Clarence River system, particularly the Mann and Nymboida rivers and associated tributaries.

States recorded: New South Wales only.

Main bioregional setting: Coastal river catchments of north-eastern New South Wales, centred on the Clarence River system.

  • Treat clear rocky streams in the Clarence catchment as potential habitat where suitable pools and cover are present.
  • Consider downstream effects on connected reaches, including sediment, altered flows, pollution and barriers to fish movement.

Distribution: Strongholds and subpopulations

The principal remnant non-stocked population is in the Mann and Nymboida river systems, including tributaries such as the Little Nymboida, Guy Fawkes and Boyd rivers. The species is also reported from other Clarence tributaries, but distribution is patchy. No remnant population remains in the Richmond River system, although stocked fish have survived in limited areas.

Natural stronghold: Mann and Nymboida river systems, Clarence River catchment.

Richmond River status: The natural population is considered extinct; stocked fish have survived in parts of the system.

  • Give particular attention to the Mann and Nymboida systems, where the species is described as relatively common in some reaches and where important breeding habitat remains.
  • Separate naturally occurring fish from stocked fish in records and impact assessments where possible.

Distribution: Population size and trend

A rigorous estimate of the total wild population has not been established. Small surveys and angler reports indicate that numbers and occupied area may have increased since protection and conservation stocking, but the evidence is uneven and stocked populations must not be treated as equivalent to secure natural populations.

Population estimate: No scientific estimate of total past or present population size is available in the supplied documents.

Historical decline: Populations collapsed from the 1920s and 1930s and continued to decline until protection in the 1980s.

Conservation stocking: Approximately 210,000 hatchery juveniles had been released across the Clarence and Richmond systems by 2002.

Habitat: Overall habitat

Clarence River Cod use clear, flowing freshwater streams with rocky beds, deep pools and substantial instream cover. They require a connected range of habitats for feeding, breeding, nursery use and refuge, rather than isolated pools alone.

The species is associated with clear flowing rivers and tributaries, rocky substrates, deep holes and a mixture of flow environments. Adults are generally found in deeper parts of the channel near cover, including around rocky islands and large boulders in fast-flowing water, although slow-flowing reaches with cover are also important.

Preferred aquatic setting: Clear flowing streams and rivers with rocky beds, deep pools and abundant cover.

Recorded habitat depth for nesting sites: 0.9 to 4.0 m.

  • Map pools, runs, riffles, rapids and connecting reaches when assessing a project site.
  • Assess upstream and downstream habitat because sediment and water-quality effects can travel beyond the work footprint.

Habitat: Structural features

Important habitat elements include large boulders, rocky shelves and islands, large woody debris, undercut banks, pool and riffle sequences, varied water velocities, suitable substrates and riparian vegetation. These features provide cover, spawning surfaces, food-producing areas and different habitats for juveniles and adults.

  • Retain large woody debris, boulders, bedrock shelves, deep pools and undercut banks unless removal is specifically authorised and assessed.
  • Protect riparian vegetation to maintain bank stability, shade, water temperature, food inputs and sediment control.
  • Use effective erosion and sediment controls for earthworks, crossings and bank disturbance.

Habitat: Flow and connectivity

Natural variation in flow and water temperature provides cues for movement and spawning. Barriers such as weirs and dams can prevent access to feeding and spawning areas, fragment populations and reduce gene flow. Water extraction, farm dams and regulated flows can reduce discharge, alter temperature and flatten the timing of runoff events.

  • Maintain fish passage at temporary and permanent crossings, weirs and other in-channel structures.
  • Avoid reducing low flows or changing spring flow cues within occupied or potentially occupied habitat.
  • Design temporary waterway diversions so fish are not stranded or excluded from connected habitat.

Foraging habitat: Diet

Clarence River Cod are large predatory fish that feed in and around pools, cover and flowing water. Their diet changes with season and body size, so habitat assessments should consider both aquatic prey production and terrestrial food inputs.

Adults prey on fish, frogs, crustaceans and a range of terrestrial animals, including snakes, birds and small mammals. Larvae initially feed on zooplankton, while aquatic insects are also important during early life stages. Stomach sampling identified 39 food taxa and showed substantial seasonal and size-related variation.

Documented prey: Fish, frogs, crustaceans, aquatic insects, molluscs, snakes, birds and small mammals.

Larval food: Zooplankton, with aquatic insects also contributing to early diet.

Diet study: Stomach contents from 268 fish were examined, with 39 food taxa identified.

  • Protect aquatic habitat that supports fish, crustaceans, molluscs and aquatic insects.
  • Retain riparian vegetation and overhanging structure that contribute terrestrial prey to the stream.
  • Avoid assuming that a site with little visible prey is unimportant, because diet changes between seasons and size classes.

Foraging habitat: Foraging locations and movement

Foraging occurs in deep pools, slower-flowing water and around boulders, snags and other cover. Radio-tracked fish showed that inter-pool movement was related to increases in flow. Males may move up to 30 km during the breeding season to locate suitable spawning sites, so feeding and breeding areas can be connected over substantial distances.

Recorded breeding-season movement: Males moved distances of up to 30 km to locate suitable spawning sites.

Daily activity: Activity is higher around dawn and dusk, with less movement at night.

  • Assess connected pools and intervening reaches rather than treating each pool as an isolated habitat unit.
  • Avoid blocking movement between deep pools, cover and potential spawning sites.
  • Schedule noisy or in-channel works outside the breeding period where practicable, and obtain species-specific advice if works cannot be avoided.

Breeding habitat: Breeding biology

Breeding occurs in spring and depends on hard spawning surfaces, cover, suitable water temperature and connected flows. The male guards the nest, eggs and larvae, making disturbance near occupied breeding sites particularly harmful.

Breeding fish are territorial and aggressive. Spawning begins when water temperatures rise above 16 degrees Celsius. Eggs are large and strongly adhesive, and are laid on hard surfaces such as rock, bedrock shelves or logs. Males clean the nesting site before spawning and provide paternal care for eggs and larvae.

Breeding season: Spring, generally September to November.

Spawning trigger: Spawning starts when water temperature rises above 16 degrees Celsius; day length is also an important cue.

Egg size: Approximately 3 mm and strongly adhesive.

Egg and larval care: The male provides care for eggs and larvae for up to 24 days.

Hatching: Begins about 8 days after fertilisation and is complete by 12 days at 17 to 20 degrees Celsius.

Age at maturity: Approximately 4 to 5 years.

Lifespan: Individuals have been aged from 0+ to 15+ years; a longer maximum lifespan was not established in the supplied documents.

  • Avoid disturbing boulders, bedrock shelves, logs and deep pool margins during the spring breeding period.
  • Keep sediment, vibration, dewatering, turbidity and flow changes away from likely nesting sites.
  • Treat a guarding adult or repeated adult observations near one cover feature as a reason to stop and seek species advice.

Breeding habitat: Breeding habitat features

Observed nests were in slow-flowing pools beneath cover such as large boulders and bedrock shelves, at depths of 0.9 to 4.0 m, with one or two distinct entrances. The nest was vigorously cleaned by the male for up to a week before spawning and was entered by the female for spawning.

Nest water depth: 0.9 to 4.0 m.

Nest setting: Slow-flowing pools beneath large boulders or bedrock shelves.

Nest entrances: Usually one or two distinct entrances.

Pre-spawning cleaning: The male may clean the nesting site for up to one week before spawning.

  • Inspect deep, slow-flowing pools beneath boulders, shelves and logs before in-channel works begin.
  • Do not remove or relocate potential nesting cover during August to November without an approved species management approach.
  • Maintain access to breeding habitat by protecting flows and removing or modifying barriers only under appropriate design and approval.

Sheltering habitat: Adult refuge

Cover is a defining feature of Clarence River Cod habitat. Adults shelter in deep water beside boulders, rocky structures and large woody debris, while different life stages use a connected range of pool, bank and substrate features.

Adults prefer deep pools and cover, including large boulders, rocky islands, bedrock shelves, woody debris and undercut banks. Cover provides shelter, ambush positions and likely protection for breeding fish, eggs and larvae.

  • Retain snags and boulders in the channel unless an approved risk assessment supports removal.
  • Keep deep pools connected to nearby runs, riffles and cover areas.
  • Avoid placing temporary cofferdams, access tracks, pumps or spoil in pool margins or beneath cover.

Sheltering habitat: Juvenile and larval refuge

Larvae initially remain associated with the benthos and later disperse through the water column. Young fish use habitat features that provide food, shelter and suitable flow conditions, although the supplied documents do not define a single juvenile refuge type or minimum cover size.

Larval development period under study: The most sensitive period identified in laboratory work was approximately day 10 to day 20 after hatching.

  • Protect shallow margins, rocky substrates, low-velocity areas and connected cover during works near known populations.
  • Prevent fine sediment from filling pools, crevices and gravel or rocky substrates used by early life stages.
  • Avoid releasing turbid or oxygen-poor water into occupied habitat.

Sheltering habitat: Riparian and bank shelter

Riparian vegetation supports bank stability, shade, water quality and food inputs, and contributes to habitat for all life stages. Clearing riparian vegetation can increase erosion, sediment delivery and water temperature while reducing habitat quality.

  • Limit riparian clearing to the minimum approved area and protect retained vegetation from machinery and stockpiles.
  • Stabilise exposed banks promptly and prevent sediment from entering pools and cover features.
  • Keep lighting, vibration and access activity away from deep pools and vegetated banks where practicable.

Threats: Clearing, sediment and water quality

The main risks are loss and degradation of instream habitat, altered flows, barriers, sediment, pollution, illegal fishing and introduced fish. Construction and infrastructure projects can reproduce several of these pressures through clearing, earthworks, crossings, dewatering and water-quality impacts.

Clearing riparian vegetation and earthworks can destabilise banks and increase suspended and deposited sediment. Sediment can reduce water clarity, smother aquatic vegetation and rocky substrates, fill deep pools and continue to move through the system after works finish. Pollution, low dissolved oxygen, altered temperature, nutrients, heavy metals and contaminated releases can cause fish stress or mortality.

  • Use site-specific erosion and sediment controls before clearing or excavation starts.
  • Keep spoil, fuels, concrete washout, chemicals and contaminated water out of drainage lines.
  • Do not discharge turbid, deoxygenated or polluted water into connected Clarence or Richmond catchments.
  • Rehabilitate disturbed banks and riparian areas with appropriate native vegetation.

Threats: Hydrology and barriers

Water extraction, regulation, farm dams and altered runoff can reduce flows, change water temperature and disrupt seasonal cues for movement and spawning. Weirs, dams, crossings and other barriers can prevent access to feeding and breeding areas, fragment populations and interrupt gene flow.

  • Maintain natural or approved environmental flow patterns, particularly through low-flow and spring periods.
  • Provide effective fish passage at new and modified crossings and assess existing barriers for removal or retrofitting.
  • Prevent fish stranding during temporary diversions, pumping, channel isolation and dewatering.
  • Consider downstream habitat and flow effects, not only the footprint of the structure.

Threats: Fire and post-fire runoff

Fire can be followed by heavy rain, increased turbidity, suspended solids, conductivity and nutrient levels, reduced dissolved oxygen and fish kills. Post-fire sediment and ash runoff can therefore affect Clarence River Cod even when fire does not directly enter the channel.

Fire vulnerability assessment: Clarence River Cod received a fire overlap score of 2.3, a post-fire mortality score of 4, and a combined score of 6.3 in the cited assessment.

  • Protect unburnt aquatic and riparian refuge areas within or beside burnt catchments.
  • Inspect downstream pools and connected reaches after fire and major rainfall before undertaking further disturbance.
  • Use rapid field assessments and ongoing monitoring to identify population loss and guide management after severe fire or sediment events.

Threats: Introduced fish, fishing and disease

Introduced fish may compete with Clarence River Cod, prey on eggs or juveniles, transmit disease or alter habitat. Illegal fishing removes breeding adults and can disturb guarding fish, increasing predation of eggs and larvae. Disease and handling stress are additional risks during capture and relocation.

Recorded diseases and parasites: Captive fish have been affected by Chilodonella hexasticha, Ichthyophthirius multifiliis and Saprolegnia; Lernaea has been recorded on wild fish.

  • Do not release non-native or unapproved fish into rivers, farm dams or connected waterways.
  • Prevent transfer of water, equipment or fish between catchments unless biosecurity procedures are followed.
  • Use authorised methods, barbless hooks where angling is used, aerated holding water and gentle handling during surveys.
  • Report suspected illegal fishing, fish kills and introduced fish through the relevant NSW agency channels.

Survey methodology: 1. Habitat assessment and survey design

Survey this species as an aquatic, structure-associated fish. Focus on clear, flowing streams, deep pools and reaches with rocky beds, boulders, large woody debris, riparian cover and suitable fish passage. Survey design must cover the project area and downstream areas that could be affected.

Map all rivers, tributaries, pools, riffles, rocky reaches, woody debris, riparian vegetation, barriers and downstream pathways within and beyond the project footprint.

Prioritise reaches with slow flow, deep pools, rocks, timber or tussocks for cover, and boulders in faster water.

Assess whether each reach provides spawning, feeding, nursery, refuge or movement habitat, because different habitat types may be used across the life cycle.

Use the project area, indirectly affected downstream areas and the wider regional context to select survey sites and methods.

Known distribution: Clarence River system, with stocked populations in limited sections of the Richmond River system

Preferred habitat: Clear, flowing streams with rocky beds, deep holes, boulders and large woody debris

  • Record water clarity, flow, depth, substrate, cover, riparian condition, barriers and recent disturbance at every survey site.
  • Do not rely on a single technique, because the species can be difficult to detect in deep, fast-flowing or visually obstructed habitat.

Survey methodology: 2. Fyke nets and other passive traps

Use fyke nets in suitable pools and sheltered reaches, following approved fish sampling methods and permit conditions.

Inspect nets frequently enough to prevent stress, injury or drowning, and minimise the time fish remain out of their habitat.

Use unbaited gee or bait traps only for small or juvenile specimens, and use light traps for larval or juvenile fish where those life stages are the survey target.

Best documented survey period: November to January, after the spawning period, for fyke nets, angling and electrofishing

Alternative electrofishing period: April to June

  • Keep captured fish handling to the minimum needed for identification, measurement and release.
  • Release fish at the point of capture unless a permit and approved translocation or holding procedure authorises another action.

Survey methodology: 3. Boat and backpack electrofishing

Use boat-based electrofishing in suitable deeper water and backpack electrofishing in shallow pools and riffles up to about hip height.

Operate equipment under the Australian Code of Practice and the relevant state permit or animal ethics requirements.

Use electrofishing during the day in low-turbidity water, but recognise that cod may hide in good visibility; night electrofishing with lights can improve detection in some situations.

Do not rely on electrofishing in deeper, faster-flowing water, where the method is less efficient.

Known handling risk: All Australian freshwater cod species are susceptible to lock jaw during electrofishing

Preferred shallow-water application: Shallow pools and riffles to hip height

  • Adjust electrofishing frequencies to reduce the risk of lock jaw and other effects in cod.
  • Hold shocked fish in a flow-through, adequately aerated facility before release.
  • If a fish shows lock jaw, gently massage the jaw area and close the mouth, then assist recovery by moving water across the gills in an aerated tank.
  • Do not electrofish at elevated water temperatures where mortality risk is increased.

Survey methodology: 4. Angling and visual searches

Use lure fishing or angling with barbless hooks in suitable habitat, particularly around pools, rocks, timber and other cover.

Plan angling at dawn, dusk or night, when cod are generally more active, and use spring and summer only where the survey avoids the breeding period and complies with closures.

Use daytime snorkelling or other visual searches where water clarity and safety allow, because sight-dependent methods are best during the day.

Use high-quality photographs and record exact locations for any sighting or capture.

Breeding period: Spring, with spawning reported from September to November

Recorded spawning habitat: Slow-flowing pools under cover such as large boulders and bedrock shelves, at depths of 0.9 to 4.0 metres

Hook type: Barbless hooks

  • Avoid surveys during the breeding season where they could disturb territorial adults, spawning sites, eggs or larvae.
  • In the Mann and Nymboida rivers and tributaries, check the current fishing closure before using angling or other capture methods.

Survey methodology: Minimum effort and reporting

  • Prepare a site-specific survey design that states the number and location of sites, method, dates, duration, gear, weather and water conditions, and the basis for concluding presence or absence.
  • Do not claim that a site is free of Clarence River cod from one unsuccessful method or visit where habitat is deep, fast-flowing, turbid or structurally complex.
  • Avoid the documented spring breeding period where survey activity could disturb fish, and obtain current advice where seasonal timing is uncertain.
  • Record species identification, life stage, length, capture or observation method, coordinates, habitat features, photographs, handling time, release location and any injury or mortality.
  • Submit confirmed records and relevant negative survey information to the relevant state wildlife or fisheries database, and provide records required by the project approval and recovery program.
  • Report any suspected illegal take, fish kill, pollution event or barrier impact to the relevant state fisheries authority.

Before habitat disturbance: Avoid and minimise habitat loss

Treat any suitable stream, pool, riparian corridor or downstream receiving water as potential Clarence River cod habitat until survey and agency advice show otherwise. The main pre-work objective is to retain aquatic habitat, water quality, movement pathways and refuge cover.

Redesign works to avoid clear rocky streams, deep pools, large boulders, bedrock shelves, large woody debris, undercut banks, riparian vegetation and connected refuge habitat.

Retain large woody debris and boulders in the channel unless an authorised aquatic habitat specialist confirms that removal is necessary and an approved replacement plan is in place.

Keep works, stockpiles, access tracks, crossings and sediment controls out of the channel and riparian zone wherever practicable.

Maintain fish passage and avoid creating new barriers, including temporary barriers that isolate pools or block access to spawning and feeding areas.

  • Set project-specific no-go areas and buffers around occupied or suitable habitat in consultation with the relevant fisheries agency and aquatic ecologist.
  • Protect upstream and downstream connectivity, not only the habitat within the construction footprint.
  • Avoid changes to flow, water temperature, turbidity, dissolved oxygen, pH, nutrients and contaminants.

Before habitat disturbance: Approvals and timing

Check the Environment Protection and Biodiversity Conservation Act 1999 before works, because Clarence River cod is listed as endangered nationally.

Check state threatened species, fisheries, waterway, fish passage, clearing, pollution and animal handling requirements in the state or territory where the project occurs.

Obtain approvals for capture, handling, electrofishing, relocation, stocking, habitat alteration and any works affecting a waterway before mobilisation.

Schedule in-channel work outside the spring breeding period where practicable, and obtain fisheries advice if timing cannot avoid September to November.

National status: Endangered under the EPBC Act

Breeding season: Spring, with spawning from September to November

  • Refer the action under the EPBC Act if it may have a significant impact on the species or its habitat.
  • Prepare a fauna and aquatic habitat management plan that names the aquatic ecologist, fauna spotter catcher, fisheries contact, equipment and stop-work authority.
  • Stage works so that retained aquatic refuges and fish passage remain available until the next section is ready.

Before habitat disturbance: Pre-clearance preparation

Complete targeted pre-clearance aquatic surveys in all affected and potentially affected reaches using methods suited to depth, flow, visibility and habitat structure.

Mark retained pools, boulders, bedrock shelves, snags, riparian vegetation, fish passage routes and no-entry areas before plant enters the site.

Inspect the work area for isolated pools, stranded fish, injured fish, pollution, recent fish kills and barriers that may have formed since the survey.

Install exclusion fencing, aquatic refuge controls or other barriers only where they will not block fish movement or cause fish to become trapped.

  • Brief operators on the species' appearance, protected status, habitat, capture response and stop-work triggers.
  • Prepare aerated holding tanks, flow-through recovery equipment, clean water, nets, measuring equipment, approved containers and contact details for the relevant fisheries authority and wildlife veterinarian.
  • Check that dewatering, diversion and rescue procedures are approved before any water is removed or a channel is isolated.

During habitat disturbance: Daily controls and machinery coordination

The fauna spotter catcher must work as part of the aquatic construction team, not as a substitute for fish passage, pollution prevention or an approved fish rescue plan. Keep plant out of the channel wherever possible and stop work before habitat or fish are placed at risk.

Inspect waterway controls, exclusion zones, sediment barriers, bypasses and retained habitat before work starts each day.

Maintain natural or approved environmental flows through the work area and prevent sudden changes in depth, velocity, temperature or water quality.

Keep fuels, concrete, chemicals, spoil, sediment, wash water and contaminated equipment away from the waterway.

Require the spotter catcher or aquatic ecologist to inspect the work area before machinery enters and to remain available during channel disturbance, dewatering or habitat handling.

  • Use a stop-work signal understood by the supervisor, plant operators and spotter catcher.
  • Move machinery only through approved access points and prevent crushing of boulders, snags, undercut banks, pools or riparian vegetation.
  • Stop work after heavy rain, a spill, fish kill, unexpected turbidity increase, loss of flow control or failure of a fish passage measure until the aquatic ecologist and supervisor reassess the site.

During habitat disturbance: Habitat feature handling and fish rescue

Retain logs, boulders, bedrock cover, deep pools and riparian vegetation in place wherever possible because they provide shelter, spawning surfaces, food habitat and refuge.

Do not remove or relocate large woody debris, rocks or aquatic vegetation without an approved method that considers fish, eggs and larvae.

If dewatering or isolation is approved, undertake a methodical fish rescue using authorised personnel, suitable nets and aerated holding facilities.

Release rescued Clarence River cod into nearby retained habitat with suitable flow, depth, cover and water quality, at the location and in the manner specified by the approval.

  • Do not transfer fish, water, mud or equipment between catchments unless specifically authorised, because introduced fish and disease can threaten cod populations and genetic integrity.
  • Keep fish in water and minimise handling, air exposure, noise and repeated capture.
  • Do not disturb suspected spawning sites, nests, eggs or larvae unless the approved rescue plan specifically addresses them.

During habitat disturbance: Animal encounters, injury and stop-work triggers

If a Clarence River cod is found, stop the activity that could harm it and notify the fauna spotter catcher, aquatic ecologist and site supervisor immediately.

Only people authorised under the relevant permit and management plan may capture, handle, identify, measure or relocate the fish.

Do not use electrofishing, angling or nets for rescue unless the method is authorised and operated by trained personnel under the approved procedure.

Place an injured or distressed fish in an aerated, flow-through recovery facility and contact the relevant fisheries authority, aquatic veterinarian or authorised wildlife carer for instructions.

Recorded species size: Up to 41 kilograms, although most recorded fish since the 1960s were less than 5 kilograms and 660 millimetres

Recovery facility: Flow-through water and adequate aeration are required for shocked or retained fish

  • Stop work if a cod is found in the active work area, if fish become stranded, if a pool is being isolated, if fish passage is blocked, or if water quality deteriorates enough to threaten fish.
  • Stop work for any fish kill, oil or chemical spill, sudden sediment plume, abnormal water temperature, loss of dissolved oxygen or uncontrolled discharge.
  • Do not resume until the cause is controlled, affected fish and habitat are assessed, and the authorised aquatic specialist approves resumption.

During habitat disturbance: Records and incident reporting

Record every capture, sighting, rescue, relocation, injury, mortality, fish kill, barrier failure, pollution event and stop-work action on the day it occurs.

Include date, time, coordinates, waterway, habitat, fish measurements, photographs, method, personnel, permit number, holding time, release location and outcome.

Notify the relevant state fisheries or threatened species authority of any mortality, injury, unauthorised take, pollution event or unexpected population concentration.

Provide records to the project environmental officer, approval authority and relevant state wildlife database.

  • Retain daily fauna and water-quality logs with construction records.
  • Update the fauna management plan if survey or rescue results show that the species uses habitat not identified before works.
  • Do not release fish into a different catchment or an unapproved site.

After habitat disturbance: Completion checks and reinstatement

Completion of construction does not end the risk to Clarence River cod. Check the work area and downstream reaches for stranded fish, habitat damage, barriers, sediment and altered flows before demobilisation and during the approved monitoring period.

Inspect the full work area, bypasses, isolated pools, channel margins and downstream receiving habitat for stranded or injured fish before removing controls.

Confirm that fish passage is open, flows are connected, pools are not isolated and temporary barriers, spoil and debris have been removed or made safe.

Remove sediment, concrete, fuel, waste and construction materials from the waterway using methods that do not create a new turbidity pulse.

Verify that retained boulders, snags, bedrock cover, deep pools and riparian vegetation have not been damaged beyond the approved footprint.

  • Complete a post-clearance aquatic fauna check after dewatering, in-channel works or bank disturbance.
  • Photograph and map the reinstated channel, habitat features, access points, barriers and any residual impact.
  • Keep exclusion fencing and water-quality controls in place until the environmental officer confirms that the area is stable and safe.

After habitat disturbance: Monitoring and adaptive management

Monitor Clarence River cod presence, habitat condition, water quality, flow connectivity and fish passage at the frequency and duration specified in the approval or fauna management plan.

Use comparable sites and methods before and after works where the project could affect a population or important habitat.

Include dawn, dusk, night or daytime visual methods and capture methods only where they are appropriate, authorised and timed to avoid breeding disturbance.

Investigate any decline in detections, fish injury, mortality, sedimentation, loss of cover or altered flow, and change the works or controls in response.

  • Continue monitoring after heavy rainfall or fire where runoff could increase turbidity, suspended solids, nutrients or other pollutants.
  • Protect unburnt refuge habitat and undertake rapid ground assessment after fire where fire and post-fire runoff could affect the species.
  • Record whether habitat rehabilitation is being used by cod and whether fish passage remains functional.

After habitat disturbance: Reporting, approvals and offsets

Submit completion, incident, monitoring and species records to the relevant state fisheries or wildlife authority and to the project approval agency.

Report any residual impact against the approved impact assessment and recovery objectives.

Apply any approved offset, compensatory habitat or conservation measure only in accordance with the EPBC approval, state approval and agency advice.

Do not treat an offset as a substitute for avoiding damage to occupied habitat, breeding habitat, refuge cover or fish passage.

  • Update the project's threatened species register and spatial database with verified records and habitat changes.
  • Provide land managers with the location and condition of retained and rehabilitated cod habitat.
  • Escalate any unapproved residual impact or failure to meet approval conditions to the environmental manager and regulator.

Rehabilitation actions: Restore channel and riparian habitat

Rehabilitation should restore connected, clear-flowing aquatic habitat with cover, stable banks, natural flow cues and fish passage. Design the works for the whole stream reach, including riparian and upstream catchment processes that control sediment and water quality.

Re-establish locally indigenous riparian vegetation suited to the waterway and its flood regime, because riparian cover stabilises banks, shades water, supports food sources and improves water quality.

Control erosion and sediment delivery from disturbed banks, tracks, stockpiles, drains and upstream works.

Reinstate or retain large woody debris, boulders, bedrock cover, undercut banks, deep pools and varied pool, run and riffle structure where approved by the aquatic ecologist.

Do not simplify the channel or remove snags merely to improve appearance or conveyance.

Habitat features to restore: Rocky substrate, deep pools, boulders, large woody debris, riparian vegetation and varied flow environments

Key sediment risk: Sediment can fill pools and smother aquatic vegetation, gravel beds and other habitat

  • Use locally sourced materials that are free of weeds, pathogens, pest fish and contaminants.
  • Place logs and rocks so they provide cover without creating a new barrier to fish movement or an unsafe flood obstruction.
  • Prevent sediment from filling deep pools, gravel beds, spawning surfaces and refuge areas.

Rehabilitation actions: Fish passage, flows and water quality

Remove redundant barriers where authorised, or install fish passage structures designed for the species and the full range of relevant flows.

Maintain environmental flows that preserve seasonal changes in water level, temperature and movement, particularly during breeding and movement periods.

Prevent water extraction, farm dams, crossings and temporary works from altering small runoff events, low flows or connectivity through occupied habitat.

Design drainage, spill control and erosion controls to prevent changes in turbidity, dissolved oxygen, temperature, pH, nutrients, heavy metals and toxic substances.

  • Inspect repaired crossings and fishways after floods, maintenance and major construction events.
  • Keep a continuous connection between pools and suitable cover wherever practicable.
  • Use the relevant water sharing plan, river flow objectives and fisheries advice when setting rehabilitation and flow requirements.

Rehabilitation actions: Predator, pest fish and fire management

Prevent the introduction or spread of non-indigenous fish, disease and contaminated water, plant, equipment or sediment.

Do not stock, translocate or release fish without written authorisation, genetic assessment and an approved conservation program.

Control pest fish where an authorised program identifies disease, competition, predation or habitat degradation risks.

Manage weeds and protect riparian vegetation so banks remain stable and water temperature and sediment inputs remain suitable.

  • After fire, inspect burnt and unburnt reaches for fish mortality, sediment pulses, turbidity, low dissolved oxygen and loss of refuge cover.
  • Protect unburnt habitat patches within or adjacent to burnt areas, as well as other unburnt refuge areas, from further disturbance.
  • Use fire and catchment management measures that reduce severe runoff into occupied streams without damaging retained riparian habitat.

Rehabilitation actions: Monitoring and success measures

Set measurable rehabilitation outcomes for water quality, flow connectivity, bank stability, riparian cover, pool depth, woody debris, boulder cover, fish passage and Clarence River cod detections.

Repeat authorised surveys using consistent sites and methods, and compare results with pre-work data and suitable reference reaches.

Inspect rehabilitation after floods, drought, fire and maintenance to identify scour, sediment deposition, failed plantings, displaced logs or blocked passage.

Adapt rehabilitation where monitoring shows continuing sedimentation, reduced cover, altered flow, pest fish, barriers or declining cod detections.

Monitoring purpose: Document population and habitat status and evaluate the effectiveness of recovery actions

Survey caution: Avoid disturbing breeding fish, eggs and larvae during the spring breeding period

  • Record the location, design, materials, date and maintenance history of every rehabilitation feature.
  • Use rapid on-ground population assessments as a baseline for judging intervention effectiveness.
  • Report monitoring results, failures, corrective actions and confirmed species records to the relevant state authority and project approval agency.

Sources