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Cobalt Blue Goby (Stiphodon semoni)

The cobalt blue goby is a small, amphidromous freshwater fish of clear, shallow, fast-flowing tropical streams. In Australia, project risk is concentrated around disturbance to rocky stream channels, rapids, waterfalls, riparian vegetation and downstream connections to the sea.

Conservation status

Commonwealth, EPBC Act 1999: Critically endangered.

Breeding season

A precise month-by-month breeding calendar is not provided. The species is tropical and amphidromous, so the life cycle may occur across the year where suitable flow and marine access are maintained.

Month values are not a documented seasonal calendar for Australia. They indicate that the supplied sources do not identify months when each process is absent or at peak.

  • Breeding: Spawning occurs in fast-flowing freshwater, but the supplied sources do not identify a seasonal peak.
  • Young: Larvae hatch after about 24 hours of egg guarding, drift to the sea and develop there for a few months. No seasonal timing is given.
  • Movement and dispersal: Larvae move downstream to the sea, and juveniles later return several kilometres inland and migrate upstream for several months. No seasonal timing is given.
  • Highest clearing risk: There is no documented seasonal low-risk period. Clearing and in-stream disturbance may affect adults, eggs, larvae, returning juveniles or feeding habitat at any time, so site-specific hydrology and survey information should guide timing.

Identification

This is a very small torrent-stream goby that holds to rocks in flowing water. Identification is easiest where adults can be observed in clear water or examined closely, because colour changes with sex, courtship and preservation.

The body is elongated and cylindrical at the front, becoming somewhat compressed towards the tail. The head is slightly depressed, the snout is rounded and projects beyond the upper lip, and the mouth is positioned below the head.

The paired pelvic fins are joined into a strong cup-like disc. This allows the fish to attach to rocks in rapids. The first dorsal fin is not pointed in males, and the second dorsal fin generally has 9 soft rays.

Dorsal fin formula: VII spines in total, followed by 9 soft rays.

Anal fin formula: 1 spine and 10 soft rays.

Pectoral fin: Usually 15 rays.

Longitudinal scale rows: 27 to 30.

Identification: Size and sex

Males are generally grey to dusky, with a bright blue-green lateral stripe in life. A white patch is present behind the pectoral fin base, and brooding or dominant males may show a bright white lateral band.

Females are paler and have a thin, serrated or zig-zagging dark lateral band. Females may also show four to six indistinct brown blotches along the band. Small males can resemble females.

Male maximum recorded size: 4.6 cm standard length.

Female maximum recorded size: 4.2 cm standard length.

Weight: No species-specific field weight is provided in the supplied sources.

  • Record standard length where possible, rather than relying on the aquarium maximum of 5.5 cm.
  • Do not use colour alone for identification, because courtship, dominance and preservation can alter the pattern.

Identification: Similar species and field signs

Stiphodon semoni is easily confused with Stiphodon atropurpureus and has also been incorrectly sold as Stiphodon elegans. The two species can be separated by range and morphology, but reliable identification may require close examination or expert confirmation.

There are no documented species-specific tracks, scats, calls, nests, sloughs or eyeshine. The most useful field sign is the presence of small gobies attached to or moving over algae-covered rocks in clear, swift stream sections.

Distinction from S. atropurpureus: Male S. semoni usually has a naked anterior half of the nape, whereas S. atropurpureus has scales there; S. semoni also usually has fewer longitudinal scale rows, 27 to 30 compared with 29 to 31.

  • For a suspected record, photograph the fish in lateral view and record the stream reach, substrate, flow conditions and distance from the coast.
  • Use the dorsal scalation and scale counts to separate S. semoni from S. atropurpureus where specimens or high-quality images are available.
  • Treat aquarium-trade names such as blue neon goby with caution, because similar Stiphodon species are frequently mislabelled.

Distribution: Australian range

The supplied sources describe a broad tropical Indo-Pacific range, but provide little detail on the Australian component. They do not identify Australian states, IBRA bioregions, strongholds, subpopulations or a national population estimate.

The species is reported from north-eastern Australia, as well as Indonesia, Papua New Guinea, the Solomon Islands, the Philippines and New Caledonia.

No Australian state, catchment, IBRA bioregion or locality is specified in the supplied sources. The Australian range should therefore be confirmed against current Australian occurrence databases and site records before field planning.

Australian states and territories: Not specified in the supplied sources.

Australian bioregions: Not specified in the supplied sources.

Known Australian range description: North-eastern Australia.

Distribution: Population information

No Australian population size, density, trend, stronghold or subpopulation structure is provided. FishBase reports high modelled resilience, with a preliminary minimum population doubling time of less than 15 months, but this is not an Australian population estimate.

Population size: Not reported for Australia.

Population trend: Not reported for Australia.

Modelled resilience: High, with a preliminary minimum population doubling time of less than 15 months.

  • Do not infer local abundance from the species' broad regional distribution.
  • Record occupied stream reaches, barriers, flow conditions and habitat disturbance separately, because the species depends on connected freshwater and marine phases.

Habitat: Stream habitat

Cobalt blue gobies occupy clear, shallow tropical streams with moderate to swift flow. The strongest habitat description is of rocky rapids, often above or near waterfalls, with bright conditions that support an algal biofilm.

The species occurs in small clear streams, including rainforest creeks and hilly streams, with moderately flowing to swift water. It is often associated with rapids preceding waterfalls and has been collected above waterfalls.

The stream bed is mainly bedrock, cobbles and boulders. Rocks are exposed to strong flow and may support a productive film of algae and microorganisms.

Water type: Freshwater, demersal and amphidromous.

Flow: Moderately flowing to swift, with rapids a commonly described habitat.

Substrate: Bedrock, cobbles and boulders.

Typical distance from the sea: Usually within 30 km of the sea.

  • Prioritise clear, shallow, rocky stream sections when assessing potential habitat.
  • Inspect rapids, rock faces, boulder margins and reaches immediately upstream of waterfalls.
  • Map riparian vegetation and leaf litter inputs, even though the fish generally uses the open rocky channel rather than dense aquatic vegetation.

Habitat: Climate and structure

The species is tropical. The supplied sources do not provide an Australian elevation limit or a defined upper or lower temperature limit in natural streams.

Sunny stream sections are important because they support the algal growth and biofilm used for feeding. Riparian vegetation lines the banks and contributes leaf litter to the channel.

Natural climate: Tropical.

Aquarium temperature reference: 20 to 28 degrees Celsius, not a confirmed natural Australian tolerance range.

Aquatic vegetation: Generally absent in the described natural habitat.

  • Retain riparian cover and stream shading patterns where they form part of the occupied reach, while recognising that sunny rock surfaces are also used for biofilm production.
  • Avoid treating a channel as unsuitable solely because it lacks aquatic plants. True aquatic plants are generally absent from the described habitat.

Foraging habitat: Food and feeding method

The species feeds by grazing across submerged hard surfaces. Its feeding habitat is therefore closely tied to stable rocks, strong oxygenation, sunlight and an established algal biofilm.

Cobalt blue gobies graze on algae and the microorganisms living within the biofilm, or aufwuchs, on rocks and other submerged surfaces. Reported food types include diatoms, green algae, benthic and epiphytic algae, and cyanobacteria.

The pelvic disc allows the fish to maintain position while browsing in rapids. Feeding groups may move over the same rock surfaces in clear, fast-flowing water.

Primary food: Algae and associated microorganisms in aufwuchs.

Foraging surface: Submerged bedrock, cobbles, boulders and other stable hard surfaces.

Foraging range: No species-specific home range or foraging distance is provided.

  • Assess algal-covered bedrock, cobbles and boulders as feeding habitat.
  • Record whether a project will scour, bury, shade, dry or otherwise remove submerged rock surfaces.
  • Consider sediment deposition and reduced flow as potential loss of feeding substrate, even where the channel remains physically connected.

Breeding habitat: Breeding biology

Breeding occurs in the adult freshwater habitat, but the life cycle includes a marine larval stage. Protecting only the spawning reach is not sufficient if downstream passage to the sea or later upstream passage is interrupted.

Adults spawn in fast-flowing freshwater. The female deposits several thousand very small eggs, and the male guards them for about 24 hours until hatching.

Newly hatched larvae drift downstream to the sea and develop under marine conditions for a few months. Juveniles later return several kilometres inland and move upstream to shallow, fast-flowing adult habitat.

Breeding season: No seasonal breeding months are given in the supplied sources.

Egg number: Several thousand minuscule eggs per female, according to the aquarium account.

Egg guarding: The male guards the eggs for about 24 hours.

Larval period: A few months under marine conditions. A related Stiphodon species is reported to have a 2.5 to 5 month pelagic larval period, but that duration is not confirmed for S. semoni.

Age at maturity: Within 12 months.

Gestation or incubation: No gestation. Eggs hatch after approximately 24 hours of male guarding.

Lifespan: Not provided.

Breeding habitat: Breeding habitat features

Spawning habitat is expected to be within the preferred fast-flowing freshwater stream sections, where rocks and boulders provide attachment surfaces and shelter for eggs and guarding males.

The amphidromous cycle requires an unobstructed connection from the spawning reach downstream to the sea, followed by access upstream for returning juveniles. Cataracts, steep slopes and waterfalls can form part of the natural upstream route, but artificial barriers may prevent passage.

  • Inspect undersides and sheltered faces of stones in swift freshwater reaches when searching for spawning habitat.
  • Maintain downstream and upstream connectivity between occupied stream habitat and the coast.
  • Assess culverts, weirs, crossings, temporary causeways and altered flow paths for effects on larvae and returning juveniles.

Sheltering habitat: Available refuges

No specialised den, hollow, burrow or roost is used. Shelter is provided by the stream bed, rock faces and spaces among cobbles and boulders in flowing water.

Adults hold position on rocks using the pelvic attachment disc. Sheltered rock surfaces, gaps among cobbles and boulders, and the lee side of bedrock features are likely to provide refuge from high flow and predators.

The supplied sources do not give refuge dimensions, minimum rock sizes, cover percentages or a defined shelter home range.

Shelter type: Rock surfaces, bedrock features and spaces among cobbles and boulders.

Shelter dimensions: Not provided.

Special structures: No dens, hollows, burrows, roosts or nests are described.

  • Retain natural bedrock, cobbles, boulders and interstitial spaces within the channel.
  • Avoid removing or rearranging rock features in rapids and shallow runs.
  • Inspect rock gaps and sheltered surfaces during low-flow conditions, while avoiding disturbance to occupied habitat.

Threats: Clearing and construction

The supplied sources do not provide a formal Australian threat assessment for this species. For development projects, the main foreseeable risks arise from damage to fast-flowing rocky streams, loss of water quality, altered flow and interruption of the freshwater to marine life cycle.

Clearing riparian vegetation can increase sediment, alter bank stability and change light and leaf litter inputs. These changes may affect the rocky surfaces and algal biofilm used for feeding.

Construction in or across the channel can bury, remove or rearrange bedrock, cobbles and boulders. Temporary works can also create barriers or low-flow areas that are unsuitable for a torrent-stream fish.

  • Keep machinery, spoil, concrete washout and stockpiles out of occupied stream channels and riparian areas.
  • Prevent sediment and fine material from coating stable rocks used for grazing and attachment.
  • Stage in-stream works to maintain flowing water and a continuous route through the work area.
  • Inspect and remove temporary barriers, pipes, bunds and causeways before reinstating the channel.

Threats: Hydrology and connectivity

The species requires highly oxygenated flowing water. Water extraction, flow reduction, diversion, impoundment and altered discharge can reduce suitable rapids and affect the biofilm food supply.

Because larvae drift to the sea and juveniles return upstream, barriers or altered flows can affect more than the immediate construction reach.

  • Assess changes to baseflow, peak flow, dissolved oxygen, temperature, turbidity and sediment deposition.
  • Map the connection from the occupied reach downstream to the sea and upstream through crossings and barriers.
  • Treat artificial barriers as a potential life-cycle risk even where adult fish remain visible upstream.

Threats: Other pressures

The supplied sources do not identify species-specific effects from roads, fire, predators or disease. These pressures may still matter where they alter stream banks, water quality, flow, sediment loads or connectivity.

The species is collected for the aquarium trade, and similar Stiphodon species are frequently confused or mislabelled. This makes accurate identification and provenance important when interpreting records.

  • Use sediment, erosion and spill controls at road crossings and drainage works.
  • Inspect post-fire streams for ash, sediment pulses, bank instability and loss of riparian cover rather than assuming fire effects from surrounding vegetation alone.
  • Confirm identification before treating a record as S. semoni, particularly where other Stiphodon species may occur.

Survey methodology: 1. Aquatic habitat assessment

Stiphodon semoni is a small amphidromous goby of clear, shallow, moderately flowing to swift tropical streams. Survey effort should focus on rocky stream sections, rapids, cobble and boulder beds, and connected waterways close to the sea.

Map all clear streams, creeks, rapids, waterfalls, rocky beds and connected drainage lines within and downstream of the project area.

Prioritise stream sections within about 30 km of the sea, as this species is commonly associated with small rainforest creeks in hilly country and uses freshwater habitat connected to marine larval habitat.

Record flow, water clarity, substrate, bank vegetation, algal growth, barriers to upstream movement and any nearby discharge or sediment source.

Preferred setting: Small, clear, moderately flowing to swift tropical streams with rocky and boulder-strewn beds

Typical position: Rapids and stream sections above or near waterfalls

Coastal association: Usually within 30 km of the sea

Survey methodology: 2. Visual and night searches

Search shallow runs, riffles, rapids, rock faces and the edges of cobbles and boulders during daylight, when fish and their algal grazing surfaces can be examined.

Use night spotlighting as a supplementary fish survey method where safe access and water conditions allow, because the species is small and may be overlooked in fast water during a single daytime inspection.

Search all suitable channel sections systematically and record the length or area searched, date, start and finish time, weather, water level, visibility and observer effort.

Adult size: Up to 4.6 cm standard length for males or unsexed fish, and 4.2 cm standard length for females

Male features: Grey overall colour, blue or blue-green lateral stripe, generally unmarked fins and a white patch behind the pectoral-fin base

Female features: Lighter body with a thin, often zigzagging or serrated dark lateral band

  • Do not enter unsafe rapids or approach waterfalls without a site-specific water safety assessment.
  • Photograph fish in the water where possible and retain diagnostic images of the lateral stripe, fins and body pattern.
  • Treat apparent Stiphodon records cautiously because S. semoni is easily confused with similar species, including S. atropurpureus and fish sold under incorrect aquarium names.

Survey methodology: 3. Aquatic sampling and identification

Use non-destructive, appropriately authorised methods suited to small benthic fish if visual searches do not provide a reliable result.

If capture is authorised, examine fish briefly in a clean, wetted container and release them at the capture point after identification.

Record coordinates, habitat, photographs, sex if known, size, waterway name and the identification basis for every record.

  • Do not infer absence from a single unsuccessful search because the fish is small, habitat-specific and associated with fast water.
  • Use an experienced fish taxonomist or museum-based identification check where S. semoni could be confused with another Stiphodon species.
  • Do not move fish between waterways during survey work.

Survey methodology: Minimum effort and reporting

  • Define survey effort before fieldwork, including the number of visits, search hours, stream length or area searched, sampling method and conditions, because the supplied documents do not specify a species-specific Australian survey effort.
  • Repeat surveys when water level, turbidity or access conditions prevent a reliable inspection of suitable habitat.
  • Submit confirmed records and negative survey results, with coordinates and effort details, to the relevant state or territory wildlife database.
  • Check the current EPBC Act listing and referral requirements before works begin, and retain the database submission receipt and survey report in the project file.

Before habitat disturbance: Avoid and minimise

Plan the project around the species' dependence on clear, oxygenated, rocky streams and its movement between freshwater and the sea. Prevent sediment, flow changes and barriers from reaching suitable channel habitat.

Retain clear stream reaches, rapids, riffles, rocky beds, cobbles, boulders and shaded or vegetated banks within the project area.

Avoid placing crossings, outfalls, spoil, stockpiles or access tracks in the active channel or in locations that can release sediment into downstream habitat.

Maintain connectivity between upstream freshwater habitat and the sea, including passage through culverts, temporary crossings and work areas.

Protect the shallow sunny rock surfaces that support algal biofilm, because the species grazes on algae and associated microorganisms.

  • Do not remove or rearrange natural cobbles and boulders unless this is authorised and unavoidable.
  • Keep riparian vegetation and leaf-litter inputs where they do not conflict with safety or statutory requirements.
  • Set project-specific exclusion zones and sediment controls around every suitable stream, with distances determined by the waterway risk assessment and approval conditions.

Before habitat disturbance: Approvals and planning

Check the current EPBC Act status and complete an EPBC referral or other Commonwealth assessment if the proposed action may significantly affect the listed species or its habitat.

Check state and territory threatened-species, fisheries, fish-relocation, waterway and animal-handling requirements before any capture, exclusion, dewatering or relocation.

Prepare a fauna management plan that identifies suitable stream habitat, survey results, authorised personnel, work limits, rescue procedures, water-quality controls, stop-work triggers and reporting responsibilities.

  • Obtain written approvals before handling, collecting or relocating fish.
  • Confirm the identity and qualifications of the fauna spotter catcher and any fish specialist before mobilisation.
  • Resolve the difference between the supplied Commonwealth listing and the FishBase assessment, which reports Least Concern globally, by checking the current legal registers rather than relying on either source alone.

Before habitat disturbance: Site preparation

Complete the pre-clearance aquatic habitat inspection immediately before works in or near suitable streams.

Mark exclusion zones, retained riparian vegetation, rock beds, riffles, waterfalls, access limits and approved machinery routes before construction starts.

Install sediment, erosion and spill controls before ground disturbance, and inspect them after rainfall and each work shift.

Use exclusion fencing or other physical controls where they can keep machinery, people, spoil and stockpiles out of the channel without blocking fish passage.

  • Stage works so that the smallest practicable section of stream is disturbed at one time.
  • Schedule in-channel works for the lowest-risk period identified by the hydrologist and regulator, while maintaining flow and fish passage.
  • Do not commence dewatering or isolate a channel until a fish rescue and relocation procedure is approved and the authorised team is present.

During habitat disturbance: Daily controls and spotter catcher duties

Treat any suitable stream as occupied until survey and authorised management show otherwise. The spotter catcher must work as part of the construction team, with authority to pause work when fish, habitat or water quality may be affected.

Inspect the work area, channel, exclusion fencing, sediment controls and access routes before machinery starts each day.

Brief operators on the mapped habitat, no-go areas, spill response, fish rescue procedure and the spotter catcher's stop-work authority.

Keep machinery, fuels, concrete washout, spoil and contaminated water out of the channel and prevent turbid water from entering downstream habitat.

Use a spotter catcher or aquatic fauna specialist during channel entry, dewatering, bank disturbance, rock removal and any activity that can strand or injure fish.

  • Maintain a daily register of inspections, personnel, machinery, water conditions, incidents, captures, relocations and released animals.
  • Stop work and notify the environmental manager when controls fail, water becomes visibly turbid, a fish is stranded or an unapproved habitat feature must be disturbed.
  • Do not restart until the environmental manager and relevant fauna authority confirm that controls and the fauna response are in place.

During habitat disturbance: Channel and habitat handling

Retain natural flow, depth variation, rocky substrate, cobbles and boulders wherever practicable.

Handle rocks and boulders carefully and return them to their original position if they must be moved under an approval.

Prevent sediment, concrete, hydrocarbons, chemicals and deoxygenated or contaminated water from entering the stream.

During isolation or dewatering, inspect pools, rock margins, shallow runs and wetted depressions for stranded fish before machinery enters.

  • Use clean equipment between waterways to avoid transferring pathogens, algae or other aquatic organisms.
  • Keep captured fish in clean, aerated, temperature-appropriate water and minimise handling time.
  • Do not release fish into a different catchment or across a barrier unless the approved relocation plan specifically authorises it.

During habitat disturbance: If the goby is found

Pause the immediate activity and keep machinery clear of the fish and its occupied habitat.

Only an authorised and competent person may capture, handle or relocate the fish.

Identify the fish using photographs and diagnostic features, including the small size, male or female colour pattern, lateral band and fin markings.

Release the fish into nearby retained habitat in the same connected waterway, only where this is allowed by the approval and relocation plan.

  • Do not place the fish in an aquarium, transport it away from the site or release it into another waterway.
  • Record the location, date, time, habitat, method, condition, identification, destination and people involved in any handling event.
  • Send injured, moribund or dead specimens to the approved aquatic fauna specialist, veterinarian, wildlife carer or museum contact nominated in the fauna management plan.
  • Treat a confirmed record, repeated detection, mortality event, loss of fish passage or major sediment release as a stop-work trigger until the environmental manager and regulator are consulted.

After habitat disturbance: Post-clearance checks

Confirm that the stream remains connected, clear and physically suitable after the work. Close out every fauna record, incident and approval condition before removing controls.

Inspect the full disturbed reach and downstream receiving waters for stranded, injured or dead fish after dewatering, channel works, heavy rainfall and removal of temporary crossings.

Check that flow, fish passage, rocky substrate, cobbles, boulders and bank stability have been restored or retained.

Remove waste, spoil, temporary barriers and sediment sources that could continue to affect the channel.

  • Keep sediment and erosion controls in place until the site is stable and approval conditions allow their removal.
  • Repair failed fencing, crossings, drains and sediment controls immediately.
  • Photograph and map the final channel condition and any remaining impact.

After habitat disturbance: Monitoring and reporting

Monitor water clarity, sediment deposition, flow continuity, bank stability, substrate condition and fish detections at the frequency set by the approval or fauna management plan.

Compare post-work observations with the pre-work habitat description and survey records.

Report confirmed detections, mortalities, injuries, captures, relocations, water-quality incidents and stop-work events to the project environmental manager and relevant authorities.

  • Provide the final report to the Commonwealth and state or territory agencies where required by approval conditions.
  • Include maps, photographs, survey effort, raw records, handling details, incident responses, monitoring results and unresolved risks.
  • Maintain controls and monitoring for as long as required by the approval, risk assessment or evidence that the stream has stabilised.

After habitat disturbance: Offsets and residual impacts

Assess residual impacts on occupied or suitable stream habitat after avoidance, mitigation, rehabilitation and monitoring measures are applied.

Apply any Commonwealth or state offset requirement only through the approved assessment and offset framework.

Prioritise measures that protect connected clear streams, rocky rapids and freshwater to marine passage rather than isolated habitat patches.

  • Do not treat aquarium records or a broad regional distribution as evidence that local stream impacts are acceptable.
  • Document why residual impacts are unavoidable and how the selected offset or conservation measure benefits the affected population or connected habitat.

Rehabilitation actions: Restore stream structure and water quality

Rehabilitation should recreate a connected, clear and oxygenated stream with stable rocky habitat and functioning riparian cover. The target is suitable habitat for a small benthic goby, not simply revegetated banks.

Re-establish natural channel shape, shallow runs, riffles, rapids and stable patches of bedrock, cobble and boulder substrate.

Return water-worn rocks and boulders to the channel where they were temporarily removed, without creating perched barriers or blocking fish passage.

Stabilise banks and disturbed ground with locally appropriate riparian vegetation and erosion controls.

Prevent ongoing sediment, nutrient, chemical and thermal inputs so that clear, well-oxygenated water can return.

  • Do not add fine sediment, sharp rock, concrete rubble or unstable fill to the channel.
  • Design culverts, crossings and drainage outlets to maintain the natural flow path and allow movement between freshwater habitat and the sea.
  • Retain sunny rock surfaces where safe and appropriate, because algal biofilm and associated microorganisms are an important food resource.

Rehabilitation actions: Riparian and aquatic habitat management

Replant disturbed banks with appropriate local riparian species to provide bank stability, shade variation and leaf-litter inputs.

Control weeds that smother banks, destabilise the channel or alter water quality, using methods that prevent herbicide entry into the stream.

Manage feral animal access, stock access and other sources of bank damage where they affect the restored reach.

Apply fire planning that protects riparian vegetation and avoids severe loss of bank cover and increased post-fire sediment delivery.

  • Do not install aquarium plants or non-local aquatic species during rehabilitation.
  • Retain natural leaf litter where it does not obstruct flow or create a flood hazard.
  • Inspect after storms, floods, fire and maintenance activities, and repair erosion before it reaches the channel.

Rehabilitation actions: Monitoring and success measures

Monitor the rehabilitated reach for clear water, stable banks, continuous flow, fish passage, retained rocky substrate and recovery of algal growth on suitable rock surfaces.

Repeat targeted fish surveys using the same search area, method and effort recorded before and during construction so that results can be compared.

Use confirmed S. semoni detections, or evidence of other suitable Stiphodon habitat use, as one biological indicator alongside physical habitat and water-quality results.

Useful habitat indicator: Clear, shallow, moderately flowing to swift water over rocky or boulder-strewn substrate

Biological context: Amphidromous fish that develops in the sea before returning upstream to freshwater

Known juvenile return scale: Larvae have been reported to swim several kilometres inland before metamorphosing and moving upstream

  • Set measurable success criteria in the rehabilitation plan for substrate stability, bank cover, sediment control, flow continuity and absence of project-related barriers.
  • Continue monitoring until the approved criteria are met and the reach is stable through relevant flow conditions.
  • Report failed rehabilitation, fish mortality, new barriers or persistent turbidity promptly and implement corrective actions.

Sources