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Pig-nosed Turtle (Carettochelys insculpta)

The Pig-nosed Turtle is a very large, highly aquatic freshwater turtle found in northern Australia and southern New Guinea. In Australia it is restricted to river systems and associated billabongs in the Northern Territory, so clearing, bank disturbance, water extraction and changes to flow can affect feeding, movement and nesting habitat on development sites.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Northern Territory, Territory Parks and Wildlife Conservation Act 1976: Near threatened.

Breeding season

In northern Australia, pig-nosed turtles mate and nest during the late dry season. Eggs remain in shallow nests through the dry season and hatch when early wet-season rain or flooding provides suitable conditions. Clearing near sandy banks and exposed sand bars carries the greatest risk from July to December.

Reproductive mode: Oviparous. Females lay eggs in shallow nests and return to the water.

Clutch size: Usually two clutches in a breeding year. Clutches average about 10 to 10.5 eggs in the Daly River, with recorded ranges of 7 to 15 eggs there and 3 to nearly 40 eggs across populations.

Incubation: About 101 days at 28°C, 69 days at 30°C and 53 days at 32°C. Well-developed hatchlings may delay emergence during embryonic aestivation until early wet-season rain or flooding.

Size at hatching: Hatchlings are about 41 to 56 mm carapace length and 19 to 30 g.

Age at maturity: Males mature at about 14 to 16 years. Females mature at about 20 to 25 years.

Nest or egg sites: Fine riverbank sand, isolated sand bars, gravel or loamy sand with minimal vegetation. Daly River nests averaged 4 m from the water's edge, 1.6 m above water level and 13 cm deep.

Breeding frequency: Females generally breed every second year and usually produce two clutches in a breeding year. The two clutches are about 41 days apart.

Confirm timing locally before works, because nesting and hatching respond to local rainfall, flooding and nest temperature, and may vary between the Daly River, Alligator Rivers and other Australian catchments.

  • Mating: Mating occurs in water, but the documents do not give separate mating dates. Reproductive activity is associated with the dry-season nesting period, from July to November in northern Australia.
  • Gravid females: Gravid females leave the water briefly to lay eggs and may travel up to 5 km to suitable nesting beaches. Gravid female activity is recorded during the late dry-season nesting period, from July to November, with Daly River nesting mainly from mid-August to early October.
  • Nesting: Australian nesting occurs from mid-July to early November. Daly River nesting generally occurs from mid-August to early October, while Alligator Rivers nesting extends from mid-July to early November.
  • Incubation: Eggs are in nests from the first laying period in July through the wet-season emergence period. Incubation is temperature dependent, ranging from about 53 to 101 days, and delayed hatching can extend nest occupancy after embryos are fully developed.
  • Hatchlings: Hatchlings usually emerge with the first wet-season rains or flooding. In northern Australia, hatching is reported from about October to December, with emergence concentrated around the onset of the wet season.
  • Active period: Adults remain aquatic and can be active throughout the year. Activity and aggregations increase during the dry season, especially from July to September, as rivers contract into pools and billabongs.
  • Highest clearing risk: The greatest risk is from July to December, when females travel to nesting banks, shallow nests contain eggs and hatchlings emerge after early wet-season rain. Sandy banks and isolated sand bars within about 4 m of the water's edge should be excluded from clearing and vehicle access during this period; aquatic refuges and submerged root cover should also be retained year round.

Identification

This is a large freshwater turtle with a distinctive pig-like snout and flipper-like forelimbs. It spends nearly all of its time in water, and females normally leave the water only to lay eggs.

Adults have a rounded grey to olive carapace covered by continuous skin rather than the hard scutes found on most Australian freshwater turtles. The shell has a rigid peripheral margin because peripheral bones are retained beneath the skin.

The nostrils sit at the end of a fleshy, forward and downward pointing proboscis. The forelimbs are elongated and flattened, with claws on the first two digits. The underside, including the jaw, is creamy white to white.

Northern Territory adult size: Males up to 45.4 cm straight carapace length; females up to 52.3 cm.

Northern Territory adult weight: Up to 16 kg.

Identification: Sexes and similar turtles

Females are generally larger than males. Males have a longer tail, but the sexes are otherwise difficult to distinguish in the field.

The combination of a fleshy pig-like snout, skin-covered shell with a rigid margin and paddle-like forelimbs separates this species from Australian chelid turtles. It may superficially resemble a softshell turtle, but the retained peripheral bones give the carapace a firm edge.

  • Do not identify the species from shell softness alone. Check for the forward-pointing proboscis and flipper-like forelimbs.
  • Hatchlings have a very soft carapace and plastron when they emerge. The shell stiffens within a few hours.

Identification: Field signs

The species vocalises underwater, producing sounds consistent with contact calls. Visual detection is most likely in clear shallow water, billabongs, plunge pools, spring-fed reaches and ribbonweed beds.

Nests are shallow excavations in fine riverbank sand, isolated sand bars, gravel or loamy sand. They are usually close to the water, in sparsely vegetated places. In the Daly River, nests averaged about 4 m from the water's edge, 1.6 m above water level and 13 cm deep.

Hatchlings have been observed concealed in the root mass of submerged Pandanus roots and stems. Tracks are not expected to be a reliable sign because the species is strongly aquatic and its flipper-like limbs are poorly suited to movement on land.

  • Inspect exposed sandy banks and isolated sand bars for shallow nest scrapes during the late dry season.
  • Treat submerged logs, root masses, leaf litter and ribbonweed beds as potential turtle habitat even when no animals are visible.
  • Record underwater calls where acoustic equipment or trained observers are being used, but do not rely on calls as the only detection method.

Distribution: Australian range

In Australia, the Pig-nosed Turtle is endemic to the Northern Territory. It occurs as separated subpopulations in larger river systems, with no confirmed resident population currently established in every river where it has been reported.

Confirmed Australian records are from the Daly River system, including the Katherine and Flora Rivers, and from the East Alligator and South Alligator River systems. The species has also been reported from the Victoria River catchment, but field searches in 2018 did not locate a resident population there.

There are records or reports from the Roper, Fitzmaurice, Adelaide, Darwin, McKinlay and other Northern Territory rivers, but several of these reports are unsubstantiated or based on single records. The species is restricted to connected freshwater channels and associated wetlands, and Australian populations are not known to use estuarine areas.

  • Northern Territory: Daly, Katherine, Flora, East Alligator and South Alligator River systems are the main confirmed areas for project assessment.
  • Treat isolated records from other Northern Territory catchments as requiring verification before assuming a resident breeding population.
  • For Australian assessments, describe the distribution by river catchment and Top End freshwater system rather than applying an unverified formal bioregion label.

Distribution: Strongholds and population information

The Daly River subpopulation includes important habitat between Claravale and Oolloo Crossings, where spring inflows, river temperatures and ribbonweed meadows are favourable. Upper South Alligator reaches, including Pul Pul billabong and billabongs in Barramundi Creek, are important dry-season refuges.

All Australian populations are considered important for recovery. Populations are genetically structured and the Daly River subpopulation has exceptionally low genetic diversity.

Historical Australian estimate: Almost 3,000 individuals across five river drainages, based on extrapolation rather than complete surveys.

Historical drainage estimates: Daly 1,256; South Alligator 980; Victoria 430; East Alligator 158; Goomadeer 105 individuals.

Historical area of occupancy estimate: About 48.6 km², calculated from estimated occupied river lengths and average river width.

Current trend: The current Australian population size and trend are not known with confidence. The recent conservation advice identifies restricted occupancy, limited mature individuals and continuing habitat-quality decline.

Australian conservation status: Vulnerable under the EPBC Act from 16 July 2024; Near Threatened under Northern Territory listing information.

Habitat: Waterways and wetlands

Pig-nosed Turtles require connected freshwater systems with suitable aquatic habitat and nearby sandy nesting banks. They use both flowing and still water, but the habitat must retain water, food resources, riparian structure and movement pathways through the wet and dry seasons.

In the Daly River, the species occupies middle reaches between the escarpment and saline sections. These reaches are clear and shallow in the dry season and deeper and more turbid in the wet season.

In the Alligator Rivers region, it occurs in billabongs and plunge pools, with recorded average depths of about 2 m. During flooding it moves from river channels into billabongs and river swamp environments.

  • Retain continuous low flow and aquatic connectivity between pools, reaches and tributaries.
  • Protect spring-fed reaches, thermal riverbed springs, billabongs, plunge pools and river swamps connected to occupied rivers.
  • Avoid activities that isolate pools, block movement or reduce dry-season water depth.

Habitat: Banks and in-stream structure

Preferred substrates include sand and gravel with leaf litter and silt. Fallen trees and branches along billabong banks provide cover and contribute leaf litter.

Females have been recorded at an average depth of 1.5 m in the Daly River, with a range of 0.2 to 4 m. Males were recorded at an average depth of 0.9 m, with a range of 0.2 to 3 m.

  • Retain vegetated riparian banks, overhanging trees, fallen timber, submerged roots and leaf-litter accumulations.
  • Prevent bank erosion, sediment entry and loss of clean sand or gravel habitat.
  • Treat low, sparsely vegetated sandy banks within about 4 m of the water's edge as potential breeding habitat.

Habitat: Climate and elevation

The Australian distribution is in the tropical wet-dry climate of the Northern Territory, with habitat conditions shaped by pronounced wet and dry seasons. The supplied documents do not provide a reliable elevation limit.

Groundwater inputs influence dry-season flows and thermal springs in the Daly River. Changes to rainfall, flooding, temperature or groundwater discharge can affect habitat availability and reproduction.

Foraging habitat: Food resources

The Pig-nosed Turtle feeds underwater and in shallow freshwater habitats, with diet changing between wet and dry seasons. Adults are omnivorous but rely heavily on riparian and aquatic plants.

Dry-season foods include seeds, leaves and fruit from riparian plants such as cluster fig, white bush apple and screw pines. Aquatic foods include ribbonweed, algae and water nymph.

Animal foods include molluscs, crustaceans, fish, carrion and benthic macroinvertebrates. Smaller turtles may take insect larvae, small shrimp and snails.

  • Retain riparian vegetation that supplies fallen fruit, leaves and seeds.
  • Protect ribbonweed meadows, algae-covered substrates and other aquatic macrophyte beds.
  • Avoid sedimentation, pollution and flow changes that reduce aquatic plants, molluscs and benthic invertebrates.

Foraging habitat: Foraging range and microhabitat

Females commonly use deeper open sand flats, while males more often use isolated logs in shallower water. Both sexes use ribbonweed beds.

Radio tracking in the Daly River recorded average linear home ranges of 7.8 km for non-gravid females and 3.2 km for males. Gravid females had an average linear home range of 8.6 km and travelled up to 5 km while searching for suitable nesting beaches.

Average non-gravid female home range: 7.8 km linear river distance.

Average male home range: 3.2 km linear river distance.

Gravid female home range: 8.6 km linear river distance.

Nest-search movement: Up to 5 km in search of suitable nesting beaches.

  • Assess the full connected river reach around a work area, not only the water immediately beside the disturbance footprint.
  • Maintain access between deeper pools, logs, sand flats, ribbonweed beds and nesting banks.

Breeding habitat: Breeding biology

Breeding depends on exposed, lightly vegetated sand or gravel close to connected freshwater. Shallow nests are sensitive to flooding, trampling, nest temperature and changes in the timing of wet-season rains.

Females usually lay during the late dry season and may produce two clutches in a breeding year. The species follows a biennial breeding cycle, so females generally reproduce every second year.

Incubation time varies with temperature. Embryos can remain developed but unhatched in the egg until early wet-season rain or flooding stimulates emergence. Sex is temperature dependent, with cooler nests producing males, hotter nests producing females and intermediate temperatures producing mixed clutches.

Australian nesting season: Mid-July to early November, with Daly River nesting generally from mid-August to early October.

Breeding interval: Females generally breed every second year.

Clutches per breeding year: Usually two clutches; in the Daly River, 80% of gravid females nested twice and 20% nested once.

Clutch size: Daly River average 10.5 eggs, with a recorded range of 7 to 15 eggs. Other sources report a wider range of 3 to nearly 40 eggs between populations.

Nest position: Daly River nests averaged 4 m from the water's edge, 1.6 m above water level and 13 cm deep.

Incubation: About 101 days at 28°C, 69 days at 30°C and 53 days at 32°C; other sources report emergence in at least 77 days.

Age at maturity: Males about 14 to 16 years; females about 20 to 25 years.

Estimated lifespan: About 80 years based on an Australian growth estimate.

  • Do not disturb sandy banks, isolated sand bars or shallow nest scrapes during the Australian nesting season.
  • Prevent cattle, buffalo, machinery and people from entering nesting areas because the nests are shallow and easily crushed.
  • Maintain natural nest shading and exposure patterns. Avoid introducing dense vegetation over open nesting sand unless this is part of an approved rehabilitation design.

Breeding habitat: Nest habitat

Nests are placed in fine riverbank sand or on isolated sand bars with minimal vegetation. Gravel and loamy sand have also been used.

The preferred nest moisture content in one Daly River study averaged about 6%. Low nest height makes nests susceptible to early wet-season flooding, while livestock and buffalo can destroy them by trampling.

  • Map exposed sandy banks and sand bars within about 4 m of the water's edge before earthworks or access works.
  • Keep stock, vehicles, plant and temporary compounds away from nesting banks.
  • Avoid altering bank height, drainage, shading, moisture or flood access during the nesting and incubation period.

Sheltering habitat: Aquatic refuges

The species shelters in water rather than in terrestrial dens or hollows. Important cover includes submerged roots, logs, leaf litter, deep pools, billabongs, spring-fed reaches and dense aquatic vegetation.

In the Alligator Rivers region, billabongs and plunge pools provide dry-season habitat. The species may aggregate in upper South Alligator reaches, including Pul Pul billabong and billabongs in Barramundi Creek.

In the Daly River, turtles use thermal riverbed springs during dry-season months, apparently for thermoregulation. During wet-season flooding they occupy billabongs and river swamp environments.

  • Retain deep pools, billabongs, plunge pools and spring-fed reaches that remain connected to occupied rivers.
  • Do not remove submerged logs, branches, root masses or leaf litter without first assessing their value as turtle cover.
  • Maintain water levels and flow conditions that prevent occupied reaches from breaking into disconnected pools.

Sheltering habitat: Hatchling and juvenile cover

Little is known about the habitat of hatchlings and very small juveniles. One Daly River hatchling was found buried in the root mass of submerged Pandanus roots and stems, about 1 km upstream of Policeman's Crossing.

The cryptic habits of young turtles and their likely high early mortality mean that absence of visible animals does not demonstrate absence of habitat.

  • Protect submerged Pandanus root masses, stems, undercut banks and other concealed shallow-water structures.
  • Use low-impact inspection methods around roots, banks and shallow margins, particularly after wet-season emergence.

Threats: Hydrology and water extraction

The main Australian project risks are loss or degradation of river habitat, reduced dry-season flows, damage to nesting banks and interruption of movement between feeding, refuge and breeding areas. The species has low genetic diversity and delayed maturity, so local losses may take many years to replace.

Dry-season extraction for agriculture can reduce flow, fragment rivers into disconnected pools and restrict access to nesting beaches, ribbonweed and riverbed springs. Groundwater extraction may also reduce spring inflows and alter river temperature.

Modelling for the Daly River found that a 3 cubic metre per second flow reduction could produce a cease-to-flow year about every 9 years under the modelled scenario. Such conditions could cause resource limitation and reproductive failure.

Modelled dry-season flow risk: A 3 m³/s reduction was predicted to result in a cease-to-flow year approximately every 9 years in the Daly River model.

Potential habitat consequences: Loss of access to nesting banks, ribbonweed beds, thermal springs and connected movement routes.

  • Maintain continuous low flow and connectivity between occupied sites.
  • Assess surface water and groundwater take together, including effects on spring discharge and dry-season pools.
  • Do not place temporary crossings, culverts, causeways or other structures where they prevent turtle movement or reduce passage flows.

Threats: Banks, vegetation and sediment

Agriculture, mining, forestry and construction can clear riparian vegetation, increase erosion and add sediment to waterways. These changes can reduce food resources, alter bank structure and make nesting beaches unsuitable.

Cattle and Asian water buffalo can trample shallow nests, damage riparian vegetation and destabilise billabong banks. A misplaced human step may also destroy multiple eggs in a shallow nest.

  • Keep clearing, stock access, vehicle movement and material storage away from riparian banks, sand bars and known nesting areas.
  • Use sediment and erosion controls that protect clear water, sand and gravel substrates, ribbonweed and benthic food resources.
  • Fence or otherwise exclude cattle and buffalo from nesting banks where practicable.

Threats: Predators, weeds and disease

Feral pigs are suspected to prey on turtle eggs and adults, based on their impacts on other northern Australian turtle species. Argus monitors and Mertens' water monitors have been recorded preying on eggs.

Invasive weeds such as bellyache bush may shade nesting banks, alter nest temperatures and affect the temperature-dependent sex ratio. Novel disease is considered a potentially catastrophic future threat because Australian subpopulations have low genetic diversity.

  • Avoid spreading invasive weeds along riparian corridors and control weeds where they are overtaking open nesting banks.
  • Apply hygiene and equipment-cleaning procedures when working between occupied freshwater sites.
  • Report sick, dead or unusually lethargic turtles through the relevant Northern Territory wildlife authority and avoid moving animals between catchments.

Threats: Roads, fire and fragmentation

The supplied species assessments do not identify road mortality or fire as quantified primary threats. However, roads, crossings, laydown areas and access tracks can affect this highly aquatic species indirectly by disturbing banks, increasing sediment runoff, removing riparian cover or interrupting water movement.

The species is poorly suited to travel over land and cannot use terrestrial movement to reconnect separated Australian river systems. Fragmentation within a catchment can therefore restrict access to food, refuge and nesting sites.

  • Keep new roads, crossings and compounds out of riparian corridors where practicable.
  • Design crossings to retain natural water depth, flow and passage along the channel.
  • Manage hot works, fire breaks and planned burns to avoid direct disturbance of nesting banks and riparian vegetation, while recognising that species-specific fire thresholds are not provided in the supplied documents.

Survey methodology: 1. Habitat assessment and records review

Pig-nosed Turtles are highly aquatic and spend almost all of their time in rivers, billabongs, plunge pools and other permanent freshwater habitats. Survey effort should focus on occupied waterways, dry season refuges, movement connections and sandy nesting banks, rather than relying on a standard terrestrial fauna survey.

Before fieldwork, map all permanent and seasonal waterways, billabongs, plunge pools, spring-fed reaches, ribbonweed beds, riparian vegetation, fallen timber and sandy or gravelly banks within and downstream of the proposal.

Review recent records and consult Traditional Custodians, local rangers, land managers and relevant wildlife authorities, particularly for the Daly, Katherine, Flora, East Alligator and South Alligator river systems.

Treat all known or likely breeding, foraging and movement habitat as habitat requiring assessment, including areas not currently occupied but that may become suitable.

Australian range: Northern Territory, including the Daly, Katherine, Flora, East Alligator and South Alligator systems.

Core Daly River habitat: The reach between Claravale and Oolloo Crossings has been identified as core habitat.

  • Record water depth, flow continuity, bank condition, substrate, riparian cover, aquatic vegetation and access for turtles between retained habitat areas.
  • Identify dry season refuges, including spring-fed reaches and deeper pools, because turtles may aggregate there as water levels fall.
  • Search for recent nesting evidence on fine sand, gravel or loamy sand within approximately 4 metres of the water's edge.

Survey methodology: 2. Aquatic observation and spotlighting

Use qualified aquatic fauna surveyors to inspect suitable river margins, billabongs, plunge pools and spring-fed reaches during the dry season, when water is clearer and turtles may be concentrated in remaining pools.

Conduct repeated dusk and night searches from banks or a suitable vessel, using low disturbance lighting and trained observers who can identify the species underwater.

Record the date, start and finish time, weather, water level, flow, visibility, survey route, observer effort, habitat searched and every turtle observation.

Australian nesting period: Generally mid July to early November, with the Daly River nesting period usually mid August to early October.

Typical observed depths in the Daly River: Females averaged 1.5 metres, with a recorded range of 0.2 to 4 metres; males averaged 0.9 metres, with a recorded range of 0.2 to 3 metres.

  • Give particular attention to deeper open sand flats used by females, isolated logs used by males, ribbonweed beds, submerged root masses and fallen timber along banks.
  • Avoid entering or walking on sandy nesting banks during the nesting period unless the work is authorised and the survey can be completed without trampling nests.
  • Use the known activity and movement information to interpret results, noting that radio tracked females had average linear home ranges of 7.8 kilometres and males 3.2 kilometres, while gravid females moved up to 5 kilometres in search of nesting beaches.

Survey methodology: 3. Nest and bank inspection

Inspect likely nesting banks during the dry season before ground disturbance, concentrating on fine sand or isolated sand bars with little vegetation close to the water.

Use an experienced ecologist to distinguish turtle nests from other bank disturbance, and avoid probing or opening nests unless the work is specifically authorised for research or rescue.

Repeat the inspection immediately before works where nesting banks cannot be retained, because nests are shallow and can be destroyed by a single misplaced footstep or by machinery and livestock.

Typical nest position in the Daly River: About 4 metres from the water's edge and 1.6 metres above water level.

Typical nest depth in the Daly River: About 13 centimetres.

  • Search during and after the mid July to early November nesting period for tracks, body impressions, disturbed sand, nest openings and hatchling emergence signs.
  • Treat nests as vulnerable to early wet season flooding, because hatching is stimulated by the first rains and flooding is a major cause of embryonic mortality.
  • Do not use a negative bank inspection as proof that the waterway is unoccupied, because adults remain in the water and little is known about hatchling and small juvenile habitat.

Survey methodology: Minimum effort and reporting

No species specific Australian survey guideline or prescribed survey effort is provided in the supplied documents, so the project ecologist must justify the number, timing and duration of aquatic searches in the survey plan.

  • Survey every waterway, billabong, plunge pool, spring-fed reach, nesting bank and movement connection that may be affected directly or indirectly by the works.
  • Use more than one survey period where works overlap the July to early November nesting season, the dry season concentration period or the early wet season hatching period.
  • Report survey dates, observer qualifications, methods, effort, routes, conditions, water levels, detections, non-detections, photographs and spatial data.
  • Submit verified records to the relevant Northern Territory or other state or territory wildlife database, and provide records to the project approval authority where required.
  • Report any new population, breeding site or movement connection to the relevant wildlife authority before disturbance proceeds.

Before habitat disturbance: Avoid and minimise

Avoid disturbance to connected freshwater habitat, dry season refuges and nesting banks wherever practicable. The species has low mobility on land, strong site fidelity in some individuals and isolated Australian subpopulations, so a local loss of habitat cannot readily be replaced by movement from another river system.

Retain continuous low flow and waterway connectivity between foraging, dry season refuge and breeding areas.

Avoid removing spring-fed reaches, ribbonweed beds, riparian vegetation, fallen timber, submerged root masses, deeper pools and sandy nesting banks.

Keep works, access tracks, stockpiles, sediment controls and drainage out of the waterway and away from nesting banks wherever possible.

Prevent changes to groundwater or surface water that could reduce dry season flow, disconnect pools, restrict turtle passage or remove access to nesting beaches.

Habitat critical to survival: Continuous low flow, connectivity, spring-fed systems, developed riparian vegetation, instream structure and fine sand within 4 metres of the water's edge for nesting.

  • Use existing cleared access routes and bridge or span waterways rather than placing temporary crossings across turtle habitat.
  • Do not allow direct discharge of sediment, polluted water, concrete washout, hydrocarbons or other contaminants into occupied or connected waterways.
  • Maintain movement connections between retained habitat and avoid creating barriers that separate males, females, nesting beaches, food resources or thermal springs.

Before habitat disturbance: Approvals and timing

Check whether the action is likely to have a significant impact on the EPBC Act Vulnerable species, its habitat, water flow, nesting areas or movement connections, and refer the action under the EPBC Act if required.

Confirm all relevant state or territory threatened species, wildlife, waterway, vegetation clearing, fish protection and animal handling requirements before works begin.

Obtain written approval for any capture, handling, relocation, nest management or work within occupied waterways where required by the relevant authority.

Current Australian listing: Vulnerable under the EPBC Act, effective from 16 July 2024.

Listing assessment criteria: Vulnerable under criteria 2 and 3.

  • Schedule bank clearing and other disturbance outside the Australian nesting period of mid July to early November wherever practicable.
  • Avoid starting works when early wet season rain or flooding could inundate nests or carry sediment into occupied habitat.
  • Stage works so that retained waterways, dry season refuges and movement connections remain available throughout construction.

Before habitat disturbance: Site preparation

Complete a pre-clearance aquatic and bank inspection immediately before disturbance, even if an earlier ecological survey recorded no turtles.

Mark no-go areas around retained waterways, spring-fed reaches, ribbonweed beds, fallen timber, riparian vegetation and sandy nesting banks.

Install exclusion fencing or other physical controls where they can prevent machinery, vehicles, workers, cattle or buffalo from entering retained banks and wetlands without blocking turtle movement through the water.

  • Brief all workers on the species' appearance, aquatic habits, nesting season, stop-work procedure and authorised handling arrangements.
  • Place sediment fencing and site drainage controls before earthworks, and inspect them after rain.
  • Keep machinery, fuel, spoil, concrete, chemicals and wash water away from waterway margins and nesting banks.
  • Include a fauna management plan with maps, contact details, handling authority, aquatic rescue equipment, veterinary arrangements and reporting forms.

During habitat disturbance: Daily controls and machinery coordination

The fauna spotter catcher must work as part of the construction team, with authority to stop the activity that presents an immediate risk to a turtle, nest or connected aquatic habitat. Pig-nosed Turtles should not be treated as a terrestrial clearance species because adults, juveniles and hatchlings are strongly associated with water.

Complete a daily pre-start inspection of waterway margins, wet areas, access routes, exclusion fencing, sediment controls and any active nesting banks.

Keep the spotter catcher in direct communication with machinery operators and use a defined exclusion zone around water, banks, nests and retained habitat.

Stop or suspend works during heavy rain, rising water, uncontrolled sediment discharge, bank collapse or any condition that could carry a turtle, nest or pollutant away from the work area.

  • Move machinery only on approved routes and keep buckets, blades, pumps and vehicles out of retained water and riparian habitat.
  • Use a spotter catcher to inspect each work area immediately before clearing, excavation, dewatering, bank access or placement of temporary crossings.
  • Do not pump water, lower a pool, isolate a channel or block a culvert without an aquatic fauna rescue and release plan approved by the relevant authority.
  • Maintain sediment, erosion, spill and stock exclusion controls for the full duration of the work.

During habitat disturbance: Handling and relocation

If a turtle is found, stop the activity that could harm it and keep people and machinery clear while the authorised fauna handler assesses the animal and the surrounding habitat.

Only a person authorised under the relevant state or territory requirements should capture, handle or relocate the turtle.

Relocate a healthy turtle only when authorised, to the nearest suitable retained habitat that preserves the same waterway connection and does not place it across a land barrier or into another catchment.

Do not move a turtle between river systems, across a road or into estuarine or unsuitable water, and do not release it into a construction pond unless that location is approved as suitable habitat.

Typical adult size in Australia: Up to 16 kilograms, with recorded straight carapace lengths up to 45.4 centimetres for males and 52.3 centimetres for females.

  • Keep handling time as short as possible, support the body, protect the head and flippers, keep the animal cool and moist, and follow the handler's approved reptile rescue procedure.
  • Do not pick up or walk across sandy banks where a nest may be present unless the authorised handler has assessed the site.
  • Place an injured, weak, overheated or contaminated turtle in a secure ventilated container and arrange prompt assessment by a reptile veterinarian or authorised wildlife carer.
  • Record the animal's location, condition, photographs, sex if confidently determined, action taken, release location, time and people involved.

During habitat disturbance: Stop-work triggers and records

Stop work and notify the site supervisor and project ecologist if a turtle, hatchling, nest, eggs, concentrated aggregation or previously unmapped habitat is found within or downstream of the impact area.

Stop work if clearing or excavation would remove a nesting bank, spring-fed reach, ribbonweed bed, dry season refuge, riparian cover or movement connection not assessed in the approved plan.

Stop work if water quality, flow or connectivity cannot be maintained as required by the approval and fauna management plan.

  • Record daily inspections, start and finish times, weather, rainfall, water levels, works undertaken, turtle observations, nest observations, incidents and corrective actions.
  • Photograph and map all detections and habitat features before they are disturbed.
  • Notify the relevant wildlife authority and approval authority within the timeframe required by the approval for any injury, mortality, nest disturbance, unapproved capture or significant habitat impact.
  • Do not resume work at the affected location until the authorised ecologist or relevant authority confirms the control measures.

After habitat disturbance: Completion checks

Post-work checks must confirm that the project has not isolated retained water, removed nesting habitat or left continuing risks in the waterway. Monitoring should cover both the disturbed area and connected habitat that may receive sediment, altered flows or displaced turtles.

Inspect the work area, downstream reach, retained banks and temporary access points after clearing and again after the first substantial wet season rainfall.

Confirm that temporary crossings, pumps, silt controls, fencing, stockpiles and construction materials have been removed or left in an approved configuration.

Check that turtles can move along the waterway and that water remains connected to retained pools, spring-fed reaches, ribbonweed beds and nesting banks.

  • Search for injured or trapped turtles in excavations, sumps, culverts, drains, sediment basins and temporary ponds before demobilisation.
  • Repair eroded banks, blocked channels, damaged riparian vegetation and failed sediment controls immediately.
  • Remove artificial barriers that could trap hatchlings, juveniles or adults after construction.

After habitat disturbance: Monitoring and reporting

Monitor retained and rehabilitated habitat through at least the next relevant dry season and nesting season where the project altered banks, flow, groundwater, riparian vegetation or access to water.

Use repeatable aquatic observation routes and record effort and conditions so that changes in turtle use can be compared with the pre-work survey.

Compare results with the approved success criteria and escalate unexpected declines, mortality, nest loss, reduced flow or loss of connectivity.

  • Submit the final fauna and rehabilitation report to the approval authority and relevant wildlife database where required.
  • Include maps, survey effort, detections, handling and relocation records, incidents, photographs, waterway condition, rehabilitation actions and outstanding risks.
  • Maintain exclusion fencing, sediment controls, stock exclusion and access restrictions until the project ecologist confirms that they are no longer needed.
  • Apply approved offsets or other compensatory measures where residual impacts remain after avoidance and mitigation.

Rehabilitation actions: Waterway and bank restoration

Rehabilitation should restore a connected freshwater system with stable banks, riparian cover, instream structure, dry season refuge and nearby sandy nesting habitat. It should be designed around the local river system and approved ecological water requirements, not only around revegetation of the construction footprint.

Reinstate continuous low flow and movement connections between retained river reaches, billabongs, springs, pools and breeding areas.

Stabilise banks with locally appropriate native riparian vegetation while retaining open, lightly vegetated sand or gravel areas needed for nesting.

Restore fallen timber, submerged root structure, leaf litter and other instream cover where these features were removed and where their placement will not obstruct turtle movement or create a flood hazard.

Protect and, where approved, re-establish aquatic macrophytes such as ribbonweed in suitable shallow freshwater habitat.

Nest substrate: Fine riverbank sand or isolated sand bars, with nests also recorded in gravel and loamy sand.

Nest proximity to water: Daly River nests averaged about 4 metres from the water's edge.

  • Use native riparian species recorded from the local waterway, including locally occurring food plants such as cluster fig, white bush apple and screwpines where suitable for the site.
  • Prevent bank armouring, dense planting or weed growth from removing all open nesting substrate.
  • Design wetland and drainage features with permanent or seasonally persistent freshwater habitat, safe wildlife access and no entrapment points.
  • Do not create new barriers between foraging habitat, dry season refuges and nesting banks.

Rehabilitation actions: Threat control

Control invasive weeds that can dominate or shade nesting banks, including bellyache bush where it occurs, while retaining suitable open nesting areas.

Prevent cattle, Asian water buffalo and other stock from accessing nesting banks and degrading riparian vegetation.

Manage feral pig access where the species occurs and where approved control programs identify a risk to turtle eggs or hatchlings.

Manage erosion and sediment at the catchment and worksite scale so that fine sediment does not reduce water quality, fill pools or smother aquatic vegetation.

  • Maintain stock exclusion fencing and inspect it after floods and wet season storms.
  • Use weed control methods that do not contaminate the waterway or disturb nests.
  • Include fire planning that protects riparian vegetation, nesting banks and dry season refuge habitat from damaging fire, while following the authorised regional fire regime.
  • Include water extraction and groundwater effects in rehabilitation monitoring where the project affects a spring-fed or low-flow reach.

Rehabilitation actions: Success measures

Set measurable success criteria before works begin and assess them during the dry season, nesting period and early wet season.

Use the same survey routes and methods as the baseline assessment where practicable, and have a qualified ecologist review the results.

Known reproductive timing: Females generally lay eggs in the late dry season, with hatching stimulated by the first wet season rains.

Temperature dependent sex determination: Incubation at 31.5 degrees Celsius or below produces all males, 32 degrees produces mixed sexes, and 32.5 degrees or above produces all females; embryos die above 36 degrees Celsius.

  • Confirm that water remains connected between retained habitat areas and that approved minimum flows are maintained.
  • Confirm that spring-fed reaches, dry season pools, ribbonweed beds, riparian cover, instream structure and suitable sandy nesting banks are present and stable.
  • Confirm that invasive weeds and stock access are controlled and that erosion and sediment discharge remain within approval limits.
  • Record turtle observations, nesting evidence, hatchling emergence, injuries and mortality, and investigate any decline rather than treating non-detection as proof of failure.
  • Continue corrective rehabilitation and monitoring until the approval authority accepts that the habitat and fauna management objectives have been met.

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