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Australian Humpback Dolphin (Sousa sahulensis)

The Australian Humpback Dolphin (Sousa sahulensis) is a coastal dolphin found in northern Australia, from Western Australia to the Queensland to New South Wales border. Shallow nearshore waters, including river mouths, mangroves, tidal channels and inshore reefs, are important habitat.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Queensland, Nature Conservation Act 1992: Vulnerable.

Western Australia, Biodiversity Conservation Act 2016: Vulnerable.

Commonwealth, EPBC Act 1999: Listed migratory. Listed migratory species are a matter of national environmental significance, so a significant impact needs referral.

Seasonal planning

Mating and calving occur throughout the year.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Year-round: Mating and calving occur throughout the year.

Identification: Appearance

It is generally dark grey, with a darker cape and flanks that can be lighter. Its low, broad-based triangular dorsal fin has no visible hump.

It is generally dark grey, with a darker cape and flanks that can be lighter. Its low, broad-based triangular dorsal fin has no visible hump.

Identification: Confirming identity

Confirm the identity of any suspected record with a specialist and a photograph or voucher, as required by the relevant permit.

Distribution: Known range

In Australia, it occurs along the northern coast from Ningaloo Reef near Exmouth to northern New South Wales, and its range extends to southern Papua New Guinea.

In Australia, it occurs along the northern coast from Ningaloo Reef near Exmouth to northern New South Wales, and its range extends to southern Papua New Guinea.

Distribution: National mapping

The Commonwealth species distribution model (SNES) maps where the species or its habitat is known, likely or may occur. Use it with local records and site inspection.

Habitat: Habitat

This inshore species uses shallow coastal waters, often near river mouths, mangroves, tidal channels and reefs. It is also found in bays, estuaries and mangrove channels.

This inshore species uses shallow coastal waters, often near river mouths, mangroves, tidal channels and reefs. It is also found in bays, estuaries and mangrove channels.

Foraging habitat: Diet

It feeds on a wide variety of fish associated with coastal and inshore habitats. Feeding may occur around mangroves, sandy-bottom estuaries, seagrass meadows and inshore reefs.

It feeds on a wide variety of fish associated with coastal and inshore habitats. Feeding may occur around mangroves, sandy-bottom estuaries, seagrass meadows and inshore reefs.

Breeding habitat: Breeding

Mating and calving occur year-round. Gestation lasts about 10 to 12 months, and calves may nurse for more than two years.

Mating and calving occur year-round. Gestation lasts about 10 to 12 months, and calves may nurse for more than two years.

Sheltering habitat: Shelter

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Threats: Threats

Threats include accidental capture in gill nets and shark nets, habitat loss and degradation, vessel strikes, pollution and climate change.

Threats include accidental capture in gill nets and shark nets, habitat loss and degradation, vessel strikes, pollution and climate change.

Threats: Works risk

Coastal development and port construction may degrade or destroy habitat, while in-water and vessel activity can contribute to disturbance or collision risk. Fisheries interactions, including entanglement in nets, and pollution are also identified threats.

Survey methodology: 1. Commonwealth guidance

Use methods consistent with the Commonwealth survey guidelines and engage a specialist with the right permits.

For EPBC Act referrals, survey effort and methods should be consistent with the ePBC Act publications, including the National Guidelines for the Survey of Cetaceans, Marine Turtles and the Dugong (2024), read with the Significant impact guidelines 1.1.

Survey methodology: 2. Limits

A non-detection is not proof of absence. Match survey timing to the species and season, and record effort.

Vegetation associations: Mangrove

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

This inshore species uses shallow coastal waters, often near river mouths, mangroves, tidal channels and reefs.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: NSW, NT, QLD, WA.

Habitat use: general

Ecosystem associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific ecosystem association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Soil and substrate associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific soil association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Water and wetland associations: Water-associated habitat mentioned in profile

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

This inshore species uses shallow coastal waters, often near river mouths, mangroves, tidal channels and reefs.

Automatically indexed from existing profile text. Not a verified preference, mapped occurrence or habitat requirement. Check the original source and regional qualifiers before use.

Evidence: Unreviewed profile-derived candidate

Confidence: Not independently verified

Region: Scope as described in the quoted profile text; not independently verified. Profile states: NSW, NT, QLD, WA.

Habitat use: general

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before disturbance: 1. Desktop and approvals

Confirm whether the project could affect the species before works begin.

Check national mapping, state records and recent surveys for the site. An action likely to have a significant impact on this nationally listed species needs EPBC Act referral, and state permits apply where it is state listed.

Before disturbance: 2. Plan to avoid

Plan in-water works, vessel movements and lighting to avoid known habitat and sensitive periods, and set observer and shutdown procedures before works start.

During disturbance: 1. Controls

Keep works inside the approved footprint and conditions.

Use spotters and exclusion zones for in-water works and vessels, and pause works if the species is seen within the zone.

During disturbance: 2. Stop and report

If the species is found unexpectedly, stop work at that spot and contact the project ecologist and the relevant agency.

After disturbance: 1. Records

Record outcomes.

Record sightings, habitat lost or retained and any injury or death, and report them under the approval conditions.

Rehabilitation: 1. Restore

Restore disturbed habitat where possible.

Remove temporary structures, restore natural flow and substrate, and monitor water quality until it returns to baseline.

Sources