The Boat Ramp at Norman Point at Tin Can Bay at the bottom end of the Great Sandy Strait is one of the few places where you can feed the rare Indo-Pacific humpback dolphins.
The Indo-Pacific Humpbacked Dolphin is listed as RARE Species in Queensland. They were removed from the Vulnerable Species list in NSW in 2002. And the species is NOT listed on the Federal Government website which could infer that it is common in most parts of Australia.
The Indo-Pacific Humpbacked Dolphin, Sousa chinensis occurs around the Indian Ocean coasts of Africa, Asia and north-western Australia, and from southern China through the Indo-Malay Archipelago to north-eastern Australia. In Australia, the species occurs in northern coastal waters from the NSW-Queenland border to Exmouth Gulf.
2. Scientific name
3. English name(s)
Indo-Pacific humpbacked dolphin
4. Taxonomic status, including species and subgroups
Osbeck (1765) described Sousa chinensis from the coast of China, but the holotype has been destroyed. The genus is in need of review and may comprise several species. S. chinensis inhabits the western parts of the genus' range. Included in S. chinensis is S. borneensis, found south and east of Indonesia (including Australia).
5. Species survival status
5.1 Australian Action Plan status
Insufficiently known (K)
5.2 IUCN status
5.3 CITES status
6. Distribution, including migration
Occurs in southern China through the Indo–Malay Archipelago to northern Australia. Recorded in Western Australia (north of 24°S), Northern Territory and Queensland, with occasional strandings reported in New South Wales (mostly north of 29°S). Not known to be migratory.
Coastal, estuarine, occasionally riverine. Tropical and subtropical. Occurs close to the coast, in less than 20 m depth. Aerial surveys in the Great Barrier Reef region may have located Sousa in waters between the outer reef and the mainland, further from shore than has been reported in the literature.
7.2 Key localities
Moreton Bay, Queensland and adjacent offshore waters, because resident population known there. Tin Can Inlet, Great Sandy Strait, Queensland because regularly seen there.
8. Marine protected areas managed for or relevant to the species
All cetaceans protected under state legislation to 3 n miles and under Australian legislation within Australian Exclusive Economic Zone (= 200 n miles). Species subject to IWC regulations (see Item 2.3) protected within Indian Ocean Sanctuary and Southern Ocean Sanctuary (see Item 5.4.6).
9. Biological overview (mainly South African data and possibly not the same species)
9.1 Growth and age
Birth, weight/length: ca 14 kg/0.97–1.08 m**
Weaning, age/length: not known
age/length: 13–14 years/ 2.58–2.74 m**
Weight, maximum: 260 kg** (male), 170 kg** (female)
Age, maximum: >40 years**
Length, maximum: 2.74 m**
age/length: 10–13 years**/not known
Calving interval: not known
Mating season: not known
Gestation: not known
Calving season: summer
Calving area(s): none known in Australian waters
Teleosts, some cephalopods and crustaceans. Littoral, estuarine and demersal reef species eaten. Feeds in association with prawn trawlers in Moreton Bay, presumably elsewhere throughout its range in Australia.
Sound—clicks, burst-pulses and whistles recorded. Whistles are pure tones ranging in frequency from 1.2 kHz to at least 20 kHz. Frequency range of whistles may be greater, but bandwidth limitations of most recording equipment prevent accurate determination of upper frequency limit. Capacity for echolocation not tested experimentally.
Social structure—occurs in groups of up to 25. Mean group size in Moreton Bay, 2.4. No data on sex differences in group formation, or on social behaviour. Appears subordinate to bottlenose dolphin when feeding near trawlers.
Behaviour—wide range observed. More spectacular aerial behaviour includes surfing, breaching, jumps (leaps to >2 m above the water surface), somersault jumps, fluke slaps, head slaps. Surfacing pattern very different from bottlenose dolphin. Tends to remain under water, surfacing only to breathe: bottlenose dolphin more likely to remain at the surface. S. chinensis surfaces in a rolling motion, poking rostrum out of the water, then arching its back as it dives.
9.5 Mortality and pathology
No good data on mortality rates. In Moreton Bay, 36% of dolphins show evidence of shark attack, suggesting mortality from sharks is significant. Very high levels of organochlorines, probably sufficiently high to kill a female's first calf, occur in South African animals. Possible that similar high pollutant loads occur in S. chinensis in Moreton Bay, but no data available at present.
9.6 Population abundance and rates of change
No data on absolute abundance. Fifty individuals have been photo-identified in Moreton Bay. Data from dugong aerial surveys along Queensland coast provide minimum estimates of humpbacked dolphins. Counts uncorrected for submerged animals. Continuation of surveys should allow monitoring of relative abundance for much of Queensland coast.
None that are not current.
11. Conservation objectives
12. Conservation actions already initiated
13. Conservation actions required
14. Organisations responsible for conservation of species
(Australian EEZ = 200 n miles)
government wildlife agencies (state waters = 3 n miles)
15. Other organisations and individuals involved
G Ross, Australian Nature Conservation Agency
Australian Whale Conservation Society
Project Jonah, NSW
Sea World, Surfers Paradise
16. Can research and management be carried out with existing resources? If no, what is required?
Planning for the conservation of S. chinensis in Australian waters is required. Much of its range in Queensland is covered by marine parks—the Moreton Bay Marine Park, Hervey Bay Marine Park and the Great Barrier Reef Marine Park. Declaration of the Great Sandy Straits Marine Park will extend this coverage. The possibilities for management in Queensland waters are therefore good. Most management will relate to water quality and maintenance of fish stocks. Strategic planning for research required, listed above, is also required. For example, monitoring will require a commitment to fund aerial surveys over several decades.
Federal/state working group should be formed to oversee environmental management of inshore habitats in northern Australia and monitor abundance of Orcaella and Sousa.
Very little is known about the species' biology. It is vulnerable because it lives so close to the coast. Given projections for human population expansion in south-east Asia, S. chinensis will probably be the first Sousa to be threatened. Australia is one of the few 'first world' countries in this species' range. As industrial, mining, fishing, farming, urban development and tourism activity in northern Australia increases, so too will the impact on these animals. It is vital that Australia takes a leading role in this species' conservation.
(Above information from: Department of Environment and Heritage)
To enquire about advertising on this site, please contact us here