Hand Feed Dolphins at Tin Can Bay

Hand Feed Dolphins at Tin Can Bay

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.

About Dolphins - Indo-Pacific Humpbacked Dolphin

About Indo-Pacific Humpbacked Dolphins at Tin Can Bay.

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.

Scientific Details - Indo-Pacific humpbacked dolphin

1. Family
Delphinidae

2. Scientific name
Sousa chinensis

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
Insufficiently known

5.3 CITES status
Appendix I

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.

7. Habitat

7.1 General
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
Physical maturity,
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**

9.2 Reproduction
Sexual maturity,
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

9.3 Diet
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.

9.4 Behaviour
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.

10. Threats

10.1 Past
None that are not current.

10.2 Current

  • Presumed habitat destruction and degradation, including noise pollution, harassment—particularly close to major cities (e.g. in Moreton Bay).
  • Incidental capture in shark nets, trawl-nets, drift-nets
  • Illegal killing, particularly by people killing for sport, e.g. spearing or shooting.
  • Live capture in Queensland (permits granted for up to 12 per year at present) and northern New South Wales.
  • Overfishing of prey species.

10.3 Potential

  • Pollution, particularly form organochlorines, because inshore cetaceans very vulnerable, especially in agricultural regions.
  • Epizootics. Marine mammals very susceptible to pathogen-induced mass mortalities.

11. Conservation objectives

11.1 Research

  • Monitor abundance, especially in key areas, to determine possible impact of threats, e.g. pollutants, habitat degradation.
  • Determine levels of pollutants in individuals and in prey fish species to assess possible impact in different areas.
  • Study habitat requirements to assess impacts of degradation.
  • Derive a relationship between aerial survey estimates and absolute abundance to allow absolute abundance to be estimated and monitored.
  • Compare genetics and morphology between Australian and other regions to assess taxonomic status of Australian animals.
  • Establish life history parameters for Australian animals to allow better interpretation of population trends and effects of threats.

11.2 Management

  • Ensure regular monitoring of the population throughout Australia to detect possible decreases in numbers.
  • Minimise possible detrimental effects, e.g. water quality.
  • Help ensure adequate stocks of dolphins' prey by contributing to fisheries management discussions.

12. Conservation actions already initiated

12.1 Research

  • Aerial surveys of Northern Territory coastline (W Freeland et al., Conservation Commission of Northern Territory).
  • Aerial surveys in Great Barrier Reef Region and northern waters of Western Australia—adjunct to dugong aerial surveys (H Marsh et al., James Cook University).
  • Carcass salvage from shark nets in Queensland.
  • Photo-identification studies in Moreton Bay and adjacent offshore waters (P Corkeron et al., University of Sydney).

12.2 Management

  • Enforce legal protection under the Whale Protection Act 1980 in the Australian EEZ and state and Northern Territory waters.
  • Funding for aerial surveys—Great Barrier Reef Marine Park Authority, Queensland Fish Management Authority and Northern Territory Conservation Commission.

13. Conservation actions required

13.1 Research

  • Using aerial survey, establish baseline estimate for minimum population in Australia, identify areas of highest density along the Australian coastline and monitor trends.
  • In selected key areas, establish sizes and trends of populations using photo-identification sight/resight techniques.
  • Coordinate aerial survey and photo-identification in selected key areas to derive relationship between aerial survey minimum estimate and estimate of absolute abundance.
  • Determine levels of pollutants occurring in populations in key areas, using biopsy of free-ranging animals.
  • Determine level of genetic interchange between local and other Indo-Pacific populations; study existing museum specimens from different regions.
  • Determine habitat requirements.
  • Determine causes of death of stranded animals, relate pollutant levels to those in key areas.
  • Improve reporting of catches and carcass salvage of dolphins in shark nets (especially off Queensland), including at least identifying animals to species.
  • Establish basic life history parameters for animals in Australian waters from carcass salvage, long-term observations of naturally marked individuals and satellite telemetry studies.

13.2 Management

  • Monitor watershed management, including effects on habitat and prey species.
  • Fisheries management should allow for the requirements of upper predators (i.e. sharks, dolphins).
  • Require reporting and specimen collection from incidental capture.
  • Ensure specimens available for appropriate scientific museums.

14. Organisations responsible for conservation of species

14.1 International:
CITES, CMA

14.2 National:
ANCA
(Australian EEZ = 200 n miles)

14.3 State:
government wildlife agencies (state waters = 3 n miles)

15. Other organisations and individuals involved
G Ross, Australian Nature Conservation Agency
Australian Whale Conservation Society
ORRCA
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.

16.1 Research

  • For coordinating and collating data from surveys dedicated to other marine species: one research assistant, one year minimum.
  • For maintaining a long-term photo-identification project: one biologist working in one area, 10 year minimum.
  • For developing and implementing computerised cataloguing system for photo-identification project: one research assistant (half-time), one year minimum.
  • For telemetry program using satellite time-depth recorders to determine the movements and activity patterns of dolphins in key areas: one biologist working in two areas,* one year minimum.
  • For program investigating time budgets of animals in different areas, to assess relative importance of feeding/foraging in different areas: one biologist working in two areas,* one year minimum.
  • For program investigating pollutant loads in free-ranging animals: one biologist working in one area,* one year minimum.
  • For program investigating genetic segregation between populations: one biologist working in one area,* one year minimum.
  • Carcass salvage.

16.2 Management
Federal/state working group should be formed to oversee environmental management of inshore habitats in northern Australia and monitor abundance of Orcaella and Sousa.

17. Remarks
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)


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