Up to 100 Snubfin Dolphins are believed to live in Townsville's waters moving between Cleveland and Halifax Bays.

Growing to a maximum length of about 2.8 metres, the Snubfin Dolphin feeds on fish and squid in river-mouths and nearshore areas.

The Snubfin is rarely sighted because it is extremely shy and scared of boats.

The best place to see the Snubfin Dolphin is around the Ross River mouth.

Until 2003, the Snubfin Dolphin was throught to be an Irrawaddy Dolphin. However in this year, dolphin researchers determined that the local populations of Irrawaddy's were a distinct species unique to Australian waters.

There are very few pictures of Snubfin Dolphins available. The pictures below are of Irrawaddy dolphins which look very similar.

Snubfin Dolphins hunt using low frequency sonar and this is potentially disturbed by noise from boats.

Because their numbers are so small in Townsville waters, there is the real possibility that the Snubfin Dolphin could become regionally extinct. This has already happened in Cairns where the Ellis Beach population was wiped out by shark nets, and has never recovered.

The range of the Irrawaddy Dolphin.

Image source: www.mmcta.org/templating/pages/IrrawaddyDolphin.html

The below information is sourced from: Review of the Conservation Status of Australia’s Smaller Whales and Dolphins - Graham J. B. Ross - February 2006

Snubfin Dolphin

Irrawaddy (Snubfin) Dolphin (Orcaella brevirostris / O. heinsohni )

The level of information available on the biology and habitat of Orcaella brevirostris / O. heinsohni , in relation to threats or potential threats it faces, is too limited to support reassessment of its currently assigned status. It is therefore recommended that its status remain as K. Establishment of the size of the population and its distribution along the Queensland coast is urgent, as numbers may be diminishing. In this process, it is also recommended that an extensive collection of biopsy samples should be initiated as soon as possible to determine genetically the taxonomic status of the species in Australian waters and its relationship with other populations of Orcaella , the sex of individuals, levels of hormones and other substances, such as pesticides; to evaluate levels of relationships between populations, including assessment of the presence of philopatry, and to contribute to an assessment of the population size on the eastern and northern shores of Australia.

The similarities with Sousa in habitat and distribution strongly suggest that a joint investigation with those studying Sousa in this region would be most appropriate.

Family Delphinidae. Irrawaddy (Snubfin) Dolphin, Orcaella brevirostris / O. heinsohni Gray 1866.

Distribution showing presence in the shelf region (based on AGSO 1996 depth/slope bathymetric classification) of the Australian marine area (based on AMBIS version 1), north of 18ºS on the west coast and 28ºS on the east coast, in waters 20m deep. The distribution is broadly based on the Species Profile and Threats database account.

EPBC Act Status: Cetacean; Approved Recovery Plan: none.

The Action Plan for Australian Cetaceans status - insufficiently known (K)

Bonn Convention: listed as migratory species.

IUCN status: Insufficiently known/ Data Deficient

CITES Status: Appendix II Orcaella brevirostris : Census of Australian Vertebrate Species 1636, updated 31 Dec. 1998.

Taxonomic status. Described by Gray 1866 (a redescription of the dolphin described by Owen the previous year).

Currently only one species recognised, Orcaella brevirostris / O. heinsohni . Phylogenetic status has been confused until recently when both molecular, genetic and morphologic evidence suggested that closest affinities are with delphinids, rather than the externally similar Monodontidae (Arnold and Heinsohn 1996; Grétarsdóttir and Árnason 1992; LeDuc 1997; Lint et al. 1990; see also Rice 1998 for discussion). Recent research has shown that the Australia/New Guinea population differs from the Asian populations genetically, morphologically and in their habitat. In his analysis of the cytochrome b gene, LeDuc (1999) found that the riverine and coastal marine forms of Orcaella brevirostris differed genetically by 5.3%; in addition, Beasley, Arnold and Heinsohn (2002) have demonstrated significant differences in the form of the mesethmoid bones, the nasal ossicles, and the degree of separation of the pterygoid hamuli, of these two forms, based on an analysis of 124 crania collected from both habitats. The authors noted 41 that the degree of morphological difference in indicative of a major geographic/ecological barrier that has operated for a considerable period. The more derived nature of skulls fromAustralia/New Guinea implies an origin from the Asian populations (Beasley et al. 2002); Orcaella in Australia and New Guinea live only in the marine environment.

These authors note that the Australian/New Guinean animals are taxonomically distinct from the Asian dolphins at the subspecific level, at least, and probably warrant recognition as a full species. The authors propose additional morphological and genetic work, before naming the taxon formally.

Conservation objectives.

The five conservation objectives are:

• Determine extent of incidental take and fisheries in northern Australian and nearby waters; Past threats include Aboriginal hunting, a few Orcaella captured for oceanaria in Queensland; current and previous incidental capture in barramundi nets, for which little data on take is available, and capture in nets set to capture sharks for the protection of bathers (Banister et al. 1996). In the Townsville area alone, Parra et al. (2002) documented 41 Irrawaddy (Snubfin) Dolphins as museum specimens, which were caught in shark nets between 1968 and 1990; this number is almost certainly an underestimate, for another 55 unidentified "dolphins" or "porpoises" were caught in the nets in the same period, some of which are likely to be Orcaella. Two dolphins were caught by the Taiwanese net fishery in the early 1980s (D. Hembree, unpublished notes from the Arafura Sea fishery; G. Ross personal communication).
  
• Determine distribution and monitor abundance in Australian waters to assess possible impact of threats, particularly effect of direct and indirect fishing activities; Coastal, estuarine, and riverine areas are important in other regions of this species' range. Australian Orcaella occur only in marine environments. These dolphins live in shallow, tropical and subtropical areas, up to 20 km from shore. No key localities are yet known in Australian waters (Bannister et al. 1996). Limited seasonal migration has been recorded in the Mekong R., Kampuchea , and the Irrawaddy R., Myanmar ( Burma ) (Bannister et al. 1996; Stacey and Arnold 1999).
  
• Obtain information on diet re trophic level and impact of fishing industry on food resources; Little information is available on the diet of Irrawaddy (Snubfin) Dolphins. Stomach contents included bony fishes, cephalopods and crustaceans from demersal, benthic and pelagic habitats (Bannister et al. 1996). Three Johnius sp. (Sciaenidae) were found in a stomach of a net-caught dolphin in the Arafura Sea (D. Hembree, unpublished notes fromA rafura Sea fishery; G. Ross, personal communication). Retrieval of all deceased Orcaella carcases is essential to obtain all possible dietary items, including otoliths and other prey items, to determine the likely prey spectrum for Australian Orcaella, and the potential impact of humans on prey stocks.
  
• Determine taxonomic relationships within and outside Indo-Pacific region to assess likely impact of threats on possible individual populations; The marine population of Orcaella in Australian waters has been identified as a new taxon, yet to be named formally (P. Arnold, personal communication, November 2002). In the event of formal recognition of a new species, the collation of biological data for this new taxon will be important, including reproductive and growth data, including whole mass and 42 mass of body parts, age determination from teeth; pesticide and hormone samples, and parasite data.
  
• Minimise possible detrimental effects on population(s), for example, from fishing and other human activities. Eight Irrawaddy drowned in Queensland shark protection nets in the period 1996-2001; seven of these were from Ellis Beach, an event that seems likely to have deleted most or all of the local population. It is strongly recommended that shark nets be replaced on the Queensland coast with drumlines.

Distribution. Orcaella brevirostris, as currently placed taxonomically, occurs along the coast from the Bay of Bengal , through the Indo-Malay Archipelago. It occurs also up rivers in places (to Bhamo , Myanmar in the Irrawaddy River , to the Lao Peoples' Democratic Republic, in the Mekong River , in Mahakam River and Semayang Lake , of east Kalimantan , Indonesia and Lake Murray , Papua New Guinea ). The new species of Orcaella is a marine form, reported in Western Australia from north of, and including Broome (18°S), the Northern Territory (Chatto and Warneke 2000), and Queensland, south to the Brisbane River (27°32'S) (Bannister et al. 1996; Paterson et al. 1998; general distribution from Stacey and Arnold 1999). Minimum estimate for areas surveyed off Northern Territory is 1227 ± 301, but the figures are uncorrected for animals below the surface (Freeland and Bayliss 1989). This estimate has been disputed (Perrin et al. 1996, in Stacey and Arnold 1999). There are no estimates of population rate of change (Freeland and Bayliss 1989). Coastal, estuarine and riverine areas are important for Orcaella in other regions. Only marine populations are known from Australia , where this species occurs in shallow, tropical and subtropical areas, up to 20 km from shore. No key localities are known in Australian waters (Bannister et al. 1996).

Biology. Age or length at physical maturity is not known; maximum weight not known but Australian animals reach 2.1-2.3 m long, and weigh 114 -133 kg; maximum age is 28 years; maximum length is 2.70 m in males and 2.30 m in females (37 Australian dolphins: Arnold, P. personal communication; Bannister et al. 1996). Weight and length at birth of a captive animal was 12.3 kg and 0.96 m; weaning occurred at 2 years old. Age at sexual maturity is unknown; length ca 2 m. Calving interval is unknown; mating season is fromMarch to June (at 11°-12°N), and April - June (at 0°-1°S). Gestation lasts 14 months (captive animal) and calves are born in August or September; the period may be extended at low latitudes or there is significant geographical variation: newborns recorded from near Calcutta in June, in Laos from April to May, and in the Townsville region in August. Births in captive Indonesian animals appear to span July to February (extralimital data fromArnold, P., pers. comm.). No calving areas are known in Australian waters, near-termfoetus and neonate recorded from Townsville (Bannister et al. 1996). Group size in Australian Orcaella brevirostris / O. heinsohni is small, ranging from 1 to 14 animals, with an overall group size of 5.4 animals; 26 of 29 sightings were within 10 km of shore, with 3 groups up to 23 km offshore (Parra et al. 2002). Parra's observations during aerial surveys suggest that Irrawaddy (Snubfin) Dolphins tend to occur in small, localised populations. Philopatry has yet to be confirmed. If this species is philopatric, the prognosis seems poor for the recovery of groups that have lost one or more members in nets (G. Parra personal communication). A better understanding of whether this species is philopatric or not is 43 important, as the impact of the loss of reproductive females from such small groups is potentially greater than that for species that live in large schools.

Threats summary. Current threats include:

- Incidental capture in nets, and the overfishing of prey species;

- Potential threats include pollution (organochlorines, particularly PCBs) which is potentially serious in view of the species' inshore nature;

- Habitat destruction and degradation

- Noise pollution

- Harassment

- Particularly close to major cities (such as Cairns) and resort developments;

- The possibility of large population losses in the event of pathogen-induced mass mortalities (epizootics) to which marine mammals are susceptible (Bannister et al. 1996).