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Indo Pacific Humpback Dolphin

Classification: Osbeck named this species Sousa chinensis in 1765, and in 1829 Cuvier named a subspecies, S. plumbea, for those individuals living west of Sumatra. A second subspecies, Sousa teuszii, is now recognised as a separate species.

Local Names: Indo-Pacific Humpback Dolphin; Speckled Dolphin.  (Sousa chinensis)

Description: This dolphin is robust, with a long beak, large melon, and well-rounded flippers. The dorsal fin rests on a 'hump', and the tailstock is thick with a keel. Indo-Pacific Humpbacked Dolphins are brown-grey, pale grey or pink-white on their upper sides, with a lighter underside and the presence of speckles. They reach a maximum of 2.8m in length, and weigh around 284kg.

Recognition at sea: The coastal habitats and distinctive dorsal fin are characteristic of this species.

Habitat: Water less than 20m is preferred with shallow banks and embayments. River channels and muddied waters are also favoured.

Food & Feeding: This species mainly takes schooling fish such as herrings and sea breams.

Behaviour: Small groups of 3-7 are common, but may congregate to form a larger group of around 25 animals. Humpback dolphins have a unique way of surfacing; the beak and often the entire head breaks the surface before the body arches tightly, making the hump and dorsal more prominent, and submerging. They rarely approach boats.

Indo-Pacific humpback dolphin, (Sousa chinensis), human/dolphin interaction, provisioning, Tin Can Bay Approximately 1974 fisher folk began feeding an Indo-Pacific humpback dolphin, (Sousa chinensis), from small craft on the waters of Tin Can Inlet and the Great Sandy Strait. The shallow estuarine waterway in the vicinity of the interaction area is well sheltered from all but the worst weather conditions, the nearest opening to the Pacific Ocean being approximately 10 kilometres to the north-northeast.

Humpback dolphins and, to a greater extent, bottlenose dolphins, (Tursiops sp.), are known to opportunistically feed by following trawlers in the region; indeed both have been observed behaving in this manner in Moreton Bay approximately 150 kilometres to the south.

Anecdotal evidence suggests that local residents have recognised this same individual dolphin, given the name of "Scar" due to its distinguishing features, since 1974. In more recent years, both recreational and commercial fisher folk have parted with some of their catch in feeding this and other dolphins in the region.

At about the time "Scar" was first observed with a neonate in late 1992 she began frequenting the Snapper Creek public boat ramp at Tin Can Bay and before long began accepting fish offered in shallow water near the water's edge from the hands of locals and tourists alike.

Fish for the purpose of hand-feeding the dolphins may be purchased from a kiosk adjacent to the interaction area. No controls exist to monitor the quality or quantity of fish dispensed for provisioning. Indeed, there are no controls on site managing the interaction and provisioning such as those, which exist in other locations where dolphins are provisioned. For this reason, grave concerns are held by conservation organizations about the situation. A number of parties have expressed commercial interest in the dolphin interaction. Some of the business ventures, which already have capitalised on the phenomenon conduct coach tours and helicopter flights. A male Rottweiler dog belonging to a nearby business proprietor was renowned for regularly swimming with "Scar" and her calf "Junior" for a number of years until his sudden disappearance in November 1996.

During 1994 we began an investigation into the history of the dolphins of Tin Can Bay and from 1 January 1995 monitored on a daily basis the regularity of visits by dolphins to the interaction area. Help was enlisted from a number of areas in this regard not the least of which being from the volunteer staff of the Coast Guard Tin Can Bay whose radio control room overlooks the interaction area.

For the ensuing 731-day period dolphins were present on a minimum of 87.5% of days. Dolphins were usually first observed at the boat ramp during the hour between 0700h and 0800h. On less than 6% of days dolphins arrived during the afternoon.

Whilst some available literature reveals tidal influence over some movements of dolphins the arrival times of the study animals were seemingly unaffected by positions of the tide.

During January 1995 two other dolphins visited the boat ramp in the company of "Scar" and "Junior". The greatest number of dolphins observed by us at the boat ramp at a single time was six. Eight dolphins have been identified by us entering the provisioning area at different times. In April 1996 a pair of dolphins known as "Beaky" and "Little Beaky" visited the boat ramp, the former (larger and with a deformed upper jaw) accepting fish. This pair visited irregularly until November 1996 from which time their presence became significantly more frequent.

In April 1995 the calf "Junior" commenced accepting fish from human hands and in the ensuing weeks was able to be touched. Children were observed riding the dolphin by holding onto the dorsal fin. An adult was observed trying unsuccessfully to climb onto the back of the dolphin. These sorts of human behaviour raise concerns for the safety of both dolphins and humans, especially in light of incidents in South America in recent years where the death of a human resulted from injuries sustained when a dolphin reacted to irresponsible actions on the part of humans.

In early January 1997 "Junior" visited the provisioning area alone for three days. During this period we received anecdotal evidence that "Scar" was seen with a neonate of a length no greater than 75 centimetres. Whilst the report was unconfirmed this was the first period of such a length that "Scar" and "Junior" had not been observed in each other's company. "Scar" returned after a three-day absence and was not accompanied by a neonate.

Considering the proximity to civilisation and the relative ease with which studies of the humpback dolphins from the Tin Can Inlet and Great Sandy Strait could be conducted, at the time of writing (February 1997) no research projects other than our own have been conducted using the Tin Can Bay humpback dolphins as subject matter.

The phenomenon continues to become more widely known through word of mouth, tourist brochures, souvenir sales, radio advertising, newspaper and magazine articles, and televised news reports and wildlife segments. Some other dolphin/human interaction sites such as Monkey Mia and Tangalooma are relatively remote; the former isolated by sheer distance from civilisation whilst the latter, being on an island, is accessible only by boat or aircraft. Tin Can Bay, with no controlling body managing the interaction, is only two hundred kilometres from the state capital of Brisbane and susceptible to escalating numbers of unsupervised persons. Clearly, the greater the delay in the necessary legislation, the greater the potential for associated problems exacerbating.

Please note these days the Government has ensured that the dolphins are well looked after and cared for. Visitors to the area now have to wash their hands in marine antiseptic liquid before feeding.  The quantity and quality of fish provided for feeding is controlled.  Visitors are not allowed to touch the dolphins and the volunteers “working” there make sure that no visitors behave in anyway that is disadvantages to the dolphins. They go out of there way to teach the public about the protection and preservation of not only the dolphins but the environment as a whole. Thanks Amanda.