Sousa chinensisSousa chinensisThe Indo-Pacific Humpback DolphinThe Indo-Pacific Humpback Dolphin

The Indo-Pacific Humpback DolphinThe Indo-Pacific Humpback Dolphin

This is, according to Wikipedia, “actually from blood This is, according to Wikipedia, “actually from blood vessels used for thermoregulation to prevent overheating vessels used for thermoregulation to prevent overheating from exertion.”from exertion.”

These dolphins generally live up to 40 years of age, the These dolphins generally live up to 40 years of age, the oldest currently found in Hong Kong, aged 33.oldest currently found in Hong Kong, aged 33.

The Indo-Pacific Humpback Dolphin, also called the Chinese WhiteThe Indo-Pacific Humpback Dolphin, also called the Chinese WhiteDolphin, belongs to the Kingdom of Animalia, the Phylum of Chordata, theDolphin, belongs to the Kingdom of Animalia, the Phylum of Chordata, theClass of Mammalia, the Order of Cetacea, the Family of Delphinidae, andClass of Mammalia, the Order of Cetacea, the Family of Delphinidae, andthe Genus of Sousa. It has a stocky body and a long, clearly defined beak. the Genus of Sousa. It has a stocky body and a long, clearly defined beak. The name humpback is derived from the hump on which the dorsal fin rests The name humpback is derived from the hump on which the dorsal fin rests upon; however, it is practically non-existent or not so well defined in some upon; however, it is practically non-existent or not so well defined in some dolphins. Males reach up to 3.2m, females up to 2.5m and the dolphins can dolphins. Males reach up to 3.2m, females up to 2.5m and the dolphins can weigh up to 284kg. Generally, they are born black, but as the Chinese White weigh up to 284kg. Generally, they are born black, but as the Chinese White Dolphins mature, their colour gradually changes until it is bright pink.Dolphins mature, their colour gradually changes until it is bright pink.

Distribution and AbundanceDistribution and Abundance

The Indo-Pacific Humpback Dolphins areThe Indo-Pacific Humpback Dolphins aregenerally distributed, as shown on the map togenerally distributed, as shown on the map tothe right, along the warm and temperate watersthe right, along the warm and temperate watersof the Indian and the Pacific Ocean. They areof the Indian and the Pacific Ocean. They arefound in many places; from Southern Australia tofound in many places; from Southern Australia toSouthern China and Taiwan. They are known toSouthern China and Taiwan. They are known toenter rivers, an example being the Yangtze enter rivers, an example being the Yangtze

River,River,estuaries or deltas (the Pearl River Delta) andestuaries or deltas (the Pearl River Delta) andeven mangroves, seemingly to favour the latter.even mangroves, seemingly to favour the latter.They also seem to prefer depths no deeper thanThey also seem to prefer depths no deeper than20m and warm temperatures from 15ºC to 36ºC.20m and warm temperatures from 15ºC to 36ºC.

According to the Agriculture, Fisheries and Conservation Department, the According to the Agriculture, Fisheries and Conservation Department, the amount of dolphins in Hong Kong waters and the Pearl River Estuary amount of dolphins in Hong Kong waters and the Pearl River Estuary numbered 217 during Winter, 78 during Spring, 199 during Summer, 209 numbered 217 during Winter, 78 during Spring, 199 during Summer, 209 during Autumn. Apparently, most of the dolphins were found close to Lantau during Autumn. Apparently, most of the dolphins were found close to Lantau Island.Island.

Behaviour and Eating HabitsBehaviour and Eating HabitsIndo-Pacific Humpback Dolphins generally travel in a pod of 3-5 other dolphins.Indo-Pacific Humpback Dolphins generally travel in a pod of 3-5 other dolphins.

Generally slow swimmers, travelling at the average speed of 4.8kph, they haveGenerally slow swimmers, travelling at the average speed of 4.8kph, they have

been known to chase off or kill sharks. They have been known to associatebeen known to chase off or kill sharks. They have been known to associate

with Bottlenose dolphins and, less commonly, with Finless Porpoises and with Bottlenose dolphins and, less commonly, with Finless Porpoises and

Long-snouted Spinner Dolphins. They are supposed to be “quite difficult toLong-snouted Spinner Dolphins. They are supposed to be “quite difficult to

approach and tend to avoid boats by diving and reappearing some distanceapproach and tend to avoid boats by diving and reappearing some distance

away in a different direction.” (Quoted fromaway in a different direction.” (Quoted from

http://www.cms.int/reports/small_cetaceans/data/S_chinensis/s_chinensis.htmhttp://www.cms.int/reports/small_cetaceans/data/S_chinensis/s_chinensis.htm))

These dolphins generally feed on reef fish, molluscs and crustaceans.These dolphins generally feed on reef fish, molluscs and crustaceans.

According to the Hong Kong AFCD, at least 20 fish species from 13 differentAccording to the Hong Kong AFCD, at least 20 fish species from 13 different

families have been identified, most commonly Engraulidae (anchovies),families have been identified, most commonly Engraulidae (anchovies),

Sciaenidae (drums and croakers) and Clupeidae (herrings, shads,sardines,Sciaenidae (drums and croakers) and Clupeidae (herrings, shads,sardines,

menhadens). The most commonly eaten fishes were lion-headed fish, variousmenhadens). The most commonly eaten fishes were lion-headed fish, various

croakers, and anchovies.croakers, and anchovies.

Environmental ThreatsEnvironmental Threats

At the time of 2006, the Indo-Pacific Humpback Dolphin was considered extinctAt the time of 2006, the Indo-Pacific Humpback Dolphin was considered extinctin the Yangtze river. In an article written in 1998, a passage says: The territorialin the Yangtze river. In an article written in 1998, a passage says: The territorialwaters of Hong Kong are highly contaminated with anthropogenic pollutants,waters of Hong Kong are highly contaminated with anthropogenic pollutants,including trace metals. Hong Kong's population of Indo-Pacific hump-backedincluding trace metals. Hong Kong's population of Indo-Pacific hump-backeddolphins (dolphins (Sousa chinensisSousa chinensis) inhabits an area where a high volume of sewage) inhabits an area where a high volume of sewagewaste discharge and the close proximity of contaminated mud pits mean awaste discharge and the close proximity of contaminated mud pits mean aconsiderable potential for trace metal contamination. Trace metalconsiderable potential for trace metal contamination. Trace metalconcentrations in the muscle tissue of fish caught from areas of high dolphinconcentrations in the muscle tissue of fish caught from areas of high dolphinabundance are notable. However, in order to gauge the amount of trace metalabundance are notable. However, in order to gauge the amount of trace metalconsumed by dolphins, whole fish must be analysed. Whole fish from areas ofconsumed by dolphins, whole fish must be analysed. Whole fish from areas ofhigh dolphin abundance have considerably higher trace metal loads thanhigh dolphin abundance have considerably higher trace metal loads thanmuscle tissue alone. Considering the consumption of prey items by dolphins, amuscle tissue alone. Considering the consumption of prey items by dolphins, adaily intake of trace metals was estimated as As, 410–518; Cd, 34–44; Co, 4–5;daily intake of trace metals was estimated as As, 410–518; Cd, 34–44; Co, 4–5;Cr, 40–50; Cu, 44–56; Hg, 51–66; Mo, 22–27; Ni, 19–24; Pb, 320–403; Se, 99-Cr, 40–50; Cu, 44–56; Hg, 51–66; Mo, 22–27; Ni, 19–24; Pb, 320–403; Se, 99-125 and Zn, 388–490 (μg kg125 and Zn, 388–490 (μg kg−1−1 body wt. per day). Concentrations of arsenic, body wt. per day). Concentrations of arsenic,chromium, lead, molybdenum and nickel in dolphin tissues were an order ofchromium, lead, molybdenum and nickel in dolphin tissues were an order ofmagnitude lower than in prey items, suggesting these elements may be magnitude lower than in prey items, suggesting these elements may be excreted by this species. excreted by this species.

Environmental Threats (2)Environmental Threats (2)

Mercury concentrations in dolphin tissues were, however, an order ofMercury concentrations in dolphin tissues were, however, an order of

magnitude higher than in prey items and could be considered potentially healthmagnitude higher than in prey items and could be considered potentially health

threatening (max: 906 μg kgthreatening (max: 906 μg kg−1−1 dry wt.). Hong Kong's Indo-Pacific hump dry wt.). Hong Kong's Indo-Pacific hump

backed dolphin population has a high dietary intake of trace metals which may,backed dolphin population has a high dietary intake of trace metals which may,

especially in the case of mercury, be a cause for concern.especially in the case of mercury, be a cause for concern.

((http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V78http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V78

3VCHGWX2D&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_ve3VCHGWX2D&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&urlVersion=0&_userid=10&md5=42a3f30d422bd687462e8d9b07a59f6rsion=1&urlVersion=0&_userid=10&md5=42a3f30d422bd687462e8d9b07a59f644

))

Other more obvious dangers include dolphins being tangled up in netting, waterOther more obvious dangers include dolphins being tangled up in netting, water

pollution, dolphin bycatch, sound disturbances, boat strikes and alsopollution, dolphin bycatch, sound disturbances, boat strikes and also

reclamation of land, leaving less living space for the dolphins.reclamation of land, leaving less living space for the dolphins.

Dolphin ConservationDolphin Conservation

There are several dolphin conservation organisations in Hong Kong, perhapsThere are several dolphin conservation organisations in Hong Kong, perhaps

the most dedicated being the Hong Kong Dolphin Conservation Society. Theythe most dedicated being the Hong Kong Dolphin Conservation Society. They

aim to increase public knowledge about the “biology and conservation ofaim to increase public knowledge about the “biology and conservation of

Chinese white dolphins and finless porpoises in Hong Kong, and cetaceans inChinese white dolphins and finless porpoises in Hong Kong, and cetaceans in

other parts of the world; preservation of dolphins and their habitats in Hongother parts of the world; preservation of dolphins and their habitats in Hong

Kong; impacts posed by dolphin-watching activities to dolphin and theKong; impacts posed by dolphin-watching activities to dolphin and the

importance of raising standard of dolphin-watching industry in Hong Kong; andimportance of raising standard of dolphin-watching industry in Hong Kong; and

global issues of whales and dolphins such as captivity, whaling, fishery bycatchglobal issues of whales and dolphins such as captivity, whaling, fishery bycatch

and marine pollution”, and also conduct scientific research on the wild dolphinsand marine pollution”, and also conduct scientific research on the wild dolphins

in Hong Kong, Taiwan and China, the education of the importance of dolphinin Hong Kong, Taiwan and China, the education of the importance of dolphin

conservation to children, and suchlike. Another organisation, the Hong Kongconservation to children, and suchlike. Another organisation, the Hong Kong

Dolphinwatch Ltd., more interested in dolphin watching, maintains that dolphin watchingDolphinwatch Ltd., more interested in dolphin watching, maintains that dolphin watching

is not just good for tourism but also giving public knowledge about dolphins. Others, suchis not just good for tourism but also giving public knowledge about dolphins. Others, such

as the AFCD of Hong Kong, focus on again dolphin conservation and various exhibitions.as the AFCD of Hong Kong, focus on again dolphin conservation and various exhibitions.

Ocean Park aims to conserve wildlife through research and education. Whale andOcean Park aims to conserve wildlife through research and education. Whale and

Dolphin Conservation Society is the world’s most active charity dedicated to conservationDolphin Conservation Society is the world’s most active charity dedicated to conservation

and welfare of cetaceans, of which whales, dolphins and porpoises belong to.and welfare of cetaceans, of which whales, dolphins and porpoises belong to.

BibliographyBibliography http://http://en.wikipedia.org/wiki/Chinese_White_Dolphinen.wikipedia.org/wiki/Chinese_White_Dolphin http://http://marinebio.org/species.asp?idmarinebio.org/species.asp?id=408=408 http://upload.wikimedia.org/wikipedia/commons/5/55/Pink_Dolphin.JPGhttp://upload.wikimedia.org/wikipedia/commons/5/55/Pink_Dolphin.JPG http://www.cms.int/reports/small_cetaceans/data/S_chinensis/sousa_chinensis_lg.jpghttp://www.cms.int/reports/small_cetaceans/data/S_chinensis/sousa_chinensis_lg.jpg http://www.cms.int/reports/small_cetaceans/data/S_chinensis/s_chinensis.htmhttp://www.cms.int/reports/small_cetaceans/data/S_chinensis/s_chinensis.htm http://en.wikipedia.org/wiki/List_of_fishes_of_India#Clupeidae_.28Herrings.2C_shadshttp://en.wikipedia.org/wiki/List_of_fishes_of_India#Clupeidae_.28Herrings.2C_shads

.2C_sardines.2C_menhadens.29.2C_sardines.2C_menhadens.29

http://en.wikipedia.org/wiki/Hong_Kong_Dolphin_Conservation_Societyhttp://en.wikipedia.org/wiki/Hong_Kong_Dolphin_Conservation_Society http://www.hkdcs.org/index_en.htm http://www.hkdcs.org/index_en.htm http://www.hkdolphinwatch.com/ http://www.hkdolphinwatch.com/ http://www.sciencedirect.com/science?http://www.sciencedirect.com/science?

_ob=ArticleURL&_udi=B6V783VCHGWX2D&_user=10&_rdoc=1&_fmt=&_orig=searc_ob=ArticleURL&_udi=B6V783VCHGWX2D&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1urlVersion=0&_userid=10&md5=42a3f30d422bd6874h&_sort=d&view=c&_version=1urlVersion=0&_userid=10&md5=42a3f30d422bd687462e8d9b07a59f6462e8d9b07a59f64