Home > Local Issues > In The Ocean > PROTECT: Dolphins

PROTECT: Dolphins



Indo-Pacific humpback dolphins: Sousa Chinensis

Dolphins are Cetaceans, Cetaceans are mammals, meaning they have hair (though you might have a hard time finding it), bear live young and suckle them, are warm-blooded, and breathe air with lungs. There are 81 currently recognized species of cetaceans;­ whales, dolphins, and porpoises. The Indo-Pacific Humpback dolphin is a species under CITES appendix 1 and highly endangered. A similar dolphin was rescued by wildlife conservationists and government officials in Khao Lak, Phang nga province that stranded in a tin mine after the Tsunami hit the Thai Andaman Sea and successfully released back to the wild.


IUCN RED LIST: Near Threatened


The available abundance estimates for the chinensis-type humpback dolphin range from a few dozen to over 1,200 for the few small areas of the geographic form’s range that have been studied so far (less than 10%). Although it is possible that the total population numbers in the low tens of thousands, there is no evidence to suggest there are more than that and some reason to suspect the relatively large subpopulation in the Pearl River Estuary, estimated at about 1,200-1,300 individuals, is exceptional. That subpopulation would likely have no more than about 650 mature individuals (estimated % mature = 50% – see Taylor et al. 2007; but also note that there is a direct estimate of 60% mature for that subpopulation – Jefferson 2000, implying as many as 780 mature individuals). Considering the apparently fragmented distribution, the inference of declines in most areas (due to threats as described above and that fact that conservation actions currently are either meager or non-existent in most of the range), and that there could well be fewer than 10,000 mature individuals, thechinensis-type geographic form would qualify as Vulnerable (C2a(i) and possibly also A4cd) if it were assessed separately. 

Geographic Range

Indo-Pacific humpback dolphins of the chinensis-type are found in shallow, coastal waters from the east and west coasts of northern Australia and from southern China in the east, throughout the Indo-Malay Archipelago, and westward around the coastal rim of the Bay of Bengal to at least the Orissa coast of eastern India (Ross et al. 1994; Jefferson and Karczmarski 2001; Sutaria and Jefferson 2004). They regularly occur in some enclosed seas, such as the Gulf of Thailand. Their distribution appears to be limited to waters of the continental shelf, and the only places where they range far offshore are those where the water remains shallow (<100 m).


Studies have been carried out in only a few parts of the chinensis-type’s range, and there is no overall estimate of total population size. Certain subpopulations are thought to be depleted, mostly by habitat destruction/degradation and bycatch in fisheries. Most abundance estimates have been less than a few hundred dolphins, but there appear to be at least 1,200 animals (CVs range from 17-119%) in the Pearl River Estuary of southern China, adjacent to and including Hong Kong and Macau (Jefferson 2000, Jefferson 2005). The Pearl River Estuary population is the only one for this geographic form with quantitative data on population trends, and despite the heavy development in the area and numerous threats, the population has shown no evidence of significant decline in the last 11 years (Jefferson 2005). 

Other places where abundance has been estimated are Xiamen, with an estimate of 80 (CV=1.08 – Jefferson and Hung 2004), and eastern Taiwan Strait, which is thought to have a population of only about 99 individuals (CV=52% Wang et al. 2007). Declines have been inferred in both of these areas, based on qualitative environmental information. An estimated 237 (95% CI = 189-318) humpback dolphins inhabit waters around the Leizhou Peninsula, southern China (Zhou et al. 2007). Data on the status of humpback dolphins in Australia are scarce, but by analogy with sympatric (and better-studied) dugongs (Dugong dugon), Corkeron et al. (1997) suggested that they were in decline there. The only statistically defensible estimates for Australian waters are of 34-54 (CVs=13-27%) in Cleveland Bay, Queensland (Parra et al. 2006a), and 119-163 (95% CIs = 81-251) in Moreton Bay, Queensland (Corkeron et al. 1997).


Habitat & Ecology

Humpback dolphins occur in tropical to warm temperate coastal waters, including open coasts and bays, coastal lagoons, rocky and/or coral reefs, mangrove swamps and estuarine areas (Ross et al. 1994, Jefferson and Karczmarski 2001, Ross 2002). They are rarely encountered more than a few kilometres from shore. They sometimes enter rivers, but rarely move more than a few kilometres upstream and usually remain within the range of tidal influence. 

Indo-Pacific humpback dolphins appear to be opportunistic feeders, consuming a wide variety of nearshore, estuarine, and reef fishes. They also eat cephalopods in some areas, but crustaceans are rare in their diet (Jefferson and Karczmarski 2001, Ross 2002). 

Chinensis-type dolphins often enter rivers, estuaries, and mangroves, preferring coasts with mangrove swamps, lagoons, and estuaries, as well as areas with reefs, sandbanks, and mudbanks (Jefferson and Karczmarski 2001). In at least China and southern Asia, they are rarely found far from estuaries and mangrove habitats (Jefferson and Karczmarski 2001; Wang et al. 2007), and they show a strong preference for river mouths in northern Australia (Parra 2006; Parra et al. 2006b). Aerial surveys of the Great Barrier Reef region demonstrate that humpback dolphins occur mostly close to the coast but also in offshore waters that are relatively sheltered, and near reefs or islands (Corkeron et al. 1997). Fine-scaled resource partitioning between humpback and Australian snubfin dolphins (Orcaella heinsohni) has been documented off Queensland, where the two species favour river mouths and modified habitats but the humpback dolphins occur in slightly deeper (2-5 m deep) waters (Parra 2006).

Major Threats

Most humpback dolphins inhabit coastal or estuarine waters of developing nations, i.e.countries with limited resources and means for environmental protection. Range-wide incidental mortality in fishing gear and habitat degradation and loss represent the greatest threats to this species throughout its range (Ross et al. 1994, Jefferson and Karczmarski 2001). 

Chinensis-type dolphins are not known to be hunted directly in significant numbers anywhere in their range. However, they are often caught in fishing nets, such as gillnets and trawls, and in anti-shark nets set to protect bathing beaches from large sharks along the coasts of Queensland and New South Wales, Australia (Heinsohn 1979, Rosset al. 1994, Parra et al. 2004). Accurate catch data for humpback dolphins in the Australian nets are unavailable, but kills in anti-shark nets off Queensland are high relative to estimated abundance (Paterson 1990, Corkeron et al. 1997). The greatest direct sources of human-caused dolphin mortality in Hong Kong appear to be incidental catches in fishing gear (most likely pair trawls) and vessel collisions (Jefferson 2000, Parsons and Jefferson 2000). Between 1993 and 1998, at least 3 humpback dolphins were killed by boat strikes and another death was suspected of being caused by a boat strike. This represented 14% of all documented humpback dolphin strandings in Hong Kong during that period (Parsons and Jefferson 2000).

Concentrations of organochlorines in cetaceans from Hong Kong coastal waters are significantly higher than those found in cetaceans in other parts of the world (Parsons and Chan 1998, Minh et al. 1999) and it has been suggested that the reproductive success of Hong Kong’s humpback dolphins (including neonatal survival) is being affected (Parsons 2004; Jefferson et al. 2006). In Hong Kong, high volumes of sewage discharge and the close proximity of contaminated mud pits means that there is considerable potential for trace metal contamination of local dolphins (Parsons 1997). Indeed, mercury concentrations in the tissues of Hong Kong humpback dolphins were found to be an order of magnitude higher than in prey items and in some cases, were high enough (max: 906 µg kg-1 dry weight) to be considered potentially health-threatening (Parsons 2004). Hong Kong discharges over 2 billion litres of sewage into the surrounding waters daily. Parsons (1997) estimated that a humpback dolphin’s minimum daily intake of sewage bacteria through ingestion of contaminated seawater could be up to 70,500 faecal coliforms. To put this in context, a one-off ingestion rate of 200-300 coliforms is considered unacceptable for humans (Parsons 2004). 

The disposal of contaminated mud from Hong Kong’s dredging and reclamation projects poses an indirect risk to humpback dolphins via their consumption of contaminated prey (Clarke et al. 2000). Humpback dolphins inhabit the waters of several coastal ports in Asia that host large volumes of ship traffic, such as Shanghai, Singapore and Hong Kong. Therefore, it is likely that they are highly contaminated with butyltin (BT) (see Tanabe et al. 1998, Tanabe 1999; Parsons 2004). 

Underwater industrial activity, such as pile-driving during pier and bridge construction, are likely to cause acoustic disturbance (e.g. the development of Hong Kong’s new airport). Boat traffic also might interfere with the dolphin’s acoustic communication (Van Parijs et al. 2001).


Conserving Endangered Dolphins, Inner Gulf of Thailand. WWF


The project will ensure the survival of the remaining populations of dolphins in the Inner Gulf of Thailand through participatory research and participatory conservation interventions, supported by strengthened awareness raising and education.


- Survey dolphins in the Inner Gulf of Thailand in collaboration with the Department of Marine and Coastal Resources and selected fishermen villages. 

- Increase understanding of local communities on their coastal resources. This could develop preliminary management interventions to improve coastal resource conservation and dolphin conservation. 

- Strengthen civil society in conserving marine and coastal resources in the Inner Gulf provinces, with the conservation of dolphins being highlighted as flagship species in healthy ecosystems. 

- Promote conservation education and raise awareness on conservation values (incl needs of dolphins) within schools and communities in remote areas


End dolphins in captivity in Thailand


8th January 2012

Open letter to the press:

Dolphins are not just born into captivity, like dogs and cats, then used for circus shows in China, Indonesia, Japan, Bangkok and eastern europe, they are snatched brutally from the wild.

This is the shocking truth of the dolphin snatchers and brutal dolphin sughterhouse at a small town in south eastern Japan called Taiji, a small quant town tucked into the hills with a nasty history of killing and stealing dolphins from the ocean.

Famed ex dolphin trainer Rick O Barry has been for three years campaigning to stop this slaughter, and its getting harder, every day to bear this brutality that Japan allows to be unchecked.

Its January the 8th 2012. I awoke this sunday morning, an otherwise beautifull morning to what should have been a lovely day. I turned over, checked the time, 7.17am. I sit up, think about the good things that will happen, breakfast with my old buddy from Koh Samui, coffee with friends from Mumbai, a few hours boating possibly into Phang Nga Bay, Phukets gorgeous national park and dinner with my wife… a nice day right.

Then i turn on my twitter account and check the overnight messages.

indigonick is my twitter acccount, and after doing the radio show last night for 89.5FM, my regular Going Green show from 5-7pm where i recap the weeks news and views globally on all things green. Twitter is a great source of green info, as it aggregates feeds from WWF, IUCN, climate scientists, eneergy specialists, eco advocates, anti plastic campaigns etc etc.

Two people i follow very closely in their campaigning travels is Rick O Barrys tweets and his team at Taiji in Japan and The Sea Shepard, whose campaigns around the world against whale hunting are always action packed and confrontational.

At 7.17am my first twitter, after a good nights sleep was


Taiji: dolphin bodies now being loaded into the butcher house. The deed is done this day in Taiji town.

24 minutes earlier the tweet ran red

Taiji:: dolphins, including at least one baby, being dragged by their tails under the tarps covering the cove

One hour earlier

Taiji: dolphins now behind nets in the killing cove. Murder soon to follow

Two hours earlier

Taiji: Approxiametely 12 striped dolphins almost in the cove.

Three hours earlier

Taiji: Confirmed. Dolphins are being driven towards the cove. Time to start contacting the embassies!

Three hours earlier

Taiji: 7 Dolphin hunting boats in drive formation close to shore

Four hours earlier

Taiji: 11 dolphin hunting boats have departed Taiji harbour. Murder is afoot. Erwin is in jail.


This is the second day of hunting Dolphins in Taiji in 2012

On the first day of hunting on January 5th, after a hunting break the dolphin boats initially drove a pod of around 200 dolphins for hours, eventually trapping up to 45 dolphins in the killing cove and brutally stabbing them to death, after taking a few to be held captive in an aquarium, so that cruel circus shows called aquariums can make money from these poor wild creatures whose lives have been brutally controlled.

THIS MUST STOP, AND STOP NOW  is the main website that highlights the Save Japan Dolphins campaign.

THE COVE, is the documentary that was made about it, and although shocking is a must see video


This week, live from Taiji, Rick has started live feeds from the killing fields. follow live, early mornings 5 am thai time, 6am HK time


Who to follow on twitter

@sjdolphins Save Japan Dolphins

@seasheperd Sea Sheperd

@RichardOBarry Rick O Barry


Leave a comment


Dolphins dont like plastic bags

The Cove movie