Platanista gangetica (Blind River Dolphin, Ganges Dolphin, Ganges River Dolphin, Ganges Susu, Indus River Dolphin, South Asian River Dolphin) Geographic Range [top] Range Description: This species occurs in the Indus, Ganges-Brahmaputra-Megna, and Karnaphuli-Sangu river systems of the South Asian subcontinent, from the deltas upstream to where they are blocked by rocky barriers, shallow water, fast currents, dams, or barrages (low, gated diversion dams). The three river systems are disjunct and therefore so are their respective dolphin subpopulations, although there may be occasional demographic interaction between the latter two during the high-water season if the freshwater plumes of the two systems meet. There is further subpopulation separation within all three systems, some of it natural but much of it caused by physical barriers constructed within the last 100 years. The subspecies P. g. minor is endemic to the rivers of the lower Indus basin in Pakistan. Historically it occurred in the Indus mainstem and the Sutlej, Beas, Ravi, Chenab, and Jhelum tributaries.

It ranged from the Indus delta upstream to the Himalayan foothills where rocky barriers or shallow water prevented further upstream movement. Development of the vast Indus Basin Irrigation System has severely fragmented the dolphin population within a network of barrages (low, gated, diversion dams) and water diversion has dramatically reduced the extent of dolphin habitat. Current occupancy is effectively limited to three subpopulations in the Indus mainstem located between the Chashma and Taunsa, Taunsa and Guddu, and Guddu and Sukkur Barrages. A few individuals still remain above Chashma Barrage and below Sukkur Barrage (Braulik 2003, Reeves and Chaudhry 1998, Reeves 1998) (see Figure 1, in Supplementary Material). The map shows where the species may occur. The species has not been recorded for all the states within the hypothetical range as shown on the map. States for which confirmed records of the species exist are included in the list of native range states. States within the hypothetical range but for which no confirmed records exist are included in the Presence Uncertain list.

For further information about this species, see 41758_Platanista_gangetica.pdf . A PDF viewer such as Adobe Reader is required. Countries occurrence: Population [top] Population: Published data on abundance consist primarily of counts conducted within discrete portions of the vast network of riverine and deltaic habitat occupied by these dolphins. Few rigorous estimates of absolute abundance, with estimates of precision, are available. The entire current range of the Indus subspecies was surveyed in 2001 and resulted in an estimate of 843–1,171 individuals, with a best estimate of about 965. The largest subpopulation, containing more than 60% of the total, is located in the Sindh Dolphin Reserve between the Guddu and Sukkur Barrages, at the downstream end of the subspecies’ range. The next largest, with about 27% of the total for the subspecies, is immediately upstream in the Guddu-Taunsa segment of the Indus.

Surveys of portions of the range of the Ganges subspecies have collectively accounted for 1,200–1,800 animals, but the true population is believed to be larger because some potentially important areas have yet to be surveyed (e.g., the Indian Sundarbans) and at least some of the counts and estimates were considered negatively biased. The greatest densities of Ganges dolphins have been observed in the Ganges mainstem in India between Maniharighat and Buxar (particularly the Vikramshila Gangetic Dolphin Sanctuary) and just downstream of there between Kahalgaon and Manihari Ghat, and in the lower Sangu River of Bangladesh. Dolphin counts in the Guddu-Sukkur segment of the Indus showed an apparently increasing trend from 1974 to 1996. If this increase was real and not an artifact of variable sighting biases, it could be explained by recovery after implementation of a hunting ban in 1974 or by permanent immigration from upstream subpopulations. No credible time series of estimates is available for the Ganges subspecies, but downward trends are plainly evident for a number of upstream tributaries.

Marked declines have occurred in the extent of occurrence for both subspecies – in the case of Indus dolphins, from approximately 3,400 km of the main channel and its tributaries in the 1870s to approximately 1,000 linear km of the main channel today. An estimated 99% of the Indus dolphin population occurs in only 690 linear km, corresponding to an 80% reduction in the area of occupancy for that subspecies. In the case of Ganges dolphins, the picture is less clearcut, but substantial portions of the range, particularly in upstream areas, have been lost. For example, in the northern Ganges tributaries, at least three of six subpopulations that were isolated by barrages have disappeared, and in a recent dry-season survey of the Son River, no dolphins were found. Kaptai Dam in southeastern Bangladesh (built in 1961) resulted in the elimination of extensive habitat in the upper Karnaphuli River.

More specific information on the subspecies is provided below: Platanista gangetica gangetica Although the aggregate range-wide abundance of Ganges River dolphins was estimated by Jones (1982) as 4,000–5,000 individuals and more recently by Mohan et al. (1997) as fewer than 2,000, these were only guesses. Population assessments have been based on counts conducted within discrete portions of the vast network of riverine and deltaic habitat occupied by these dolphins. Few rigorous estimates of absolute abundance, with estimates of precision, are available. Available counts and estimates are summarized in Table 1 (see Supplementary Material).

Highest "densities" of Ganges River dolphins (defined as animals per linear river kilometer) have been observed in the Ganges mainstem between Maniharighat and Buxar (1.5/km) (Sinha, unpublished) - and within this segment particularly in the Vikramshila Gangetic Dolphin Sanctuary (2.8/km) (Smith, unpublished) and just downstream between Kahalgaon and Manihari Ghat (near Katihar) (3.4/km) (Sinha, unpublished) - and the lower Sangu River, Bangladesh (1.4/km) (Smith et al. 2001). A few Ganges River dolphins were still present during the mid 1990s as far downstream in the Hoogly River as Kakdwip (Sinha 1997). In the Sundarbans of Bangladesh a minimum of 134 Ganges River dolphins were counted resulting in a "density" estimate of 0.09 individuals/km, with Irrawaddy dolphins Orcaella brevirostris replacing Platanista in higher salinity waters of the southern and western portions (Smith, unpublished).

No information is available on the status of Ganges River dolphins in the Indian Sundarbans, except for historical reports of occurrence (Anderson 1879, Jones 1982). Roughly accounting for duplicate counts or estimates in Table 1 (see Supplementary Material), the total of about 1,200–1,800 animals provides a reasonable lower range for the total metapopulation abundance. However, considering that areas with potentially large numbers of animals have not been accounted for at all (e.g., Indian portion of the Sundarbans Delta) and that at least some of the counts and estimates are known to be negatively biased (e.g., see Smith et al. 2001), the true number could be several times as high. Numerical Declines: Although no credible time series of abundance estimates are available for most of the subspecies' range, the numbers shown in Table 1 (see Supplementary Material) imply downward trends in a number of upstream tributaries (see also Range Declines below). Range Declines: The range of the subspecies has declined progressively since the nineteenth century when it was mapped by Anderson (1879).

No dolphins have been reported in recent years between the Madhya Ganga Barrage at Bijnor and the Bhimgoda Barrage near Haridwar, at the upstream limit of their historical range in the Ganges (Sinha et al. 2000). This suggests a roughly 100 km decline in their range in the Ganges River since the late 1800s. In recent years, dolphins have not been reported in the Yamuna River above the Chambal River confluence during the dry season because upstream channels have become too shallow and polluted to support dolphins, but the segment may still be occupied during the monsoon (Sinha et al. 2000). Historically, they were found year-round in the Yamuna River approximately 400 km upstream to Delhi (Anderson 1879). Elsewhere in the Ganges mainstem, four extant subpopulations are isolated by barrages, including Farakka Barrage located approximately at the center of the subspecies' overall range.

In the northern Ganges tributaries, of the six subpopulations that were isolated above or between barrages, three have been extirpated (in the Gandak River above the Gandak Barrage and in the Sarda River above the upper and lower Sarda barrages) (Sinha et al. 2000) and one reduced to insignificant numbers (in the Kosi River above the Kosi Barrage) (Smith et al. 1994). Ganges River dolphins have apparently been extirpated from the Son River (at least during the dry season) based on a survey covering ca. 300 km upstream of the Ganges confluence, above and below the Indrapuri Barrage (Sinha and Sharma 2003). Occasional reports of dolphins in the reservoir behind Kaptai Dam (built in 1961) of the KS system occurred until the mid-1990s (Ahmed 2000), but recent surveys have found no evidence that the subspecies survives there (Smith et al. 2001).

Thus, the dam's construction is likely to have caused a substantial reduction in the subspecies’ range in southeastern Bangladesh, but in the absence of any historical information on occurrence in the upper Karnaphuli no quantitative estimate of range reduction is possible. No surveys have been conducted in the Damodar River system but a single dolphin was rescued after becoming stranded in a deep pool after flow was diverted during the dry season by an upstream barrage. The downstream effects of at least ten dams and barrages constructed in its mainstem and tributaries has probably severely reduced and fragmented dolphin habitat (Smith et al. 2000). Platanista gangetica minor Direct-count surveys of the largest subpopulations have been conducted regularly by the Sindh and Punjab Wildlife Departments since the early 1980's, but described methods do not provide a basis for evaluating bias, estimating precision, or detecting trends in abundance (Reeves and Chaudhry 1998).

Dolphin counts between Guddu and Sukkur Barrages show an apparent increase from 139 dolphins recorded in 1974 (Pilleri and Zbinden 1973–74), to 290 in 1979 (Pilleri and Bhatti 1980), and 458 dolphins in 1996 (Mirza and Khurshid 1996). If this increase was real and not an artifact of variable sighting biases, it could be explained by recovery of the subpopulation after implementation of a hunting ban in 1974 (see Conservation Actions below) or by permanent immigration from upstream subpopulations (see Major Threats below). A comprehensive review of previous survey data is presented in Reeves and Chaudhry (1998) and Reeves et al. (1991). The most recent and comprehensive assessment of the Indus Dolphin population was a survey of their entire range conducted in March and April 2001 that resulted in a minimum abundance estimate of 965 dolphins (based on the sum of best estimates of group size of all sightings).

High and low estimates of group size were also recorded. The sum of high estimates was 1,171 and the sum of the low estimates 843. This survey also documented a pronounced increase in the abundance and encounter rate of dolphins as the survey vessel proceeded downstream. The largest subpopulation is located in the Sindh Dolphin Reserve between the Guddu and Sukkur Barrages, at the downstream end of the range. Best estimates of 602 total dolphins and 3.6 dolphins/linear km were recorded for this section, 259 dolphins and 0.74 dolphins/linear km for the section between Guddu and Taunsa, and 84 dolphins and 0.28 dolphins/linear km for the furthest upstream section between Taunsa and Chashma. Two dolphins were seen upstream of Chashma Barrage and 18 downstream of Sukkur Barrage. The minimum abundance estimate of 965 dolphins for the subspecies is likely to be close to the actual population size due to measures taken in the field to increase sighting efficiency.

Essentially all potential dolphin habitat was surveyed in the Indus mainstem, including secondary channels and braids off the main channel, from a non-motorized vessel (mean survey speed = 5 km/hr), which maximized detection opportunities. Double-concurrent counts were also conducted from a second vessel traveling behind the primary survey vessel. Sightings were considered unique if they were greater than 750 m distant from another group according to the GPS positions. Preliminary analyses indicate that the primary survey vessel missed less than 10% of dolphin groups, and no groups of more than three individuals (mean group size recorded was 2.0; SD = 1.6; range 1–11) (Braulik 2004). The probability of double counting dolphins due to their movement from surveyed to unsurveyed areas overnight was considered to be balanced by the probability that an equal number of dolphins were missed altogether due to their movements in the opposite direction.

The linear extent of occurrence of the subspecies has declined from approximately 3,400 km of Indus mainstem and its tributaries in the 1870s (see Anderson 1879) to approximately 1,000 linear km of the mainstem today (Braulik 2004). An estimated 99% of the dolphin population occurs in only 690 linear km, which corresponds to an 80% reduction in the area of occupancy (Anderson 1879, Reeves et al. 1991, Braulik 2003, Braulik 2004). During the 1970s and 1980s there were occasional reports of dolphin occurrence between barrages in the lower reaches of the Indus tributaries (Reeves et al. 1991). No recent surveys have been conducted in those areas. However, due to an increase in upstream water abstraction and a decline in dry season flows, it is unlikely that any dolphins remain in these reaches. For further information about this species, see 41758_Platanista_gangetica.pdf .

A PDF viewer such as Adobe Reader is required. Current Population Trend: Habitat and Ecology [top] Habitat and Ecology: South Asian river dolphins are generally concentrated in counter-current pools below channel convergences and sharp meanders and above and below mid-channel islands. Annual monsoon-driven floods cause great variability in the dolphins’ access to large parts of their range. Isolation in seasonal lakes or deep river channels sometimes occurs, as does "escapement" from the rivers into canals and reservoirs. Deltaic (brackish) waters are a component of the total range, but Ganges dolphins are not generally known to occur in salinities greater than 10 ppt. More specific information on the subspecies is provided below: Platanista gangetica gangetica Ganges River dolphins are generally concentrated in counter-current pools below channel convergences and sharp meanders (Kasuya and Haque 1972, Smith 1993, Smith et al. 1998) and above and below mid-channel islands, bridge pilings, and other engineering structures that cause scouring (Smith, unpublished data). Their fidelity to counter-current pools is probably greatest in fast-flowing channels (Smith et al.

1998). Annual monsoon-driven floods cause great variability in the dolphins’ access to large parts of their range. Isolation in seasonal lakes sometimes occurs (especially in the Brahmaputra basin), as does "escapement" from the river channels into artificial water bodies such as canals and reservoirs. Deltaic (brackish) waters are a major component of the total range, but Ganges River dolphins are not generally known to occur in salinities greater than 10 ppt, although they have been recorded in waters as saline as 23 ppt (Smith and Braulik, unpublished data). Platanista gangetica minor Indus River dolphins generally occur in the deepest river channel and are less common in secondary channels and small braids (Bhatti and Pilleri 1982, Braulik 2003). Reported habitat preferences include channel constrictions, confluences, and deep, low-velocity water (Kasuya and Nishiwaki 1975, Khan and Niazi 1989, Braulik 2004).

During the low-water season (October to April), barrages divert almost all river water such that dolphin habitat downstream of Sukkur Barrage and in some tributary segments has been eliminated. As water levels drop in the winter, dolphins are concentrated in the remaining deep areas, including the head ponds upstream of barrages. Systems: Use and Trade [top] Use and Trade: It is hunted locally for food, and to extract oil which is used as a fish attractant. Threats [top] Major Threat(s): Water development projects have dramatically affected the habitat, abundance, and population structure of this species throughout its range. In addition to fragmenting populations, dams and barrages have degraded downstream habitat and created impoundments with high sedimentation and altered assemblages of fish and invertebrate species. Canals branching from the river channels upstream of barrages represent population "sinks", as dolphins enter them with little or no prospect of safe return; this problem has been especially well documented in Pakistan. More dams and barrages are either under construction or in advanced planning stages.

Water diversion and use in the South Asian subcontinent, including interbasin transfers, will continue to be driven principally by the escalating demands from agriculture, industry, and municipalities; by strategic considerations; and by the need to control flooding. Pollutant loads in South Asian rivers can be expected to increase with industrialization and the spread of intensive agricultural practices facilitated by water diversion. The capacity of these rivers to dilute pollutants (e.g., arsenic, DDT) and salts has already been drastically reduced because of upstream water abstraction, diversion, and impoundment. Again, this problem is bound to worsen as more development takes place. Deliberate killing of river dolphins has declined in many areas but still occurs at least occasionally. Dolphins are hunted by tribal people in the upper Brahmaputra for their meat and by fishermen in the middle reaches of the Ganges for their oil, which is used as a fish attractant. Mortality in fishing gear, especially gillnets, is a severe problem for Ganges dolphins throughout most of their range. They are particularly vulnerable because their preferred habitat is often in the same location as the fishing grounds.

A specific problem in parts of India and Bangladesh is that, because dolphin oil is highly valued as a fish attractant, fishermen have a strong incentive to kill any animals found alive in their nets and even to set their nets strategically in the hope of capturing dolphins. More specific information on the subspecies is provided below: Platanista gangetica gangetica Water Development Projects Construction of at least 50 dams and dams within the known or suspected historical range of the subspecies (Smith et al. 2000) has dramatically affected its habitat, abundance, and population structure. The subspecies exists as a metapopulation, with numerous subpopulations isolated to varying degrees by mostly manmade but also natural barriers, as outlined in the preceding section. In addition to fragmenting dolphin populations, dams and barrages degrade downstream habitat and create reservoirs (known as head ponds (or pondage in India) in the case of barrages) with high sedimentation and altered assemblages of fish and invertebrate species. For example, luxuriant growth of macrophytes and excessive siltation have eliminated suitable habitat immediately above Farakka Barrage (Sinha 2000).

Moreover, the insufficiency of water released downstream of this barrage has eliminated dry-season habitat for more than 300 km, or until the Ganges (Padma)-Brahmaputra confluence (Smith et al. 1998). It has also allowed salt water to intrude an additional 160 km into the Sundarbans Delta (Rahman 1986), further decreasing the amount of suitable habitat for this obligate freshwater dolphin (Reeves et al. 1993). A high dam has been planned for some time just upstream of the dolphins' current (or at least recent) range in the Karnali River, Nepal. If built, this structure would almost certainly eliminate the small amount of dolphin habitat in Nepal’s last river with a potentially viable dolphin population (Smith and Reeves 2000). Disturbance and environmental degradation associated with geotechnical feasibility studies and bridge and road construction for the dam already may have contributed to a decline in the number and range of dolphins above the Nepal-India border (Smith 1993, Smith et al. 1994).

Another high dam has been proposed for the Surma River in Cachar, India, which would certainly affect dolphins downstream in the Kalni-Kushiyara distributary (Smith et al. 1994). Since the 1980s, momentum has been growing within India to proceed with large-scale inter-basin water transfer projects, which will involve additional dam construction and diversion of water from rivers inhabited by dolphins. Although no final decision has been taken to proceed with construction, feasibility studies are to be completed in December 2005 and detailed project reports in 2006. It was anticipated in 2004 that, if built, the entire project would be finished by 2016. During the May 2004 national elections in India all political parties supported the construction of inter-basin water transfer projects and promised to accelerate the construction process.

Several key categories of potential threat are: (a) further fragmentation of the dolphin metapopulation, (b) reduction or elimination of habitat simply in terms of dry-season flow, (c) "escapement" of dolphins into canals where they are unlikely to be able to get back into rivers and are therefore doomed, (d) cascading effects from interrupted migrations of prey organisms, degradation of prey spawning habitat etc., (e) contaminant flux leading to significant changes in chronic and/or acute exposure to toxins, (f) loss of complexity (channelization, sediment entrapment upstream of dams, etc.) making the rivers less habitable for dolphins, etc, and (g) downstream effects on the ecology of the delta (e.g., saline encroachment, loss of sediment). Embankments cause sediments to be deposited in the riverbed instead of on the floodplain, thereby eliminating or reducing the extent of the eddy-counter currents where dolphins are generally found. (Smith et al. 1998). They also restrict access to floodplain habitat critical to the reproduction and growth of riverine fish species (Boyce 1990).

Approximately 3,500 km of embankments have been constructed in the Ganges mainstem and Gandak, Buri Gandak, Bagmati, Kamala, Yamuna, and Son tributaries (Mishra 1999). Dolphins were apparently extirpated from at least 35 km of the Punpun tributary of the Ganges after embankments were constructed in 1975 (Sinha et al. 2000). Although plans for constructing an extensive system of embankments in the rivers of Bangladesh under the Flood Action Plan (FAP) coordinated by the World Bank (see World Bank 1990) have been drastically scaled-down, several projects are currently planned or being constructed that will have adverse effects on dolphin habitat. These include the Bank Protection and River Training Project (FAP 21/22), Brahmaputra River Bank Priority Works, and Jamalpur Priority Project (FAP 3.1) (Smith et al. 1998).

Environmental assessments of these projects have not considered river dolphins, nor have they acknowledged the cumulative impacts of planned embankments, and others built before the FAP, on the fish and crustacean species eaten by river dolphins. Other sources of habitat degradation in the GBM system include dredging (Smith et al. 1998) and the removal of stones (Shrestha 1989), sand (Mohanet al. 1998), and woody debris (Smith 1993). These activities compromise the ecological integrity of the riverine environments, especially small tributaries where suitable habitat is limited and disproportionately vulnerable to local disturbance. Dolphin habitat is also threatened by water abstraction from surface pumps and tube wells, especially in the Ganges where the mean dry-season water depth has declined dramatically in recent years (Sinha, unpublished). Although the long-term implications of reduced dry-season flows in the Ganges are catastrophic, both for the survival of river dolphins and a major portion of the world’s human population that inhabits the Ganges basin, the cumulative effects of reduced water supplies have received little attention.

Meanwhile, new projects to divert dry-season flow, such as Kanpur Barrage in the upper Ganges, continue to be constructed (Smith et al. 2000). Toxic Contaminants Organochlorine and butyltin concentrations in samples from the tissues of Ganges dolphins were high enough to cause concern about effects (Kannan et al. 1993, 1994, 1997; Senthilkumar et al. 1999). Pollutant loads can be expected to increase with industrialization and the spread of intensive agricultural practices facilitated by water diversion. River dolphins may be particularly vulnerable to industrial pollution because their habitat in counter-current pools downstream of confluences and sharp meanders often places them in close proximity to point sources in major urban areas (e.g., Allahabad, Varanasi, Patna, Calcutta, and Dhaka). Furthermore, the capacity of rivers to dilute pollutants (e.g., arsenic, DDT) and salts has been drastically reduced in many areas because of upstream water abstraction, diversion, and impoundment. Again, this problem is bound to worsen as more development takes place.

Hunting Deliberate killing of river dolphins is believed to have declined in most areas but still occurs at least occasionally in the middle Ganges near Patna, India (Smith and Reeves 2000, Sinha 2002), in the Kalni-Kushiyara River of Bangladesh (Smith et al. 1998), and in the upper reaches of the Brahmaputra River in Assam, India (Mohan et al. 1997). Dolphins are killed by tribal people in the upper Brahmaputra for their meat and by fishermen in the middle reaches of the Ganges for their oil, which is used as a fish attractant. Mortality in Fishing Gear Mortality in fishing gear, especially gillnets, is a severe problem for Ganges River dolphins throughout most of their range (Mohan 1995, Smith and Reeves 2000). They are particularly vulnerable because their preferred habitat is often in the same location as the fishing grounds. In the middle Ganges, although harpooning is now "rare", mortality in fishing nets remains "widespread" (Sinha 2002).

A specific problem is that, because dolphin oil is highly valued as a fish attractant, fishermen have a strong incentive to kill any animals found alive in their nets and even to set their nets strategically in the hope of capturing dolphins (described by Sinha 2002 as "assisted incidental capture"). Meaningful quantitative data on the magnitude of catches, either deliberate or incidental, are unavailable and unlikely to become available in the absence of a well-organized, adequately funded, and incorruptible fishery/wildlife management system. Platanista gangetica minor The most significant threat to dolphins in the Indus has been the construction of at least 25 dams and barrages that have severely fragmented the population and reduced the amount of available habitat (Smith and Reeves 2000). Upstream subpopulations may lose individuals downstream if dolphins move through barrage gates when they are open in the wet season. Individuals are unlikely to move upstream through a barrage because of strong downstream hydraulic forces at the gates. While there have been no direct observations of dolphins moving through a barrage, they often swim through regulator gates into irrigation canals, which, although smaller, present a similar obstacle (Braulik 2002).

Evidence for permanent downstream emigration includes that each subsequent downstream subpopulation is larger than the one above (see Range and Population above), despite the reduced linear extent and availability of water in downstream segments. Encounter rates in the farthest downstream subpopulation (between Guddu and Sukkur Barrages) are very high (3.60 dolphins/linear km), approaching three times those recorded in similar surveys elsewhere for Platanista dolphins (Braulik 2003). The possible large increase in the dolphin subpopulation between Guddu and Sukkur Barrages (described above) may be due to reproduction and reduced mortality alone, or may be augmented by downstream emigration. Even a low emigration rate could dramatically affect the persistence of upstream subpopulations (Reeves et al. 1991, Reeves and Smith 1999). Since the mid 1990s, there have been increasing reports of dolphins trapped in irrigation canals near Sukkur Barrage. Dolphins have survived for several months in the canals until they are drained in January for annual de-silting and maintenance.

Between January 2000 and December 2002, 34 dolphins were reported trapped in these canals. Twenty-four were successfully rescued and returned to the Indus River, while the remainder died (Bhaagat 1999, Braulik 2002, WWF-Pakistan unpublished data). One of the direst threats to the survival of the Indus River Dolphin is probably the escalating demand for water. Pakistan is a largely desert nation, with a rapidly growing human population and fast developing industrial and agricultural sectors that demand increasing amounts of water. Several years of extreme drought have depleted aquifers that would normally be expected to augment river flows in the dry season. Pollution may be affecting the viability of the subspecies, especially considering the decline in flushing and dilution due to reduced flows. The Indus River corridor is not highly developed and above the Panjnad River confluence, the habitat is likely to be relatively unpolluted. However, more than 75% of the dolphin population occurs downstream of the confluence with the Panjnad River, which receives a large pollution load from the industrialized cities of the Punjab.

There are almost no facilities for treatment of municipal waste in Pakistan and few controls on industrial effluent. Massive fish kills have reportedly become common from industrial pollution in urban areas and from pesticides used on irrigated crops grown along the riverbanks (Reeves and Chaudhry 1998). The pressures on river water supply and continued untreated discharge of pollutants imply that there will be a continuing decline in the amount and quality of dolphin habitat. Deliberate killing for meat and oil was a traditional and widespread practice until at least the early 1970s (Pilleri and Zbinden 1973–74). Hunting is now banned although poaching occasionally occurs. Similar to all cetaceans, this subspecies is vulnerable to entanglement in fishing gear and vessel collisions. However, the areas of the Indus River where dolphins are extant are not heavily fished or utilized by vessels and these factors may not be major threats at present. Incidents of accidental killing and observations of dolphin carcasses and products are documented in Reeves et al. (1991) and Reeves and Chaudhry (1998).

Conservation Actions [top] Conservation Actions: The species is legally protected in all range states and occurs in a number of national parks and other designated areas, including dolphin reserves or sanctuaries, where at least nominal enforcement takes place. In Pakistan, the enforcement of regulations prohibiting dolphin hunting appears to have arrested a rapid population decline in the Indus during the early 1970s. Also in Pakistan, a program exists to rescue dolphins trapped in irrigation canals and return them to the Indus main channel. Field trials in India to determine the effectiveness of shark and scrap fish oils as catfish attractant have been judged successful, but it is unclear to what extent fishermen have converted to using them instead of dolphin oil. It is listed on CITES Appendix I. More specific information on the subspecies is provided below: Platanista gangetica gangetica Ganges River dolphins are legally protected from hunting in all range states. The Vikramshila Gangetic Dolphin Sanctuary, Bihar, India, between Sultanganj and Kahalgaon in the mainstem of the Ganges River was designated as a protected area for dolphins in August 1991 but there is little government support to enforce protective measures.

The legal protection in India has been described as "completely ineffective" (Sinha 2002), however, a small measure of progress was the convening of the Regional Seminar on Environmental Laws in the Vikramshila Gangetic Dolphin Sanctuary, Bhagalpur, India in November 2003 (Anon 2002). Also, recent proceedings of the Patna High Court (C.J.W.C. No. 5628 of 2001) directed the state and federals governments to allocate funds for supporting efforts to conserve and monitor dolphins in the Ganges. In a few smaller tributaries, dolphins receive nominal protection by virtue of the fact that small portions of their habitat are within or adjacent to national parks and sanctuaries (e.g., Kaziranga National Park in Assam, India, National Chambal Sanctuary in Madhya Pradesh, India, and Royal Bardia National Park and Katerniya Ghat Gharial Sanctuary, respectively north and south of the Nepal-India border.

Although field trials have shown that shark or fish oils would be efficient substitutes for dolphin oil as a fish attractant and some fishermen in the middle Ganges are now using oil made from fish scraps as an alternative, most apparently continue to use dolphin oil by preference or because suitable alternatives are not widely available in either the Ganges or Brahmaputra systems (Mohan and Kunhi 1996, Smith et al. 1998, Bairagi 1999, Sinha 2002). Platanista gangetica minor In 1972, dolphins were protected under the Wildlife Act of Sindh and in 1974 the government of Sindh declared the Indus River between the Sukkur and Guddu Barrages a dolphin reserve. The government of Punjab prohibited deliberate killing of dolphins in the Punjab Wildlife Protection Act in 1974 and established the Taunsa Wildlife Sanctuary and Chashma Wildlife Sanctuary in 1983 and 1984, respectively (Reeves et al. 1991, Reeves and Chaudhry 1998, Chaudhry and Khalid 1989).

Enforcement of regulations prohibiting dolphin hunting appears to have arrested the rapid population declines reported by Pilleri and Zbinden (1973–74) for these river segments. A programme sponsored by the United Nations Development Programme (UNDP) to rescue dolphins trapped in irrigation canals and return them to the Indus mainstem has had some success in reducing mortality (Braulik 2002, Bhaagat 2002). Citation: Smith, B.D. & Braulik, G.T. 2012. Platanista gangetica. The IUCN Red List of Threatened Species 2012: e.T41758A17355810. . Downloaded on 19 January 2017.

Disclaimer: Global Species : Platanista gangetica (Ganges River Dolphin; Susu; Ganges river-dolphin) Platanista gangetica (Ganges River Dolphin; Susu; Ganges river-dolphin) Contents Synonyms: Delphinus gangetica; Plantanista gangetica; Platanista gangetica gangetica Wikipedia Abstract The South Asian river dolphin (Platanista gangetica) is a freshwater or river dolphin found in India, Bangladesh, Nepal and Pakistan which is split into two subspecies, the Ganges river dolphin (P. g. gangetica) and Indus river dolphin (P. g. minor). The Ganges river dolphin is primarily found in the Ganges and Brahmaputra Rivers and their tributaries in Bangladesh, India and Nepal, while the Indus river dolphin is found in the Indus River in Pakistan and its Beas and Sutlej tributaries. View Wikipedia Record: Platanista gangetica Endangered Species View IUCN Record: Platanista gangetica EDGE Analysis A stocky freshwater dolphin, characterised by a long beak containing large, visible teeth.

Like most river dolphins, this species has little need for vision in the muddy waters it inhabits, and as a result has tiny, non-functional eyes that lack lenses. Individuals use echolocation to detect food and navigate, and  to a very small extent  for communication. The species lives in one of the most densely populated areas of the world. It is threatened primarily by the damming of rivers for irrigation and electricity generation, which degrades habitat, isolates populations and prevents seasonal migration. Concerted conservation action is needed if this species is to survive. Uniqueness Scale: Similiar (0) Indus River Dolphin (Platanista gangetica minor) - Office of Protected Resources - NOAA Fisheries Office of Protected Resources Indus River Dolphin (Platanista gangetica minor) Did You Know? · Indus River dolphins have very small eyes that resemble pinhole openings. Some scientists believe they are functionally blind, sensing only light levels and direction. · They vocalize almost constantly, emitting trains of high frequency (15-150 kHz) echolocation clicks. · When surfacing to breathe, these dolphins make a sound similar to a sneeze.

CITES Appendix II - throughout its range Taxonomy The Indus river dolphin is a subspecies of the Ganges river dolphin (Platanista gangetica) . Species Description Indus River dolphins, sometimes called "bhulans," are one of two separate subspecies of South Asian river dolphins. The other recognizable geographic form or subspecies is the Ganges River dolphins (Platanista gangetica gangetica), also sometimes called "susus." The Indus River dolphin subspecies is one of the world's most endangered cetaceans. Indus River dolphins are about 7-8.5 ft (2.2-2.6 m) and weigh 150-200 lbs (70-90 kg). The Indus River subspecies is considered slightly smaller than the Ganges River subspecies (Jefferson et al. 2008). Females are slightly larger than males. They have an unusual robust or chunky body with a low triangular "dorsal" fin located far (about two-thirds) down their back. They have a rounded "melon" , a very long narrow beak, extremely small eyes, and noticeable external ears.

A longitudinal ridge can be found on the melon as well as from the dorsal fin to the tail. The eyes are poorly-developed (lack a crystalline eye lens) and located above the corners of the mouth (Shirihai and Jarrett 2006). These animals have a uniformly gray coloration pattern with a pale white or pinkish underside, giving a slight counter-shading effect. As this species ages and matures, the melon gradually becomes less rounded. Indus River dolphins are usually found individually or in pairs, but have been occasionally seen in larger groups of up to 10 or more animals. Little information is available or known on the social structure of these groups. Indus River dolphins' swimming behavior is often described as active, yet timid and reserved. This species is frequently seen swimming on its side, especially when in captivity. When at the water's surface, these animals can breach or just lift their heads and beaks out of the water. "Breaching" may occur as a response to threats and other disturbances (Shirihai and Jarrett 2006).

Indus River dolphins' generally dive for 30-90 seconds, but are capable of holding their breath for up to several minutes. During dives they use their long beaks to probe the sediment along the bottom of the river to feed on prey such as clams, fish, and shrimp. They have 26-39 pairs of teeth in each jaw that are useful for grasping prey. The fang-like teeth in the lower jaw are comparatively longer and curved, and may interlock, overlap, and be visible outside the mouth. As these animals get older, the teeth become worn-down. Groups may coordinate their movements to cooperatively feed on prey. Indus River dolphins become sexually mature at lengths of about 5.5 ft (1.7 m) or more, and begin breeding between 6-10 years of age. Females give birth year-round to a single calf that is about 2-3 ft (0.7-0.9 m) long. Mothers may also nurse calves for about 1 year before weaning. The estimated lifespan of this species is about 30 years.

Habitat Indus River dolphins prefer the fresh and possibly brackish, shallow (usually less than 100 ft or 30 m), murky waters of the Indus River system in Pakistan. This species may occur in the main channels of rivers and in tributaries and lakes during the flood season. Ganges River Dolphin Species Guide - WDC I. II (P. g. gangetica) Classification: The classification of the South Asian river dolphin continues to be hotly debated in scientific circles. Originally thought to be the same species, the Indus bhulan and Ganges susu were listed as separate species in 1971 due to apparent differences in skull structure and blood proteins. However this speciation has never been fully accepted and currently the two populations are recognised as subspecies of the species Platanista gangetica; those found in Nepal, India and Bangladesh are classified as P.g. gangetica while those found in the Indus River in Pakistan are known as P. g. minor. Appearance: This dolphin has a distinctively long slender beak with sharp, pointed teeth. Proportionally longer in females than in males, the beak is designed for quick snapping action to capture fast prey.

It has a prominent melon and, unlike most cetaceans, the cervical vertebrae of the South Asian River dolphin are not fused, allowing it to flex its neck. It has broad paddle-shaped flippers, a stocky body, a small triangular dorsal fin, and its fluke is broad with pointed tips. The colouration of the South Asian river dolphin is variable, ranging from chocolate brown or tan to greyish or pale blue, with the belly paler than the rest of the body. The eyes are small, lack a crystalline lens and are almost useless, though vision isn't very effective in cloudy estuary habitats. They may be able to sense light intensity and direction but not distinct shapes. While several other species overlap its range and are often confused with Platanista, it is physically unique and relatively easy to identify in the wild. Behaviour: Both subspecies of South Asian River dolphin are generally found alone or in pairs, and occasionally in small groups. Little is known about their behaviour as they tend to be elusive, fast moving and shy of boats. They are not demonstrative or acrobatic but when distressed, they may breach, though this is a rare behaviour. P.g.

gangetica's habit of surfacing at a steep angle with its beak and head sticking out of the water often causes it to be confused with the gharial, a type of crocodile also found in the Ganges River and tributaries. These dolphins sometimes gather in counter-current pools near channel convergences, sharp meanders and human-built structures that cause similar effects. These features probably help to concentrate their prey. Distribution: P.g. gangetica is found in the Ganges-Brahmaputra-Meghna and the Karnaphuli-Sangu river systems and their tributaries, while P.g.minor is found only in the Indus River. Due to their riverine habitats, both face threats from human activities although to different degrees. (1) P.g.minor - Barrages or dams have segmented their traditional range, fragmenting the population of the Indus susu. Much of its range is not habitable year round due to fluctuating water levels and recent increases in demand for water and problems with drought further reduce their range. In the dry season, many individuals become trapped in irrigation canals. Other threats include habitat destruction and degradation, entanglement in nets and fishing gear, and pollution.

(2) P.g. gangetica - Although now greatly reduced, there is some deliberate, illegal killing of Ganges river dolphins. They are taken due to the perceived fisheries competition, the value of their oil in traditional medicines, as bait, and for food. Other threats include increased growth of aquatic plants and chemical pollution. More significant, however, is accidental capture in fishing operations, especially gillnets. Gaining accurate population data is difficult for this species but it is clear that numbers are small and that its range is greatly reduced. In the case of the Indus susu its historical range has been reduced by up to 80%. Fewer than 1,000 individuals are thought to remain in the Indus River and double that in the Ganges and associated rivers. The species is listed by IUCN as Endangered (2008). Distribution map: Ganges River Dolphin | Freshwater Dolphin | Species | WWF Ganges River Dolphin e Habitats Freshwater rivers Dolphins are one of the oldest creatures in the world along with some species of turtles, crocodiles and sharks. The Ganges river dolphin was officially discovered in 1801.

Ganges river dolphins once lived in the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh. But the species is extinct from most of its early distribution ranges. The Ganges river dolphin can only live in freshwater and is essentially blind. They hunt by emitting ultrasonic sounds, which bounces off of fish and other prey, enabling them to “see” an image in their mind. They are frequently found alone or in small groups, and generally a mother and calf travel together. Calves are chocolate brown at birth and then have grey-brown smooth, hairless skin as adults. Females are larger than males and give birth once every two to three years to only one calf. What’s the difference between a dolphin and a porpoise? And other river dolphin facts When we think of dolphins and porpoises, we often don’t think of fresh water. But in parts of South America and Asia, several rivers are home to these charismatic species. Dolphins are among the world’s oldest creatures, along with some species of turtles, crocodiles and sharks. They provide important indicators of the health of rivers.

Continue Reading h More Stories h Why They Matter The Ganges river dolphin is important because it is a reliable indicator of the health of the entire river ecosystem. The government of India declared it the National Aquatic Animal in 2009. Threats No reasonable doubt that the last individual has died EW Known only to survive in cultivation, in captivity or as a naturalised population CR Facing an extremely high risk of extinction in the Wild EN Facing a high risk of extinction in the Wild VU Facing a high risk of extinction in the Wild NT Likely to qualify for a threatened category in the near future LC Does not qualify for Critically Endangered, Endangered, Vulnerable, or Near Threatened Traditional boat on the Ganges River. Infrastructure Ganges river dolphins are divided into isolated groups because of the construction of more than 50 dams and other irrigation-related projects. This makes them susceptible to inbreeding and more vulnerable to other threats because they cannot move to new areas. Dolphins trapped above a dam are exposed to poaching, especially during dry summer months. Dolphins below a dam are threatened by heavy pollution, increased fishing activities and vessel traffic.

They also have less food because dams disturb the migration, breeding cycles and habitat of fish and other prey. Bycatch The habitat of the Ganges river dolphin is within one of the most densely populated areas of the world. Ganges river dolphins and people both favor areas of the river where fish are plentiful and the water current is slower. This has led to fewer fish for people and more dolphins dying as a result of accidentally being caught in fishing nets, also known as bycatch. The Ganges river dolphin is still hunted for meat and oil, which are both used medicinally. The oil is also used to attract catfish in net fishery. Pollution Industrial, agricultural, and human pollution is another serious cause of habitat degradation. Each year, 9,000 tons of pesticides and 6 million tons of fertilizers are used in the vicinity of the river. High levels of pollution can directly kill prey species and dolphins, and completely destroy their habitat. As the top predator, river dolphins have been known to have high levels of persistent toxic chemicals in their bodies, which is likely to adversely affect their health. What WWF Is Doing WWF works to reduce habitat degradation caused by dams, irrigation canals, and water withdrawals.

We also work to mitigate pollution of freshwater ecosystems and dolphin deaths from fishing bycatch and deliberate removal of the species. Monitoring Populations In Nepal, WWF surveyed the Ganges river dolphin populations in the Karnali River and its tributaries, analyzed the threats to the dolphins and their habitats, and then provided recommendations to policymakers about how to protect them. WWF also monitors dolphin populations and threats in important habitats in India. Encouraging Communities to Protect Dolphins WWF encourages local communities along a vital stretch of dolphin habitat to use natural fertilizers, not dispose of domestic sewage in the river, reforest the river bank, and ban commercial fishing and sand-mining activities. Ganges River dolphin | WWF Ganges River dolphin Amazon River Dolphin Ganges River dolphin The Ganges River dolphin or Susu, lives in one of the most densely populated regions of the world. One of the main threats to the species is loss of habitat due in large part to the creation of dams and irrigation projects. Plataniste or Ganges river dolphin (Platanista gangética), Karnaphuli river, Bangladesh.

© WWF / François Xavier PELLETIER Key Facts Common Name Ganges river dolphin, blind dolphin, Ganges dolphin, Ganges susu, Gangetic dolphin, hihu, side-swimming dolphin, South Asian River Dolphin, Indus River Dolphin ; Plataniste du Gange (Fr); Delfín del Ganges (Sp) Scientific Name Ganga and Brahmaputra river system Length Conservation and religion join to save Ganges dolphin A blind dolphin in one of the world's most densely populated area The Ganges River dolphin, or susu, inhabits the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh. This vast area has been altered by the construction of more than 50 dams and other irrigation-related projects, with dire consequences for the river dolphins. The Ganges River dolphin lives in one of the world's most densely populated areas, and is threatened by removal of river water and siltation arising from deforestation, pollution and entanglement in fisheries nets. In addition, alterations to the river due to barrages are also separating populations.

A recent survey conducted by WWF-India and its partners in the entire distribution range in the Ganga and Brahamaputra river system - around 6,000 km - identified fewer than 2,000 individuals in India. This dolphin is among the four "obligate" freshwater dolphins - the other three are the baiji now likely extinct from the Yangtze river in China, the bhulan of the Indus in Pakistan and the boto of the Amazon River in Latin America. Although there are several species of marine dolphins whose ranges include some freshwater habitats, these four species live only in rivers and lakes. Plataniste or Ganges river dolphin (Platanista gangetica), Karnaphuli river, Bangladesh. © WWF / François Xavier PELLETIER Priority species Cetaceans (whales, dolphins & porpoises) are a priority species . WWF treats priority species as one of the most ecologically, economically and/or culturally important species on our planet. And so we are working to ensure such species can live and thrive in their natural habitats. Physical Description A long thin snout, rounded belly, stocky body and large flippers are characteristics of the Ganges River dolphin.

Although its eye lacks a lens (this species is also referred to as the "blind dolphin"), the dolphin still uses its eye to locate itself. The species has a slit similar to a blowhole on the top of the head, which acts as a nostril. The dolphin has the peculiarity of swimming on one side so that its flipper trails the muddy bottom. This behaviour is understood to help it to find food. Being a mammal, the Ganges River dolphin cannot breathe in the water and must surface every 30-120 seconds. Because of the sound it produces when breathing, the animal is popularly referred to as the 'Susu'. The movements of the Ganges River dolphin follow seasonal patterns, although the details are not well known. However, it seems that animals travel upstream when water level rises, and from there enter smaller streams. Size Females are larger than males and attain a maximum size of 2.67 m. Males are about 2.12 m. Colour The colour of the dolphin is greyish brown. The calves and young ones are dark in colour but as the animal grows in size, the colour lightens.

Bangladeshi fisherman with a Plataniste or Ganges river dolphin (platanista gangética), Karnaphuli river, Bangladesh. © François Xavier Pelletier / WWF Ecology and Habitat Once found in 'large schools' The species is found exclusively in freshwater habitat. In Nepal, it inhabits clear water and rapids. In Bangladesh and India, individuals live in rivers that flow slowly through the plains. The Ganges River dolphin favours deep pools, eddy counter-currents located downstream of the convergence of rivers and of sharp meanders, and upstream and downstream of mid-channel islands. 'Susu' shares its habitat with crocodiles, freshwater turtles and wetland birds, many of which are fish eaters and are potential competitors with dolphins. Social Structure In the 19th century, Ganges River dolphins were once found in 'large schools' close to urban centres along the river. Nowadays, groups are considerably smaller, and individuals may also be found alone. The average size of a number of groups surveyed recently in the Ganges River system was two individuals.

Life Cycle The young wean within their first year, and males reach sexually maturity at around 1.70 m (5.6 ft), when they are about 10 years of age. The oldest male animal on record was about 28 years old. Breeding The gestation lasts from 9 to 11 months, and one calf is usually born, once every 2 to 3 years. There is no specific birth period, although females usually give birth from October to March, with a peak in December and January at the onset of the dry season. Diet The diet includes a variety of fish and invertebrates, namely prawns, clams, catfish, freshwater sharks, mahseers (except in India), gobies and carp. Ganges River dolphins normally chase surface dweller fishes and grovel mud dweller fishes in shallow water with the help of their long snout. They cannot chew and usually swallow their prey. Typical daily scene along the Ganges River, people bathing and having their ritual ablutions. Hindu temples in the background. Varanasi, India © Michèle Dépraz / WWF Why is this species important? The presence of dolphin in a river system signals a healthy ecosystem.

Since the river dolphin is at the apex of the aquatic food chain, its presence in adequate numbers symbolizes greater biodiversity in the river system and helps keep the ecosystem in balance. Home fragmented by barrages Previous population and distribution During the last century, thousands of freshwater dolphins rolled and jumped in their natural habitat, which once ranged throughout the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Nepal, India, and Bangladesh, from the Himalayan foothills to the Bay of Bengal. In 1982, the population in India was estimated to be between 4,000 and 5,000 individuals. Today, it is difficult to sight a dolphin in the rivers. Extensive modifications of this species' habitat have reduced its once abundant population throughout its range. The distribution in the Ganges has diminished by approximately 100 km (62 miles) since the 19th century, with hundreds of kilometres of tributary habitat lost to irrigation barrages. There has been a concomitant reduction in water flow. Current population and distribution Today the population has a much reduced range, and is divided by dams into isolated groups.

The lowest estimate for the total population is 1,200–1,800 individuals. Although the population size has decreased compared to historical levels, it is still considered to be large enough to sustain the species in the future if adequate conservation measures are taken soon. What are the main threats to the Ganges River dolphin? Habitat and subspecies under severe threat The survival of the Ganges River dolphin is threatened by unintentional killing through entanglement in fishing gear; directed harvest for dolphin oil, which is used as a fish attractant and for medicinal purposes; water development projects (e.g. water extraction and the construction of barrages, high dams, and embankments); industrial waste and pesticides; municipal sewage discharge and noise from vessel traffic; and overexploitation of prey, mainly due to the widespread use of non-selective fishing gear. Habitat loss and degradation More than 50 dams and irrigation-related projects have had an adverse impact on the habitat of this species. These projects result in major changes in the flow, sediment load, and water quality of rivers, which affects the quality of waters downstream.

As a result, there has been a serious decrease in fish production, while the extraction of river water and siltation from deforestation are also degrading the species' habitat. In some cases, habitat alterations have resulted in the genetic isolation of dolphin populations. Pollution Pollution levels are a problem, and are expected to increase with the development of intensive modern industrial practices in the region. Compounds such as organochlorine and butyltin found in the tissues of Ganges River dolphins are a cause for concern about their potential effects on the subspecies. Fisheries bycatch Bycatch in gillnets and line hooks is also a major source of mortality for this subspecies. Directed take Although the killing of this dolphin for meat and oil is thought to have declined, it still occurs in the middle Ganges near Patna, in the Kalni-Kushiyara River of Bangladesh, and in the upper reaches of the Brahmaputra. In fisheries for large catfish in India and Bangladesh, dolphin oil and body parts are used to lure prey, and Ganges River dolphins are used to this end. Efforts have been made in India to test shark liver and sardine oil and fish offal to find an alternative for dolphin products. The latter appears promising.

The Tehri dam on the Ganges River, in the state of Uttarakhand, India. The dam became operational in 2005, and is the 5th largest in the world. It is part of a project in which the Indian government plans to link 37 major rivers through a series of dams and canals to provide drinking water and generate electricity. In the WWF's report 'World's Top 10 Rivers at Risk', the Ganges River has been identified as one of the 10 at risk, due to the water withdrawal. © Joerg Hartmann / WWF-Germany

Question: The Indian endangered species Platanista gangetica gangetica is a?
Answer: River dolphin