The Indus River dolphin (Platanista gangetica minor) is a freshwater cetacean that occurs only in the Indus Riversystem in Pakistan and India. This review provides a comprehensive summary of issues surrounding Indusdolphin conservation, and includes a description of their distribution, the threats they face and a discussion ofconservation and research activities, options and priorities. Information was gathered from published currentand historical literature, newspaper articles, and unpublished reports. Prior to construction of the Indus Irrigationsystem dolphins occurred in 3500 km of the Indus River system. Their range has now declined by 80% due tofragmentation of river habitat by barrages and large-scale diversion of water for irrigated agriculture. The sub-species was estimated to number approximately 1450 individuals in 2011, and occurs in 6 subpopulations,three of which are probably too small to persist. There is an urgent need to evaluate whether dolphins movethrough barrages, as this has the potential to extirpate upstream subpopulations. Pre-requisites for dolphintranslocations to combat this problem are outlined.Mortality infishing gear and high levels of chemical pollutioninwater courses are both increasing threats exacerbated by depleted flows. Research and conservation prioritiesinclude maintenance of river flows, mortality monitoring, canal rescues and community-based conservation.Conservation and research action is urgently needed to prevent the Indus dolphin from succumbing to thesame fate as the baiji.
The Indus River dolphin (Platanista gangetica minor) is an endan-gered, obligate freshwater cetacean that occurs only in the Indus Riversystem in Pakistan and India (Fig. 1). The subspecies is red-listed as En-dangered due to an 80% reduction in distributional range and a highlyfragmented population (Braulik et al., 2014c). Indus dolphins, alsocalled ‘blind dolphins’ because of their reduced eyes and poor vision,are mammals of high conservation priority because of their evolution-ary distinctiveness and threatened status (Isaac et al., 2007). Althoughblind dolphins are potentially charismatic top predators, that couldfunction as ‘flagships’ for aquatic conservation, little is known abouttheir basic biology. The factors that influence their survival and havedriven their decline are not well understood, and the best strategy forconserving them remains unclear. The Indus dolphin and the closely re-lated Ganges River dolphin (P. g. gangetica), also red-listed as Endan-gered, are assigned to a monotypic family, the Platanistidae. This isone of the more ancient cetacean families that diverged approximately29Million Years (MY) ago, 22MY beforemodernmarine dolphins arose(Xiong et al., 2009). Recent genetic studies showed that Indus and Gan-ges dolphins diverged from each other approximately 0.5MY ago and, ifthey are shown to have morphological differences, the two subspeciesmay be recognised as separate species in the future (Braulik et al.,2014b).
Several reviews of Indus dolphin conservation statuswere publishedin the 1980s and 1990s (Reeves, 1998; Reeves and Brownell, 1989;Reeves and Chaudhry, 1998). There has been a substantial increase inknowledge since then, and the purpose of this paper is to provide anupdate and comprehensive summary ofwhat is known about Indus dol-phins today, including descriptions of their status and themajor threatsthey face and a discussion of conservation and research activities andoptions.
2. Materials and methods
Over a period of several decades we have compiled publishedcurrent and historical scientific papers from international and SouthAsian journals, unpublished government and NGO reports, andPakistani university theses, as well as newspaper and magazine articlesin English, French, Urdu or Sindhi that relate to Indus dolphins. All avail-able documents were summarised in preparation for this review. Thereview is organised as follows: 1) background information on the eco-logical and social setting, 2) Indus dolphin historical and current statusand trends, 3) summary of threats to the dolphins including those caus-ing direct and indirect mortality, and 4) details of conservation optionsand research priorities.
3. The Indus River
The Indus River originates in Tibet, flows through northwest Indiaand enters Pakistan in the north flowing for the entire length of thecountry to the Arabian Sea (Fig. 1). It has five main tributaries: the Jhe-lum, Sutlej, Chenab, Ravi and Beas. These rivers merge to form the Panj-nad River, which has flow almost equivalent to the Indusmainstem. TheIndus leaves the Himalayan foothills and enters the plains at Kalabaghjust upstream of Jinnah Barrage, and then flows at a gentle gradient(average 13 cm/km), south-southwest, for 1600 km to the sea.
The river runs through semi-desert and irrigated agricultural land. Itis broad, shallow and braided and naturally highly turbid. It is sand-bedded and is constantly eroding its bed and banks, so consequentlythere is very little rooted vegetation either submerged or on thebanks. The configuration of channels, islands and sand bars is constantlychanging, andmajor changes occur during the annual flood. Air temper-atures rise to 50 °C from May to September, and drop to near freezingbetween December and February; river water temperatures show sim-ilar but less extreme fluctuations. River discharge is highly seasonal:
peak flows of 20–30,000 m3/s occur between June and August whenthe river is fed by Himalayan melt-water and monsoon run-off, whileflows as low as 300 m3/s occur in the dry season between Decemberand April. Human habitation is sparse but increases with proximity tothe delta. The only large towns along the Indus are Dera Ismail Khan,Sukkur and Hyderabad. The river is little used for commercial traffic,probably because passage is repeatedly blocked by barrages, and thefew vessels present are oar-powered or motorised ferries and smallfishing boats.
At present, the Indus plains are composed of desert, semi-desert,scrub and irrigated agricultural lands. However, several centuries agothe native vegetation and fauna of the area was primarily forest andgrassland inhabited by numerous large mammals including the tiger(Panthera tigris), leopard (Panthera pardus), Asiatic cheetah (Acinonyxjubatus venaticus) and Indian rhino (Rhinoceros unicornis). All but theleopard are now locally extinct. Freshwater mega-fauna in the IndusRiver system previously included mugger crocodiles (Crocodyluspalustris) which were hunted extensively and are now found in only afew isolated areas of Sindh (Ahmad, 1999). The harmless, fish-eatingcrocodilian, the gharial (Gavialis gangeticus), was once widespread butis now extinct in Pakistan (Ahmad, 1999). Two species of otter, thesmooth otter (Lutra perspicillata) and the Eurasian otter (Lutra lutra),were once common, but these animals were decimated by hunting fortheir pelts and now persist in only a very few locations (WWF-Pakistan unpublished). Eight species of turtles inhabit the Indus Riversystem, including four soft-shelled species that can reach more than1 m in length and four smaller hard-shelled species. Freshwater turtlesused to be abundant, but a new illegal trade in soft-shelled turtle partsfor use in Chinese traditional medicine has resulted in massive turtlekills and greatly reduced wild turtle numbers (Pakistan WetlandsProgramme/WWF-Pakistan, 2008). A commercially important fisheryfor the migratory shad (Hilsa ilisha) existed in the Indus River prior toconstruction of the barrages that blocked their migration. The fishused to enter the Indus River in great numbers each year in the middleof January, ascended the river to spawn during June, July and August,and returned to the sea in November (Islam and Talbot, 1968). Beforeconstruction of Sukkur barrage in 1932, Hilsa would migrate all theway to present-day Taunsa barrage. The Kotri and Sukkur barragescontain fish ladders but these were inappropriately designed for useby Hilsa. The fishery has totally collapsed resulting in the loss ofaround 9000 jobs and an important source of protein for local people(Moazzam, 1999). The Indus dolphin is one of the last aquatic mega-faunal species remaining in the Indus River system.
4. Status of dolphins and their habitat
4.1. Historical information on Indus River dolphins
4.1.1. Historical distribution and abundanceA detailed map of Indus dolphin distribution was produced by John
Anderson in 1879. Anderson sent letters to government offices acrossBritish India asking for detailed information on river dolphins. He said“Notwithstanding that the inquiry was of a novel and rather unusual char-acter, the replies were most complete and full of interest, and, more-over,examples of the dolphin were sent to me from the Indus, Ganges and Brah-maputra”. In the mid-1870s, Indus dolphins apparently never enteredthe ocean, but were found throughout the year in the Indus, Jhelum,Ravi, Chenab and Sutlej Rivers from the Himalayan foothills to the estu-ary, a linear range of around 3500 km. Theywere reported as constantlypresent at Kalabagh and in April as far upstream as Attock (Fig. 1). Thereports all confirmed that dolphins occurred furthest upstream duringthe flood season and that their distribution contracted when riverflow was low.
It is difficult, almost 150 years later, to verify the information collat-ed by Anderson but all other published reports from that time agreewith it, and in general, it appears to be reliable. The only exception is
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in Nepal which was not under British Administration, and where theupper distribution of the Ganges River dolphin was later found to be100 km further upstream than shown on Anderson's map (Kasuya andHaque, 1972). Dolphins were reported by Anderson to extend their dis-tribution into the foothills of themountains in the Indus and JhelumRiv-ers, in the Beas and Sutlej they reached only to the base of the foothills,and in the Ravi and Chenab their distributional limit was further down-streamon theplains, apparently delimited by theGrand TrunkRoad, themajor transport route at the time. These small differences in the up-stream extent of distribution may be due to the seasonal range fluctua-tions being reported differently in different rivers, or to the fact thatdiffering habitat in each river resulted in different upstream distribu-tional limits.
A regular steamboat servicewasmaintained on the Indus only in theearly to mid-1800s (MacLagan, 1885), consequently, there are few ac-counts of travel on the river that can be examined for dolphin sightingsto verify Anderson's map. Alexander Burnes led the first British expedi-tion on the Indus travelling from the delta to Lahore. He reported dol-phins in the Indus from the delta to Sukkur and also sighted several atthe confluence of the Ravi and Chenab in July 1835 (Burnes, 1835). Afew years later, dolphins were reported to be present south of Thatta(Burnes, 1842) and to be “very numerous” between Thatta and Sukkur(Hall, 1848). In the 1860s, dolphins were noted to ascend the Punjabrivers (Adams, 1867), and a specimen collected from the Sutlej present-ed to the Indian museum in the 1800s confirms their presence in thatriver at that time (Anderson, 1879). At the far upstream end of theirrange there is a report from the 1840s that ‘before its junction withthe Sutlej, the Beas is frequented with porpoises’ (Anon., 1846). This isthe same area where dolphins were recently re-discovered in India(Behera et al., 2008). These few records are all in agreement with thedistribution described by Anderson.
In 1874 it was reported that Indus dolphins were most abundant inthemiddle or lower third of their range (Jerdon, 1874), which is consis-tent with the present relatively high density area on the Indus in north-ern Sindh. Prior to large-scale water diversion, the Indus River hadapproximately four times the annual discharge of the Jhelum or Chenab,six times that of the Sutlej and thirteen times that of the Ravi (IUCN,2011). If discharge alone can be considered a crude indicator of dolphinabundance, the Punjab tributaries may have supported lower dolphindensities and smaller numbers than the Indus historically, and theJhelum and Chenab may have had greater dolphin abundance thanthe smaller Ravi, Sutlej and Beas. In 1901 it was reported that Gangesand Indus dolphins were not numerous and had once been far morewidespread, indicating that more than 100 years ago they were alreadyperceived to be in decline (Blanford, 1901).
4.1.2. Development of the Indus basin irrigation systemThe Indus plains are semi-arid, and the vast majority of the rain falls
during the summerwith the result that agriculture is reliant on the abil-ity to divert water from the rivers. Since the 1880s (just after Andersonproduced his map), 19 irrigation barrages have been constructed on thelower Indus within, or at the limits of, the former range of the dolphins(Fig. 1). The Indus basin irrigation system is now claimed to be the larg-est in the world. Barrages are low, gated diversion-dams composed of aseries of gates (usually 60–70) that control the elevation of an upstream‘head pond’ maintained not to store water, but to divert it into lateralcanals.
The first six barrages were commissioned at the end of the 19th cen-tury and were located on the rivers of Punjab. Completion of Panjnadbarrage in 1933 split the former range of the Indus dolphin into two,separating animals in the Indus River from those in the five Punjab trib-utaries. By 1940, the tributaries were already fragmented into seven dif-ferent sections by barrages whereas barrage construction had only justbegun on the Indus mainstem and dolphins could move relatively un-impeded along its length until the completion of several barragesaround 1960. The longest stretch of unfragmented habitat and the
mean fragment size have declined steadily as the Indus Basin rivershave become progressively more subdivided (Fig. 2).
The partition of British India in 1947 saw creation of a new interna-tional border that bisected the Indus River system. The Indus WaterTreaty was agreed in 1960 and the flows of the Indus, Jhelum and Che-nab, amounting to 75% of the total, were allocated to Pakistan, and thewater in the Ravi, Beas and Sutlej Rivers was allocated to India. Thishas had two significant consequences for Indus dolphins: 1) India hasthe rights to the Ravi and Sutlej therefore all the water in these riversis utilised within India, and they are now usually dry by the time theyenter Pakistan, and 2) most of Pakistan's water resources are in thewest of the country but the greatest human population and the majorirrigated agricultural areas are in the east. This situation was addressedby the construction of massive link canals to transfer water from thewestern rivers to those in the east so that agricultural lands south ofthe Ravi and Sutlej could continue to be irrigated (Fig. 1). Prior to con-struction of the link canals, some flow remained in each river for its en-tire length so that land adjacent to the furthest downstream barragecould be irrigated. Opening of the link canals allowed for the completediversion of a river's flow at upstream barrages as the river could bereplenished downstream by a link canal. Since the 1970s, for severalmonths of the year the Ravi and Sutlej have been almost completelydry and no water is released through Khanki, Qadirabad, Trimmu andPanjnad barrages on the Chenab River, Balloki and Sidhnai on the Raviand Suleimanki and Islam on the Sutlej (Federal Flood Commission,2010) (Fig. 1).Water diversion has been steadily increasing and the cul-tivable area expanding as new canals are built, existing canals are ex-tended, their capacity is increased and barrages are refurbished.Meanwhile, river discharge has been declining steadily (IUCN, 2011).
4.2. Current status of Indus River dolphins
4.2.1. Present distribution and abundanceThe historical range of Indus dolphins has been fragmented by bar-
rages into 17 river sections. Dolphin sighting and interview surveysshowed that dolphins have been extirpated from ten river sections, per-sist in six sections and are of unknown status in the section of the SutlejRiver on the India-Pakistan border (Braulik et al., 2014a). Indus dolphinsnow occur in five subpopulations on the Indus mainstem, bounded byJinnah, Chashma, Taunsa, Panjnad, Guddu, Sukkur and Kotri Barrages(Fig. 1). A sixth subpopulation occurs in the Beas River in India(Behera et al., 2008). River dolphins have been extirpated from theIndus mainstem upstream of Jinnah Barrage and downstream of Kotribarrage and from the five Indus tributaries in Pakistan (Braulik et al.,2014a). The linear extent of occurrence is now approximately1000 km (Braulik, 2006) and approximately 99% of the dolphin popula-tion occurs in only 690 km of river, which corresponds to an almost 80%reduction in effective linear range since the 1870s (Reeves et al., 1991).
Three comprehensive surveys have been conducted to estimateabundance of Indus dolphins throughout their current range. Thesewere conducted at five-year intervals, in 2001, 2006 and 2011(Table 1). All three surveys consisted of direct counts by three observersfrom a viewing platform on an oar-powered wooden vessel travellingdownstream along a thalweg transect, a methodology described initial-ly by Smith and Reeves (2000). In 2006 and 2011, direct counts wereconducted from vessels travelling in tandem, separated by 1 km, andmark-recapture was used to correct for groups that were missed,resulting in higher point estimates of abundance along with measuresof precision (Braulik et al., 2012a; Noureen, 2013). The metapopulationabundance estimates in all three surveys were similar, ranging between1200 and 1750 individuals for the entire subspecies (Table 1). The larg-est and most important subpopulation is located between Guddu andSukkur barrages in northern Sindh. This short, 190 km river sectionsupports approximately 70% of all Indus dolphins, at encounter ratesapproaching 10 individuals/km. Dolphin encounter rate and subpopula-tion abundance decline in each river section as one proceeds upstream.
Fig. 2. Illustration of the total number of fragments of Indus dolphin habitat against year, and the length of the largest portion of unfragmented habitat against year. The red line denotes theonset of barrage construction and the light grey line, the mean fragment length.
Between Jinnah and Chashma barrages only a few isolated individualswere recorded in 2001 and 2006, and it is possible that dolphins havesince been extirpated from this area.
4.2.2. Trends in abundance between Guddu and SukkurBraulik et al. (2012a) reported that from 1974 to 2008 at least 22
dolphin counts were conducted between Guddu and Sukkur barrages.Counts showed a steady increase from 138 individuals in 1974 to 902in 2008, a statistically significant rate of increase equivalent to approx-imately 5.65% per year. Similarly, two different groups conducteddolphin surveys between Guddu and Sukkur in 2001 and 2006, and al-though the abundance estimates generated in each year were differentdue to differences in methodology, both groups recorded a 60–65%
Table 1Summary of Indus dolphin subpopulation and metapopulation abundance estimates and estim
DC= Direct Count; MR-TV=Mark-recapture on data from tandem vessels; a = count was revwas not surveyed due to security concerns; c = Sukkur-Kotri was surveyed in 2010, and Taunsthe 2011 metapopulation abundance estimate is combination of the three d = 33.8 km of thedolphin count includes sighting rates extrapolated from adjacent river sections to account for
increase in dolphins over the same 5-year period (Braulik et al.,2012a). Braulik et al. (2012a) discussed in detail whether this apparenttrendwas real or not and concluded that the lack of confidence intervalson all of the counts precluded any firm conclusions about populationgrowth rates. However those authors also concluded that all surveys in-dicate an increase in the subpopulation between Guddu and Sukkursince the 1970s.
Until the 1970s, dolphins were hunted in Pakistan (Anderson, 1879;Pilleri and Zbinden, 1973–74). Hunting was banned by the SindhWild-life Act (1972) and, in 1974, the Indus Dolphin Reserve was establishedbetween Guddu and Sukkur barrages. The probable increase in dolphinabundance between Guddu and Sukkur likely signifies a degree ofpopulation recovery following the cessation of dolphin hunting. It is
ation methods during the last 12 years.
Sukkur-Kotri
Total Meta-populationestimate
Reference
18 965–1140a 1200
(Braulik, 2006)(Braulik et al., 2012a)
4b 1410 (Braulik et al., 2012a)3.4%) – 1447 (CV = 57.2%) 1550–1750 (Braulik et al., 2012a)
34c 1312 – (Noureen, 2013)
3%) – 797(CV = 21.3%)
1452 (Noureen, 2013)
ised upwards to account for animals in 33.3 km that was not surveyed; b = entire sectiona-Guddu in 2012. These two counts were added to the rest of the 2011 survey data so thatIndus downstream of Guddu Barrage and a 31.8 km side channel were not surveyed; e =unsurveyed sections.
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unlikely that the increase is due to improvements in habitat or preyavailability, as new dams and barrages continue to be constructed, theIndus flood cycle and sediment transport processes have been greatlydisrupted, dry-season discharge has declined, and levels of pollutionhave increased dramatically as Pakistan becomes industrialised. Countsrecorded from all other Indus dolphin populations over the last 15 yearshave remained stable (Braulik et al., 2012a).
4.3. Short summary of Indus dolphin ecology and biology
The diet of Indus dolphins appears to vary according to location and/orseason, but is generally composedof a large variety of bottom-dwellingfish(including catfish and carp) and prawns (Butt, 1977; Pilleri and Zbinden,1973–74; Roberts, 1997). Dolphins surface rapidly and unpredictably,making photography and collection of biopsies challenging. They neverapproach boats or bow ride, and individual photo-identification isimpractical because most animals lack unique features.
Indus dolphins are generally observed alone or in groups of two orthree, occasionally in aggregations of as many as 20 or 30 individuals.Prior to the construction of dams and barrages, the dolphinsmoved up-streamduring thefloods and downstreamduring the low-water season.
The maximum lifespan may be 33–35 years (Ohsumi, 1979). Fe-males grow larger than males and both sexes become sexually matureat 7–10 years of age. Gestation likely lasts around 10–11 months(Brownell, 1984). Limited observations of very small, solitary individ-uals feeding on fish indicate that South Asian river dolphins are weanedquickly, probably within a fewmonths after birth, a situation that couldoccur where there are no predators and a reliable food supply. Indusdolphins probably have an annual or biannual reproductive cycle,which would explain their observed high rate of population increaserelative to most other cetaceans.
Indus dolphins produce echolocation clicks but no whistles. In cap-tivity and in the wild they echolocate almost continuously, producing20–50 clicks per second (Herald et al., 1969; Pilleri and Pilleri, 1987).Click frequencies are primarily 50–80 kHz, with a secondary peak at160–200 kHz and a dominant frequency of around 80 kHz (Pilleriet al., 1976). The acoustic emission field is highly directional, extendingin two relatively narrow cones dorsally and ventrally in front of the dol-phin (Pilleri and Pilleri, 1987). In shallow water and in captivity Indusdolphins have been observed to swim on their sides (Herald et al.,1969).
5. Threats
A summary of threats, mitigation measures and current research isprovided in Table 2.
5.1. Direct causes of mortality
5.1.1. HuntingDetailed accounts of the hunting bags of British officers, often total-
ling thousands of birds and mammals of numerous species, were regu-larly published in the 1800s and early 1900s. We could trace no recordsthat included a dolphin or porpoise, therefore Indus dolphins apparent-ly were not targeted by colonial hunters.
Freshwater dolphins were however killed by numerous indigenousgroups along the Indus River, in Sindh and Punjab, over the course ofseveral centuries (Anderson, 1879; McNair, 1908). The meat was usedas food, and the oil asmedicine and for lighting. Lowis (1915) gave a de-tailed explanation of how dolphins were captured by the local Kehalpeople inDera Ghazi Khan. They constructed a viewing platform in shal-low water, and attached a fish to a nearby stake. A tethered tame otterwas released into the water and would try to reach the fish. The noiseof the otter would attract a dolphin and as it approached the dolphinwould attempt to catch the fish attached to the stake, at which pointthe fisherman would cast his net over the dolphin, capturing it.
In the early 1970s, dolphin hunting was widespread in Sindh andseveral boats were equipped for their capture (Pilleri, 1972). Althoughthe Muslim majority disdained dolphin meat for religious reasons,non-Muslims (not clear which religion) continued to consume it. Thedolphin became a protected species in 1974 when the Wildlife Acts ofSindh, Punjab and the Khyber Phakhtunkhwa (KP) Provinces werepassed, and a reserve for the Indus dolphin was declared in the190 km stretch of river between Guddu and Sukkur barrages. Within afew years, and following some prosecutions in the courts, dolphin hunt-ing in Sindh ceased (Bhatti and Pilleri, 1982). With enforcement of theban on dolphin hunting in Sindh, the hunters moved upstream intoPunjab to avoid the strict controls downstream. It was reported in1977 that upstream of Guddu barrage many boats were equipped tocatch dolphins. Reeves et al. (1991) reported that Kehal fishermenbelow Kalabagh were engaged in hunting dolphins, and also that dol-phin hunts took place at Chashma, Ghazi Ghat and Taunsa in the early1980s. There is no evidence that Indus dolphin hunting has continuedanywhere in Pakistan since then.
5.1.2. Fisheries interactionsMortality from accidental capture in fishing gear is the greatest
threat to most cetaceans (Reeves et al., 2013). Indus dolphins are acci-dentally captured in nets when they stray into irrigation canals which,due to their narrow and shallow dimensions, are easily and heavilyfished. Net entanglement is a major concern between Sukkur andKotri barrages where the Indus flow is so severely depleted that fixednets span the river. However, in general, the Indus River main channelhas not been intensively fished as fishing activity is concentrated inside channels and adjacent pools that are reported to be warmer andhave higher fish densities (Khan, 1947). The low intensity of fishing inthe main channel is also partly due to the swiftness of the current,which limits the manoeuvrability of oar-powered boats. However en-tanglement is an increasing threat as boats become mechanised andbetter able to negotiate the main channel.
In the past a fish contractor system was in place in which the rightsto fishing groundswere auctioned by the government and purchased bypowerful fish contractors. Contractors allowed fishing only on the con-dition that fishermen surrendered approximately 75% of the fish catchto them, and that the remainder was sold to them below market value(Jabbar, 2005). In 2007 the contractor system in Sindh was abolishedand now local indigenous fishermen can obtain their own licences tofish. This action is likely to affect the other provinces soon (Anon.,2011). Although the new system is believed to be more equitable forfishermen, it has led to larger numbers of unskilled fishermen usingthe river, and a coincident jump in the number of dolphin deaths.From 1993 to 2010 a total of 35 dolphins were reported dead betweenGuddu and Sukkur, however in 2011 alone 45 dead dolphins were re-ported, and another 15 from January to May 2012 (Waqas et al.,2012). The2011 total includes at least 6 dolphins thatwere killedwithinthe Protected Area when insecticides were dumped into the river to in-crease fish catch (WWF-Pakistan, 2011). Since 2012mortality rates ap-pear to have declined: only six deathswere recorded from2013 to 2014,possibly because fisheries enforcement and community awareness ac-tivities have increased. Additional research on this issue is essentialand could include studies to investigate the factors that influence sus-ceptibility to bycatch and ways to reduce entanglements.
5.1.3. Canal entrapmentIndus dolphins occasionally enter irrigation canals through the flow-
regulator gates adjacent to irrigation barrages. Canals run for hundredsof kilometres and are heavily fished and readily accessible to people.Therefore canal-entrapped dolphins are at high risk. Dolphins trappedin canals generally remain close to the main river, but some have beenknown to travel over 170 km (Bhaagat, 2002; Khan, 2005). Each yearall canals are drained for several weeks to allow for maintenancework. Even if trapped dolphins survive until canal closure, they will
Table 2Details of the threats to the Indus River dolphin ranked by priority (in descending order from top to bottom) with details on research and mitigation.
Threat Priorityforsubspecies
Current/future/historical
Increasing/decreasing
Moreresearchrequired?
Mitigationstrategy
Mitigation atlocal/regional/nationallevel
Mitigationunderway
References
Migration throughbarrages
Highest All Stable Yes Unclear, possibly translocationor possibly deterrents
certainly die when the canal is drained, and therefore a dolphin rescueprogramme was initiated in 1992 by Sindh Wildlife Department andWWF-Pakistan. Between 1992 and 2014, 147 trapped dolphins weredocumented; of that number, 113 were rescued successfully while 34died (Waqas et al., 2012). Some animals died during capture and thecause of death was believed to be capture-related stress rather thandrowning in the net. Animals that survived capture always survivedtransport and release although post-release survivalwas notmonitored.The number of dolphins reported in canals varies dramatically fromyear to year, presumably due to differences in the numbers entering inthe first place but also to differences in the efficiency of detection,which depends on many logistical factors. Reports have been receivedoccasionally of dolphins trapped in canals that originate from Gudduor Taunsa barrage, but this is rare probably because there are fewer dol-phins present above these barrages, and perhaps because of differencesin the location of the canals and different rivermorphology near thebar-rages. Research to understand when and how dolphins traverse thegates, and what influences this process, would help in designing mea-sures to reduce the problem.
5.2. Indirect causes of mortality
5.2.1. Water pollutionThe magnitude of surface water pollution in Pakistan has increased
at a dramatic rate as the country has rapidly industrialised and it isnow recognised a significant problem (Directorate of LandReclamation Punjab, 2007; Qadir et al., 2007). As of 2005, only around8%of urban and industrial wastewater, by volume, underwent even pri-mary treatment, allowingmore than 90% of industrial andmunicipal ef-fluent to enter rivers and lakes (World Bank, 2005). The plains areintensively cultivated with cotton, wheat and sugar cane and pesticideuse has increased at an annual rate of about 6% (World Bank, 2005). In-secticides sprayed on crops mix with irrigation water, which leachesthrough the soil and enters groundwater aquifers and also re-enterswater courses. The discharge from tanneries, textile mills, wood andjute mills, sugar mills, distilleries and pulp and paper factories is themajor source of chemical pollution. The Punjab rivers flow throughthe industrial and agricultural heartland of Pakistan and as a conse-quence are more polluted than the Indus mainstem, which passesthrough more remote areas (Directorate of Land Reclamation Punjab,
2007). More than three quarters of all Indus dolphins occur in theIndus below the Panjnad River confluence and therefore live down-stream of cities inhabited by more than 100 million people. Studies ofGanges River dolphins showed substantial tissue accumulation ofheavy metals, organochlorine pesticides and polychlorinated biphenyls(PCBs) (Kannan et al., 1993) as well as accumulation of butyltins 5–10times greater than the levels found in their prey (Kannan et al., 1997).Commonly used pesticidesDDT, Cypermethrin, Deltamethrin and Endo-sulfan were found in the tissue of three Indus dolphins that died inSukkur in January 2011 (WWF-Pakistan, 2011). Given the high pollut-ant loads in the some of the rivers, South Asian river dolphins are likelyto be exposed to some of the highest levels of pollutants of all cetaceans,both through prey consumption and direct contact. Although this expo-suremay result in negative health effects now or in the future, this issuehas yet to be investigated in any depth for this subspecies.
5.2.2. Freshwater suppliesThe greatest threat to Indus dolphins originates from the irrigation
network, in the form of habitat fragmentation by barrages and degrada-tion or removal of habitat due to the extraction of water (Braulik et al.,2014a). Low dry-season river discharge, due to water extraction at irri-gation barrages, was shown to be the principal factor responsible for1) the spatial pattern of the dolphins' range decline, 2) the temporalpattern of subpopulation extirpation and 3) the speed of extirpation fol-lowing habitat fragmentation (Braulik et al., 2014a). The probabilitythat an Indus dolphin subpopulation is still extant increases with in-creasing median dry-season river discharge. Where dolphins have al-ready disappeared, they were extirpated earlier and more quicklyfrom river sections where discharge was lower. Dolphins were morelikely to persist in the core of the former range becausewater diversionshave been concentrated near the range periphery. Habitat fragmenta-tion and degradation are intertwined and in combination they havecaused the decline of the Indus dolphin.
Reductions in flow affect dolphins directly by reducing the physicalspace available to them, reducing average water velocity and depthand increasing water temperature. During the dry season Indus dol-phins are concentrated in the remaining deep pool habitat in the river,and they avoid shallow river sections (Braulik et al., 2012b). They selectareas of river that have large cross-sectional area and volume, especiallyat depths greater than 1 m, presumably to reduce the risk of becoming
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isolated in small pools and tomaximise foraging opportunities. Removalof water from the river exacerbates and concentrates anthropogenicthreats, for example, by increasing the concentration of nutrients andpollutants, and forcing the dolphins to congregate in deep pools thatare also important areas for fishing, thereby increasing the chances ofnegative interactions with humans (Braulik et al., 2012b; Chaudharyet al., 2012; Kelkar et al., 2010).
The statement, ‘In a land where it seldom rains, a river is like gold’(Albinia, 2008), could not be more appropriate anywhere than inSouth Asia. Access to water is one of the most politically charged issuesin Pakistan. The vast majority of the nation's water comes from theIndus River, and the river passes through neighbouring India prior toentering Pakistan, which makes river discharge a sensitive matter. Thefinite surface water resources are under great pressure from a largeand rapidly growing Pakistani population and an expanding economicand agricultural sector. New dams, barrages, river linking projects, andhydropower developments are planned, many are already under con-struction, and there is constant demand for more cultivable land. Percapita water availability has dropped to one of the lowest levels world-wide, and at present there is little culture of water conservation (AsianDevelopment Bank, 2010). The projected demand for water is predictedto outstrip availability before 2025 (Siddiqi and Tahir-Kheli, 2004).Consequently, the future of Indus dolphins is tied to much broader na-tional issues of governance, security, poverty alleviation and watermanagement.
5.3. Climate change
One response of cetaceans to climate change is that their rangesmayshift to remain within preferred climatic conditions (MacLeod, 2009).Species and populations such asmany of the river dolphins that have re-stricted geographical distributions, with little or no opportunity forrange expansion, are expected to be especially vulnerable. Under differ-ent climate change scenarios, Indus river discharge was predicted to in-crease dramatically (N90%) by 2050 (Palmer et al., 2008). This positivenews is tempered by the fact that because of the great discrepancy be-tween water availability and withdrawals for human use, the Induswas still predicted to remain one of the most water-stressed basins(Kundzewicz et al., 2008; Palmer et al., 2008). The models suggestthat climate change alone is unlikely to spell doom for Indus dolphinsand, if better water conservation practises are adopted in the future,water supplies may in fact increase, signifying a positive change forthe dolphins.
It is possible that, if global temperatures rise and a greater propor-tion of Indus flow is derived from rainfall as opposed to glacial melt,riverwater temperatureswill rise.Water temperatures in themainstemof the Indus River vary fromapproximately 5 °C inmid-winter to at least33 °C in early summer, an annual temperature range of almost 30 °C(Braulik, unpublished). Indus dolphins have evolved the capability tocopewith large temperature fluctuations, so theymay bemore resilientto climate change-driven increases in water temperature than specieswith more uniform habitat. However it is still possible that the effectsof climate change on the dolphins' prey or broader ecosystem willprove detrimental to them.
5.3.1. Dams and barragesPakistan depends almost completely on irrigated agriculture for em-
ployment, to feed its large and booming population (185 Million, 1.6%growth per annum in 2014) and as the major source of its internationalexports. Large dams on the Indus River are often advocated as themeans to satisfy demand for electricity and stimulate economic growth.Pakistan has plans to add 10,000 MW through five projects by the year2016, and another 14 projects totalling about 21,000 MW are understudy for construction by 2025. Meanwhile, India has many damsunder construction or planned on the Indus tributaries where theyflow through Indian Territory prior to entering Pakistan. A recent
study on theMekong River found that construction of all planned tribu-tary dams there would have catastrophic impacts on fish biodiversityand on the floodplain's fish productivity, far greater than the combinedimpact of six upper mainstem dams on the lower Mekong River itself(Ziv et al., 2012). New dam construction will likely continue for sometime on the upper Indus and the consequences for people, fisheriesand dolphins located downstream are unclear.
Fortunately, further fragmentation of Indus dolphin habitat by con-struction of new barrages is unlikely, as the current network is adequatefor distributing water to the present agricultural area. If there is a needto irrigate additional land, it is likely that new canals rather than entirelynew barrages will be constructed.
5.4. Population dynamics and downstream migratory attrition
For most of the year barrage gates are virtually closed to ensure thatwater is diverted into canals. Consequently only a small opening is pres-ent at the base of the gate and it would be difficult for a dolphin to phys-ically pass through this. Barrage gates are fully open and the river flowunimpeded to allow passage of high floods, which generally last for afew days or weeks, and for three weeks at each barrage during lowflows when the canals are closed for maintenance. During these briefperiods the flow through the barrage is still extremely rapid (greaterthan around 5 km/h in the dry season and much greater in the flood)and turbulent, but there is no physical obstruction preventing dolphinsfrom passing through a barrage (see Fig. 3).
It has been suggested that dolphins sometimes move through bar-rage gates and between subpopulations (Reeves et al., 1991). The onlysolid evidence of this is from a single radio-tracked dolphin releasedabove Sukkur barrage during canal closure that traversed the barragein both an up- and downstream direction several times. The barragegates were eventually closed, leaving the animal below the barrage,trapped in a new subpopulation downstream from its origin (WWF-Pakistan, unpublished). This example from a single dolphin showsthat movement through Sukkur barrage is possible, but as each barragehas a very different design and operation, as well as different dolphindensities in adjacent portions of the river, this does not prove thatcross-barrage movement is a regular occurrence at Sukkur or that dol-phins can move through other barrages.
However, the potential implications of such movements are great.For example, if animals do regularly move through barrages and theyare more likely to move downstream than upstream, the result wouldbe the gradual attrition of upstream subpopulations and the augmenta-tion of those downstream. Migration of this type could dramatically de-plete upstream subpopulations over time, especially as many of theseare already very small, potentially leading to their gradual extirpation(Reeves et al., 1991).
Several aspects lend weight to the downstream migratory attritionhypothesis:
a) Many dolphin subpopulations located in the upper reaches of rivershave been extirpated over the last century and it is those down-stream that have persisted (Braulik et al., 2014a).
b) Each subsequent downstream subpopulation, except the last, is larg-er than the preceding one, despite a continually diminishing riverflow (Braulik, 2006). The exception to this is the small subpopula-tion furthest downstream between Sukkur and Kotri barrages thatpersists despite severely depleted river discharge rendering the hab-itat marginal. It is possible that this subpopulation is augmented by,or consists solely of, migrants from the upstream subpopulation(Guddu to Sukkur).
c) Dolphins enter irrigation canals through gates that are very similarto barrage gates. Once dolphins enter canals they are usually unableto travel back upstream through the canal gates and return to theIndus River. As dolphins are known to pass downstream through
Fig. 3. Photographs showing 1. a gate at Taunsa barrage which is virtually closed and 2. a gate at Guddu barrage which is fully open because it is canal closure and the barrage is not di-verting water.
canal gates regularly, it seems likely that they also pass downstreamthrough similar barrage gates.
The magnitude of dolphin migration at each barrage would likelyvary based upon differences in engineering design, operational cycle, di-version capacity and location as well as dolphin density in each subpop-ulation. Barrage permeability would determine subpopulationimmigration and emigration rates, and therefore whether migration re-sults in a net attrition or augmentation of that subpopulation. For exam-ple, if the downstream migration rate at a barrage is high, thesubpopulation upstream would suffer rapid attrition. Alternatively, ifthe downstream migration rate at a barrage were low, the upstreamsubpopulationwould contribute fewmigrants downstreamandmay in-stead exhibit its own net increase from upstream immigrants. Sukkurbarrage diverts more water than other Indus barrages and its gates aretherefore lowered, or closed, for a larger part of the year. High dolphinabundance between Guddu and Sukkur barrages may therefore be theresult of high immigration through Guddu barrage and low emigrationthrough Sukkur barrage, resulting in an overall augmentation of theGuddu to Sukkur subpopulation by downstream migration (Braulik,2006).
6. Conservation options and research priorities
6.1. Mortality monitoring
The demonstrated link between extirpation of Indus dolphin sub-populations and low river discharge is important for macro-levelconservation strategies. However, there is still very little informationon what the immediate or proximal causes of death of individualIndus dolphins are. Inmany threatened or endangered long-livedmam-mals, variation in mortality (particularly adult mortality) is a primarydeterminant of population growth. Therefore, describing the causesand rates of mortality is an important component of conservation re-search to guide conservation actions. An important step is to establisha national stranding network so that animal deaths, associated bio-logical information, and determination of causes of death can be docu-mented systematically. This would involve reporting of deaths to adesignated authority, systematic collection of data that are stored in acentral location, collection and analysis of tissue samples using standardprotocols, and training of responders in necropsy techniques. Until sucha system is in place, it will not be easy to identify or respond to peaks inmortality thatmay be cause for concern.Without information on the in-cidence of Indus dolphin deaths and their causes it is not possible to de-sign conservation measures to reduce mortality, or easily monitor the
effectiveness of existing strategies. A functioning stranding networkwould also allow the collection of other important life history andhealth data that are at present almost completely lacking. Such a net-work would be the first of its type in Pakistan and given the lack of vet-erinary capacity, infrastructure (power, freezers etc.) and technicalexpertise, it would require considerable investment to get off theground. Clearly it would be important to begin with a basic systemthat could be expanded over time.
6.2. Protected areas (PAs)
The Sindh Dolphin Reserve is one of very few freshwater PAs desig-nated specifically to protect river dolphins. The Reserve was establishedin response to a specific threat, that of dolphin hunting, which at thattime was determined to be the major threat to the subspecies. The ap-parently consistent increase in dolphin abundance since reserve estab-lishment indicates that it was very effective at combating that threat(Braulik et al., 2012a). However, other than the ban on dolphin huntingthere are few restrictions on human activities within the Reserve—verylimited management of fishing activity, pollutant discharges and vesseltraffic. As human populations increase and new threats emerge, it islikely that the Reserve as presently designed and managed will becomeless effective at conserving dolphins. Managers need to find ways toadapt and respond to changing conditions if the Reserve is to continueproviding dolphins with meaningful protection.
Meanwhile, the section of river from Taunsa to Guddu barrage inPunjabwas also declared a PA for dolphins in 2014, and there is interestin gazetting other stretches of river in KPK Province. Obviously, the sim-ple creation of PAs does not guarantee the long-term survival of vitalecosystemsor endangered specieswithout carefully considered and im-plemented management. Among a total of 25 PAs in northern Pakistan,16 lack baseline information, 22 do not have anymanagement plan, and19 are without anymanagement infrastructure (Nawaz, 2007). As such,they are ineffective at protecting the environment. Given that nationalgovernance is very weak, and large parts of the river are outside of gov-ernment control and instead run by tribal landlords, legislated PAs willnot be effective without community involvement. Many of the peoplewho live by the river are among the very poorest communities andthey have relied on the river for their livelihoods for generations. There-fore community-based conservation is likely to be the most effectiveconservation strategywhether inside or outside a formal PA framework.A system of community- and ecosystem-based management, withzoned PAs that include highly protected reserves in critical areas aswell as buffer zones that allow human uses such as carefully managedtourism and fishing, would be ideal. This has been successfully
39G.T. Braulik et al. / Biological Conservation 192 (2015) 30–41
implemented for river dolphins in the Sundarbans of Bangladesh (WCS/Bangladesh Cetacean Diversity Project, 2014).
Freshwater PAs have characteristics that are quite different to thosein other ecosystems because they tend to be greatly affected by activi-ties that occur outside their boundaries, as water arrives from upstreamor runs off from nearby terrestrial areas. Practises such as dam buildingor diverting water for agriculture can occur outside PA boundaries andyet have major negative consequences for habitat within the PA. Assuch, the dolphin PAs in Pakistan are likely to be most effective for con-servation when attempting to manage localised threats such as fishing,hunting, vessel traffic or point sources of pollution, whereas for otherimportant threats such as depleted river flows, dams and distant pollut-ant sources a river basin-wide approach will be needed.
6.3. Downstream migration
Discussion of whether or not dolphins move through irrigation bar-rages and in what directions and numbers permeates most of the ques-tions surrounding the conservation of Indus dolphins. Obtaining agreater understanding of this issue is of high priority because, depend-ing on how many individuals move and in which predominant direc-tion, the persistence of upstream subpopulations may be threatened,and there may be a continual loss of dolphins to areas of marginal hab-itat downstream. It is not possible to measure or count the number ofdolphins thatmove through a barrage visually unless individuals actual-ly surface inside a gate which has seldom been seen. Tracking dolphinsusing radio tags may show that single animals have traversed a barrage,but tags can't be deployed on sufficient animals to be able to quantifypopulation-scale movements. Satellite and GSM tags aren't feasible touse on these river dolphins because they spend insufficient time at thesurface (about 1 s) to obtain or transmit a signal. Barrages are politicallysensitive structures so it is difficult to get permission from the govern-ment to attach any sort of acoustic or electronic device to them. Anchor-ing fixed passive acoustic recorders in, and on either side of, thebarrages was attempted (Braulik, unpublished) and the rapidly flowingwater and large amount of floating and submerged debris in the rivermeant that anchor lines had to be cleaned hourly to prevent foulingand loss of the expensive devices. It appears theoretically possible touse acoustic tracking to record animals moving through a barrage, butit would be necessary to have the devices inside the mouth of everygate—again logistically difficult and expensive. The turbidity of thewater precludes the use of underwater video. It is possible that high-resolution, multi-beam acoustic imaging such as that used for countingmigrating salmon could be used for quantifying dolphin movement(Rawding and Liermann, 2011).
As it is not feasible to collect biopsies from these dolphins with cur-rently available methods, the use of genetics to provide information onsuch things as abundance, sex ratio, reproductive success or changes ingenetic diversity over timewill be challenging, if even possible. Rescuedanimals are a source of genetic material, but these all originate onlyfrom the largest sub-population and it is those upstream that are ofgreatest concern.
6.4. Translocation
Dolphin subpopulations in the Indus River system are being slowlyextirpated primarily from the upstream portions of their range(Braulik et al., 2014a). There appears to be a domino effectwith subpop-ulations upstream disappearing prior to those immediately down-stream. The Jinnah-Chashma subpopulation has only a handful ofanimals and is on the brink of extirpation, while the Chashma-Taunsasubpopulation is estimated at 96 individuals (Noureen, 2013) and theBeas River subpopulation consists of only approximately 10 animals(Behera et al., 2008). The possibility has been raised of translocatingIndus dolphins from the high-density, largest subpopulation (Gudduto Sukkur) to a subpopulation with low abundance.
Translocation programmes typically have varied goals that includebolstering genetic heterogeneity of small populations, establishing sat-ellite populations to reduce the risk of species loss due to catastrophes,and speeding recovery of species after habitat restoration (Carpenteret al., 1989). If upstream Indus dolphin subpopulations are decliningdue to downstream migratory attrition and individuals are concentrat-ing between Guddu and Sukkur barrages, then translocating dolphinsout of this high-density subpopulation to supplement the low numbersin upstreamareasmay be sufficient to prevent the extirpation of severalvery small subpopulations.
The subpopulation between Guddu and Sukkur barrage is relativelylarge (estimated as 1289 in 2006), occurs at high density (10.35 km−1),appears to have been increasing over the last 30 years (Braulik et al.,2012a) and could likely sustain the removal of a modest number of in-dividuals per year. In general, translocation success is highest when an-imals are wild-caught and originate from a high-density, increasingpopulation (Carpenter et al., 1989).
Capturing dolphins in the wide, fast-flowing river would be fraughtwith difficulty and danger to both dolphins and capture teamandwouldbe ill-advised. However, dolphins become trapped in irrigation canalsevery year and are rescued and returned to the river (Waqas et al.,2012). These animals would die if theywere not captured and thereforeare ideal candidates for translocation. In general the dolphin rescue pro-gramme in Pakistan demonstrates that these animals are fairly robustduring transport, the greatest risk of mortality being during capture(Waqas et al., 2012). However it is important to note that we knownothing of survival after release as this has not beenmonitored. Animalscaptured and transported to overseas dolphinaria in Japan, Switzerlandand the USA in the 1960's did not survive at all well (Herald et al., 1969;Kasuya, 1972; Reeves and Brownell, 1989).
A translocation programme would need to be well-researched andcarefully planned prior to implementation. It would be necessary toconsider animal welfare, impacts on the founder subpopulation, habitatand threats for the receiving subpopulation, and how to achieve long-term monitoring of released individuals and the whole population. Ata minimum the following components would need to be investigatedthoroughly:
• Habitat. Without good habitat quality and low threat levels in therange of the receiving subpopulation, translocation has little chanceof success regardless of how many organisms are released or howwell they are prepared for release (Carpenter et al., 1989). Before anIndus dolphin translocation programme could be considered serious-ly, detailed studies of habitat and threats in the receiving environmentwould be required. Previous studies have shown that channel geome-try and river morphology are significantly different andmore suitablefor dolphins between Guddu and Sukkur barrages than in the habitatsof subpopulations upstream (single sinuous deep channel, versusshallow braided channels) (Braulik et al., 2012b). However, river dis-charge is greater in upstream areas, and it was shown, based on phys-ical characteristics, that these upstream subpopulations should beable to persist for several centuries (Braulik et al., 2014a). Preliminaryobservations indicate threat levels to be similar in all areas, but pollu-tion is likely to be greatest downstream.
• Monitoring individual survival. It is not possible to observe or photo-graph Indus dolphin individuals well enough in the field to allow fortheir identification using either natural orman-mademarks. Dead an-imals are seldom found because they wash downstreamwith the cur-rent. Therefore survival of released animals would need to beaccomplished by radio tracking.
• Monitoring subpopulations. Regular population monitoring to identi-fy changes in subpopulation abundancewould be essential. A translo-cation programme would be determined to be successful if thefounder supopulation was not severely affected by the removals,and the small recipient subpopulations upstream either increased insize or were at least maintained at current levels.
Indus dolphins are not yet so threatened that the loss of a few indi-viduals would outweigh the advantages of maintaining additional sub-populations. If conducted cautiously and with careful planning, such abold management action is worthy of serious consideration becausethe long-term conservation benefits of establishing or maintaining ad-ditional Indus dolphin subpopulations may well be worth the risks.
6.5. River management
Irrigation barrages on the Indus Riverwill not be removed and advo-cating removal as a dolphin conservation strategy would be unrealisticand counter-productive. If Indus dolphins are to persist, they must doso within the current configuration of fragmented habitat. The strategythat is most likely to be successful for Indus dolphins is managing theIndus River so that the natural hydrological regime is at least partiallyrestored or maintained. Determination of the environmental flows orthe quantity and quality of water required for ecosystem preservationand resource protection is an integral part of modern river basin man-agement, and essentially means that enough water is left in a river toensure downstream environmental, social and economic benefits(Dyson et al., 2003). It requires negotiations among stakeholders to rec-oncile the different interests that compete for the use of water, especial-ly in river basins such as the Induswhere competition is alreadyfierce. Itrequires that relationships among flow, suitable habitat and species areunderstood and described by linking the physical properties of riverstretches, e.g. depth and flow velocity, at different measured ormodelled flows, with the physical conditions that key animal or plantspecies require (Tharme, 2003). Describing the flow needs of river dol-phins could be a large, expensive and complicated exercise. It wouldhave to include specific evaluations of river discharge, hydrology anddolphin habitat use over a range of flows and seasons and ideallywould include information on dolphin life stages, reproduction and for-aging, all information that is currently incomplete or lacking entirely.Hydrology–ecology relationships frequently exhibit non-linear re-sponses to flow, and thresholds based on those responses can be instru-mental for managing environmental flow programmes (Shafroth et al.,2010). Given that extraction of water from the Indus River is one ofthe primary threats to Indus dolphins, and anticipating that some kindof environmental flow study will be conducted in the future, it wouldbe prudent to begin gathering data on Indus dolphin habitat use sothat they are available as input to such a study.
Water scarcity is experienced by almost all Pakistanis. As stated bythe World Bank (2005), “the survival of a modern and growingPakistan is threatened by [lack of] water. The facts are stark”. There isfrequent tension between the provinces over the allocation of riverwater, with Sindh, located downstream, being especially sensitive toits vulnerable position (Shah, 2009). Despite this tension and the atten-dant publicity, there is almost no concept of water conservation inPakistan; the focus is almost entirely on obtaining and capturing morewater from the rivers and from ground water. The irrigation system isextremely inefficient, water delivery is unreliable and inequitable, andcrop yields per cubic metre of water are below international standardsand those of neighbouring countries (World Bank, 2005). Forty percentof the water diverted from the Indus basin in Pakistan is lost in convey-ance and in the late 1980s it was estimated that improvements in sup-ply efficiency could save 14.8 billion m3/yr. of water. Canal lining is onesuch improvement (World Commission on Dams, 2000). Water con-servation and good stewardship would go a long way to improvingthe water resources situation in Pakistan, and this would have far-reaching benefits for society as well as for river ecosystems and Indusdolphins.
7. Conclusions
The conservation status of the Indus River dolphin is not yet as direas that faced by the baiji (Lipotes vexillifer), the vaquita (Phocoena
sinus), or the Mekong Irrawaddy dolphins (Orcaella brevirostris) {IUCN,2015 #3109}. However it remains one of the world's most endangeredmammals and its long-term prognosis is not at all good. Despite agreat increase in knowledge about Indus dolphins over the last 20years, there are still many important unanswered questions that arevital to address if the species is to be conserved effectively (Table 2).Do dolphinsmove through barrages and thus between subpopulations?Are upstream subpopulations declining in abundance? How muchwater is enough to sustain a dolphin population? How is the new legis-lation concerning fisheries and protected areas affecting the dolphinpopulation? Of top research priority is the need to understand andquantify movement of dolphins through barrages and the implicationsof this on population dynamics. Although challenging to assess, thereare realistic options for mitigation of dolphin movement through bar-rages that could be implemented and help solve the problem. By con-trast the other high-priority threat, limited dry-season river flows, is afar-reaching issue that will require political solutions, as well as socialinterventions and ecological understanding; it will require investmentand influence that is way beyond species conservation.
It is important that we do not allow ourselves to become paralysedby the lack of certainty about some threats, and that the search formore information does not become the sole focus. It is essential thatconcrete conservation actions be taken immediately. These shouldfocus on what is known: that declining river flows threaten the dol-phins, small upstream subpopulations are especially vulnerable to extir-pation and need rigorous protection, and fisheries-related mortality isan increasing problem. With reference to the extinction of the baiji,the Scientific Committee of the International Whaling Commission(IWC, 2008) stated that “despite extensive scientific discourse formore than two decades, little effort was made to implement any realconservation measures for this species. In hindsight, the extinction ofthis species is not surprising; species cannot be expected to save them-selves”. Conservation and research action is urgently needed to preventthe Indus dolphin from succumbing to the same fate as the baiji.
Acknowledgements
Reviews of earlier versions of this manuscript were provided bySimon Northridge and Phil Hammond. I thank Andy Read and VincentJanik for the original suggestion to write this manuscript. Valuablefunding for preparation of the paper was provided by the US MarineMammal Commission (E4047595).
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