Showing posts with label River Dolphin. Show all posts
Showing posts with label River Dolphin. Show all posts

Friday, February 26, 2010

Call goes out to save the Ganges Dolphin


The Ganges River Dolphin was declared the national aquatic animal last month, but is still in urgent need of being saved from extinction, experts on the subject said. There are only about 2,000 left, down from tens of thousands just a few decades ago.Participating in a two-day seminar here on conservation of the Ganges River Dolphin, the experts said its numbers continue to dwindle alarmingly due to killing, pollution and the break-up of its habitat by building dams. "Conservation of the Ganges River Dolphin should be given priority by all," Wildlife Institute of India director P.R. Sinha told IANS. "It should be given the same importance as conserving tigers." He was one of the dozens of national and international experts who attended the workshop Monday and Tuesday. It was organised by the working group for action plan for dolphin conservation, set up by the central Ministry of Environment and Forests to finalise India's dolphin conservation plan. The group is likely to submit its report to the ministry by April. "Conservation of the Ganges River Dolphin must be initiated on a massive scale because freshwater dolphins are found only in some countries in South America and Asia," said Randall Reeves, chairman of the International Union for Conservation of Nature (IUCN) cetacean (whales, dolphins and porpoises) specialist group. IUCN has classified the species as endangered. Reeves said one way to save the dolphins was to turn stretches of river where they were found into tourist spots, as had been done in South America. Well-known expert on Ganges River Dolphins R.K. Sinha said dolphins are the lifeline of the Ganga (Ganges). "If the dolphin numbers increase in the river, it will be a positive sign for a clean Ganga and if the numbers decrease, it is a negative sign of increasing pollution," he said. Experts discussed how to get Ganges River Dolphins the status of "indicator species" for gauging the success of Ganga cleaning mission. R.K. Sinha said that since dolphins were at the apex of the food chain in the river, their condition would help assess whether the steps taken to clean the river Ganges were working. R.K. Sinha, who has been researching on freshwater dolphins for over two decades, asserted that immersion of idols in rivers after Hindu festivals poses a grave threat to aquatic life. He suggested that "man-made water bodies" be used for immersing idols. "The Ganga is already highly polluted, and its ecosystem is under pressure. The immersed idols will create more trouble for dolphins and people dependent on the river for drinking water," said R.K. Sinha, a professor of zoology at Patna University. Untreated sewage, rotting carcasses and industrial effluents that find their way into the Ganga during its 2,500-km-long journey from the Himalayas to the Bay of Bengal have also affected the dolphins, he said. Bihar's Minister for Disaster Management Devesh Chand Thakur assured the experts that the state government was committed to conservation of Ganges River Dolphins. "The state government has decided to provide funds for conservation of the dolphins from the next fiscal year," Thakur told the experts during his address Monday. The minister said an awareness campaign would be launched among fishermen and boatmen in the state for conservation of Ganges River Dolphins. Experts at the conference estimated the current population of Ganges River Dolphins at around 2,000, with about half of these in Bihar and Uttar Pradesh. The World Wide Fund for Nature (WWF) says that in the 1980s, there were around 3,500 in the delta region alone. According to WWF, the range of the Ganges River Dolphin covers seven states - Assam, Uttar Pradesh, Madhya Pradesh, Rajasthan, Bihar, Jharkhand and West Bengal. The upper Ganga (in Uttar Pradesh), Chambal (Madhya Pradesh and Uttar Pradesh), Ghaghra and Gandak (Bihar and Uttar Pradesh), Ganga from Varanasi to Patna (Uttar Pradesh and Bihar), Sone and Kosi (Bihar), Brahmaputra from Sadia (foothills of Arunachal Pradesh) up to Dhubri (on the Bangladesh Border) and Kulsi River, a tributary of the Brahmaputra, form its ideal habitats. The Ganges River Dolphin is one of four freshwater dolphin species in the world. The other three are found in the Yangtze river in China, the Indus in Pakistan and the Amazon in South America. The Ganges River Dolphin (Platanista gangetica) is found in India, Bangladesh and Nepal. In appearance, it is identical to the Indus River Dolphin. WWF says Ganges River Dolphins prefer deep waters, in and around the confluence of two or more rivers. They share their habitat with crocodiles, fresh water turtles and wetland birds. It has a sturdy, yet flexible, body with large flippers and a low triangular dorsal fin. It weighs up to 150 kg. The calves are chocolate brown at birth and become greyish brown in adulthood with a smooth and hairless skin. Females are larger than males. The maximum length of a female is 2.67 metres and of a male 2.12 metres. Females attain sexual maturity at 10-12 years, while the males mature earlier. The gestation period is 9-11 months and a female gives birth to only one calf, once in 2-3 years. The Ganges River Dolphin is blind. It finds its way and and its prey in the turgid rivers waters through echo-location.

Thursday, January 21, 2010

Ganges river dolphin declared national aquatic animal


The critically endangered Ganges river dolphin has been declared India's national aquatic animal, a government spokesperson said here Tuesday. The India chapter of World Wide Fund for Nature (WWF) estimates only about 2,000 of these dolphins remain.
The spokesperson of the Ministry of Environment and Forests said the main reasons for the decline in the dolphin numbers to a critically low level were "poaching and habitat degradation due to declining flow, heavy siltation and construction of barrages causing physical barrier for this migratory species".

The decision to declare the Ganges river dolphin India's national aquatic animal was taken Oct 5 last year during the first meeting of the newly-constituted National Ganga River Basin Authority, the spokesperson added.

According to the WWF, the dolphins are to be found in rivers of seven states — Assam, Uttar Pradesh, Madhya Pradesh, Rajasthan, Bihar, Jharkhand and West Bengal. Their ideal habitats are in the Ganga, Chambal, Ghaghra, Gandak, Sone, Kosi, the Brahmaputra and Kulsi rivers.

The spokesperson said Ganges river dolphins have been included in the Schedule-I of the Wildlife (Protection) Act, 1972, "thereby affording them the highest degree of protection". The WWF said despite this, "the absence of a coordinated conservation plan, lack of awareness and continuing human pressure are posing an incessant threat to the existing dolphin population".

Now their important habitats have been declared protected areas, the spokesperson said, adding: "Financial and technical assistance is (being) provided to the state governments under centrally sponsored schemes for conservation and protection of wildlife including dolphins and their habitat."

"Financial assistance is (being) provided for conducting scientific research on the habitat, behaviour, population status of river dolphins," he added.

The Ganges river dolphin has a sturdy, yet flexible, body with large flippers and a low triangular dorsal fin. It weighs up to 150 kg. The calves are chocolate brown at birth and become greyish brown in adulthood with a smooth and hairless skin. Females are larger than males.

The maximum recorded size of a female is 2.67 metre and of a male 2.12 metre. Females attain sexual maturity at an age of 10-12 years, while the males mature earlier. The gestation period is 9-11 months and a female gives birth to only one calf, once in 2-3 years.

Dolphins are among one of the oldest creatures in the world along with some species of turtles, crocodiles and sharks. Ganges river dolphins are generally blind and catch their prey in a unique manner. They emit an ultrasonic sound which reaches the prey. The dolphin then registers this image in its mind and subsequently catches hold of its prey.

Thursday, June 18, 2009

Mekong River Dolphin near extinct


Pollution in southeast Asia's Mekong River has pushed freshwater dolphins in Cambodia and Laos to the brink of extinction, according to an international conservation group.The World Wide Fund For Nature (WWF) said only 64 to 76 Irrawaddy Dolphins remain in the Mekong after toxic levels of pesticides, mercury and other pollutants were found in more than 50 calves who have died since 2003."These pollutants are widely distributed in the environment and so the source of this pollution may involve several countries through which the Mekong River flows," said WWF veterinary surgeon Verne Dove in a press statement.The organization said it was investigating how environmental contaminants got into the Mekong, which flows through Cambodia, Laos, Myanmar, Thailand, Vietnam and the southern Chinese province of Yunnan.The WWF added that Irrawaddy dolphins in Cambodia and Laos urgently needed a health programme to counter the effects of pollution on their immune systems.The Mekong River Irrawaddy Dolphin, which inhabits a 190 kilometre (118 mile) stretch in Cambodia and Laos, has been listed as critically endangered since 2004, the WWF said.Their numbers had already been cut by illegal fishing nets and Cambodia's drawn-out civil conflict, in which dolphin blubber was used to lubricate machine parts and fuel lamps.The Mekong is one of only five freshwater habitats in the world for the Irrawaddy Dolphin, and Cambodia was thought to support its largest remaining population.With their pale grey skin and blunt beaks, Irrawaddy Dolphins resemble Porpoises more than their sea-going cousins, and congregate in a handful of the Mekong's natural deep-water pools.The river is also the world's largest inland fishery, producing some 2.5 million tonnes of fish per year valued at more than 2 billion dollars.

Friday, June 05, 2009

Saving the Irawaddy dolphin in Cambodia


Coffs man Troy Saville is in Cambodia fighting to save the Irrawaddy dolphin.SubmittedA COFFS Harbour man is fighting a desperate battle to save a rare freshwater dolphin from extinction.Marine mammal expert Troy Saville, who returned to Coffs for a quick visit last week, is part of a last-ditch effort to save the Mekong River Irrawaddy dolphin.And unless these efforts are successful, this CITES-listed freshwater dolphin is doomed to follow China's Yangtze River dolphin, which became extinct less than two years ago.Troy Saville became well known in Coffs Harbour for his work on the care of marine mammals at the Pet Porpoise Pool, where he worked with its founder Hec Goodall. He was later the head curator of animals at the Coffs Harbour Zoo.For the last year he has been part of a World Wildlife Fund and Worlds Conservation Society team working in Cambodia. The team has been studying the mortality of the rare dolphins in the Mekong River."The total population is about 66-86 animals," Troy said. "We have photographed 70 over three years, but the mortality rate with calves over the last five years has been 70-80 per cent.There have been 88 dolphin deaths recorded since 2003, putting the animal at the verge of extinction. The Mekong's Irrawaddy dolphins are suffering from a 'toxic soup' effect, a recipe Mr Saville describes as: "a little mercury; heavy metals; DDT, PCBs and stress - all combining to deplete their immune systems and make them susceptible to pathogens."The team, led by internationally-recognised marine mammal veterinarian Verne Dove, are about to present a new three-year program to the Cambodian government to be pro-active and save the dolphins. Verne Dove also has a Coffs Harbour connection - she once worked as a volunteer at the Pet Porpoise Pool under Hec Goodall.One of the reasons for Troy Saville's current visit home was to talk to Hec Goodall about catching methods and to try to persuade their 81-year- old mentor to go to Cambodia to help them as a consultant.The rescue program involves capturing the dolphins for health checks, satellite tagging and vaccinating them against Aeromonas as well as using artificial insemination to expand the gene pool, because three very small populations of dolphins in the Mekong are physically separated by rapids and waterfalls.While the dolphins are Troy's main concern, he is also involved with a project which has found crocodiles believed to be from a species thought to have died out, the Siamese crocodile.The crocs are currently being held in a refuge in Cambodia while DNA testing is carried out.

Monday, December 17, 2007

Cambodia tries "delphino-tourism"

Cambodian 'River Guards' keep watch over a Mekong River treasure23 hours agoKAMPI, Cambodia (AFP) Ñ The absence of fishing boats on this stretch of the Mekong river, just a few kilometres (miles) north of the eastern Cambodian town of Kratie, means military policeman Em Pheap is doing his job.One of about 80 "river guards", he is part of a groundbreaking conservation effort which has been credited with helping pull the Irrawaddy dolphin back from extinction."There, there!" he pointed excitedly during a recent patrol on the river, shouldering his assault rifle and standing high on the back of the boat.The pair of dolphins, dark slivers on the horizon, broke the surface with a gentle exhale of breath heard over the murmur of the current running through the submerged trees in this vast monsoon season flood plain.The total number of Mekong dolphins is unknown, but marine specialists say the mammals remain some of the world's most critically endangered.With their pale grey skin and blunt beaks, they dolphins resemble porpoises more than their sea-going cousins.Their numbers already vastly reduced by Cambodia's drawn-out civil conflict -- dolphin blubber was used to lubricate machine parts and light lamps -- these graceful creatures are now falling prey to development and the attendant problem of over-crowding as this wild corner of the country opens up.The Mekong is one of only five freshwater habitats in the world for this species of dolphin, and Cambodia supports its largest remaining population, thought to hover around 100 congregating in a handful of natural deep-water pools."The Kratie-Stung Treng stretch of the Mekong is their last stronghold," said Richard Zanre, the World Wildlife Fund's freshwater programme manager in Cambodia, describing a river habitat running 200 kilometres (125 miles) from Kratie to Stung Treng, Cambodia's last large port before the Mekong crosses over into Laos.War and the ensuing lawlessness kept the region largely out of the reach of researchers for decades. But since around 2001, biologists and other wildlife experts have discovered an unexpectedly rich biosphere.At its core are the dolphins, "a flagship species for the conservation of the river," says the WWF.Desperate to revive a plummeting population, the government created the river guards, the first organisation of its kind and part of a conservation effort launched last year after a spate of mysterious dolphin deaths.But while the guards appear to have had some success in bringing dolphin numbers back up, they have been met with hostility and sometimes violence from local villagers who make their living along the river."The most important thing is to cooperate with the people," said Touch Seang Tana, chairman of the government's Commission for Mekong River Dolphin Conservation."Without the participation of the local people in conservation, we will not be successful."A spike in deaths among mostly dolphin calves last year left officials scrambling to re-think their conservation efforts as Cambodia prepared to launch one of its most ambitious tourism efforts to date: the Mekong River Discovery Trail.The Trail, which hopes to bring tourism and development to one of Cambodia's most-neglected regions, roughly follows the dolphins' habitat.The animals' survival is crucial to the plan's success, officials say."No dolphins means no tourism. No tourism means no development," Tourism Minister Thong Khon said last week as the Trail, a joint UN-Cambodian project, was announced.The solution, according to Touch Seang Tana, was to try to radically change the economy of the river to make dolphins more valuable alive than dead.Alternate means of livelihood would be introduced to villages along the river to take advantage of a booming tourism sector that has already benefited other parts of the country."My idea is... to try to get poor fishermen to change over to tourism," Touch Seang Tana told AFP. "I give them tour boats" to bring visitors to see the dolphins.Reducing villagers' dependence on fishing is hoped to also see a drop in the use of gillnets.Cheap and easy to use, gillnets are as efficient a killer of dolphins as they are of fish, said Touch Seang Tana, a marine scientist by training who blames this now illegal fishing method for "99 percent" of dolphin deaths.But getting local fishermen to risk their livelihoods for an animal that is of little value commercially or as food has been hard, he explained."I tried to invite them to meetings to explain our actions, even tried to pay them money... But they didn't come, they sent their pregnant wives," he said."We decided then that we'll confiscate (fishing gear) and then they came. They came with knives, they wanted to kill the river guards," he added."They want to kill all of the dolphins because they are keeping people from making a living."Since the introduction of the river guards, however, illegal net fishing, along with the use of explosives or electrical charges to catch fish -- practices that also inadvertently kill dolphins -- have dropped, said guard Em Pheap."Before it was a big problem, but now people are understanding more about this," he said.The WWF's Zanre told AFP that while the number of dying dolphin calves is still dangerously high, "adult dolphin mortalities have declined" as a result of conservation.Even before the Discovery Trail becomes a reality, its successes are evident in Kampi, where dolphins have become the local industry.Aside from the boats lining up for sightseers, nearly every house along the narrow tree-lined road shadowing the river hawks tiny dolphin carvings."Everyone earns the money, even the children, from dolphins. You can see their livelihood has changed -- you can see televisions in houses, some people even have motorcycles," Touch Seang Tana said."The dolphin is so important. I tell them 'The dolphin is everything for you' and now they can see that," he added."Its future is their future."

Friday, September 14, 2007

Black market dolphin oil for sale in India

The river dolphin is truly in danger as traditional medicine vendors are selling dolphin oil openly in Guwahati's streets.Brahmaputra is one of the last habitats of the gangetic river dolphin, which has been battling for survival. Travelling down the Brahmaputra one is rarely able to spot them a few times, which is but a fading proof of there existence.A few yards away from the riverbank a different story presents itself, an inconspicuous display of traditional medicine. Not an uncommon sight anywhere in India, but Lila Kanta's exhibit is quite extraordinary, a white eagle's claw, tiger bones, skulls and various parts of animals but a shocking revelation was the open sale of dolphin oil. NDTV: What is it used for?Vendor: For pain and gout and such things. This dolphin oil is good but better still is the mixture of dolphin and tiger oil.NDTV: How easily do you get this stuff?Vendor: Very difficult, we have to tell them in advance. They charge about Rupees 500-600 for a bottle.While several organizations, NGO's, enforcement agencies claim they are trying to protect the river dolphin found in the Bramhmaputra, right on the banks of the river, within the premises of the Deputy Commissioner's office, one comes across Lila Prasad's shop, a makeshift shop of traditional medicine where one can find dolphin oil.Lila Prasad's son is a policeman. He himself was in the police in the 5th battalion and he has been running this lucrative trade of commodities illegally purchased for 36 years.But this could well be a fake.''Even if its a fake it has criminal intent and this is punishable under law, carrying fake rhino horns for example. It shows that dolphin oil has demand,'' said Bihab Talukdar, Secretary, Aranyak.Just as Lila Kanta's display was a revelation, NDTV also came across Babul in the main market area of Guwahati selling the same oil. He said, that he procures the oil from Dehukakhana, Mongoldoi, an hour's journey from Guwahati. If the trade on dolphin is so open this could be the one of the last stories on the amazing dolphin.

Wednesday, September 05, 2007

Increase in fish brings huge leap in marine mammals at Thames River

Dolphins, seals and porpoises could soon become a far more common sight along the Thames, scientists said today.More than 100 of the sea mammals have been spotted in the river over the last year.Researchers say numbers could greatly increase in coming years as the creatures begin to feed in the river more often because of an increased number of fish.Tide turns: a porpoise in the Thames near Wapping. Zoologists say marine mammals are becoming a common sight with seals in Docklands and dolphins as far up river as Tower BridgeThe figures come from the Zoological Society of London's marine mammal sightings survey. It found that bottlenose dolphins, common and grey seals and harbour porpoises were a common sight between Richmond and the estuary at Southend.Dr Renata Kowalik, from the society, said: "We have anecdotal evidence that numbers are increasing, although this is only our second year of data so it is hard to predict a trend. We are seeing a lot of seals in Docklands, and we believe the increased number of fish mean they are feeding in the river now."Dolphins have moved further up the Thames, with one sighting between Westminster Bridge and Tower Bridge.However, the survey also indicates that sea mammals which make their way as far as Tower Bridge may find themselves in a precarious situation.Propeller collisionsSeveral dead harbour porpoises have been reported shortly after live sightings, and have suffered injuries consistent with boat and propeller collisions,.Dr Kowalik said: "Some areas of the river can be very dangerous for these animals, so we need to monitor exactly where they are."We are going to be working with several studies in other parts of the UK to see if the increases we see are mirrored elsewhere. We would urge members of the public to take part - we need all the sightings we can get."The society's survey, now going into its fourth year, is providing the first comprehensive picture of marine mammal life in the Thames. "These findings are really important to enable us to build up a picture of the Thames' role in the ecology of British marine mammals," said Dr Kowalik."Once we have established our baseline data over the next few years we will be able to determine trends, identify threats and effectively manage habitats in the Thames."Londoners who want to report sightings can fill in the form at www.zsl.org/thamessurveyTop of Page ©2007 Associated Newspapers Ltd · Terms & Conditions · Privacy

Monday, September 03, 2007

Extinct Baiji Dolphin spotted in the Yangtze river


The reported sighting of a Yangtze River dolphin, or Baiji, means there is still a chance for people to take further action and protect the cetaceans in the Yangtze from extinction, according to World Wildlife Fund।


The Chinese media reported that a local businessman in Tongling City in east China's Anhui Province filmed "a big white animal" with his digital camera on August 19. The footage was later confirmed to be the Baiji by Prof. Wang Ding, a leading scientist in Baiji study at the Institute of Hydrobiology of the Chinese Academy of Sciences.
It is the first Baiji reportedly found in the Yangtze since the scientific expedition last year, during which no single Baiji was spotted.
Based on the river's geographic and hydrological complexity and the official definition of extinction by IUCN, WWF and many scientists agreed that this species was "functionally extinct", but thought it was still too early to declare its extinction।


"This sighting presents a last hope that the Baiji may not go the way of the dodo bird," said Karen Baragona, Yangtze River Basin Program leader at World Wildlife Fund. "Other species have been brought back from the brink of extinction like the southern right whale and white rhinos, but only through the most intensive conservation efforts."
WWF has been actively involved in the protection of cetaceans and their habitat in the Yangtze River. "WWF calls for immediate joint efforts to provide a living space for this beautiful animal, which is a key species indicating the health of its habitat -- the Yangtze River. To be effective, efforts must address agriculture, water resources, transportation, environmental protection and sanitation to reduce human disturbance and protect the cetaceans in the river," Baragona said.
Last year, WWF cooperated with other stakeholders to finish drafting a protection strategy and action plan to improve the protection capacity of nature reserves.
"Protections will be implemented under the WWF program to conserve the Baiji and the Yangtze together with related stakeholders," Baragona added.
Note: This story has been adapted from a news release issued by World Wildlife Fund.

Friday, August 31, 2007

New hope for Chinese dolphin thought probably extinct

A creature believed to be the rare Chinese white dolphin has been sighted in the Yangtze river, an expert said Wednesday, renewing hope for a mammal recently declared as probably extinct. Video footage by a resident of eastern Anhui province purportedly taken this month appears to show the critically endangered white dolphin, known in China as the "baiji", frolicking in its native Yangtze habitat, said Wang Ding, one of the world's leading authorities on the species."We cannot confirm it 100 percent but it looks pretty much like a baiji," Wang, a researcher with the Chinese Academy of Sciences, told AFP.Wang led a survey by scientists from around the world last year in search of the dolphin which came up empty, and he told AFP earlier this month the 20-million-year-old species was "likely extinct."But he said the new sighting means there is hope. "If there is one, then we have more there," he said.The Anhui resident, Zeng Yujiang, was quoted by Xinhua news agency as saying he filmed the dolphin, easily identifiable by its long, tooth-filled snout and low dorsal, along the banks of China's longest river on August 19.Devastating pollution, illegal fishing and heavy cargo traffic on the Yangtze have been cited as key factors in the demise of the species.Up to 5,000 baiji were believed to have lived in the Yangtze less than a century ago, according to the baiji.org website, a conservation group.Wang said he planned to search for the dolphin along the stretch of river where the footage was purportedly shot.Although the sighting will likely renew hopes for the long-term survival of the baiji, experts say at least 50 of the animals will be needed to prevent the gene pool from irrevocable degeneration and eventual extinction."The problem is if we don't do something, the animal will be gone for sure, and quite soon," Wang said. "If we have 50 of them, that would be very good. But we can't expect too much."Wang also said another creature, believed to be the finless porpoise, appeared to be swimming along with the white dolphin.The finless porpoise is also endangered but not as critically as the baiji.The last confirmed count of the white dolphin by a research team was conducted in 1997, when just 13 were recorded.The baiji.org website blames illegal fishing and massive discharges of industrial and agricultural waste into the river.Other rare species that live in the Yangtze, such as the Chinese sturgeon and the finless porpoise, also face possible extinction.

Friday, February 09, 2007

Japanese tech may save India's river dolphins

NEW DELHI (Reuters) - Japanese technology to track and monitor the behavior of India's endangered Ganges River Dolphins using underwater acoustics will play a vital role in efforts to conserve the freshwater mammals, the WWF-India said. The Gangetic cetaceans are one of only four species of dolphins in the world which inhabit rivers and lakes and are much less common than their marine counterparts, numbering only around 2,000 in India, according to the conservation group.Over the last 25 years, their numbers have halved -- trapped in fishing nets, hunted for oil, dead from pollution or the construction of dams along the Ganges river which stretches from the northern Himalayas to India's east.WWF-India said researchers from the University of Tokyo have developed an underwater acoustic device or hydrophone which measures the individual sonar pulses or the clicking sounds emitted by the dolphins which are as unique as fingerprints.>From this, they can locate the dolphin from up to one kilometer (0.6 miles) away and track its movements. "The problem in studying the dolphins is that they are under the water and it is very difficult to monitor or identify them," Sandeep Behara, from WWF-India's Freshwater and Wetlands Programme told a news conference late on Thursday."Now we can identify their individual clicks and get an idea of populations, analyze their behavioral and migration patterns and feeding habits ... this will help in conserving the animals," he said.The dolphins are blind and emit sonar pulses in order to navigate and find their prey along the Ganges and Brahmaputra river system, which stretches across 6,000 km (3,730 miles) and spills into the Bay of Bengal.Tamaki Ura, head of the Underwater Technology Research Center at Tokyo University, said the hydrophones would not harm the mammals."The hydrophones are totally passive sonar instruments which do not make any sound and do not impact the dolphins," said Ura. WWF-India said the findings of such research will broaden knowledge of conservationists about the river dolphins and help focus initiatives aimed at saving the threatened mammals.