India conducts first official survey of Ganges dolphins

Conservation programme aims to protect the endangered species and restore biodiversity of the polluted river, reports The Straits Times

Nirmala Ganapathy for The Straits Times, part of the Climate Publishers Network

Tuesday 28 July 2015 11.22 BST

The conservation of dolphins in India’s holiest, but most polluted waterway, is under the spotlight as the country conducts its first official count of the freshwater species.

An estimated 450 volunteers, government experts and conservationists will take part in the exercise, which spans the states of Jharkhand, Uttar Pradesh, Bihar and West Bengal, in November and December.

“This is the first time a unified survey will be done for an aquatic animal. It has been done for elephants and tigers but this is more complicated,” Dr Sandeep Behera, consultant at the government’s National Mission for Clean Ganga, told The Sunday Times. “We are doing the survey in winter, when water levels drop and we can capture numbers in small isolated pockets and get a good idea of the population.”

The government also hopes to gauge the health of the river in the process. “This time we have taken aquatic biodiversity as an indicator of how pollution is affecting the Ganges,” said Dr Behera.

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Improved monitoring gives Ganges river dolphin better survival odds

Using a combined visual-acoustic survey method could be a more effective way of monitoring the endangered Ganges river dolphin scientists have found.

Previously it was believed that visual survey methods - reliant on conservationists spotting and recording surfacing dolphins - were the most cost-effective way of surveying the species. The study revealed that detecting the sound that dolphins emit using a method called a combined visual-acoustic survey, can improve the ability to detect population trends and reduce survey costs.

Scientist Nadia Richman from the zoological Society of London (ZSL) said: “Freshwater cetaceans occupy some of the most densely populated and polluted river systems in the world. We need to make decisions about the best way to manage these species before another becomes extinct. However, these decisions need to be based on evidence which means we need methods that can detect changes in population size in the quickest time possible and for the least cost.”

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An Ancient Biosonar Sheds New Light On the Evolution of Echolocation in Toothed Whales

Apr. 4, 2013 — Some 30 million years ago, Ganges river dolphins diverged from other toothed whales, making them one of the oldest species of aquatic mammals that use echolocation, or biosonar, to navigate and find food. This also makes them ideal subjects for scientists working to understand the evolution of echolocation among toothed whales.

New research, led by Frants Havmand Jensen, a Danish Council for Independent Research / Natural Sciences postdoctoral fellow at Woods Hole Oceanographic Institution, shows that freshwater dolphins produce echolocation signals at very low sound intensities compared to marine dolphins, and that Ganges river dolphins echolocate at surprisingly low sound frequencies. The study, "Clicking in shallow rivers," was published in the journal PLOS ONE.

"Ganges River dolphins are one of the most ancient evolutionary branches of toothed whales," says Jensen. "We believe our findings help explain the differences in echolocation between freshwater and marine dolphins. Our findings imply that the sound intensity and frequency of Ganges river dolphin may have been closer to the 'starting point' from which marine dolphins gradually evolved their high-frequent, powerful biosonar."

The scientists believe these differences evolved due to differences in freshwater and marine environments and the location and distribution of prey in those environments.

Continued:  http://www.sciencedaily.com/releases/2013/04/130404152625.htm

Gangetic dolphin survey in Uttar Pradesh provides some good news

10% increase in Gangetic dolphins 

October 2012. WWF-India, in partnership with the State Forest Department of Uttar conducted a 3 day survey and awareness program in and around Uttar Pradesh to raise awareness about the Ganges River Dolphin. The survey, the total number of Gangetic dolphins in UP rose from 600 in 2005 to 671. In an earlier WWF-India report, the population of Gangetic dolphins in 1982 was estimated to be around 4000-5000 in India, but it is now less than 2000 with an annual mortality estimated to be at 130-160 animals.

The campaign involved the following activities:

A survey of the number of dolphins across approximately a 3000km stretch of the Ganges and its key tributaries (Yamuna, Son, Ken, Betwa, Ghagra, and Geruwa)

Awareness programs for local communities in and around the banks of the Ganga for the conservation of the aquatic mammal

Capacity building of stakeholders associated with the conservation of the Ganges River Dolphin

Ganges River Dolphin

The Ganges River Dolphin, one of the four freshwater dolphins of the world, commonly known as the "Susu" or "Soons" is an endemic fauna of the Ganges, Brahmaputra, and Meghna river systems. The Ganges river dolphin prefers to stay in the deep waters in and around the confluence of two or more rivers. 'Susu' shares its habitat with crocodiles, freshwater turtles and wetland birds many of which are fish eaters and are potential competitors with dolphins. Often known as the "Tiger of the Ganges" the river dolphin is an indicator animal, which has the same position in a river ecosystem as a tiger in a forest

The survey was carried out under the aegis of the HSBC- supported Rivers for Life, Life for Rivers program.

http://www.wildlifeextra.com/go/news/gangetic-dolphin-survey.html

Three new wildlife sanctuaries - Bangladesh

The government of Bangladesh has created three new wildlife sanctuaries for the endangered Ganges River and Irrawaddy freshwater dolphins, the last two remaining species of freshwater dolphins in Asia.


Working with the New York-based Wildlife Conservation Society (WCS) to identify key habitat for the dolphins, Bangladesh officials created the sanctuaries in the Sundarbans, the world’s largest mangrove ecosystem. The three sanctuaries will protect the dolphins in 19.4 miles of mangrove channels with a total of 4.1 square miles — a small area that WCS biologists characterized as the start of a wider effort to save the dolphins. No precise numbers exist on the number of remaining Ganges River and Irrawaddy dolphins, although in 2009 WCS scientists discovered a population of roughly 6,000 Irrawaddy dolphins. The two dolphin species have suffered severe population declines because of fatal entanglements in fishing gear and the depletion of their prey as huge amounts of fish and crustaceans are caught as by-catch in fine-mesh “mosquito” nets used to catch fry for shrimp farming. A third Asian species of freshwater dolphin, the Yangtze River dolphin in China, recently went extinct. 


http://e360.yale.edu/digest/endangered_freshwater_dolphins_to_be_protected_by_bangladesh_sanctuaries/3336/