Category: Wildlife

Gangetic river dolphins in the Sundarbans struggle with swelling salinity

KV Prasad Jun 13, 2022, 06:35 AM IST (Published)

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Indias national aquatic animal, the endangered Gangetic river dolphin (Platanista gangetica gangetica), is rarely visible in the waterways of the Indian Sundarbans. A study sheds light on the rise in salinity in the water and reduced freshwater flow for the mammals disappearing act in the iconic estuarine habitat.

A survey of a nearly 100-km stretch of the Sundarbans delta in India adjoining Bangladesh, has confirmed the presence of the dolphin populations only in the westernmost segment, in the lower reaches of the river Hooghly, where the salinity is lower than that of natural seawater.

The mammals stayed away from the central Sundarbans, found the survey, where siltation in the waterways has disrupted freshwater flow leading to high salinity levels.

The easternmost part of the Indian Sundarbans having freshwater connectivity with river Padma of Bangladesh is moderately saline but the salinity level increases downstream and the southwest part of Bangladesh Sundarbans is hyper-saline.

Published in the Journal of Threatened Taxa, the survey indicates a “possible decline in the range of Platanista gangetica in the Indian Sundarbans” attributing the extirpation to a triple whammy of elevated sedimentation, reduced freshwater discharge and swelling salinity.

India’s “Dolphin Man”, ecologist Ravindra Sinha agreed with the findings and observed that earlier, in the entire Sundarbans including different water channels and tributaries/distributaries one could spot the Ganges dolphins.

“Gangetic dolphins are obligatory freshwater animals and they never enter the sea. They are found in brackish water zones such those in the Sundarbans estuary. But freshwater flow has declined over the decades and sea water has ingressed, increasing the salinity. They are rarely visible now, whereas once they were plenty,” Sinha, Vice Chancellor Nalanda Open University, told Mongabay-India.

Inhabiting one of the most densely populated regions of the world, the Gangetic river dolphin is one of the only four surviving river dolphins globally, as the Yangtze River dolphin is virtually extinct, noted Sinha, one of the authors of the Conservation Action Plan for the Gangetic Dolphin 2010-2020.

The research team included Sangita Mitra (presently with National Biodiversity Authority, Chennai) and Mahua Roy Chowdhury, a marine biologist from the University of Calcutta, West Bengal.

“Significant increase in salinity levels were documented in the river Ganges in India after the commissioning of the Farakka Barrage,” the study said, referring to the project in West Bengal that began operations in 1975.

Looking at the pan-India scenario, Sinha explained the biggest threat to Gangetic dolphins is the declining flow in the river Ganga as erection of dams and barrages and water-intensive agriculture in the basin contribute to the base flow petering out and fragmenting their habitats.

Records dating to 1879 reveal the freshwater-loving mammals swam along the entire length of the Ganga and Brahmaputra rivers, and all their tributaries from the delta at the Bay of Bengal till the Himalayan foothills. Even in the month of May, when the Ganga was very low, dolphins were seen as far up the Yamuna in Delhi.

(by Sahana Ghosh)

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KV Prasad Journo follow politics, process in Parliament and US Congress. Former Congressional APSA-Fulbright Fellow

8 critically endangered white-backed vultures to be released to the wild

KV Prasad Jun 13, 2022, 06:35 AM IST (Published)

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Eight captive-reared critically endangered white-backed vultures are set to take wings early next year for the first time in India since the vulture conservation centre near here was set up in September 2001.

The Jatayu Conservation Breeding Centre on the edge of the Bir Shikargaha Wildlife Sanctuary is a joint project of Haryana and the Bombay Natural History Society (BNHS) with the British government’s Darwin Initiative for the Survival of Species Fund to investigate the massive decline of three critically endangered Gyps species of vultures in India.

Six captive-bred vultures and two rescued from the wild will be tagged with a 30-gram device for satellite telemetry each with a battery backup of three-four years and this will help understanding their behaviour and survival instincts in the wild, BNHS Principal Scientist Vibha Prakash told IANS here.

He said the vultures would be released most probably by March-April next year in the Bir Shikargaha sanctuary where the BNHS is working to declare it as vulture safe zone, which extends transboundary into Himachal Pradesh where the wildlife awareness among the villagers is quite high.

“If any of the released vulture die or get injured, we can recover them. Satellite telemetry will help us to know the cause of death and prevent other vultures dying from that cause.”

The satellite tags will also be useful in discovering whether the captive-bred birds behave normally in the wild with other closely-related species.

In the first event of its kind in South Asia, the government of Nepal and national and international conservation organisations released critically endangered white-backed vultures in the wild on November 9, 2017.

India is home to nine species of vultures. Three of these species, the white-backed, long-billed and slender-billed vultures, underwent catastrophic population declines of greater than 90 per cent in the mid-1990s. The birds are now listed as critically endangered.

The vulture, a nature’s scavenger, cleans the environment of animal carcasses. Villagers rely on them to dispose of cattle carcasses.

The reason, say biologists, for bringing the vultures to the brink of extinction in South Asia mainly to the extensive use of diclofenac in treating cattle.Vultures that consumed the carcass of animals treated with diclofenac died with symptoms of kidney failure. The Indian government banned its veterinary use in 2006.

BNHS scientist Prakash said “if there is no toxicity-related death of these eight birds in two years, then we will go for release of 20-25 birds each year”.

“We are planning to introduce 100 pairs each of the three species of white-backed, long-billed and slender-billed in the wild in the next 10 years. Before that, findings from the first proposed release batch will be crucial in the future programmes.”

The long-billed and slender-billed vultures will be released in Madhya Pradesh and Assam, respectively.

Officials admit the flight to freedom of these endangered vultures is still caught in red-tapism in the Haryana Forest Department, which has been authorised to procure 10 platform terminal transmitters or satellite telemetries through global bidding.

“These birds have been shifted to the pre-release aviary for over a year and a half. Twice their release was postponed last year. The only hurdle is the procurement of satellite telemetries and that too is bogged down by bureaucratic delays,” an official, requesting anonymity, told IANS.

“The birds are now two to four years old and this is the best age group for their release. The delay in their release will definitely delay the vulture reintroduction programme,” he added.

Prior to this release, two captive Himalayan griffon vultures were released in the wild in June 2016 from the Pinjore centre on an experimental basis.

Both birds were wing-tagged and leg-ringed for identification, but not tagged with satellite transmitters.

It was part of Asia’s first Gyps Vulture Reintroduction Programme under which the captive-bred birds were to be introduced in the wild.

The team managed to monitor one released bird for a day before it disappeared, while the second bird was tracked for almost a month and never sighted again.

The Pinjore centre, Asia’s first centre of its kind, houses 289 Gyps species vultures; 198 of them bred at the facility that is funded by the central government.

Two such conservation and breeding centres are in Rani in Assam and Rajabhatkhawa in West Bengal.

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KV Prasad Journo follow politics, process in Parliament and US Congress. Former Congressional APSA-Fulbright Fellow

San Francisco’s wild parrots roosting across the city

KV Prasad Jun 13, 2022, 06:35 AM IST (Published)

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San Francisco’s famous birds immortalized in the book and movie “The Wild Parrots of Telegraph Hill” are now roosting in several neighborhoods throughout the city, a newspaper reported Saturday.

The parrots are roosting in other neighborhoods beyond their original home on the city’s Telegraph Hill, The San Francisco Chronicle reported.

The original flock of a few dozen squawking birds Mark Bittner wrote in his book have turned into a population of more than 300, according to the bird rescue group Mickaboo. They can be seen flying in formation in small flocks throughout the city now and have been sighted as far south as Brisbane, about 15 miles south of the city.

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KV Prasad Journo follow politics, process in Parliament and US Congress. Former Congressional APSA-Fulbright Fellow