- In the 1970s, gharial populations had declined by about 96% across their entire distribution range in the Indian subcontinent. The government launched a crocodile conservation project, establishing five crocodile sanctuaries, including the Katraniaghat Wildlife Sanctuary which houses a part of the Girwa river.
- Intensive captive breeding and habitat protection played a crucial role in reviving gharial populations momentarily, with numbers plummeting again soon after, exacerbated by changes in river flow and vegetation.
- Vegetation removal, creation of artificial sandbanks and other measures have been initiated in the recent years to boost their numbers, and ensure their long-term survival.
In Uttar Pradesh’s Bahraich district, the Katarniaghat Wildlife Sanctuary (KWS) appeared on the conservation map in the 1970s owing to its role in safeguarding the future of the Critically Endangered gharial. It was only a matter of time, however, until anthropogenic and environmental pressures caused a decline in their numbers yet again. Recently, new measures have been initiated to revive the resident gharial population and is already showing results. The collective efforts of local authorities and conservationists caused gharial nest numbers in KWS rise to 36 in 2022, from 19 in 2019.
Gharials are endemic to South Asia. Historically, they were found in the riverine ecosystems of India, Pakistan, Bangladesh and southern parts of Bhutan and Nepal. According to the International Union for Conservation of Nature (IUCN), an estimated 5,000 gharials could be found in the wild in the 1940s. By 1976, there were less than 200. In India, this fish-eating reptile was on the brink of extinction at the time, with populations dropping by about 96% across its entire distribution range.
Concerned, the government launched a crocodile conservation project in 1975, with a goal to increase the numbers of India’s three crocodilian species – the freshwater crocodile, gharial and saltwater crocodile. They began breeding and rearing them in captivity, and then releasing them in the wild.
Gharials are top predators and keystone species in running freshwater systems. They play a crucial role in bringing nutrients from the bottom of the riverbed to the surface, thus increasing fish populations and helping maintain the aquatic ecosystem. “Of the three crocodilian species, the gharial is the most efficient fish catcher because of its unique snout. It derives its name from “ghara”, the Indian word for pot, because of a bulbous knob present at the end of its snout,” says Akash Deep Badhawan, a divisional forest officer at KWS.
A success story from the 1970s
KWS was among the first five sanctuaries declared since the project began, as it was home to gharial populations breeding in the Girwa river. Established between 1975 and 1982 along with KWS were the National Chambal Sanctuary, Satkosia Gorge Wildlife Sanctuary, Son Gharial Sanctuary and Ken Gharial Sanctuary. By 1991, about 12,000 gharial eggs were collected from the wild and captive breeding nests were set up. Over 5,000 juveniles were released back into rivers. Of these, 3,500 juveniles were released in the National Chambal Sanctuary, the largest gharial reserve in the country, spread across Uttar Pradesh, Madhya Pradesh and Rajasthan.
“Eggs were sourced from here [KWS] and sent to the Kukrail Gharial Rehabilitation Centre in Lucknow. Once they incubated, hatched and reared, juveniles were reintroduced into rivers across India, including Ramganga in Corbett National Park,” says Gaurav Vashistha, a wildlife biologist who is leading a Conservation Leadership Programme to conserve gharials in India, particular in Katarniaghat.
The project was effective – gharial numbers rose to 1,500. In 1991, the Union Ministry of Environment and Forests withdrew funds, which stopped the captive breeding and egg collection programmes.
Slowly, the numbers began to fall again. The adult population nosedived, with a 58% reduction across its range in just nine years, from 1997. Today, it is estimated at around 800, globally, according to WWF-India. The gharial now survives only in the waters of India and Nepal. In India, they are found within the tributaries of the Ganga: Girwa (Uttar Pradesh), Son (Madhya Pradesh), Ramganga (Uttarakhand), Mahanadi (Odisha), Gandak (Bihar), and Chambal (Uttar Pradesh, Madhya Pradesh and Rajasthan).
Ecosystem changes and their impact
Part of the Girwa river that runs through KWS has a large gharial population, estimated at more than 70 in 2022. They are restricted to a 20 kilometre stretch since the damming in 1976 (Girijapuri barrage). The barrage gates are opened annually for maintenance and during the monsoon. “It functions as a one-way exit for gharials, particularly juveniles, who are unable to return when the gates are closed,” says Vashistha. As a result, KWS has historically had low juvenile recruitment.
In 2010, however, a natural channel shift occurred in the upstream part of the Karnali river in Nepal. It reduced the water flow in the Girwa stretch where gharials nest. In response to the mainstream channel shift, a small resident freshwater dolphin population moved into the adjoining Kaudiyala channel where the flow was greater and the water deeper than in the Girwa. The gharials in the Girwa, however, did not shift.
The reduced flow also caused rapid vegetation growth on sandy substrates. To understand its impact on gharial nesting, a study was conducted at these sites from 2017 to 2019. In areas with sandbars – where the gharial basks, nests and lays eggs – had transitioned to woody cover, the number of nests had reduced by more than 40%.
Renewed conservation efforts
Once the causes of gharial population decline were identified, forest authorities and researchers collaborated to initiate protection measures for the gharial and its habitat. The Gharial Conservation Programme was launched to study the isolated and wild breeding gharial population in KWS and nearby aquatic habitats. “The goal is to identify potential gharial habitats and associated threats, and work with stakeholders to establish a long-term monitoring and conservation plan,” says Badhawan.
Vegetation removal was initiated in 2019 to augment nesting opportunities at previous and potential nesting locations. Sandbanks were artificially constructed in 2020. “It is an efficient restoration method. We do not aim to implement it annually. It can, however, provide additional protected habitat to help gharials explore and breed naturally. This year, we also plan to ensure higher survival of hatchlings by captive holding during floods in the monsoon,” says Vashistha.
Natural breeding and external augmentation or facilitating the improved health of the gharial’s habitat increased the population and nest counts to 70+ and 36 in 2022, respectively. Last year also saw a hatching success rate of 93%. However, the problem of anthropogenic pressures persist. “Large rivers have already been altered by dam construction and/or water extraction. Although gharials do breed in such modified habitats, nesting sites are often limited and the river-reservoir habitat does impose constraints. At KWS, we want to focus on extending protection and identifying new habitat areas so that new nesting site options are explored. We are also looking to maintain and further increase nesting efforts within the resident population, and boost hatchling survival and juvenile recruitment,” says Vashistha.
In the meantime, KWS is back on the tourist map and brings in wildlife enthusiasts from all over the country. “It is Terai’s best-kept secret, full of sal and teak trees, and wetlands. It is arguably one of the best places in the country to see the gharial, the Gangetic dolphin and saltwater crocodile in a single habitat, and learn more about them,” says Seema Sharma, a wildlife enthusiast who travelled from Mumbai to see them.
Banner image: A hatchling emerges from an egg. Photo by Gaurav Vashistha.