The population of gharials, a critically endangered species, has steadily increased along the Gandak river. Photo by Subrat Kumar Behera.

The gharial reinforcement project

“Despite available knowledge about gharial population in the Gandak, little effort was made to document and implement conservation measures until the survey supported by WTI and other conservation organisations documented presence of about 15 gharials in the Indian stretch of the river in 2010 and proposed conservation measures including strengthening of the remnant population,” said Samir Kumar Sinha, the head of species recovery division, WTI.

The work for the conservation started in 2014 when WTI and Bihar Forest Department jointly started the gharial reinforcement project in the river Gandak. Around 30 captive-born and reared gharials from the Sanjay Gandhi Jaivik Udyan (Patna Zoo) were released in the Gandak, followed by post-release monitoring.

“The release stock comprising of sub-adult individuals (3 males and 27 females) was examined for health condition and acclimatised by providing live fish as food for six weeks to allow for inculcation of hunting skills in them. Prior to transportation, each individual was sexed and marked,” he said. Gharials are marked by distinctive marks in the bony part of their tail. “Two individuals were fitted with satellite transmitters, while VHF [Very High Frequency] tags were implanted on four individuals for remote monitoring.” A VHF tag is a transmitter that sends out signals that can be picked up by a corresponding receiver.

Six months after their release, monitoring results found 60 percent (18 out of 30) of the released gharials surviving in the wild. The team also spotted several gharials released by Nepal almost 75-100 kilometres from their release site. “We also found the captive-born and released gharial had started sharing the habitat with wild individuals. This showed the presence of habitat selection instinct in the captive-born and reared gharials,” said Subrat Kumar Behera, assistant manager, WTI.

The third and last batch of captive-bred gharials being released in Gandak river. WTI and Bihar Forest Department jointly started the gharial reinforcement project. Photo by Subrat Kumar Behera.

An ideal habitat

More success came in 2016 when the WTI located six nests with 148 eggs in Chiurahia Reta near Ratwal Brige in Gandak. The nests were protected involving locals until successful hatching and the success was approximately 24 percent.

The discovery made the Gandak river the fourth extant breeding site of gharial in the country, in addition to Chambal, Girwa and Ramganga rivers.

In 2018, the team identified the congregation sites in the month of February and two nests with 57 eggs were found near the Ratwal Bridge. Due to bank erosion, the nests were shifted scientifically to a safe distance from the water line in the same site. About 35 percent eggs hatched successfully.

The land-use features have also made Gandak a perfect habitat for the reptiles. The sand banks and bars that are important for basking and nesting activities constitute about 4.49 percent of the area.

Additionally, gharials also use the sand banks or bars with temporary agriculture activity which is about 10.92 percent of the area. The average water depth recorded in the lean season is around 2.64 metres which is sufficient for adults and sub-adult gharials that prefer deeper areas as compared to juveniles and yearlings.

Gandak river was identified as the fourth extant breeding site of gharials in the country, in addition to Chambal, Girwa and Ramganga rivers. Photo by Subrat Kumar Behera.

Gandak also has less fishing pressure as fishing activities are not recorded in more than 55 percent of the stretch. Encounter rate of fishing boat and individuals involved in fishing has been 0.3 and 1 per km respectively.

Moreover, the wetlands associated with the river covering 7,929 hectares area are fish breeding grounds that keep the river replenished with fish resources. The lesser human settlements within 2 km of the banks are temporary in nature and farmers undertake farming only in non-rainy seasons.

H.K. Roy, the field director of Valmiki Tiger Reserve which covers a portion of Gandak said that the state government is serious about increasing the population of gharials and their habitats.

“The Bihar government has sanctioned a budget of over Rs. 27 lakhs (Rs. 270,000) for building a hatchling centre in Motihari and for creating awareness among people, particularly those living in close vicinity of the river, regarding the reptiles,” he said. “We are distributing pamphlets and other material to the locals to inform about gharials and crocodiles as often people get confused and consider the former as dangerous while infact gharials mainly survive on fish and have rarely attacked humans. We are also imparting training to our staff members to spot the gharials using scientific techniques.”

He said that the river is relatively better protected up to 40 km stretch after entering Bihar due to the location of Valmiki Tiger Reserve on the left bank and Sohagi Barwa Wildlife Sanctuary in Uttar Pradesh on the right bank for approximately eight kilometres.

Favourable habitat conditions and a comparatively lesser disturbed river have aided in the conservation of gharials along Gandak river. Photo by Subrat Kumar Behra

The need for conservation policies

But everything is not hunky dory for the gharials in Gandak. Among the prominent challenges for their survival is the Gandak Barrage, as the release of excess water often creates problems for gharials.

In March 2017, increased water level in the river due to opening of gates of the Gandak Barrage submerged the sand banks that destroyed the gharial nesting grounds. In rare cases, small gharials have also known to get caught in fishing nets, resulting in their death.

“There has to be a change in the policy level from the top and authorities must discuss with wildlife experts before releasing water from the barrage as often the nesting sites get destroyed. The nests should be shifted to a higher ground before the water is released. The community level participation is also vital as often nests get destroyed by animals,” said B.C. Choudhury, Crocodile Specialist group member of International Union for Conservation of Nature (IUCN) Species Survival Commission (SSC).

“We have also submitted a proposal to the Bihar government to declare the stretch of the river Gandak as conservation reserve because it also houses endangered species of turtles and dolphins apart from gharials. The government can also develop eco-tourism by facilitating the sightings of gharials and dolphins. It will not only give employment to locals but will also inspire them to protect the gharials,” he added.

He concluded that there are several stretches where human activities prominently affect habitats of aquatic life. This needs to be managed and mitigated to ensure secured habitat to life forms of the river ecosystem.

In March 2017, increased water level in Gandak river due to opening of gates of the Gandak Barrage submerged the sand banks and destroyed the gharial nesting grounds. Photo by Subrat Kumar Behera.

 

Banner image: A gharial basking on the bank of Gandak river, Bihar. Photo by Subrat Kumar Behera.

Article published by Sandhya Sekar
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