Crocodile Chronicle

The Gharial Breeding Centre in Chitwan National Park has for decades played a critical role in saving the endangered fish-eating crocodile from extinction. Now, the gharial faces a different set of challenges.

Climate breakdown is raising the temperature of Nepal’s plains. The Narayani and Rapti Rivers that flow through Chitwan National Park are increasingly polluted. Gharials are often trapped in fishing nets and die. And the reptile has a sex problem.

In nature, the gharial’s sex ratio is already skewed, with 8 females for every male gharial. Now, climate change may be widening this gender gap.

In fact, during a recent visit the breeding centre had only one male among 32 adult gharial. The male gharial has a distinct bulbous growth at the tip of its snout, which only develops when the reptile reaches adulthood.

“It is as if the gharial as a species is predisposed to struggle in its natural habitat,” says Prem Poudel of WWF Nepal, whose Terai Arc Landscape (TAL) program supports conservation in protected areas. "The eggs hatch in July, right in the middle of the flood season.”

Gharials lay up to 90 eggs at a time in deep pits along the sandy banks of the Narayani and Rapti in spring. It is only later when growths appear on their snouts that breeders can confirm if they are male or female.

Research has shown that if gharial eggs are incubated at higher temperatures, more of them are female when they hatch. This is how global warming could be skewing the sex ratio even more towards female.

The breeding centre in Kasara hires Bote fisherfolk indigenous to the area as nest watchers to locate and collect eggs. The eggs are then incubated until they hatch.

This year, the breeding centre collected 247 eggs, out of which 195 hatched. The gharial are released when they are five years old.

Over the years gharials have been released into Chitwan’s rivers, but also in the Karnali and Babai that run through the Bardia National Park. In 2019, conservationists discovered the first nesting site of 100 gharials hatchlings in the Babai, and in 2022, 28 baby gharial were found in a tributary of the Karnali.

Besides the 32 adults at the breeding centre, there are currently 759 hatchings, sub-adults and juvenile gharial. Meanwhile, 265 gharial were counted last December in their natural habitat inside Chitwan National Park, 152 in the Rapti and 113 in the Narayani. Of them, only six are male, three in each of the rivers.

“When we opened the national park, we directed our attention almost exclusively on Nepal’s declining tiger and rhino populations,” recalls Ram Prit Yadav, who was a ranger in the late 1960s even before Chitwan National Park was established, and became its first warden. “It was only later that we realised the wealth of the biodiversity here, including the gharial.”

Yadav subsequently led efforts to launch the Gharial Breeding Centre, which was established in 1978. Since then, the gharial population has rebounded but their numbers have declined in the Narayani River mainly due to upstream pollution.

There are only few male gharial in nature, and they can only be distinguished by the bulbous growth on their snout. Photo: JUSTIN GRIFFITHS

Meanwhile, in the Rapti, the gharial population has been increasing because the river flows mostly inside the national park where illegal fishing and pollution is monitored. Translocated gharial have not fared as well in the Kosi and Kali Gandaki.

Despite this, Yadav considers Nepal’s efforts to save this unique crocodile a success.

“The government has put a lot of effort into protecting the gharial, now it is up to us to help,” says Yadav. “Gharials have now established a strong presence in the Rapti, and in Bardia, Banke and Suklaphanta. This is a testament to Nepal’s conservation effort. ”

The Department of National Park and Wildlife Conservation (DNPWC) and the Department of Forests collaborated with conservation partners and local communities, to draw up the Gharial Conservation Action Plan (2018-2022) to further breeding research.

Even so, conservationists worry about Nepal’s ability to maintain and increase the country’s gharial numbers because of the accelerated destruction of Nepal's riverine habitat from sand-mining, factory effluents, and competition with humans for fish.

Says WWF’s Poudel: “There were gharials in all major river ecosystems in the past. Human settlement, river pollution, and dams contributed to them becoming critically endangered.”

Gharial often get tangled in the traditional nylon fishing nets used illegally by locals. In 2023, a male gharial was found dead in a tributary of the Rapti River after it was snagged on one such net.

The construction of dams and barrages like the one on the Gandaki on the Indian border prevent gharials from swimming back upstream when they are swept down in the monsoon.

Says Yadav. “In the long run, we must ensure that these critically endangered animals have clean rivers to thrive in, plenty of fish to feed on, and are not at the risk of being swept downstream.”

National park officials here worry that tigers and rhinos get all the media attention, overshadowing gharial conservation — which means the budget for the breeding centre does not get a priority.

“We are tasked with the responsibility of rearing and conserving these animals, but funds are decreasing,” a conservation official told us. “We even have to ration meals for the gharial.”

Even Yadav acknowledges that Nepal cannot go it alone to protect these rare reptiles for much longer: “Climate change is throwing the sex ratio out of balance, so our conservation effort must extend beyond Nepal’s protected areas to the international stage.”