Radio tagging attempt to save critically endangered crocodile

Chitwan, Nepal – Fourteen gharials fitted with radio tags have been released into the Rapti River in Nepal in an attempt to identify the reasons for the alarming decline in population of this critically endangered member of the crocodile family.

The tagging, carried out by Nepal’s Department of National Parks and Wildlife Conservation in collaboration with WWF-Nepal, is also intended to study the movement pattern of the gharials, to assess its survival rate and find out about its preferred habitat in Nepal.

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The gharial, which mostly inhabits deep, fast-flowing rivers, is characterized by its long and slender snout whose fragile jaws render it incapable of devouring any large animal including human beings. Its name derives from the protruberance at the end of the adult male’s snout that resembles a Ghara, an earthen pot common to India and Nepal.

The gharial is the first crocodilian species to be re-categorized as Critically Endangered on the 2007 IUCN Red List. With an inferred population of 5,000 to 10,000 in the 1940s, its numbers plummeted due to organized hunting for skin in the 1950s and 1960s, which led to a scattered and isolated population in India, Nepal, Pakistan and Bangladesh.

Although hunting is no longer a threat, the construction of dams, barrages, irrigation canals, sand-mining and riverside agriculture have all resulted in the irreversible loss of habitat for the gharial. Between 1981-2008, 691 gharials were released in the Narayani, Rapti, Karnali, Babai, Koshi and Kali Gandaki rivers but numbers continue to dwindle. A 2008 survey found just 81 individuals in the various rivers of Nepal, the number probably boosted by the release of captive-bred gharials.

The gharial is now considered to be confined to the river systems of the Brahmaputra (India and Bhutan), the Indus (Pakistan), the Ganges (India and Nepal), and the Mahanadi (India), with small populations in the Kaladan and the Irrawady in Myanmar.

The 14 gharials released into the River Rapti this week had transmitters attached to the scutes on their tails and each gharial has been given a different number and radio frequency. They will be monitored by Radio Frequency Identification (RFID) technology by a team from Chitwan National Park. 

WWF's Country Representative to Nepal, Anil Manandhar, said: “The study will help diagnose the causes of decline in the gharial population. It will also help us better understand the gharial’s habitat use, knowledge that is crucial for saving the most threatened crocodile in the world.”

Sarala Khaling, regional co-ordinator of the Critical Ecosystem Partnership Fund which has jointly funded the project with WWF, said: “Although conservation efforts such as the tagging and release of gharials are important steps in saving the species, a lot more is needed to ensure its long-term survival. 

“Integrated efforts that include captive breeding, research and monitoring, and especially safeguarding gharial habitat and prey, are urgently needed.” 

The monitoring of the released gharials will be helpful in formulating a long term conservation action plan to save them. “The water quality of Nepalese rivers is better suited for the gharial’s survival,” said Dr Antoine Cadi of the French NGO Awely which helped the team from Chitwan National Park to fit the gharials with radio transmitters. “If they are not saved in Nepal, they will be closer to extinction.”