Three decades after it was brought back from the brink of extinction, the rare Indian crocodile, known as the gharial, is turning up dead by the dozens on the banks of River Chambal. Forest officials are at a loss to explain why.
Since mid-December, the National Chambal Wildlife Sanctuary has confirmed 76 deaths along the river, which begins in Madhya Pradesh and runs through Rajasthan and Uttar Pradesh.
Gadiraju Sudhakar, a Chambal district forest officer, said the initial post-mortem reports suggested the cause of death to be liver cirrhosis and stomach ulcers. Further tests show lead levels in the liver that "though not toxic, can trigger suppression of the immune system," Sudhakar added.
All the more puzzling, other species that inhabit the Chambal River ecosystem, including dozens of fish species on which the gharials feed, appear to be healthy.
Follow-up tests on the fish also revealed heightened lead content. But in both the fish and the gharials, the lead levels are below levels considered lethal, the forest official said. Environmentalists are pressing forest officials for answers on the source of the lead and why the crocodiles died while their prey were unaffected.
The gharial, native to South Asia, is one of the most endangered freshwater crocodile species. The World Wildlife Fund believes it is extinct in its former habitats of Pakistan, Bhutan and Myanmar.
An estimated 1,300 gharials are left in the wild, mostly in India, according to the fund. The World Conservation Union has recently upgraded it from being an "endangered" to a "critically endangered" species.
The recent deaths have further depleted the stock of breeding pairs to less than 200, conservationists and the Forest Department believe. The Indian Government, under pressure from conservationists, set up protected areas in 1979 along the Chambal River to prevent poaching of their skin for high-grade crocodile leather, and it raises eggs in captivity to protect them from predators.
The Chambal is one of the cleanest rivers in the country, according to the Central Pollution Control Board in New Delhi. The Forest Department suspects that a possible source of lead could be the Yamuna River, which gathers industrial waste from the capital and several nearby industrial towns and meets the Chambal further downstream.
Fish swim upstream in search of cleaner water, particularly during the monsoons.
No tests have been carried out yet to determine the source of the lead. Devendra Swarup, head of the veterinary medicine department at the Indian Veterinary Research Institute in Izatnagar, Uttar Pradesh, which conducted the liver tests on the dead gharials, emphasised the need for international expertise on this issue, which, if unresolved, could have "dire consequences" for the future of Indian wildlife.
Conservationists say the gharial deaths are important because they could be the first sign of river contamination and of potential threats to the rest of the ecosystem.
Saher Mahmood New York Times
