The Population Of Gharial: Important Facts And Figures

What is a Gharial?

The gharial is a crocodile species that is native to the Indian subcontinent, where it prefers open water habitats. It is also known as the fish-eating crocodile, Indian gavial, and long-nosed crocodile. This species can be differentiated from other crocodiles by its long, thin nose which has a bulbous point. It has an average length of between 11 and 15 feet and an average weight of between 350 and 550 pounds, although specimens have been recorded at much larger sizes. This reptile spends most of its time in the water and is unable to walk across land with ease as other crocodiles do, moving instead with a sliding action. Its diet consists almost exclusively of fish, although the gharial may also consume some insects or frogs. The unique shape of its nose helps the gharial fight water resistance, allowing it to catch its food source. When breeding, this species build nests within the sandbars of large, slow-moving rivers.

Conservation Status

The gharial could once be found throughout all of the large river systems and waterways on the Indian subcontinent, from the Irrawaddy river in Myanmar to the Indus river in Pakistan and the Ganges Basin in between. In the late 19th century, researchers reported seeing large groups of gharial along 6,835 miles of rivers over a total area of 7,722 square miles. Scientists believed the global population size of this species to be somewhere between 5,000 and 10,000 at this time.

Today, however, the gharial inhabits only 2% of its historical range in largely fragmented subpopulations. It can no longer be found in several rivers including the Brahmaputra river, the Indus river, and the Irrawaddy river. Its population size is currently recorded as only around 182 in the wild. This number represents a 96 to 98% population decline between 1946 and 2006. Additionally, this loss of the gharial population is expected to continue at a rate of 25% over the next generation. These factors have prompted the IUCN to list the conservation status of the gharial as critically endangered on the Red List.

Threats

This species faces a number of threats including poaching, fishing, agriculture, and habitat destruction.

Gharial poaching was once a much larger problem than it is today. Previously, this species was valued for its skin, which was used to make leather products. Additionally, the gharial was killed, preserved, and mounted on displays as a trophy. While this practice has decreased, this species is still valued in traditional medicine. Many local communities in Nepal, and to a smaller extent in India, believe the bulbous nose, penis, and fatty tissue of the gharial hold medicinal properties. Many other communities continue to seek out gharial eggs as a delicacy. Between 2001 and 2005, nearly all of the gharial nests along the Girwa river were disturbed and the eggs were taken for human consumption.

The fishing industry also poses a threat to the remaining gharial population. In order to catch a large number of fish, humans cast gill nets into the waters. These nets are deadly to the gharial and once they are caught, the reptile is unable to surface for air.

Subsistence agriculture and livestock grazing disturb the sandy banks used by gharial for basking and breeding. During the dry season, which corresponds to gharial mating season, local farmers move their crops and livestock closer to river edge in order to increase access to water. This movement infringes upon gharial territory and damages their nests.

This species has also been subjected to significant habitat destruction and loss. As the human population continues to grow and development efforts increase within these countries, gharial habitats are increasingly fragmented and altered. Dams pose a significant threat by blocking waterways, leaving gharial populations further separated and in ever-decreasing habitat ranges. As previously mentioned, this species is unable to walk long distances across land in search of water as are other crocodiles.

Gharials in the Wild

As previously mentioned, the recorded number of mature gharial living in the wild is only 182. These individuals inhabit 8 separate and fragmented habitats throughout Nepal and India. Additionally, researchers believe that approximately 14% of this population erroneously includes non-mature males, which would drop the actual mature population size to 157. This number is estimated by counting gharial nest locations, which provides a more accurate count of the mature population size.

The remaining gharial of India can be found in the waterways of several protected areas, including the: Katarniaghat Wildlife Sanctuary, Son River Sanctuary, National Chambal Sanctuary, Corbett Tiger Reserve, and Satkosia Gorge Sanctuary. In the Corbett Tiger Reserve, researchers recorded a population of around 100 in 2008, although many of these have since been lost. Gharial found within the rainforest biome in the Satkosia Gorge Sanctuary are not active breeders. The largest actively breeding population is believed to inhabit the Chambal river in the National Chambal Sanctuary. In 2006, researchers counted a total of 68 nests here. The second largest breeding population is found in the Katarniaghat Wildlife Sanctuary, where 20 nests were identified in the same year.

The total mature gharial population in Nepal is around 35 and 6 nests were recorded here in 2006. Subpopulations can be found in the Karnali-Babai and Narayani-Rapti rivers of Nepal within the Bardia National Park and the Chitwan National Park, respectively. The gharial living in the Karnali-Babai and Kosi rivers are believed to be non-reproducing.

Gharials in Captivity

Gharials are also being kept in captivity across the world at zoos, biological parks, and sanctuaries. These centers can be found in India, Nepal, the US, Europe, Singapore, Sri Lanka, and Pakistan. Both the Gharial Breeding Center in Nepal and the National Chambal Sanctuary in India have active captive breeding programs. Once these gharial reach between 2 and 3 years of age, they are either sent to other zoological parks or released into the wild. To date, captive-bred gharials released in the wild have not successfully reintegrated. Unfortunately, data was not collected on these captive-bred populations and little is actually known about the behavior and adaptation processes of released gharials.