India: Lost Borna snakehead rediscovered after 85 years

The Borna snakehead Channa amphibeus, also known as the Chel snakehead, has been rediscovered in India’s Himalayan region. The species was regarded as one of the rarest and hardest-to-find snakehead species in the world, and scientists had already suspected that it was extinct.

A research team led by Jayasimhan Praveenraj and Tejas Thackeray of the Thackeray Wildlife Foundation (TWF), a non-profit research and conservation organization based in Mumbai, has now documented the species again on the banks of the Chel River in Kalimpong, North Bengal. As reported in the journal Zootaxa, the last documented sighting of this species dated back to the early 20th century.

C. amphibeus was recorded exclusively in the Chel River, part of the Brahmaputra basin, in 1840, 1845 and 1938. After that, it was considered lost for more than eight decades. The last known specimens were collected by the naturalists G. E. Shaw and E. O. Shebbeare between 1918 and 1933. Despite several scientific surveys in its known range, the species could not be documented again for a long time.

What are snakeheads?

Snakeheads (Channidae) are predatory freshwater fishes represented by more than 50 species in Asia (Channa) and Africa (Parachanna). In Asia alone, 37 snakehead species are known, many of which are exported as ornamental fish. Their evolutionary history goes back more than 50 million years, with an origin in the Himalayan region. Climatic changes such as the intensification of the Asian monsoon favored their spread.

Snakeheads are known for their ability to take up atmospheric oxygen via a suprabranchial organ, which allows them to survive in oxygen-poor waters and even to make short journeys over land. Their flat, elongated head resembles that of a snake, which gave them their name. Some species have earned a reputation as invasive “monster fish” because of their adaptability and aggressive hunting behavior.

New records in 2024

In September 2024, the research team succeeded in collecting three specimens of the Borna snakehead and preserving them for later study. Additional photographic records supplemented the discovery. The scientists received clues about the species from the Rabha, an ethnic group living along the Chel River, who reported having eaten a snakehead. Because of the historical records from this region, the research team traveled to the site.

Identifying the supposedly extinct fish species took four months, because the scientists had to compare the fish’s characteristics with earlier records. Biometric measurements, such as eye diameter, helped confirm that the species was indeed identical to the specimens last seen in 1938.

With a body length of 80 to 100 centimeters, the Borna snakehead is among the largest snakehead species. The genus includes both dwarf forms only 25 centimeters long and specimens that can grow to more than one meter. Like all snakeheads, this species is an obligate air-breather that depends on atmospheric oxygen for respiration.

Significance of the rediscovery of Channa amphibeus

This rediscovery is of major scientific importance. For the first time, biometric and genetic data could be collected. In addition, there is now the first image of a living specimen of C. amphibeus, which local tribal communities call “Bora Chung.” The species is characterized by iridescent green scales and a yellow stripe, features that distinguish it from other snakeheads.

The research team now plans to investigate the reproductive behavior of the Borna snakehead and develop conservation measures. It also intends to analyze possible threats resulting from environmental change.

Threats and conservation measures

At present, no specific threats to the Borna snakehead are known. However, the International Union for Conservation of Nature (IUCN) points out that habitats in mountain streams are affected by sedimentation resulting from deforestation and agricultural practices. This may have contributed to the decline of C. amphibeus populations in the past.

The rediscovery of this species also raises questions about population size and ecological resilience. While snakeheads are known for their high adaptability and some species have already been documented as invasive, it remains unclear whether the Borna snakehead, with its low population density and restricted range, could play a similar ecological role. The results of the new study underscore the need for further research into population size as well as potential threats from habitat loss and environmental change.

According to the researchers, this rediscovery is not only a gain for biodiversity, but also underscores the urgent need for greater efforts to protect the species.