The Snakeheads are a legendary group of fishes. These predators of Asian waterways may not be as famous as the Piranhas of South America but they are formidable hunters in their own right. They belong to the genus Channa, of the family Channidae. The Channidae are members of the Order Perciformes (clade Percomorpha), the most numerous of the vertebrate orders, containing fish as diverse as Archerfish, Barracudas, Cichlids, Gobies, Jacks, Marlins, Perches, Remoras, Swordfish, Tunas and Wrasses. The genus Channa is distributed over Asia, stretching from Iran in the west to Korea in the east. Till recently, it was thought that there were only 35 species in the genus. The latest studies show that there might, in fact, be as many as 53 species. Or even more. One species, the Northern Snakehead (Channa argus) has obtained notoriety as a dangerous invader of North American and European rivers. Given below is a report from ‘The Hindu’ (a newspaper popular in South India) describing the increase in Snakehead species:
Earlier, it was widely believed that there were 38 species in this group. However, DNA-level analysis showed that there were several more species than first thought. The species strength of snakeheads could be 53 or even more, said Rajeev Raghavan, Assistant professor of the Kerala University for Fisheries and Ocean Studies, Kochi, which is one of the partnering institutions in the project. The research findings were recently published in PLOS ONE. Snakeheads are of great demand in the domestic market for food as well as for ornamental purposes. Since these species are mostly found in the inland waterbodies, no data on their catch is available. It’s mostly the brightly coloured ones from northeastern India that find their way into aquaria.
The barcoding also succeeded in identifying new species Channa from Assam, foothills of Bhutan, Myanmar and another one from Congo. The analysis of the data revealed that the eastern Himalaya and the adjoining region of Myanmar were hotspots for snakehead diversity, as up to 10 snakehead species described during the last quarter century originated from this region, explained Dr. Raghavan. India is currently home to 15 species of Channa and the species diversity could go up as more studies would be undertaken.
Four currently known species — Channa bankanensis found in Indonesia and Malaysia, Channa marulius, Channa striata and Channa gachua — found in the Indian subcontinent and parts of southeast Asia, are considered species complexes, where different species are currently known under a single name because their taxonomy is poorly known or studied, he explained. More taxonomic studies on the species complexes are required for conservation purposes as many of the currently wide ranging species are listed as of “least concern” in the Red List of IUCN.
Image Attribution: The image above from Wikimedia Commons, is taken from an illustration in the book ‘Bosquejo Geográfico é Histórico-Natural del Archipiélago Filipino’ published in 1885. It shows a Striped Snakehead (Channa striata) that is native to South and Southeast Asia.