A zoology scholar and former professor has warned the state fisheries department of the possible presence of an omnivorous species of fish in reservoirs that can wreak havoc with river ecology if not contained.
Firoz Ahmad, who was vice chancellor of Nilamber Pitamber University, Daltonganj, claims to have spotted the red-bellied piranha ( Pygocentrus nattereri), native to the Amazon river basin in South America, being sold at the Hatia fish market in Ranchi earlier this week.
"When I asked the fish vendor where he got his fascinating catch from, the man said Chandil Dam (in Seraikela-Kharsawan). The fish were big and had razor-sharp teeth. The half a dozen red piranhas on sale weighed around a kilo each. If I am not entirely mistaken, this is the first time the piranha has been seen in Jharkhand. And, remember, it is not a migratory species," he told this correspondent on Thursday.
But state fisheries director Rajiv Kumar, whom Ahmad had contacted after doing some Internet research, said he doubted red piranha presence in Chandil or elsewhere in Jharkhand.
"Some exotic species are common in aquariums and are perhaps also raised in isolation in Bengal waters. As far as I know, the ones seen at Hatia market are locally called Bengal pacu," said Kumar.
Nevertheless, Ahmad maintained that introducing curbs on the breeding and sale of piranha were necessary to prevent extinction of indigenous species. The typical diet of red-bellied piranhas includes plants, insects, worms, crustaceans and other fish. In packs up to hundreds, piranhas are known to feed on birds and animals as large as egrets and capybara.
"Aquariums often illegally import piranhas. Someone may have released these fish into a river from where it reached Chandil Dam. If piranha sale is a growing trend here, it is bad news," Ahmed warned.
"These fish are foragers and are known to destroy biodiversity. We already have a precedent. Indigenous magurs (catfish) have vanished from here after the invasion of Thai magurs. Also, one no more sees pathar chattas, a local variety of fish that used to be abundant at waterfalls," he pointed out.
Referring to a similar sighting of the piranha in India a year ago, he said though distribution and habitat studies suggest that the omnivorous fish is native to South America, it has been seen in other continents too. "The fish were spotted by the Wildlife Institute of India, Dehradun, in Godavari river. It was locally known as Roop Chand and was a common item in market stalls."
Wildlife expert and zoologist D.S. Srivastava, who saw a couple of photographs clicked by Ahmad at Hatia, also told this correspondent that the fish appear to be the red-bellied piranha.
"The silver flecked body with red tinge near the belly suggest they are adult red piranhas. Juveniles have darker spots instead of the flaming tinge. However, morphological study can confirm what it is," Srivastava said, adding that the best way to stop piranha infestation in rivers was to launch a crackdown on unauthorised aquariums.
But fisheries director Kumar, a former student of Ahmad, claimed there was no evidence that indigenous fish were vanishing. "Thai magur is banned here, but I don't know if pacu is," he said.
The pacu is said to be related to the piranha, but does not have similar teeth. While the piranha have razor-sharp teeth, the pacu have squarer ones that look uncannily human and have a less severe underbite.
