Kolkata: Discovery of predator fish that resembles an alligator concerns experts

Experts are concerned about the discovery of a predatory fish that can grow up to eight feet from Subhas Sarovar in Kolkata’s eastern fringe of Beliaghata as it can destroy local ecosystem and biodiversity.

A local angler, Shibu Mondol, caught a 3.5-feet long Alligator Gar – a fish that resembles an alligator with long sharp teeth and equally predatory instincts and sometimes known to attack humans – two months ago.

Biodiversity experts, ecologists and anglers say the fish could kill almost every other fish in the lake. The prehistoric relatives of this mega fish inhabited many parts of the world, but today gars live only in North and Central America. Of the seven known species, the Alligator Gar is the largest.

 “It is a highly carnivorous fish. It not only kills other fishes but there are reports of it attacking humans too. The fish’s egg is also poisonous. It has no natural enemies and hence can become invasive in no time destroying the local ecosystem and biodiversity,” Mathe Rajeev Mathew, expert member of the National Biodiversity Authority and the Telangana State Biodiversity Board, said.

Alligator Gar has already become a nuisance in Telangana and Andhra Pradesh and reports of the fish spreading fast and becoming invasive in water bodies of Tamil Nadu are also pouring in. In 2015, an Alligator Gar was caught from a well in Dadar in Mumbai.

A group of experts has been called in to tackle the menace.

“This is the first time that this species has been caught in the city. We would like to send a team and collect the specimen. We would also try to explore the lake to check if their population has proliferated and how big is the threat,” KC Gopi, a fish expert of the Zoological Survey of India, said.

Experts say they are usually smuggled into the country to be reared in aquariums. But when the fish starts gaining size and kills other fish, owners often release them in the local water bodies.

“We have had a similar experience with another aquarium fish called the Crocodile fish while working in East Kolkata Wetlands. They are bought by aquarium keepers and then released into wild when they grow big. Crocodile fish are now found in almost every pond and lake in Kolkata and are destroying the local biodiversity,” Dipayan Dey, who heads the city based NGO South Asian Forum for Environment, said.

Mondol – the person who caught the fish - gave a scary account of how he caught the fish as it tried to attack him and snap his finger. Mondol is a member of the West Bengal Angler’s Association and fishes regularly in Subhas Sarovar.

“Unlike a Rohu or Katla fish, which usually tries to drag the rope deep into the pond after it is hooked, this fish was lying idle in the water like a tortoise. When I started pulling it out of the water, I was shocked to see the alligator-like snout. I screamed and local residents soon rushed to the spot. The fish after being pulled out not only made a dart to bite me but also killed a Katla fish which I caught earlier,” Mondol said.

The Alligator Gar that Mondol caught weighed more than five kilos.

One of Mondol’s friends killed the fish and ate its meat that tasted sour. Mondol, however, managed to retain the skin and head and is drying to preserve it.

“We couldn’t cut the fish with a knife. It was so hard that it had to be hacked with an axe,” Mondol said.