The exotic fish, Piranha, found in the Godavari River is believed to have escaped from the confines of captive breeding. The fish is also captive bred in Kerala and Andhra Pradesh for aquarium trade and also as a commercial fish due to its high protein value. According to marine biologists, care must be taken during breeding to ensure that it is not released in natural aqua systems as it is an invasive species. He said other similar ornamental species as Paradise Fish, Croaking Gourama, etc, have also been traced in Chembarambakkam and Red Hill lakes near Chennai.
According to Dr Abhijit Mitra, Oceanographer, Department of Marine Science, University of Calcutta, the origin of this fish can be traced back to South East Asia. Species like the red-bellied Piranha for instance is even cultured in various parts of Bangladesh, including Tongi, Mymensingh, Comilla and Khulna. These fish grow up to about 40 cms in length weighing about 1.5 kg. Piranha is an exotic culturable species and has a lucrative trade, he said.
He further said that Piranha traced in Godavari probably got released from Dhavaleswaram in Rajahmundry of the Andhra Pradesh’s East Godavari district, where polyculture of exotic fish is practiced. However, it is not surprising to find them in the market, considering that it is a delectable fish and is in high demand. Even the commonly eaten fish Telapia is actually a native of Africa from Mozambique Channel.
According to scientists in Wildlife Institute of India, these exotic fish are invasive in nature which dominates the natural aqua systems. Being carnivorous, they devour the other fish in the river. Even accidental releases from aquarium culture sites disturb the general food chain of the system. The experts stressed on norms to regulate the aquarium trade and the need for a separate authority to regulate these breeding of invasive species. Stringent measures need to be taken to monitor the aquarium fish trade and their release into water bodies, including man-made lakes as well as tanks. While these would emerge as breeding grounds for such invasive fish, they would eventually wipe out native freshwater fish.
The experts said that the need is to create awareness among the quarantine department, customs and forest department on the threat to native species by alien species. Even the guidelines of IUCN stress the need to focus on preventing the loss of native biodiversity at the hands of invasive alien species, they added.
