Banned catfish spreads rapidly in Chennai’s marshlands – Times of India

CHENNAI: African catfish, a banned invasive species which poses a threat to native environment, is spreading rapidly in water bodies of Chennai’s southern suburbs.
Catfish prey on native fish varieties, reptiles, amphibians and sometimes small birds, causing damage to the biodiversity of the area.
Avian photographer M Ramachandran who spotted shoals of catfish (each around 1.5ft long) in Sholinganallur marshland, said, “If catfish are not removed immediately, it will consume small fish and birds will stop visiting the marshland in search of food.” Usually, flamingoes and other migratory birds visit the lake from the third or fourth week of March, he said, requesting the government to engage local fishermen to remove the catfish.
S Sandilyan, former fellow on invasive alien species, National Biodiversity Authority, Chennai, said the chances of eradicating African catfish are less because the species has a high breeding potential and there is no predator available to prey on it. “Unless the state government recruits experts and launches a separate project with adequate funds and manpower, it is going to be difficult to eradicate. With the present effort, we can only manage the situation,” Sandilyan said.
African catfish (Clarias gariepinus) were introduced in India from Bangladesh with the aquaculture species tag. Initially, this species was introduced in West Bengal, Assam and Andhra Pradesh, later in 1993-94, it entered into Kerala and Tamil Nadu, and was largely cultured by farmers. The low operational costs and high profit led to farming intensification of the invasive species. During floods, these fish escape the farm and once it enters a pond, lake, or wild environment, it spreads quickly.
Based on several scientific studies, in 1997, the National Committee for the introduction of species in India banned the rearing of catfish. However, some farms continue to breed it. The National Green Tribunal in 2000 ordered the government to act against such illegalities. However, till date these species are bred.