Bengalaru: Finally, the State government seems to have woken up to the destructive effect of the African cat fish (Clarias garipeneus) on native aquatic biodiversity.
In the last one month, major cat fish rearing ponds in the north of the city have been shut down by the government. Fish experts have, however, warned that unless the government completely eradicates this fish species, the threat to the survival of our native fish and water ponds will continue.
This invasive species of fish has already made its way to water ponds around the State and are now being found in rivers. When the fish was first introduced into India, no one had any idea of the ferocious nature of this breed, which feeds on almost every living thing in an aquatic pond-- fish, frogs, tadpoles, larvae etc. The cat fish can survive adverse weather conditions and highly polluted water tanks too.
In the recent fish census, scientists found a decrease in the numbers of native fish species in city tanks. While other factors, such as heavily polluted water, have destroyed the fish population, the cat fish is also responsible.
The fish is banned under Section 5 of the Environment Protection Act and a fine of Rs 1 lakh and imprisonment is the punishment for violating the law, but the law has never been used in India. M. F. Rehman, retired scientist from the Centre For Inland Fisheries Research Institute (CIFRI) says that the government had been informed a decade ago about the ill effects of introducing the African cat fish.
“But governments across the country seem to be woken up only now. It’s too late to control African cat fish rearing when a majority of the fishery departments are hand-in-glove with the breeders. The government must go for total eradication of this species in the coming days,” he says.
“The recent raids on fish breeding centres around Bengaluru were done to reduce birds around the airfield where the air show is scheduled to be held. But the fish has already made its way into the Tungabhadra and Varada rivers. Fish breeders in Tumkur and Chitradurga are rearing cat fish in large quantities and they are sold openly in the market,” Rehman adds.
According to Dr T. V. Ramachandra, head of the Energy and Wetland Research Group from IISc, African cat fish breeding has definitely affected the lake biodiversity in Bengaluru.
“When many native species of fish are found dead in the highly contaminated water, we have recorded African cat fish breeding well. This is due to the absence of predator fish for the African cat fish,” Dr Ramachandra says.