Invasive fishes aplenty in rivers; pose threat to local fish breeds
Thrissur: The local fish breeds will have a major threat from the foreign fish breeds from farms and dams that was washed away into rivers after the floods. It is assumed that over 20 lakh invasive fishes were washed away into rivers and other water resources during the flood. Fishes from aquariums also reached the rivers.
In the background of this, state biodiversity board has summoned a meeting of delegates from all universities on September 4 to discuss the threat from invasive fishes to the local breeds.
Three major issues
- Some invasive fishes are capable of living in polluted water too. So in the race between the fishes to survive in polluted water resources, local fish breeds will be completely destroyed.
- Local fish breeds will be feeds for the invasive fishes which gulp whatever it come across.
- Presently there is a natural carnivore for fishes in the river. So the organism will be balanced. But in the case of invasive fishes, there is no carnivore in our ecosystem. So number of invasive fishes will rise in Kerala
Foreign fish breeds in Kerala
Red Belly is the most popular fish breed in Kerala. It is from South America. Red Belly species were largely farmed in Kuttanad. It is also known as Nattar. Other fishes and leaves near the river banks are the feed for this fish. Local fish breeds will face a major threat as these fishes will eat fish eggs too.
African catfish which is locally known as African Mushi is another threat to the local fish species. Though African catfish farming is banned in Kerala, large number of this species have been caught from Periyar and Chalakudi river after the floods.
It is reported that African catfish has been illegally farmed in 15 dams in Kerala. Poultry waste has been given to these fishes to add more weight. As this fish is capable to breathe air, it is taken by train from Bangladesh to Kolkata in order to supply to various parts of the country.
Tilapia and Pangasius fish (Malyasian vaala) are other invasive fishes which invade our water resources.
Sucker catfish, three spot Gourami and similar aquarium fishes were also spotted. These fishes will eat eggs of local fish breeds.
After the floods, Arapaima of 35 kg, an invasive fish, was caught from Chalakudi river. It is the largest fresh water invasive fish found in Kerala.
Meanwhile, Kerala University of Fisheries and Ocean Studies (KUFOS) has asked to take samples of invasive fishes caught from rivers.
“These invasive fishes should be studied in order to conclude the threat from these fish species,” said Dr Rajeev Raghavan, associate professor of KUFOS.