The linking of the Godavari and the Krishna rivers in Andhra Pradesh, which was inaugurated last year, seems to have led to an unforseen problem.

Fishermen in Guntur district’s Tadepally village on the banks of the Prakasam Barrage, which straddles the Krishna, are complaining that a species of fish, hitherto never seen in the river before, was damaging their nets and scaring away other fish. Consequently, they say their catch, and earnings, have dropped.

“I have been a fisherman since I was child,” said Paikam Suresh, 35, of Tadepally village. “Nowadays we are catching a new kind of fish which we call rakashi. This rakashi is ruining our livelihood.”

Drop in income

Rakashi, in Telugu, means the devil. The fishermen of Tadepally have given the fish this name thanks to the havoc it is wreaking with their livelihood.

The carnivorous fish belongs to the armoured catfish family. It is not native to the Krishna river, where species like the Bengal carp (catla), reba carp, grunter, white carp (mrigal), the snakehead (murrel) and other small fish called jalalu locally are found.

The rakashi is more trouble than it is worth. For one, there is scant demand for it. Then, fishermen complain that the rakashi’s fins get entangled in their nets, and it takes at least two hours to extricate it. If 10 such fish get entangled in one net, it can take the whole day to get them out. Fishermen say they are often forced to cut their nets to extricate these fish.

All this has affected their daily income.

Suresh and his fellow fishermen say they used to earn Rs 500 a day from catching 200-300 fish. Now their catch has dwindled, and no one wants to buy the rakashi that they invariably catch.

“We are a poor family and because of this fish our nets are being spoiled,” said Suresh. “Each net costs a minimum of Rs 5,000. Also the Rakashi feeds on other fishes in the river and we are losing our livelihood.”

He added: “Recently officials from the Fisheries Department came and examined the fish and told us not to sell or eat it.”

Suresh said that the fish had only been spotted since the Pattiseema lift irrigation project started. The Rs 1,300 crore project, inaugurated in August 2015, is envisioned to take 80 thousand million cubic feet of water from the Godavari through the Krishna to Andhra Pradesh’s parched Rayalaseema district.

Dangerous for diversity

Flummoxed experts are now studying whether the new species entered the Krishna river from the Godavari.

“Even we came know about this only recently,” said M Basava Raju, joint director of fisheries, Andhra Pradesh. “It might have come due to the interlinking of Godavari and Krishna waters. Even we don’t know the exact reason. We have asked our officials to investigate.”

Farida Tampal, state director, Worldwide Fund for Nature in Hyderabad sounded an alarm, saying that the armoured catfish doesn’t belong to either the Godavari or the Krishna rivers.

“It is highly carnivorous and an aggressive breeder too,” she said. “We have to take immediate steps to eradicate this breed. Government officials don’t take anything seriously until we lose all our fish diversity. It feeds on other fish species, especially on fingerlings. That way it is more dangerous.”

Tampal added that the rakashi is a native of South America that lives in shallow muddy waters and hooks onto pebbles using its spines.

Since the fish also feeds on algae, it is much sought after across the world as an aquarium fish, as it keeps the tanks clean. Tampal added that even the South Americans are trying to eradicate this fish from their rivers.

Environmental impact study

Marine experts say that rivers should not be interlinked without studying the environmental impact of such projects on marine life.

“Before interlinking rivers, we have to consider many things,” said marine biologist A Manimekalan. “We have to study the native species present in that area, see how breeding is affected if rivers are interlinked.”

Manimekalan added: “Rivers can be interlinked if they have the same native species in both waters. Otherwise the entire ecosystem will be disturbed.”

Tampal agreed. “Apart from different species, even pollutants can be carried from other river to another and water quality could change,” she said. “It is difficult to predict all this as this type of research is very poor in India. Interlinking needs to be studied seriously before implementation.”