DEDURU OYA: An invasive fish is threatening the livelihood of people in this northwestern village by aggressively eating traditional fish and shellfish species in the Deduru Oya reservoir, but the Sri Lankan fishers want to turn the adversity into an advantage.
Fishermen on thereservoir have noticed over the past two years a dwindling number of the fish they have been typically catching, while the snakehead fish, which have never be seen in Sri Lanka before, have been appearing in droves.
The snakehead fish, seen in countries like Thailand and Indonesia, could have arrived in Sri Lanka with imported ornamental fish, local officials said. When they started outgrowing the tanks, it was likely that their owners released them into the reservoir.
Dr. Kelum Wijenayake, an academic researching the fish, said there is no species above the snakehead in the food chain of Sri Lanka’s ecosystem, and that the Deduru Oya reservoir has provided them with an ideal breeding ground with ample food and no predator.
They also often come to the surface to inhale outside oxygen and are able to survive with just enough water to keep them hydrated, he said. They have sharp teeth, strong jaws and are aggressive eaters, which means their increased presence can damage the local ecosystem that evolved over millennia, he said.
