In Deduru Oya, an invasive snakehead fish has rapidly colonized a reservoir, reducing native fish and prawn catches and growing far larger than local species — one weighed about 7 kg (15 lb). Efforts to control it with an angling contest failed, so fishers are promoting angler tourism and producing salted-dried snakehead as new local products. These measures aim to create income while encouraging removal, though experts stress coordinated management and trade controls are needed to protect the ecosystem.
From Threat to Opportunity: Sri Lankan Fishers Turn Invasive Snakehead Into New Income
In Deduru Oya, an invasive snakehead fish has rapidly colonized a reservoir, reducing native fish and prawn catches and growing far larger than local species — one weighed about 7 kg (15 lb). Efforts to control it with an angling contest failed, so fishers are promoting angler tourism and producing salted-dried snakehead as new local products. These measures aim to create income while encouraging removal, though experts stress coordinated management and trade controls are needed to protect the ecosystem.
11:07 AM, 11/13/2025Environment
From Threat to Opportunity: Sri Lankan Fishers Turn Invasive Snakehead Into New Income
DEDURU OYA, Sri Lanka — An invasive predator fish has rapidly colonized the Deduru Oya reservoir in northwestern Sri Lanka, undermining traditional catches of native fish and shellfish. Local fishers say numbers of species they once relied on have fallen over the past two years while sightings of an unfamiliar snakehead fish have surged.
Local officials suspect the snakehead was introduced through the ornamental fish trade: hobbyists who found the fish outgrowing home tanks may have released them into the reservoir. Dr. Kelum Wijenayake, a researcher studying the species, warns that the snakehead faces virtually no natural predators locally and has found ideal breeding conditions in the reservoir — abundant food, few checks on population growth, and habitat tolerance that includes surfacing to breathe air and surviving low water levels.
“They have sharp teeth, strong jaws and are aggressive eaters,” Dr. Wijenayake said, adding that their presence can significantly disrupt an ecosystem that evolved without such a predator.
Snakeheads also grow much larger than most native freshwater species. Fisherman Nishantha Sujeewa Kumara said he once caught one weighing about 7 kilograms (15 pounds), while native fish typically weigh less than a kilogram. The species is difficult to catch with nets and is more often taken by angling, which is why the community first noticed them only after a visiting recreational angler landed one.
Authorities organized an angling competition to reduce numbers, but fishers say that effort failed to control the population. Rather than simply fighting the invasion, local fishers are exploring ways to make it economically useful. Ranjith Kumara, secretary of the area’s fishers association, has proposed promoting angler tourism as a regular control method that could also create alternative livelihoods for villagers who mainly depend on fishing and farming.
Other residents have turned to processing the fish. Fisherman Sujeewa Kariyawasam produces salted, dried snakehead products and says that while fresh snakehead has limited market demand, the dried product is a tasty local delicacy gaining popularity. “As demand grows, more snakeheads will be caught for processing, which will also help curb their spread,” he said.
Local efforts to create markets for the invasive fish could help reduce numbers and provide new income streams, but researchers and authorities say integrated management — including monitoring, public awareness and controls on the ornamental fish trade — will be needed to protect Sri Lanka’s freshwater ecosystems over the long term.