Sri Lankan villagers adapt to threat of snakehead fish invasion

"An invasive fish is threatening livelihoods in a northwestern Sri Lankan village by devouring traditional fish and shellfish species in the Deduru Oya reservoir, but local fishers aim to transform this challenge into an opportunity. Over the past two years, fishermen have observed declining numbers of their typical catch while snakehead fish, previously unseen in Sri Lanka, have appeared in abundance."

"According to local officials, the snakehead fish, common in Thailand and Indonesia, likely arrived with imported ornamental fish. When they outgrew home aquariums, owners probably released them into the reservoir. Dr Kelum Wijenayake, a researcher studying the fish, explained that snakeheads have no natural predators in Sri Lanka's ecosystem. The Deduru Oya reservoir has provided them with an ideal breeding ground with ample food and no predator, he said."

"These fish can surface to breathe air and survive with minimal water. Their sharp teeth, powerful jaws, and aggressive feeding habits threaten the local ecosystem that has evolved over thousands of years, according to Wijenayake. Snakeheads also grow considerably larger than native freshwater species. Fisherman Nishantha Sujeewa Kumara reported catching a 7kg (15lb) specimen, while native species typically weigh less than 1kg."

An invasive snakehead fish has appeared in the Deduru Oya reservoir, rapidly increasing in abundance and replacing traditional fish and shellfish harvested by local fishers. The species likely arrived via imported ornamental fish released when owners could no longer keep them. Snakeheads have no natural predators in Sri Lanka, can breathe air and survive in minimal water, and have sharp teeth, powerful jaws and aggressive feeding habits that threaten ecosystems evolved over millennia. They grow much larger than native freshwater species, with specimens of about 7kg reported versus typical native sizes under 1kg. Fishers have attempted control efforts like angling competitions but have not reduced populations and are exploring ways to turn the invasion into economic opportunity.

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