‘They ate the shrimp, they even ate the crab’: Thai fishers count the cost of a voracious invader
Get the Energy newsletter
Daily energy & climate — solar, EVs, oil, the policy fights and tech bets shaping the transition. Free.
- Blackchin tilapia, native to west Africa, was first reported spreading in Thailand in 2011 in Samut Songkhram and has since infiltrated at least 19 provinces across central and southern areas, from Bangkok's canals to Pattaya's coastal waters.
- Thai fisher Wallop Khunjaen lost nearly all of his million baby shrimp to the invasive fish within two months, forcing him to abandon shrimp farming altogether, and reports that native fiddler crab have vanished locally.
- Thai authorities have rolled out multiple control measures — releasing Asian sea bass as predators, developing sterile-offspring variants of the tilapia, and paying fishers to remove them — pulling out thousands of tonnes, though experts say it is too late to eradicate.
- Khon Kaen University assistant professor Thotsapol Chaianunporn said the most sustainable path is economic use of the fish, including animal feed, fermented fish sauce, or as food, though traders report low consumer demand.
- Charoen Pokphand Foods Plc faces a lawsuit from fishers accusing the agribusiness giant of introducing the species after legally importing 2,000 blackchin tilapia for breeding research in 2010; the company denies responsibility, citing a closed-system protocol and funded research concluding the invasion was not the result of a "single introduction."
- Bangkok fisher Thanandon Charoenhiransaku said a single net cast three times in local canals easily pulls in 20 to 30 kg of blackchin tilapia, warning the crisis could spread across Thailand's borders.
- Monitoring tools including environmental DNA (eDNA) sampling — described by James Cook University's Dean Jerry as a "DNA soup" — alongside underwater facial-recognition cameras and acoustic tracking, are now being deployed worldwide for early detection of fish invasions.
Why it matters: For Thailand's 19 affected provinces, the economic damage is already locked in — experts say the fish cannot be eradicated, so livelihoods from shrimp farming and coastal fishing are permanently altered. The pending lawsuit against Charoen Pokphand Foods tests whether agribusinesses can be held liable for legally imported species that escape into wild ecosystems.
