Blackchin Tilapia Outbreak in Samaesan Bay in Chonburi Concerns Fishermen

Yesterday, March 19, 2025, reporters visited the parking area for small fishing boats along the coast of Samaesan Bay in Chonburi Province, to investigate the issue of the blackchin tilapia, which has invaded the local marine waters of Samaesan Bay. This follows complaints from fresh seafood vendors and fishermen who are concerned that the invasion could damage the marine ecosystem and cause hardship to their fishing livelihoods.

Upon interviewing Mrs. Krongkaew Phatkaew, a 52-year-old seafood vendor, she said that her son went out to set nets to catch mullet fish but instead caught several blackchin tilapia, weighing about half a kilogram. She noted that the blackchin tilapia were unusually large. Currently, when fishing, they are catching fewer crabs, squid, and other fish, and even when they do catch something, the quantities are significantly reduced. She is unsure whether this is due to the blackchin tilapia preying on juvenile fish and crabs.

Meanwhile, Mr. Prasert Phithakkon, President of the Samaesan Fishery Association, stated that small-scale fishermen setting nets along the coast to catch mullet for personal consumption unexpectedly caught several blackchin tilapia in their nets. After inspecting the area, it was confirmed that these were indeed blackchin tilapia. He has reported the issue to the Sattahip District Fisheries Office and the Chonburi Provincial Fisheries Office to raise awareness and seek urgent solutions to address the problem.

Yesterday, small fishing boats went out to set nets again and continued to catch blackchin tilapia, though smaller in size than before. This suggests that the blackchin tilapia population is rapidly expanding and reproducing widely. This evening, they plan to set nets again to monitor the quantity of blackchin tilapia caught.

The blackchin tilapia is a major concern in Samaesan Bay because it is an invasive species from West Africa that disrupts the local marine ecosystem by preying on small fish, crustaceans, and plankton, potentially reducing populations of native species like mullet, crabs, and squid.

Its rapid reproduction and adaptability to varying conditions allow it to spread quickly, outcompeting local wildlife and threatening biodiversity, while also decreasing catches for fishermen and seafood vendors, thus harming their livelihoods. With no natural predators in this non-native environment and a resilience that makes eradication difficult, the tilapia’s unchecked spread could lead to long-term ecological damage and economic losses if not addressed promptly.