Nearly a year after thousands of dead fish washed ashore and an invasive plant blanketed nearly 70% of Lake Suchitlán, El Salvador's largest freshwater body, fishers and residents are still waiting for answers from the government. The lake, also known as Cerrón Grande, is a crucial hydroelectric reservoir and Ramsar wetland site, home to 12 of El Salvador's 14 native fish species and endangered wildlife like cougars and ocelots.
The 2025 Crisis: Die-Off and Plant Invasion
In August 2025, water lettuce (Pistia stratiotes) covered nearly 70% of the lake's 135 square kilometer surface. The bloom followed a fish die-off that left thousands of dead fish along the shores. Plastic waste accumulated, and fishers reported declining catches and income, with daily earnings around $15. The military was mobilized to assist with clean-up, and many fishers joined clean-up crews or relied on relatives' income.
Alberto Castillo, a boat operator in Suchitoto, said: "The clean-up seemed impossible. People are starting to come back very slowly, but during these months we had to take different jobs, getting only 30% of what we were making before."
Official Silence and Scientific Gaps
No official explanation has been provided by President Nayib Bukele's government. The environment, agriculture, and health ministries have not commented on how the water lettuce was removed or whether chemicals were used. Researchers from the University of El Salvador's toxicology laboratory (Labtox) analyzed water samples weeks after the die-off, finding no anomalies in nutrient levels or cyanobacterial blooms. However, they cautioned that monitoring during the die-off was impossible due to dense plant mats blocking sampling points.
Labtox does not test for pesticides like paraquat, a highly toxic chemical known as Gramoxone. Residents reported seeing agriculture-use drones flying over the lake before the die-off, but no authority has acknowledged using drones or chemicals.
Long-Term Pollution and Livelihood Impact
Scientists and environmental groups had warned for years about untreated sewage, agricultural runoff, and weak enforcement. Gabriel Cerén, a biologist, said: "What facilitates the reproduction [of the water lettuce] is the high amount of nutrients that the Lempa River gets from fertilisers that end up in the lake and concentrates a high amount of nitrogen and sulphates." The nutrient overload depletes oxygen, killing fish and boosting mosquitoes.
Tourism, an alternative income source, collapsed as the water turned opaque and foul-smelling. Visitors stopped coming for boat tours, birdwatching, and lakeside restaurants. Public health reports list gastrointestinal and acute respiratory infections as common in lake communities. Residents report skin rashes after swimming and increased mosquito populations.
Regional Context and Ongoing Concerns
Similar crises affect Central American lakes, including Lake Coatepeque in El Salvador, Lake Atitlán in Guatemala, and Lake Yojoa in Honduras. In June, a storm swept large amounts of rubbish into Lake Suchitlán. Residents like Noel Avalos, a fisherman from Copapayo, continue to eat contaminated fish out of necessity. "We eat them out of necessity," he said. "Our bodies have had to adapt."
Castillo added: "The lake needs an urgent study. We've had fish die before, but nothing like this. First the water lettuce, then the plastic, now the fish – it demands attention." Avalos fears conditions remain ripe for another crisis: "This has become the perfect breeding ground for it to happen again and again. It's pure contamination."
