Water Lettuce Covered 70 Percent of El Salvador Lake in 2025

The Guardian reported that nearly 70 percent of Lake Suchitlán’s 135 square kilometre surface was covered by water lettuce in August 2025. The invasive plant triggered a fish die-off that washed thousands of dead fish onto the shore overnight in communities such as Copapayo.

Fishers who normally earned about $15 a day joined military-assisted clean-up crews or turned to relatives’ crops for income.

Lake Suchitlán is El Salvador’s largest freshwater body and a Ramsar wetland site that supports 12 of the country’s 14 native fish species. It also feeds the Cerrón Grande dam, which supplies roughly 28 percent of national hydroelectric power. The Guardian reported that tourism around the lake fell after the water became opaque and emitted a persistent foul smell.

Alberto Castillo, a boat operator in Suchitoto, stated that the clean-up appeared impossible and that operators earned only 30 percent of previous income during the months of disruption. Gabriel Cerén, a biologist, said high nutrient loads from fertilisers carried by the Lempa River enabled rapid reproduction of the plant and concentrated nitrogen and sulphates in the lake.

Researchers from the University of El Salvador’s Labtox laboratory sampled the water weeks after the die-off and found nutrient levels within expected ranges with no active cyanobacterial bloom.

They noted that dense mats of water lettuce had blocked access to sampling points during the event itself. Residents recorded videos of agriculture-use drones flying low over the lake in the days before the die-off, though no authority has confirmed any spraying of chemicals. In June 2026 the government-run newspaper reported large amounts of rubbish swept into the lake after a storm.