Why in news?
A thick mat of water lettuce has covered nearly 80 percent of Lake Suchitlan in El Salvador, choking one of Central America’s largest artificial lakes. The infestation has disrupted fishing and tourism, threatening the livelihoods of thousands of local families.
Background
Water lettuce (Pistia stratiotes) is a free‑floating aquatic plant believed to be native to tropical Africa or South America. Its leaves form a rosette of thick, velvety foliage with feathery roots dangling beneath the surface. The plant reproduces rapidly by sending out runners and can double its biomass in a matter of weeks. While it is cultivated in water gardens, it is listed as an invasive or noxious weed in many countries and can smother entire lakes and rivers.
Impacts on Lake Suchitlan
- Loss of livelihood: The floating weed has blocked boat channels and fishing nets, forcing around 3,000 fishermen to stop working and causing economic losses of over US $1.3 million.
- Ecological damage: Dense mats shade out native plants, reduce oxygen levels and lead to fish kills; they also provide breeding grounds for mosquitoes and other pests.
- Role of pollution: Nutrient‑rich sewage and agricultural runoff entering the lake have fuelled the explosive growth of water lettuce.
- Removal challenges: Soldiers, government workers and local residents are manually removing the weed but lack equipment; heavy rains risk spreading the weed downstream.
Significance
- Need for preventive action: The crisis illustrates how untreated wastewater and nutrient pollution can trigger invasive species outbreaks.
- Global invasive species threat: Water lettuce is found throughout the tropics; controlling it requires integrated weed management and improved water quality monitoring.
Sources: Reuters, University of Minnesota Extension
