How Pollution Is Devastating an Indonesian Lake

Uncontrolled fish farming, population growth, and logging have all taken a toll on Indonesia’s Lake Toba. Photographer Binsar Bakkara returns to his home region to chronicle the environmental destruction. 

More than 1,500 tons of fish suddenly turned up dead in Indonesia’s largest lake earlier this year, a mass asphyxiation from a lack of oxygen in the water caused by high pollution levels. The event threatened the livelihoods of hundreds of fish farmers and the drinking water for thousands of people, and it shed light on the rapidly declining conditions in Lake Toba, the largest volcanic lake in the world. 

Population growth, development, deforestation, and a booming caged fishing industry have severely degraded the lake’s water quality over the last two decades, scientists say. There are now 12,000 cages in the lake, each containing upwards of 10,000 fish, which is double or triple their capacities. Agricultural fertilizers, sewage, and most prominently, fish food have increased the levels of phosphorous in the lake three-fold since 2012, according to a government report. The lake, located in the northern part of Sumatra, is classified as either eutrophic or hyper-eutrophic, meaning it has excessive nutrients that can create dead zones with low oxygen levels. 

Continue reading at the Yale Environment 360

Photo: The mass fish kill took days to clean up. More than 100 Lake Toba fish farmers lost their entire stock, costing them thousands of dollars. 

Photo Credits: Binsar Bakkara