Lake Toba is the largest volcanic lake in the world occupying the caldera of a supervolcano on the Island of Sumatra in Indonesia.

Millions of fish were found dead by fishermen between May 3 and May 5, 2016. Officials are unable to find the source of the mass killing but think it is linked to the lack of dissolved oxygen in the water. Could the drop in oxygen content in the north-east of lake Toba be the result of volcanic activity of some kind?

It all started one month ago, when fishermen at Lake Toba started to find dead fish in their nets.

But the mysterious die-offs have suddenly increased beginning of this month, when professional fishermen caught more than 320 tones (May 3, 2016) and then 800 tons (May 5, 2016) of dead fish… In overall about 1500 tones in 3 days! So millions of fish!

Fishermen report these apocalyptical fish kills have never happened before. Normally, they only find a few dead fish. But this time, all the fish are dead.

Officials aren’t able to clearly pinpoint the cause of this still unexplained mass die-off but believe it is related to the lack of dissolved oxygen in the water.

Could the drop in oxygen content in the north-east of lake Toba be the result of volcanic activity of some kind?