Thousands of small sardine-like fish have been found dead in lake Alalay, but no one is completely sure what caused oxygen levels in the lake to drop so dramatically
Thousands of dead fish have washed up onto the shores of a lake in Bolivia.
Just before they died, some of the fish had just hatched from their eggs in lake Alalay, in the central Bolivian city of Cochabamba.
No one yet knows the number of dead fish, but they have stockpiled five cubic metres (177 cubic feet) so far, so it’s possible there is over a tonne of dead fish in the lake.
According to local media reports, the most affected species was the “platincho” fish which is similar in appearance to sardines.
The fish carcasses were taken to a local dump.
Authorities believe low oxygen levels in the waters of Lake Alalay, due to the the highly polluted water, in addition to the last heatwave in 2015, led to the massive fish kill, but the exact cause of the conditions were unclear.
Oxygen levels dropped from 5 millimetres per litre to 2.8 millimetres, according to a preliminary laboratory report, released by local authorities.
Results will be compared with reports from SEMAPA, Cochabamba’s municipal water company and the University of San Simon.
Environmentalists have said the lake is constantly threatened by fires, namely one last year, as well as discharge of sewage.
Authorities are analysing an immediate measure to oxygenate the lake to prevent more fish from dying. Nevertheless, local media reported equipment to help oxygenate the lake was not working.
“It is an environmental disaster. Thousands of fish are already dead, or millions of dead fish. You can see wheelbarrow after wheelbarrow and mechanical shovels full of unfortunately dead fish,” said an unidentified natural resources worker.
In 2015, local authorities allocated a budget of 9 million bolivians (£900,000) for the recovery of the lake to no avail.
“They are small fish that were just hatching, or just coming out of the eggs, they were growing and as they were weak, they have not been able to resist this kind of change and that is why they have died,” said an environmentalist from the municipality of Cochabamba.
Alalay is the last urban lake that lies within the city of Cochabamba.
The lagoon was created around 1930 to prevent flooding of the city with the swelling of River Rocha but it also helps to absorb moisture and organic matter.