Dead fish pollute Rio lagoon

Thousands of fish went belly-up in a Rio de Janeiro lagoon this week after stormy weather and other factors caused oxygen levels to drop in the water.

The dead fish began floating to the top of the water on Tuesday (March 12) and, by Friday (March 15), city workers had pulled more than 65,000 metric tons (71 tons) of dead fish from the Rodrigo de Freitas Lagoon in south Rio.

The city's environmental office said the low oxygen levels were caused by several factors including an over abundance of organic material that washed into the lagoon after heavy rains and excessive heat.

The lagoon, near the Ipanema neighbourhood, will serve as a venue for rowing and canoeing events when Rio hosts the Summer Olympic Games in 2016.

In 2009, the city removed more than 100 metric tons (110 tons) of dead fish from the same body of water.