This article is more than 5 years old

This article is more than 5 years old

Thirty-two tonnes of dead fish have been cleared out of the lagoon where the Olympic rowing and canoeing events will take place next year, officials in Rio de Janeiro said on Wednesday.

More than 60 people from the city’s sanitation department have been working daily since last Wednesday to remove the fish, with many thousands washed up on the shore, and will keep doing so until the problem is resolved, department officials said.

Specialists dispute what caused the fish to perish, with some claiming it is down to a sudden drop in water temperature and others saying pollution is to blame.

The unhappy phenomenon on the banks of the Lagoa Rodrigo de Freitas is not new, with large amounts of dead fish appearing at regular intervals for more than a decade.

The lagoon is one of Rio de Janeiro’s picture postcard settings and will host canoeing and rowing events during the 2016 Olympics.

Water quality has been a major concern for organisers, with the Guanabara Bay where the Olympic sailing events will be held also coming under criticism.

The Rio de Janeiro state government promised to reduce the amount of raw sewage flowing into the bay by 80% but has since admitted that goal is unlikely to be met.