Thousands of dead fish washed up on the shores of the Rodrigo de Freitas Lagoon, a Rio de Janeiro tourist attraction, Brazilian authorities said Wednesday.
A large amount of organic matter that entered the lagoon as a result of two recent large storms consumed oxygen and brought it down to critically low levels, Carlos Alberto Muniz, the municipal environment secretary, told Efe.
This situation caused a massive die-off of shad, whose number had risen since mid-February after the fish had entered the lagoon to spawn, Muniz said.
The city government now is working to remove the rotting fish and the strong odor associated with them and had collected 12 tons of dead shad as of Wednesday, the official said.
The lagoon is connected to the Atlantic Ocean via a canal that splits the beaches of Ipanema and Leblon, and that feeding-in of seawater on Wednesday helped improve oxygen levels, Muniz said.
A 65-year-old fisherman named Walter told Efe on the shores of Rodrigo de Freitas, which is to be cleaned up and used for aquatic events such as rowing in the 2016 Olympics, that he believes the large fish die-off occurred because the water in the lagoon is not renewed.