Dead fish have continued to wash up on the banks of a Rio de Janeiro lake that is scheduled to hold Olympic rowing competitions during the 2016 games . Fish die-offs are a frequent occurrence in Rio 's waterways , which are choked with raw sewage and rubbish . The latest incident , affecting thousands of small silvery fish called twaite shad , began several days ago at the Rodrigo de Freitas lake , where the Olympic canoeing and rowing events are to be held . The Rodrigo de Freitas lagoon will hold the Brazil 2016 Olympics rowing and canoe competitions . Currently , the lake is littered with thousands of dead fish due to the raw sewage and rubbish within it . With neighbors complaining about the stench , employees of the city 's waste management company have been working to clear away the dead fish . 'Every year there are these die-offs , sometimes bigger , sometimes smaller , ' said photographer Alex Moutinho , who has lived near the lake for over three decades . 'It 's one more Brazilian shame . ' In a statement , the city 's environmental secretariat said the latest incident was the result of recent rains and high sea levels , which caused the lake 's water temperature to plummet . The statement stressed that twaite shad are sensitive to variations in temperature , adding that oxygen levels in the lake were normal . Officials say the recent problems are the result of rain , which caused the lake 's temperature to plummet . The city 's waste management company have been brought in to clear the lake of the dead fish . Vultures feed on the dead fish on the shore of the Rodrigo de Freitas lagoon in Rio de Janeiro on Monday . Previous fish die-offs in the lake have been blamed on pollution-related drops in oxygen levels . The cause of February die-off of twaite shad in the Guanabara Bay , where the Olympic sailing events are to be held , were not known . Rio 's water quality has become a contentious topic ahead of the 2016 Olympics . Authorities had pledged to clean up some of the waterways including the Guanabara Bay ahead of the games but now admit those promises wo n't be met , sparking sailors to voice worries about possible health and safety threats posed by competing in the sewage and garbage-filled waters . Residents concerned about the water quality of a canal in the Rio neighborhood of Recreio staged a protest on Sunday . Hundreds of demonstrators linked arms along the Canal das Taxas , which is filled with raw sewage from nearby condominiums . The canal flows into a lagoon where the Olympic Park is being built .
The Olympic de Freitas lagoon will hold the 2016 Olympic rowing races . Currently , the lake is filled with thousands of dead twaite shad fish . Rio 's waterways are choked with raw sewage and rubbish , and concerns have been raised over health and safety ahead of the Olympics . Officials say the deaths are due to a plummet in the water temperature .