Something fishy going on at Rio de Janeiro's Olympic Bay

In this Feb. 28, 2015 photo, a street cat that survives on fish scraps nestles on a net being repaired by Manuel Batista de Moraes at the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. The 76-year-old fisherman no longer goes out on the water and makes his living mending fishing nets. Its a constant task, he said, because the trash that fishermen encounter rips the nets apart. (AP Photo/Leo Correa)

In this March 3, 2015 photo, a cutlassfish caught in Guanabara bay lays on a fisherman's bike, which he planned to take home, at the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. Slowly, year after year, fishermen's catches have diminished. The men blame industrial and sewage pollution for their empty nets. (AP Photo/Leo Correa)

In this March 3, 2015 photo, a fisherman repairs his net at the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. For decades, fishermen have trolled the bay that will host Olympic sailing events in 2016, setting their nets at dawn, hoping to catch sea bass, Atlantic bigeyes and shrimp. But slowly, year after year, the catches have diminished. The men blame industrial and sewage pollution for their empty nets. (AP Photo/Leo Correa)

In this Feb. 28, 2015 photo, trash litters the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. High tides bring in waves of garbage daily, so fishermen dont bother trying to keep the docks clean. (AP Photo/Leo Correa)

Dead fish and trash float in the polluted Guanabara Bay in Rio de Janeiro, Brazil, Wednesday, Feb. 25, 2015. Rio de Janeiros state environmental agency is trying to determine why thousands of dead fish have been found floating where next years Olympic sailing events are to be held. (AP Photo/Leo Correa)

The Flavio Rodrigues, a retired rail worker, fishes on the shore of Guanabara Bay where dead fish float in Rio de Janeiro, Brazil, Wednesday, Feb. 25, 2015. Rio de Janeiroís state environmental agency is trying to determine why thousands of dead fish have been found floating where next yearís Olympic sailing events are to be held. (AP Photo/Leo Correa)

Trash litters the shore of Guanabara Bay in the Caju neighborhood of Rio de Janeiro, Brazil, Wednesday, Feb. 25, 2015. Rio de Janeiros state environmental agency is trying to determine why thousands of dead fish have been found floating in waters where next years Olympic sailing events are to be held. The fish were discovered Tuesday during a routine water testing of the sewage- and trash-filled bay. (AP Photo/Leo Correa)

In this Feb. 28, 2015 photo, trash floats on the water along a fence line in Guanabara bay in Rio de Janeiro, Brazil. About 30 fishermen work out of the garbage-strewn docks sitting right under the Red Line highway leading to the international airport, where the polluted waters of the Fundao and Cunha canals meet to flow into the bay. (AP Photo/Leo Correa)

Flavio Rodrigues, a retired railway worker, walks between dead fish floating in the water and trash scattered along the shore of Guanabara Bay in the Caju neighborhood of Rio de Janeiro, Brazil, Wednesday, Feb. 25, 2015. Rio de Janeiros state environmental agency is trying to determine why thousands of dead fish have been found floating in waters where next years Olympic sailing events are to be held. The fish were discovered Tuesday during a routine water testing of the sewage- and trash-filled bay. (AP Photo/Leo Correa)

In this March 3, 2015 photo, residents stand outside the fish market at the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. Local fishermen bring their morning catches around 11am to the market on the dock where residents can find fish like "corvinas," "olho de cao" and "tainha" at lower prices than at supermarkets. (AP Photo/Leo Correa)

In this Feb. 28, 2015 photo, a poor catch sits in the basket of fisherman Edmo Rodrigues da Costa as he navigates his boat back to the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. These nine fish are all he had to show for four hours of early morning fishing. Slowly, year after year, fishermens' catches have diminished in the sewage-infested waters of the city's Guanabara bay. (AP Photo/Leo Correa)

In this Feb. 28, 2015 photo, fisherman Edmo Rodrigues da Costa shows a shrimp he caught in Guanabara bay in Rio de Janeiro, Brazil. Rio state authorities say theyre working to make good on a pledge made in Rios Olympic bid to cut the bays pollution by 80 percent. But Costa, 59, and the other fishermen who see the water up close day after day say theyve witnessed little improvement. (AP Photo/Leo Correa)

In this Feb. 28, 2015 photo, dead fish and trash float inside a discarded drawer in Guanabara Bay in Rio de Janeiro, Brazil. Rio state authorities say theyre working to make good on an Olympic pledge to cut the bays pollution by 80 percent, but local fishermen who see the water up close day after day say theyve witnessed little improvement. (AP Photo/Leo Correa)

In this March 3, 2015 photo, a fisherman returns to the dock in the Vila Pinheiro slum, part of the Mare complex in Rio de Janeiro, Brazil. For decades, fishermen have trolled the bay that will host Olympic sailing events in 2016, hoping to catch sea bass, Atlantic bigeyes and shrimp. But slowly, year after year, the catches have diminished. The men blame industrial and sewage pollution for their empty nets. (AP Photo/Leo Correa)

In this Feb. 28, 2015 photo, a ship sits anchored at a shipyard in a canal off Guanabara bay in Rio de Janeiro, Brazil. Local fishermen men blame industrial and sewage pollution for their empty nets. About 30 fishermen work out of the docks sitting right under the Red Line highway leading to the international airport, where the polluted waters of the Fundao and Cunha canals meet to flow into Guanabara bay. (AP Photo/Leo Correa)