RIO DE JANEIRO (AP) – Rio de Janeiro’s state environmental agency says it is investigating a fish die-off that has left thousands of carcasses floating in waters where sailing events are to be held when Brazil hosts next year’s Olympics.

The dead twaite shad, small whitish gray fish, were discovered Tuesday by inspectors conducting routine water testing in Rio’s sewage- and trash-filled Guanabara Bay. The agency was conducting tests to determine the cause of the die-off, with results expected in a week, it said in a statement Tuesday.

The discovery of the fish, which were washing up on the coastline outside Rio’s international airport and about 12 kilometers (7.5 miles) from the starting point for the 2016 Olympic sailing events, comes amid a visit by International Olympic Committee inspectors, in Rio to check up on the city’s progress in preparing for the games.

It also follows upbeat comments by Rio…