article_snippet.sent: 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.
article_snippet.sent: 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. '
article_snippet.sent: 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.
article_snippet.sent: a statement stressed that twaite shad are sensitive to variations in temperature, adding that oxygen levels in the lake were normal.
article_snippet.sent: Officials say the recent problems are the result of rain, which caused the lake's temperature to plummet .
article_snippet.sent: Previous fish die-offs in the lake have been blamed on pollution-related drops in oxygen levels.
article_snippet.sent: 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.
highlights_snippet.sent: Officials say the deaths are due to a plummet in the water temperature .