From the article:
Over the past two years, Mr. Perreault’s oyster farm on B.C.’s south coast has experienced 80 to 90 per cent mortality of young shellfish – the normal attrition rate is 50 per cent – and last year, nearby Pendrell Sound had a massive die-off of wild oysters.
“It was in the billions,” he said of the Pacific oysters that died only a few months after they hatched.
“It’s hard to say without having somebody there monitoring what’s going on. It could be food related. Maybe there were too many oysters and there was not enough food and they just starved – or something else [is happening] in the water like the acidity level,” he said. “To be frank, we don’t know a lot about it and that’s what’s scary.”