Vancouver Island's scallops and oysters are mysteriously dying out

The pristine, sheltered sounds off Vancouver Island, British Columbia, offer the cleanliness and protection ideal for farming oysters, clam, scallops, and other shellfish. Since the 1970s, the industry has grown so rapidly that the area once supplied nearly two-fifths of Canada’s farmed shellfish and is the coastal community’s economic backbone.

Further down the coast, the US’s $270-million Pacific Northwest shellfish industry is teetering (paywall) following the mysterious 2008 oyster die-off.

Scientists aren’t sure what the culprit is. Environmental stressors are rising, creating a complex interplay of factors. For instance, BC’s typically chilly coastal waters are warming—and that’s shifting the timing of zooplankton blooms, which in turn feed the shellfish. Scientists say seemingly slight ecosystem changes have likely compound the destruction of a deadly oyster herpes virus that has been wiping out oysters in France and Australia.

But something is killing them off. In the last two years, nine-tenths of baby oysters have died in Desolation Sound farms (the normal mortality rate is about 50%). Scallop farmers off Vancouver Island have reported mass die-offs of their hatchlings since 2010. British Columbia’s share of Canada’s aquaculture industry is in a tailspin.

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http://qz.com/311345/the-worlds-scallops-and-oysters-are-mysteriously-dying-out/