Are oysters canaries in the coal mine?

For the sixth year, Willapa Bay bivalves’ reproductive process is failing

Failure of the natural reproductive process of commercial Pacific oysters for the sixth year in a row is a disturbing indication that environmental conditions in the Pacific Ocean and Willapa Bay are seriously discombobulated.

Part of the problem is water too cold for the season. We’re used to hearing that good chilly water is essential for wild salmon health. However, really frigid deep-ocean water and cool summer weather have been a double-whammy for Pacific oysters.

Many types of marine life – and terrestrial life, too – prosper only within a relatively narrow range of environmental values. The right temperature at one stage of life may not be the opportune temp at another time.

News stories this week in the Chinook Observer and the Seattle Times about hard times for commercial shellfish growers are disturbing and illuminating. As the Times observed, “Few know better than Northwest oyster growers that ecological upheaval is still rattling their industry – and that it may be a sign of greater marine-world shifts to come.”

This item in the Observer about levels of partial carbon dioxide, a leading culprit in climate disruption, deserves special attention:

“The PCO2 levels in the bay have vacillated from 1,500 to 5,000 parts per million due in large part to clear-cutting of timber near rivers that enter the bay and the eradication of 10,000 acres of spartina. Experiments in Netarts Bay west of Tillamook, Ore., have shown that a level of PCO2 above 600 parts per million are correlated with difficulties raising oyster larvae.”

The aftereffects of spartina control ought to fade away fairly soon, but rampant deforestation is a more troublesome and long-term matter. The upwelling of deep water also is terribly worrisome, but poorly understood. Some scientists think the big issue for oysters is the water’s cold temperature, but others fear that the carbon dioxide we’ve emitted into the air is changing the ocean’s fundamental chemistry.

Humans are adaptable. Some of Willapa’s smart oystermen have responded to peculiar conditions before. And they are doing so now, in part by switching some effort to Manila clams, which are doing surprisingly well. Going forward, maybe cold-tolerant native Olympia oysters will become a bigger part of the answer to a fickle environment.

But other oystermen, totally reliant upon Pacific oysters, are hovering at the brink of financial ruin. Looking back on this time, historians may see them as the canaries in the coal mine of climate disruption, some of the first people in the Lower 48 to suffer from the experiment that humanity is inadvertently conducting with our atmosphere.

The Daily Astorian, 5 August 2010. Article.

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