Tag Archives: carbon dioxide

The Demise of Bivalves and Shell Creation

oyster new york

 

The acidification of Oceans is well documented.  Many species are unable to survive the increase of acid occurring so the ability of the Oceans to absorb carbon dioxide is radically diminishing.  One of the drastic affects of this process is the inability of the bivalves to create shells.  This was exacerbated by the National Park Service’s decision to close a very important supplier in Northern California of these delicate creatures, Drakes Bay Oyster Farm-the largest of the lot and provider of up to forty percent for the other companies.  In 2013, they raised eight million oysters.  An oyster can filter up to forty gallons of water a day.

Kevin Lunny, owner of federaaly closed Drakes Bay Oyster Company

Kevin Lunny, owner of federally closed Drakes Bay Oyster Company

After much litigation and pubic outcry, Drakes Bay Oyster Company will close this year after eighty years in existence.  It does reside on federal lands.  All the other suppliers, most notable is the Hog Island Oyster Company on Tomales Bay, depend on them.  Drive up Route One any weekend day, and the road is congested with cars parked cheek to jowl up the entire coastline.

Publisher enjoying the spoils of Drake's Bay Oysters. Photo by Shaun Fenn

Publisher enjoying the spoils of Drake’s Bay Oysters. Photo by Shaun Fenn

Like New York, documented in the wonderful book Oysters, San Francisco was awash in oysters as the settlers arrived.  They were a mainstay in the diets, including being sold from carts on the streets, but before too long they were depleted by overfishing. Oysters began to be ‘seeded’ by the mid-1850s.  This hatchery process is very delicate and concentrated in the Pacific Northwest, starting with microscopic larvae, it has become a very scientific process.

Acidification of nautilus seashells

Acidification of nautilus seashells

Humans are dumping seventy million tons of carbon dioxide into the atmosphere every day.  Oceans absorbs about a third of it.   The Ocean is now thirty percent more acidic than it was two hundred years ago.  It is not the acid that prevents the oysters from growing shells, but the concomitant lack of carbonate ions in the water.  They need these ions to build their shells.  This is compounded in the Pacific Ocean by the upwelling of water that has spent 30 – 50 years in depths that have absorbed more carbon dioxide from decomposition in the Ocean.

Ocean Acidification diagram

Ocean Acidification diagram

When oysters are grown in the vats as larvae, adding pH-raising chemicals can control water conditions.  But when it is time for them to be set out in the Ocean for one to two years to mature, they are vulnerable to the vagaries of the conditions.  Seeds are now at a premium and the suppliers cannot meet the demand. One of the largest, Whiskey Creek, produces only 25% of its demands despite the buffering of the pH.  Furthermore, the seeds are much less healthy and fewer survive to maturity.

Gutting0007

Woman shucking oysters on the waterfront

UC Davis Bodega Marine Lab partnered with Hog Island in 2012 to collect data on the water conditions. This author grew oysters in Tomales Bay for a few years in a community program with the intention of starting a commercial fishery.  The governmental restrictions were too onerous to overcome.  In contrast to Marin County, Humboldt County, to the north, is assisting farmers to develop fisheries; in fact Hog Island is starting a hatchery there now.

17 vintage postcard italy fishing boat catania

In only fifteen years, according to the respected publication, Nature, acid levels will increase to a level of no retreat that will not be able to support oysters, as well as other shellfish – clams, mussels and snails.  If India continues to dig deeper for dirty coal without regard to emissions as they have stated, and the GOP win their battle for the XL Pipeline shipping sludge that is twenty percent more polluting while taking three gallons of water for one gallon of sludge to produce, stripping forests – the conditions of the fisheries will be extinct by 2050.

Oyster feast. Photo by Kim Steele

Oyster feast. Photo by Kim Steele

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