Critic’s Notebook

It’s Official: Global Warming Is Killing Oysters

What it means for connoisseurs. What it means for the planet.

By Kathryn Robinson April 16, 2012

Consider the oyster. And the ocean.

Last week came definitive word from scientists at NOAA and Oregon State University: The decreasing pH content of our oceans is one of the factors responsible for the alarming oyster die-offs in Northwest waters over the past seven years.

Decreased pH—higher acid levels—results from the ocean’s absorption of carbon dioxide emissions. Researchers have suspected for years that the increased acidity of the ocean is killing its inhabitants. This is the first North American proof.

I called Jon Rowley—who does marketing and promotions for Taylor Shellfish Farms, but whose long history with every aspect of Northwest seafood makes him more like Oyster Czar—and he told me it’s only getting worse. “We’re looking at 150 years of CO2 emissions getting absorbed by the oceans, and it looks like we’re reaching a tipping point,” he said. “It shows up first in the shellfish because if the pH isn’t right they can’t form a shell. So it’s rather serious.”

To find out how serious, he put me on to Taylor Shellfish’s production manager and resident oyster-growing expert, Benoit Eudeline. Because of ocean upwellings that happen at estimated 50 year cycles, Benoit explained, the acidic water now lapping onto Northwest shores was created from air that was high in CO2, but nowhere near high as it is today. When today’s air rolls in on the waves of 2062—it will be much more acidic. “We’re sending ourselves a poison gift in the mail, and it’s going to come whatever we do,” Benoit said.

Many of the Northwest’s most prolific oyster beds haven’t seen natural spawning of oyster larvae in years; Willapa Bay’s going on eight. Oyster hatcheries provide the overwhelming majority of oysters to restaurants and bars, and since many hatcheries have had success mitigating the problematic pH conditions, restaurant patrons have not been denied their bivalves. Still, even big successful hatcheries like Taylor Farms have suffered due to changing conditions, losing a large percentage of their oyster larvae a few years back. Both Rowley and Eudeline predict that availability of oysters will almost certainly decline, with prices increasing in turn.

And a decrease in the availability of happy hour half-shells isn’t even the scariest prospect.

“My concerns go beyond the oysters,” confessed Rowley. “The main food sources for a lot of the fish in the ocean are tiny shellfish. If they can’t make shells, then you’re looking at an impact on the entire food chain of the open ocean.”

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