Oysters on Acid

Oyster producers in Oregon and Washington have been fighting to save their livelihoods for many decades, with the most recent of threats caused by rising ocean temperatures. The damage comes in the form of dead and dissolving larvae and is due to a number of related stressors.

When oysters reproduce, they release larvae – tiny mobile creatures that are incapable of eating until they settle on a fixed location. Once settled, the larvae begin consuming the nutrient stores provided by their egg and constructing their fancy new oyster shell.

To construct their shells, oyster babies pull carbonate ions from the water to create aragonite, a kind of calcium carbonate. However, as ocean temperatures rise, the water becomes more acidic. The more acidic the water, the less carbonate available for the oysters to utilize. This can be fatal to young oysters in a number of ways, causing them to run out of egg-energy before finishing their shell and developing feeding organs, increasing their risk to bacterial infections, and affecting their development into robust adults.

Whiskey Creek in Oregon and Taylor Shellfish Farms in Washington have been working to combat these losses since the mid-2000s. One way they have found to mitigate the impact to their larvae stock is to balance out the pH of the water they use. By adding special sensors to their water pumps, water that is especially acidic is identified and mixed with more neutral or basic water.

While this does not address the big picture causes of oyster loss—nor does it speak to the damages to oyster populations in the wild—it has been a much-needed bandage to the westcoast industry. Next time you get ready to suck a bugger-like oyster off its freshly steamed shell, remember that somewhere baby oysters are dissolving in their breeding tanks because they can’t collect enough carbonate ions…

By Anthony Vitale