A Pearl In the Rough, Oyster Aquaculture and How it Works

By Maddie Brooks

While your first thought of an oyster might involve the words “slimey” and “overpriced”, they may in fact be the key to both providing cheap food and reducing excessive CO2 produced by traditional methods of farming. Three billion people rely on the ocean as their primary source of animal protein, with 10-12% of the population relying specifically on fisheries and aquaculture, making shellfish a key cheap, accessible protein source, especially for developing nations.

Shellfish farming, in addition to providing protein, also acts as a major sequester of carbon. Oyster shells are made of a substance called calcium carbonate, which uses inorganic carbon to create the structure. For every ton of oysters farmed, 441 kg of CO2-eq is taken out of circulation, and for every 1 ton of bivalve protein produced, only 11 tons of greenhouse gases are emitted, as compared to 340 tons for every 1 ton of edible beef product. In addition to sequestering carbon, the structure of some aquaculture oyster reefs can help to dampen storm influence, protecting nearby shorelines and reducing the risk of erosion.

The aquaculture industry has lots of positive impacts, but one thing could stand in the way of its progress and success as an industry: climate change.

This year, a record shattering heat wave hit the Pacific Northwest like never before, with temperatures in the 100’s, with peaks at 108 F in Seattle. During this time, sixty shellfish farms in Washington state applied for federal disaster aid after the double whammy of extreme heat and afternoon low tides killed most of their shellfish stock. Most oyster farms use some sort of intertidal system to simulate natural environments. These methods range from long lining, where a rope is stretched along the ground in the intertidal region at low tide and supported about a foot above the ground with pegs, to mesh bags attached to the ground. The result is oysters are exposed to open air at some points in the day during low tide, which is normally combated by the oysters closing their shells and retaining as much water as possible. During the heat wave however, shellfish across the state essentially cooked above water because temperatures were too high for too long. The damage caused by the heat wave hit those who use shellfish as both a source of food and income the hardest, and serves as a brutal reminder of the oncoming consequences of climate change.

Though the events of this past summer certainly took a toll on farmers, the industry is still alive and well. Washington state is the nation’s biggest producer of farmed clams, oysters and geoducks, with more than $100 million in annual harvests, and is home to the oldest and largest shellfish farm and distributor in the US: Penn Cove. Shellfish farmers and agriculture technology companies are developing new methods to grow stock faster and stronger using new farming techniques or by creating new hybrids that are resistant to the effects of climate change. Support this growing industry by looking into shellfish farms in your area, and purchasing from local farms if you're able. The world’s your oyster!