The Hog Island Oyster Company spends more time thinking about greenouse gasses than you might imagine. For them, climate change isn’t just a threat to their operating model, total yield, or harvesting costs, but to the very survival of oysters as a species. Hog Island Oysters are grown in the tidal waters of Tomales bay, where changing tides bring in rich nutrients and phytoplankton from the sea, creating an ideal environment for growing oysters1. In the past years, however, the tides have been bringing in a less welcome guest, and in increasing quantity: CO2 dissolved from the atmosphere into the ocean.
The threat to the oyster industry is not the global temperature increase, but the acidification of the sea. Roughly 30% of the CO2 that is released into the atmosphere is absorbed by the ocean, which drastically increases the acidity of the water2. Further, “upwelling”, or the phenomena where the wind pushes surface water away from shore and circulates deeper (and more acidic) water toward the shore/tidelands, has been on the rise due to changing weather patterns. This increase in acidity effectively dissolves the calcium carbonate shells of many shellfish, leaving smaller softer shells and weaker oysters3. This impact is most notable in the oyster’s larval stage, as the weakened state makes the baby oyster more susceptible to disease. Hog Island noticed a sharp increase in mortality of infant oysters several years ago, and has since moved their “nursery” into a controlled environment, to protect from the ocean’s acidity in the oyster’s most vulnerable stage. This strategy is working for the time being, but the company is unable to keep more mature oysters in such a controlled environment as the larger oysters take considerably more space and require much more access to the nutrients carried in by the ocean tides.
As the oysters’ environment become more acidic due to increase in CO2 concentrations (expected to rise
from 400 ppm to 600 ppm by the end of the century2), farmers will need to control the oysters’ environment more carefully and later into their life, which will cause an exponential increase in cost to Hog Island. The company is currently preparing for future climate change by building an additional “nursery” to develop young oysters in Humboldt Bay, CA, and by pairing with researchers from UC Davis’ Bodega Marine Laboratory to develop future solutions to the threat of climate change3.
The company’s operating model is most likely to change through significant increase in R&D expenditures to keep the oysters alive. One avenue to explore via research is selective breeding, a well-known practice that has been used in the past to maximize oyster size, yield, and susceptibility to disease4. The facilities and staff required to breed, grow, and measure different breeds of oyster would amount to a large increase in the firm’s expenses.
Genetic modification should also be considered as a tool for the company and researchers. A study released in 2009 showed that animals with lower concentrations of magnesium in their shells were less susceptible to increased ocean acidity, and thrived in water with up to 900 ppm of CO22. Genetic engineering has also already been used on oysters, but again to increase overall yield as opposed to increase resilience toward ocean acidity5. If researchers could find small modifications to the genetics of the oyster’s shell to decrease the magnesium levels, it may lead to a more resilient breed.
Lastly, Hog Island Oyster Co may need to consider a dramatic overhaul of their farming technique by building facilities (isolated from the ocean) to farm their oysters from the larval stage through maturity. This would drive costs up significantly, as the 160 acres of growing area would need to be isolated from the sea and controlled for acidity. They would then need to find an acceptable replacement for the ocean’s natural circulation: the food and nutrients brought in with the tides and the waste product from the oysters carried away. Engineering a replacement for the natural tide would be the most difficult, as oyster taste and quality is driven by some very small factors in their specific environment, and finding the right combination of nutrients, minerals, and other qualities of the water would take intense experimentation. This will be a research and capital heavy project but may very well be required if CO2 levels in the ocean continue to rise over the next few decades.
 Hog Island Oyster Co. “Farming Oysters” https://hogislandoysters.com/oysters/farming
 Oceanus Magazine. “Ocean Acidification: A Risky Shell-Game” http://www.whoi.edu/oceanus/feature/ocean-acidification–a-risky-shell-game
 San Francisco Chronicle. “Oyster Farmers Worried as Climate Change Lowers Ocean pH” http://www.sfchronicle.com/bayarea/article/Oyster-farmers-worried-as-climate-change-lowers-6445523.php
 (abstract) Calvo et. al “Dual disease resistance in a selectively bred eastern oyster,Crassostrea virginica, strain tested in Chesapeake Bay” http://www.sciencedirect.com/science/article/pii/S004484860200399X
 The Telegraph. “Genetically ‘Improved’ Oysters Behind France’s Shellfish Plague” http://www.telegraph.co.uk/news/worldnews/europe/france/2656892/Genetically-improved-oysters-behind-Frances-shellfish-plague.html