The impact of climate change is reverberating through industries worldwide, and few are feeling the effects as acutely as the local oyster farmers in Morro Bay. For over a hundred years, these farmers have cultivated oysters in the bay's rich waters, but now face serious threats to their multi-million-dollar enterprise due to shifting climate conditions. As ocean acidification becomes a growing concern, local farmers are stepping up with creative solutions to safeguard their livelihoods.
Beneath the surface of Morro Bay, nearly five million oysters are flourishing, while on land, shuckers work tirelessly to meet the increasing demand for these delicacies. Robert Moon, a crew member at Morro Bay Oyster Company, shares that they process about "800 dozen a week, fluctuating based on demand."
However, the changing climate is presenting new challenges for oyster aquaculture. Variations in temperature and pH levels, particularly due to ocean acidification, are becoming significant hurdles for farmers. Nick Soares, who collaborates closely with local farmers through the Morro Bay National Estuary Program, acknowledges, "We are very aware of the changes in temperature and pH, with ocean acidification being a major concern."
At Cal Poly’s Center for Coastal and Marine Science, researchers are diligently investigating these environmental shifts. In Dr. Emily Bockmon's lab, students and faculty are tracking how rising levels of carbon dioxide in the atmosphere are altering seawater chemistry. "We have comprehensive evidence showing that seawater pH has been declining over time, correlating with increased atmospheric CO2," Bockmon explains, drawing attention to the critical data that informs their studies.
To illustrate this alarming trend, one can refer to a graph documenting atmospheric carbon dioxide levels (measured in parts per million) since 1958 at the Mauna Loa Observatory in Hawaii. As more carbon dioxide permeates the atmosphere, a portion dissolves into ocean waters, resulting in the formation of carbonic acid. This reaction inevitably leads to a decrease in pH levels.
This decline in pH creates a cascade of effects throughout marine ecosystems. However, for oyster farmers, the most pressing issue lies in shell development. Bockmon elaborates, "The reduction in seawater pH over time could create an environment that makes it increasingly difficult for oysters to form their shells."
The most critical phase of an oyster's life cycle is its earliest stages, which are particularly susceptible to these changing environmental conditions. Nate Reiss from Grassy Bar Oyster Company emphasizes this vulnerability, stating, "Ocean acidification complicates hatchery operations, especially when the oyster larvae are still extremely small; they struggle to develop their shells."
Oyster seeds begin their journey in the Floating Upweller System, or FLUPSY, where they grow from mere millimeters to the size of a quarter before being introduced to the bay. A visual comparison shows how small 6-10mm oyster seeds on the left contrast with the quarter-sized oysters on the right.
Fortunately, oyster farmers in Morro Bay benefit from unique local conditions that offer some protection against these challenges. "We produce very robust shells here, which is a significant advantage of our water quality," Moon notes. "Brittle shells are not a common issue for us, and generally, our oysters manage quite well."
The influx of water from Chorro Creek plays a vital role in this resilience by delivering compounds that help neutralize acidity, thus serving as a natural buffer against acidification. Soares mentions, "It appears that the creek's contributions are buffering the bay somewhat by adding various carbonate ions, assisting in preventing acidification."
Despite the relatively limited losses experienced in Morro Bay, hatcheries along the West Coast are facing severe difficulties. "I’ve heard reports of a hatchery in Oregon struggling significantly with this issue, which is where I originally come from," Reiss shares.
While local effects haven't manifested yet, experts predict that widespread acidification will be a reality within the next century. According to the Environmental Protection Agency, the oceans are currently experiencing their highest acidity levels in two million years. For further insights, you can explore more details from the EPA.
"We anticipate that pH levels in Morro Bay will decline in the upcoming decades, and this is a challenge that the farms will need to address," Bockmon warns.
In response to these impending challenges, local oyster companies are already taking proactive steps. "From my viewpoint, both Morro Bay Oyster Company and Grassy Bar Oyster Company are innovating and discovering effective strategies to adapt," Reiss notes positively.
These companies are investing in the native Olympia oyster market and are also exploring the implementation of pH-lowering seagrasses in their farming practices as preventative measures. "There’s been considerable discussion about co-locating seagrasses with oyster beds to manage varying seawater chemistry, as seagrasses can help elevate seawater pH," Bockmon adds.
Despite the daunting challenges on the horizon, local farmers continue to express optimism about finding viable solutions. "California’s oyster farms are rapidly identifying ways to tackle these issues, and I genuinely believe there’s a great deal of hope for the future," Reiss concludes.
If you have a story that you'd like Meteorologist Vivian Rennie to investigate, feel free to reach out via email at Vivian.Rennie@ksby.com.
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