Changing waters, changing views: Stakeholder perspectives on ocean acidification and adaptations in shellfish aquaculture
Shellfish aquaculture is a vital industry in the US, but one which faces mounting challenges threatening both productivity and business viability. Research often fails to align with growers’ immediate needs, so researchers set out to help close this gap in a new study published in Aquaculture Reports, interviewing over 30 commercial shellfish growers across the US Pacific region.
Funded as part of NOAA’s Ocean Acidification Program, former Research Scientist at the University of Washington School of Aquatic and Fishery Sciences (UW SAFS) and now a Fisheries Resource Management Specialist with NOAA Fisheries, Connor Lewis-Smith led the research to document how industry participants perceive ocean acidification threats and evaluate emerging adaptation strategies that are actively being researched: parental priming and native species portfolio diversification.
The research team included scientists from NOAA Northwest Fisheries Science Center (NWFSC), Puget Sound Restoration Fund, UW SAFS, and the University of the Virgin Islands. They interviewed owners, field managers, hatchery managers, and other staff from operations across five states on the Pacific Ocean: Washington, Oregon, California, Alaska, and Hawaii. “Operations ranged in scale and included hatchery, nursery, and growout components. We also included tribally managed and tribally affiliated businesses,” Lewis-Smith said.
Taking a step back in time to 2013, concern about ocean acidification among shellfish growers was four times higher than among the general public, a result of the hatchery crisis of the mid-2000s, where hatchery-produced oysters started dying by the billions along the Northwest coast. Today, ocean acidification remains a concern, but less so. Based on interviews among growers in 2023-2024, the team found ocean acidification to be a lower-priority concern compared to other stressors such as temperature, disease, harmful algal blooms, and regulatory constraints.
“Many growers are unsure whether declining survival or productivity is due to ocean acidification, other environmental changes, or a combination,” Lewis-Smith said. “This nuance, where ocean acidification is seen as an ever-present “enemy on the hill,” but not necessarily the most urgent battle, points to the need for research and risk communication that reflects the interconnected nature of aquaculture stressors.”
Enhanced monitoring and adaptation to changing environmental conditions is actively supported across the industry, and this is where research plays a critical role, not only to deliver these adaptations, but to align them with growers’ practical realities and decision-making needs. In the study, the researchers looked at growers’ perceptions of two adaptation strategies to ocean acidification: parental priming and native species portfolio diversification.
Parental priming uses environmental conditioning of the parental generation to enhance the resilience of shellfish offspring. Native species portfolio diversification involves cultivating native species, such as Olympia oysters and geoduck clams, which may offer inherent resilience to ocean acidification.
“Historically along the Pacific coast, the shellfish aquaculture industry has relied heavily on introduced species, such as Pacific oysters originally imported from Japan over a century ago, and they now account for the vast majority of production. Manila clams are another major contributor, also introduced,” Lewis-Smith shared. “These species became dominant in the early 20th century as native oyster populations like the Olympia oyster collapsed due to overharvest and habitat degradation.”
Researchers found higher levels of skepticism towards native species diversification stemming from regulatory hurdles, limited market demand, and slower growth rate of some species. Current regulations restrict the propagation of native species to preserve genetic diversity, while from an economic perspective, native species like Olympia oysters grow more slowly and may not meet market preferences for size, taste, or shucked-meat yield. There’s also an infrastructure concern to address, with restructured farming practices required for some native species. “We found that 69% of respondents cultivated at least one native species, and some are actively expanding their native offerings, however the industry’s core remains centered on introduced species,” Lewis-Smith said.
On the flip side, parental priming was viewed as a promising, if still experimental, strategy—one that 64% of growers and hatchery operators would consider if backed by strong scientific evidence. By conditioning broodstock to low pH or other stressors during gonadal maturation—to enhance offspring resilience—this strategy doesn’t require overhauling product lines, shifting consumer preferences, or navigating regulatory pathways. Concerns about this strategy were also uncovered during the study, emphasizing the financial and logistical burden of adopting new protocols, and stressing broodstock during critical life stages.
“We found that the relatively high interest in parental priming reflects a broader industry trend toward cautious innovation, where growers are open to new strategies, but only when those strategies are empirically validated, operationally feasible, and financially justifiable,” Lewis-Smith said.
In addition to gathering information on the industry’s perspective on environmental stressors and emerging strategies, the team concluded that collaboration between growers, researchers, and policymakers is essential for co-producing relevant adaptation strategies that are scientifically sound and operationally feasible. “The industry has already shown collaborative success in implementing monitoring and buffering systems after the 2005–2009 ocean acidification induced hatchery shortages,” Lewis-Smith said. “However, sustained engagement and support are needed to develop and scale newer strategies like priming or diversification, especially given the sector’s diversity and regulatory complexities.”