Mitigation Strategies to Reduce OA Impacts on C. gigas

Motivation and Project Description:

Oysters provide critical ecosystem services including providing habitat, locally buffering against corrosive conditions, and serving as a harvestable resource (Waldbusser et al., 2013). Oyster health and survival are threatened by changing carbonate chemistry environments. Anthropogenic increases in pCO2 have caused a subsequent shift in carbonate chemistry. Declines in carbonate ion (CO32-) availability has caused shifts in calcite saturation state (Ω CaCO3). For calcareous organisms such as oysters, who require carbonate ions to construct their shells this is of particular concern.

Oyster shells may become a source of alkalinity upon death when dissolution is no longer balanced or exceeded by calcification. Oyster reefs have been shown to be a source of alkalinity in reef-building populations such as the Eastern oyster (­Crassostrea virginica) (Waldbusser et al., 2013), however, Pacific oysters are non-reef building populations, and are thus limited in their alkalinity production. Shell plantings, collections of oyster shell material, have been suggested as a possible mitigation strategy for ocean acidification impacts on Pacific oysters, however, no studies to date have rigorously investigated their influence on oyster condition. This study seeks to examine how oyster health varies with culturing practices. Specifically, we examine how the presence of shell bags as well as elevating oysters off the mudflat may alter oyster health.

Objectives of this study are to:

  1. Examine the effectiveness of using condition index to determine oyster health and,

  2. Determine optimal shell planting practices in oyster aquaculture to mitigate ocean acidification impacts.


This work was funded by Oregon Sea Grant (Grant ID: R/SAQ-21-Shiel).

Current Status:

The field portion of this research was conducted in Netarts Bay, OR between 2016 and 2018. 


Related Conferences and Outreach:

CERF 25th Biennial Conference, Mobile, AL (November 2019) - Poster

Sophia Wensman, Alyssa Shiel, George Waldbusser

Abstract: Efficacy of utilizing shell plantings to mitigate ocean acidification impacts on oyster (Crassostrea gigas) health.

Leading and Enaboling Adolescent Futures in STEM, Corvallis, OR (April 2019-January 2020) - Mentor and Facilitator

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