For this research, the university of washington, NOAA, and baywater shellfish will collaborate to integrate oceanographic measurements, field work, and laboratory experiments to examine the…

For this research, the university of washington, NOAA, and baywater shellfish will collaborate to integrate oceanographic measurements, field work, and laboratory experiments to examine the physiological tolerance and survival of diploid and triploid crassostrea gigas (pacific oyster) under multiple stressors. When combined with economic information and summarized in a decision support tool, our results will help shellfish growers balance the risks and benefits of planting triploid oysters (that are marketable in summer) against the potentially higher mortality of triploids compared to diploids as a function of the multi-stressor environment. The potential higher mortality associated with triploids creates a risk assessment challenge for growers. Growers must choose whether to plant diploids, which have a lower mortality, but are unmarketable in the summer or plant triploids, which can be sold year-round, but may DIE before they can be harvested. We plan to develop a decision support tool that will allow growers to quantitatively assess which ploidy is the better option for a particular site given the effect of multiple stressors. The tool could be applied both in the current season for real-time decisions and be used as part of a forward-looking assessment to improve climate adaptation for the shellfish industry in washington state. Project objectives: 1. Examine how the natural variability of temperature, PH, and dissolved oxygen influences the survival, gametogenesis and physiology of diploid and triploid oysters in farm settings. 2. Quantify the effects of PH, temperature and oxygen on the physiological performance of adult c. Gigas in a laboratory setting using single and multiple stressor experiments. 3. Develop a decision tool for growers to evaluate the likely impacts of multiple stressors on triploid and diploid oysters in puget sound, washington.