Mitigating the effects of multiple stressors in oysters: comparison of diploid and triploid Crassostrea gigas
Why we care
Ocean warming, acidification, and hypoxia are increasing threats in the world’s coastal waters, with potentially severe consequences for marine organisms and ocean economies. Waters in the Pacific Northwest are naturally more corrosive with low pH values, making this region particularly vulnerable to the effects of acidification. This region is also a leading producer of farmed shellfish in the U.S. Summer mortalities of Pacific oysters are a growing concern for the shellfish industry. There is also an increasing concern that triploid (seedless) oysters, which grow faster than their reproductive diploid counterparts, are marketable during their summer spawning season, are more sensitive to summer mortality events. Not much is known about what causes these events, though growers and researchers suspect it is a combination of stressors and disparate responses by oysters with different ploidy (number of chromosome copies). This project investigates how oysters with different ploidy tolerate the natural variability of pH, temperature, and dissolved oxygen.
What we will do
Researchers and shellfish growers from Baywater Shellfish Farms will collaborate to better understand the tolerance of Pacific oysters with different genomes. They will integrate oceanographic measurements, field work and laboratory experiments to examine the physiological sensitivity and survival of diploid and triploid oysters under multiple stressors. Diploid oysters, like us, have two sets of genetic material from their parents. Triploid oysters have three sets and are often referred to as “seedless”.
The team will monitor pH, temperature, and dissolved oxygen on commercial farms and investigate the influences of these conditions on the survival, gametogenesis and physiology of the farms’ diploid and triploid oysters. Researchers will also assess the effects of these conditions on oyster performance in a controlled laboratory setting.
Finally, the team will develop a decision tool for growers by combining economic information with the data collected from the farm and laboratory experiments. This simple-to-use planning tool will help Puget Sound 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.
Benefits of our work
Through a strong partnership between NOAA researchers and shellfish growers, this work will ultimately inform shellfish grower management and business decisions. A key outcome is a decision tool for growers that allows them to balance the risks and benefits of oyster planting approaches in their areas.
Investigators
Jacqueline L. Padilla-Gamiño, University of Washington
Jonathan (Joth) Davis, Baywater Shellfish Farms
Paul McElhany, Northwest Fisheries Science Center
Shallin Busch, Northwest Fisheries Science Center
This work was funded in partnership with the NOAA Sea Grant Aquaculture program.
Image: Oyster grower in Samish Bay next to lines of raised Pacific Oysters on a sunny day. Credit: Puget Sound Partnership
