Effects of Thermal Stress Events and Correlated Response on Thermal Tolerance of the Eastern Oyster (Crassostrea virginica)

Abstract

The eastern oyster (Crassostrea virginica) is an economically and ecologically important species. There is interest in improving the heat tolerance of this species for both aquaculture and restoration purposes. I examined the effects of induced acquired thermal tolerance (ATT) and genomic selection for Dermo disease resistance on the heat tolerance of this species. In the induced ATT study, oysters were exposed to sublethal heat stress at pre- and post- metamorphosis life stages. After recovery, animals were exposed for 30 days to 25 °C, 36 °C, 38 °C, and 40 °C. In the genomic selection study, genomically selected, phenotypically selected, genomic control, and wild control oyster lines were exposed for 20 days to 23 °C, 28 °C, 36 °C, and 38 °C. We did not see an impact of induced ATT on heat tolerance. However, the genomically selected oysters survived significantly longer at 38 °C than the other lines, indicating a positive relationship between disease tolerance and heat tolerance.