Transgenerational plasticity responses of larvae of Sydney rock oysters (Saccostrea glomerata) to ocean warming

Ocean warming and marine heatwaves are expected to significantly affect marine species' physiology, compromising species survival. Yet, the degree of acclimation through transgenerational plasticity (TGP) is unknown, particularly early life stages (larvae) of ecologically and aquaculturally important species such as oysters. Here, we assess the TGP response to elevated temperatures in larvae from two genetically distinct families of Sydney rock oyster, Saccostrea glomerata. Adults were exposed to control (24 °C) and warm (28 °C) for ∼8 weeks during reproductive conditioning. Subsequently, within-family crosses were made and percentage development, abnormality, shell size and LT50 of larvae were measured after 48 h exposure to temperatures ranging 24.3-36.0 °C. Overall, larvae from warm parents had greater development, lower abnormality, but were smaller at higher temperatures compared to those from control parents. Furthermore, parental exposure to warming increased LT50 of larvae by approximately 2.0 °C in one family. Our findings suggest that TGP may provide S. glomerata larvae with resilience against warming and may provide buffer time for them to adapt.