Model Behavior: Swimming behavior and climate change impact larval transport of the only native oyster (Ostrea lurida) in the…

Foundation species in marine ecosystems are often sessile invertebrates that rely on a planktonic larval stage for transport between populations and the colonization of new habitats. Larval transport is controlled by advection from currents but is mediated by swimming behavior and responses to water conditions such as temperature and salinity. Through the use of biophysical modeling, we can incorporate hydrodynamic forces with biological models to predict where larvae are delivered and how transport is impacted by different swimming behaviors and changing ocean conditions. Output from these models can inform restoration efforts through highlighting areas of potential settlement and more suitable habitats, allowing for more effective use of limited resources. Here, I use an Rbased biophysical particle tracking model to assess the impacts of swimming behavior (Chapter 1) and climate change (Chapter 2) on the larval transport of Olympia oysters (Ostrea lurida), a key foundation species in the Salish Sea that have undergone dramatic population reduction since European colonization of the Pacific Northwest coast. My results show that some restoration sites support larval retention and export better than others and may have more suitable habitat for retained larvae, but site-specific knowledge of swimming behavior is critical to understanding its effects on larval transport. I find that Olympia oyster larvae may fare better under future climate conditions, with increased growth and potential export, which could improve retained populations and connectivity between them. I further assess the implications of swimming behavior and climate change on larval transport, propose restoration recommendations, and highlight the usefulness of the transport model for other planktonic species in the Salish Sea.