Date of Completion


Degree Type

Honors Thesis


Biology (BIOL)

First Advisor

Dr. M. Christina Vasquez


Climate change has negatively altered seawater conditions, which may have severe implications for marine ecosystems. Mussels are susceptible to environmental changes since they are primary consumers and filter-feeding bivalves. Two species of particular interest to the West Coast of the U.S. are Mytilus galloprovincialis and M. trossulus. M. trossulus is native to the California Coast and was historically prevalent from Southern California to Washington. However, with increased shipping and rising seawater temperature, M. galloprovincialis, an invasive species from the Mediterranean, pushed the species range of M. trossulus poleward. M. trossulus is more tolerant of cold seawater with variable salinity while M. galloprovincialis thrives in warmer, more saline water. Recent studies have shown zones of hybridization in Central California where both species co-exist. By understanding the dynamics of abiotic seawater conditions and how they have been altered by climate change, we can make better predictions of where M. galloprovincialis might take root next. Using publicly available data from NOAA, CeNCOOS, and SCOOS I characterized patterns in seawater temperature (oC), salinity (ppt), oxygen concentration (mg O2/L), and pH level at various sites throughout San Francisco Bay, CA from 2010 to 2020. My results show that San Francisco Bay is variable with site-specific differences in salinity and temperature. Based on each species’ environmental stress tolerance levels, M. galloprovincialis is likely the dominant species at Fort Point, Tiburon, and the East Bay, while M. trossulus is likely more prevalent at Carquinez.