The California mussel (Mytilus californianus)
is a habitat engineer and important prey species for keystone species. A preferred food source for the sea star Pisaster ochraceus, the California mussel has also been a source of food for people along the California coast for over 10,000 years. They are found from Baja California to Alaska in the rocky intertidal. Their large beds provide protection to other organisms from abiotic stress and predation. A single mussel bed can sustain diverse communities with representatives from over 10 marine invertebrate phyla.
Changes in the abundance, size, and shell morphology of the California mussels have been a consequence of climate change and disease-related decline of their primary predator P. ochraceus. Whole-genome sequencing data from populations along the coast of California will provide new insights into variable population responses and help identify regional genetic differences.