Pacific sardine (Sardinops sagax), or South American pilchard, is a neritic, coastal pelagic species caught down to depths of about 40 m, that forms large schools. Pacific sardine off the West Coast of North America is thought to consist of three subpopulations or stocks (Vrooman 1964): a northern (“cold”) subpopulation (northern Baja California to Alaska), a southern subpopulation (outer coastal Baja California to southern California), and a Gulf of California subpopulation have been distinguished by population studies (Hill et al. 2015). A recent genetic study shows two different possible configurations: one possibility considers a single population between the southern subpopulation and the Gulf of California subpopulation, or that these are separate populations (Hid Coronel 2020), as described by (Vrooman 1964). (Lecomte et al. 2004) theorizes that the population is not geographically structured, but rather responds to a basin model, where in times of population crash the distribution contracts to its optimal range, which would explain low genetic differentiation along its distribution. For the purpose of this profile, and considering that both assessment and management also consider it as the stock, the population is considered as the entire Gulf of California.