Northern anchovy, Engraulis mordax is a small pelagic schooling fish distributed between Southern Baja California, Mexico, and Northern British Columbia, Canada (Schwartzkopf et al. 2022). This is an important forage species for many predators, including fish, birds, and mammals. Three subpopulations (northern, central, and southern) are typically recognized based on electrophoretic, morphometric, and meristic characteristics (McHugh 1951 in (Schwartzkopf et al. 2022))(Vrooman et al. 1981) and growth rates (Parrish et al. 1985), with the southern subpopulation including central-southern Baja California and the Gulf of California (Kuriyama et al. 2022)(Schwartzkopf et al. 2022). However, a basin model is proposed for this species, in which under adverse conditions, distributions contract to an optimal range, while the population crashes, and from where it would expand once conditions restore, and therefore, no apparent genetic structure would be found (Lecomte et al. 2004). Additionally, subpopulations show annual and seasonal movements, and overlapping and interchanging distributions (Schwartzkopf et al. 2022).

In the area of distribution of the subpopulation, the harbor that presents important anchovy landings is Sonora (DOF 2022)​. In the Gulf of California, the anchovy is part of a multispecific fishery that primarily targets the Pacific Sardine (South American Pilchard, Sardinops sagax) (García-Sandoval and Chávez 2019)(DOF 2022). Assessments do not include Baja California, and focus on the Gulf of California, where the main fishery for small pelagic fish occurs, and coincides with Region B proposed by INAPESCA to better manage the fishery (DOF 2019).