Pacific chub mackerel has a wide Indo-Pacific distribution (Froese and Pauly 2019). In the Northeast Pacific, the distribution spreads from Southeastern Alaska to Mexico, including the Gulf of California (Crone et al. 2019). Originally, biological samplings of physical characteristics determined that five populations were occurring: California and British Columbia, northern Baja California, central Baja California, the Cape San Lucas region, and the Gulf of California (Roedel 1952, at (Hernández et al. 2000)). Another study found only two stocks, from southern California to Vizcaíno Bay and the other for the entire Gulf of California, overlapping at Magdalena Bay (Gluyas-Millán and Quiñonez-Velázquez 1996). Three spawning aggregations exist: one in the Gulf of California and two in Baja California, one of which extends to Southern California and is exploited by the US and Mexico (Crone et al. 2019). A northwards migration to feeding waters off the coast of Oregon and Washington states and a southwards return to spawning areas off the coast of Southern and Baja California connect fisheries in both countries (Crone et al. 2019).

Therefore, Mexico and the US share a population (spawning aggregation) of mackerel, but information from the Mexican side is scarce, whereas the US performs assessments on it every two years (Hill and Zwolinski 2021).