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). Different studies have found a varying number of populations along this distribution (Roedel 1952, at (Hernández et al. 2000))(Gluyas-Millán and Quiñonez-Velázquez 1996). The most recent studies found three spawning aggregations: one in the Gulf of California and two in Baja California, one of which extends to Southern California, which 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).