The Pacific chub mackerel has a worldwide distribution. There is limited information on the stock structure of Scomber japonicus off the coast of Ecuador, where it is locally named "macarela". Some authors state that in the SE Pacific, differences in growth patterns would suggest that the stocks in the Ecuadorian and Peruvian coastal regions would be distinct and separated by the Equatorial front (Patterson et al. 1993). Other authors suggest the existence of one stock in the south of Ecuador and north of Peru (which is more intensively exploited by the Ecuadorian fleet) and another stock in the south of Peru and north of Chile (Cucalón-Zenck et al. 2000). However, none of the above stock differentiation can be considered as entirely conclusive (Patterson et al. 1993)(Cucalón-Zenck et al. 2000). The stock status was assessed in the past in Ecuadorian waters (Patterson et al. 1993)(Cucalón-Zenck et al. 2000); most recently by (Canales et al. 2019)(Canales et al. 2020)(Canales and Jurado 2021) considering the same assessment unit within Ecuatorian waters, in lack of a known stock structure. However, there is evidence of a single population throughout the species' distribution, along the Ecuadorian, Chilean and Peruvian coasts (Barahona et al. 2017)(Minte-Vera 2019).