The Spanish mackerel (Scomberomorus brasiliensis) is of high commercial value throughout its distribution. In Northeast Brazil, this important fishery resource has been under strong fishing pressure since the 1960s, with length composition changing between 1998–2001 and 2020–2022. Length frequency distributions, exploitation indicators, and gear selectivity indicated the effects of overfishing on stock size structure, with excessive withdrawal of spawners and reduced numbers of adults larger than 60 cm in catches. In addition, gear selectivity changed, with reduced size at first capture in the 40-mm mesh. Our results indicated that the species is unsustainably exploited in the study area and suggested both growth and recruitment overfishing.