Fatty acids, selenium, and vitamin B12 in chub mackerel (Scomber colias) as nourishment considering seasonality and bioaccessibility as factors

•Chub mackerel is a rich source of EPA, DHA, Se, & vitamin B12.•Fatty acid bioaccessibility percentages were usually high, being mostly above 60%.•Se bioaccessibility was 91–95% & vitamin B12 bioaccessibility was 77–83%•Based on bioaccessibility, meeting Se requirement would entail 107–114 g mackerel/day.•For EPA + DHA & vitamin B12, 15–51 g mackerel/day would meet nutrient needs.