Active flux seasonality of the small dominant migratory crustaceans and mesopelagic fishes in the Gulf of California during June and October

•Migrant biomass and respiratory flux were estimated in mesopelagic organisms.•The largest migrant biomass were mesopelagic fishes followed by decapods.•Fishes showed high values of respiratory flux at the centre-eastern coast of the gulf.•Midriff Islands region had one of the highest values of crustacean respiratory flux.•Micronekton respiratory flux was higher during June than during October.