Carbon remineralization by small mesopelagic and bathypelagic Stomiiforms in the Northeast Atlantic Ocean

•Highest abundances of Cyclothone spp. were observed between 400–600 m and 1000–1500 m depth, both during day and night.•Smaller species were found in the mesopelagic zone than in the bathypelagic zone.•Oxygen consumption rates of Cyclothone spp. decreased with temperature and body mass.•Biomass and community respiration were positively associated to productivity with highest values in the eutrophic and temperate stations.•Carbon remineralisation by non-migrant fishes organisms was low compared to zooplankton and microplankton.