Eastern boundary current systems (EBUS) present contrasted levels of anoxia. A shallow oxycline reduces the habitat for most species, concentrating pelagic life within a thin surface layer. This is particularly significant at night when diel migrant organisms occupy the surface oxygenated layer to ‘pay their oxygen debt’. Such organisms’ concentration can enhance trophic interactions among species. Some winners indeed benefit from the lower energetic cost to forage. On the other hand, certain species cannot survive within a too narrow oxygenated habitat and are expulsed from the system. In addition, habitat compression does not occur in the vertical plane only. Indeed the oxycline/pycnocline is not a flat boundary but is shaped by internal wave, submeso- and meso-scale processes. This lead to local downward deformation of the clines, generating small-scale oases for life. In this context, the objective of this work is to review the impact of the oxygen minimum zone, in particular the spatiotemporal dynamics of its upper boundary, on planktonic and nektonic (fish and squids) species in EBUS. In addition, we will discuss on the consequences for population dynamics and foraging efficiency of air-breathing predators, in particular seabirds and fishers.