The literature has been reviewed for information on hypoxic responses in marine bottom-living invertebrates and fishes, as a basis to define safe oxygen conditions for marine bottom communities in the North Sea and adjacent waters. bottom communities in the North Sea and adjacent waters. Hypoxic sublethal and lethal levels are tabulated according to systematic and functional groups of fauna. There is need for concern when the oxygen level drops below 65% of air saturation, and levels below 20% (1,2 ml/l) are considered as serious. Controlled experiments in basins with sediments are proposed in furure work
