Few Holocene marine species extinctions have been recorded, and these have been of range-restricted species, mainly mammals and birds, over the past 300 years. However, marine extinctions may be more widespread than is currently appreciated, because it is difficult to observe the last individuals of a marine species, and because of a fallacious but widespread perception that marine organisms cannot be driven to extinction. Today's extensive overexploitation of global fisheries has a historical and prehistoric precedent in archaeological evidence for the local collapse of many fisheries and shellfish beds, and regional extinction of marine populations. The observed human capacity for causing rapid and widespread terrestrial extinctions combined with the rapidly increasing scale of human impact on the sea forewarn of an impending marine extinction event. The scale of this may be the equivalent of concatenating both of the terrestrial late Quaternary extinction waves into a much shorter timeframe.