In common with many fish stocks in the North Sea, cod are heavily exploited with as much as 60% of the fishable stock being removed annually(1). The International Council for the Exploration of the Sea (ICES), which advises fishery managers on the state of fish stocks in the northeast Atlantic, has recommended that exploitation rates be reduced considerably and immediately, in order to prevent further stock decline(1). We examine the most recent ICES assessment of the North Sea cod stock(1) to see if the present exploitation regimen is sustainable. Our analysis suggests that not only is the present exploitation rate unsustainable, but that even regimens dose to the maximum sustainable yield may be potentially prone to risk. There is a need for swift and effective action to protect the stock and avoid the problems of the much publicized collapse of cod stocks off the coast of Atlantic Canada(2,3).