Between 1949 and 1955, the State Department pushed for an international fisheries policy grounded in maximum sustainable yield (MSY). The concept is based on a confidence that scientists can predict, theoretically, the largest catch that can be taken from a species’ stock over an indefinite period. And while it was modified in 1996 with passage of the Sustained Fisheries Act, MSY is still at the heart of modern American fisheries management. As fish populations continue to crash, however, it is clear that MSY is itself not sustainable. Indeed, the concept has been widely criticized by scientists for ignoring several key factors in fisheries management and has led to the devastating collapse of many fisheries. Carmel Finley reveals that the fallibility of MSY lies at its very inception—as a tool of government rather than science. The foundational doctrine of MSY emerged at a time when the US government was using science to promote and transfer Western knowledge and technology, and to ensure that American ships and planes would have free passage through the world’s seas and skies. Finley charts the history of US fisheries science using MSY as her focus, and in particular its application to halibut, tuna, and salmon fisheries. Fish populations the world over are threatened, and All the Fish in the Sea helps to sound warnings of the effect of any management policies divested from science itself.