In 1954 and 1957 Gordon and Schaefer respectively described the idea of maximum sustainable yield (MSY) – that is, the amount of fish that could be taken by commercial fishing operations to maximize reproduction by the system year after year. Since then, it has been heralded as the mathematical panacea to fisheries management.
Gordon and Schaefer also described the maximum economic yield which threw price relations into the mix. It describes the point at which the fishers will make the most money, accounting for revenue and their expenses. Note in the graph below the fold that the maximum economic yield (MEY) is below the MSY in terms of effort. Gordon and Schaefer imagined a private manager or government overseer that could calculate the MEY and regulate fisher behavior in order to meet it. The idea was meant to be win-win for the fishers and the fish.