Sustainable Yield

Sustainable yield is the catch a stock can produce indefinitely without reducing its biomass over time, the harvest matched to the stock’s surplus production. In the logistic Schaefer model surplus production traces a dome against biomass, so a range of sustainable yields exists below the peak, and the peak itself is the maximum sustainable yield at about half the unfished biomass. Any catch above the surplus production at the current biomass draws the stock down; a catch equal to surplus production holds it steady. Managers treat sustainable yield as the ceiling that fishing mortality and total allowable catch must respect.