4.3.13 (HL)—MSY risks

Managers should harvest below estimated MSY because stock size, recruitment, mortality and environment are uncertain.

If the estimate is too high, catch removes breeding adults faster than replacement. Lower reproductive potential then shrinks the next stock, making the same quota more damaging.

A model predicts MSY=1,000 tonnes; a precautionary 700-tonne cap leaves room for forecast error and poor recruitment.

It reduces the chance that uncertainty pushes removal beyond replenishment and starts a reinforcing decline.

A buffer is not arbitrary under-management; it is a response to uncertainty and irreversible stock loss.