A simple bieconomic model (the Gordon-SChaefer model) is estimated for three species of tuna in the Eastern Tropical Atlantic. The model conformed well to the data and afforded estimates of maximum sustainable yield, bioeconomic and open access equilibria. Strong marginal stock effects were...

Adjustment of small, medium, and large Vermont dairy farms to successively tighter constraints on phosphorus loss was modeled using linear programming. Aggregate response to phosphorus control was estimated for an area from farm marginal costs. Medium and large farms have lower costs than small...