MobLab
Instructions
Aa

# An Open-Access Fishery

## Background

• Each of a number of fishing fleets fishes in an area
• Each season, each fleet chooses how many fish to catch
• The fish remaining at the end of season grows before next season starts
• Fish-stock growth depends on number of remaining fish
• Low growth when stock is either very low or near area's capacity
• The smaller the fish stock, the more costly it is to catch fish

## How to Play

• Your catch depends on both your effort level and the current fish stock
• Each round, use the slider to choose an effort level from 0 to 100
• Graph shows profits for each possible effort level
• Click Submit to submit chosen effort level

## Payoff Computation

• $${\small \text{Revenue}=5\times\text{Your Catch}=5\times(\frac{\text{Fish Stock}}{\text{Area Capacity}}\times \text{Your Capacity}\times\frac{\text{Your Effort}}{100}})$$ $${\small \text{Your Cost}=80 \times \text{Your Effort}^2 - 50 \times \text{Your Effort}}$$
• $${\small \text{Catch}=\frac{300,000}{900,000}\times 250,000 \times\frac{27}{100}=22,500}$$ $${\small \text{Revenue}=5 \times \text{Catch}=\112,500}$$ $${\small \text{Your Cost}=80 \times 27^2 - 50 \times 27 = \56,970}$$ $${\small \text{Revenue}-\text{Costs}=\55,530}$$