# Greater Tuna

Welcome to Greater Tuna, a simulation game exploring sustainable management of renewable resources. This page is the instructions; the game itself is available via the link at the bottom of the page.

### Object of the game:

Find the profit-maximizing level of fishing effort for a sustainable harvest of a search fishery.

### How to play:

Each turn you must decide how much effort to devote to fishing. Enter the value using the Effort slider. When you're happy with your level of effort (!), click the "Next Turn" button to see how things turn out.

### Details about the fish:

This particular fishery is described by a biological growth function of the following form:

• Spawn = NatGrow*StartPop*(CarryCap-StartPop)/CarryCap
where Spawn is the number of new fish, StartPop is the population at the beginning of the period, and NatGrow and CarryCap are parameters. The population at the end of the period will be given by:
• EndPop = StartPop + Spawn - Harvest

where Harvest is the number of fish harvested by people (more on that below). This will become the starting population for the next period. (Just to make sure there aren't any ambiguities please note that Spawn, Harvest, EndPop and StartPop may vary with time while NatGrow and CarryCap are parameters.) It will be up to you to determine the numerical values of NatGrow and CarryCap. This should be a matter of observing a few data points and doing a little algebra.

### Details about the industry:

The harvest of fish is given by a function of the form:

• Harvest = Tech*StartPop*(Effort/100)
where Harvest is the number of fish caught, Tech is a parameter (initially unknown), and Effort is the level of effort. (The factor of 100 appears here for computer convenience rather than economics: it allows the slider to read from 0 to 100 instead of from 0 to 1.) Finally, the fishery is also a price-taker in both the fish and labor markets. Its total revenue and total cost are given by:
• Revenue = $1*Harvest • Cost =$2000*(Effort/100)
The goal of the game is to find the profit-maximizing level of effort AND to end up with a sustainable population--that is, one for which StartPop equals EndPop at the optimum level of effort.

### Link to the game itself:

URL: http://wilcoxen.maxwell.insightworks.com/pages/408.html
Peter J Wilcoxen, The Maxwell School, Syracuse University
Revised 03/12/2008