Environmental Decision Making - EDM

Adding A Gar Population to the Model



1. Pull down the Gar block from the library.

2. Connect the block as you wish, but be prepared to explain your reasons for doing so. (Note: We wish to see what happens to the bass when gar are present.)

3. Attach the new gar block to the fourth connector on the plotter. How the sunfish, bass, and gar populations change over time should be recorded.

4. Run the simulation.

5. Take a few minutes to change the graph so that the gar values are labelled on the graph. You should click on the first tool in the plot window to do this. In the first column, fourth row from the top, click the empty label box and type "Gar kg/ha".

If you find the weight of any fish too low to read it from the graph, be sure to click on the eighth box in the plot window (showing two arrows) to redraw the plot so that all values will fit inside the plot. You may wish to move the gar from the Y1 axis to the Y2 axis as we have done with the bass.

6. Run as many simulations as you wish. (Keep in mind that changing more than one variable at a time is not recommended.)

Describe your results and explain the nature of these relationships as you see them.



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