FREC 240--EXAM #2 (Take-Home)
OPEN-ACCESS FISHERY MODEL
(use Excel or equivalent spreadsheet program)
The data
for this assignment summarize annual yields, effort levels and
dockside
prices (in 1976 dollars) for mid-Atlantic yellowfin hake. Download this
datafile and import it to Excel or whatever
other spreadsheet program you're using.
Create
an Effort-squared column adjacent to your effort column. (Insert a
column
between Effort and Price.) Using the spreadsheet program's
regression procedure (Tools-DataAnalysis-Regression in Excel), estimate
a quadratic effort-yield function of the form
YIELD = B1EFFORT + B2EFFORT2
Under "Input" enter the Yield range as the Y-variable; the Effort and
Effort-Squared ranges as the X-variables. Force the Intercept
term to zero (check Excel's "Constant is Zero" box). After executing
the
regression module, calculate a column of predicted yields and include
it in your graph to check that the predicted yield points trace out a
quadratic
curve passing through the actual yield datapoints. (Note: if you
don't have DataAnalysis in Excel's Tools menu, use Tools-AddIns and
check
the AnalysisToolPak add-in.)
- Use the estimated function to calculate the level of E that
maximizes
sustainable
yield from this fishery. Plug the value of EMSY into the
Effort-Yield
equation to solve for maximum sustainable yield (MSY). Show your
calculations.
- Use the regression utility to estimate an inverse demand
function
for yellowfin hake:
PRICE = C0 + C1YIELD.
Do not force a zero intercept (uncheck the "Constant is Zero"
box).
- Use the estimated effort-yield and demand equations to develop a
predictive bioeconomic model of the fishery.
In a separate column of your spreadsheet, enter effort levels
from 0 to 1000 in increments of 25. In adjacent columns calculate:
- the predicted yield (from your estimated effort-yield function)
for each EFFORT level;
- the predicted demand price for that yield (from the estimated
demand price equation);
- the predicted total revenue (predicted yield times predicted
price) for the industry; and
- the total cost for the industry, assuming a cost of $0.55 per
unit effort.
- the total profit for the industry (TR-TC)
- Create an X-Y graph of effort (horizontal axis) against yield,
total
revenue, total cost and profit (as lines); add appropriate title and
legend). Print this graph.
- In an adjacent column in your spreadsheet, calculate the average
cost
per
pound of hake (total cost divided by yield). Create an X-Y graph of
yield
(horizontal axis) against demand price and average cost (as lines; add
appropriate title and legend). Print this graph.
- TR has (or should have) two separate peaks at two different yield
levels.
Why?
- TC intersects (at least it should) TR at three different
points. Label these intersections A, B and C. Demand should intersect
supply
at three different points. Which intersection corresponds to point A on
the TR-TC graph? Which corresponds to point B? Which to point
C?
Explain.
- Calculate the consumer surplus associated with the
highest-price/lowest-yield
equilibrium point on the supply and demand graph.
- Calculate the consumer surplus associated with the
lowest-price/highest-yield
equilibrium point on the supply and demand graph.
- Explain why the middle intersection point is not a stable
equilibrium
for the industry.
- At what level of effort are industry profits maximized?