21


receive the highest return. Thus, in the case depicted by Figure 4,

fishermen will enter the fishery and allocate their effort such that the

value of average productivity (VAP) of the two grounds is equal to

average cost (r) and, hence, equal on all grounds. Thus, OE' units of

effort will fish on Ground 1 and OE2 units will produce on Ground 2.

Effort levels, El and E2, correspond to the effort levels that would

produce a catch equal to maximum sustainable yield. This makes it

apparent that the result of unregulated competition in this common

property resource industry leads to effort levels greater than that

necessary to harvest maximum sustainable yield. One final point of

note is that on both grounds, effort is employed past the point of nega-

tive marginal productivity. This represents Gordon's (1954) theory

explaining the results of production from a common property resource

under a competitive regime.

 Gordon also proposed a bioeconomic model of the fishery at the

 industry level. Schaefer (1957) presented essentially the same model.

 Due to the wide use of the so-called Schaefer model in fishery theory

 and its similarity to Gordon's formulations, the following analysis

 follows Schaefer.

 The Schaefer model begins with the definition of the long-run

 equilibrium industry production function. This function, based on a

 logistic population growth function, was shown in equation (8) to be a

 special case of the GSPM. Equation (9) restates equilibrium catch

 function as

 C = aE(b E) (9)

 2 K1M
 where a and b in terms of the constants in equation (8), and
 K1 q