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regulation and the "economically efficient" management goal of attaining

maximum economic yield. In all cases, these results were obtained from

models which treated the fishery as a single aggregate operating with a

constant product price. The purpose of this section is to first relax

the assumption of a constant product price and then extend the results

to consider the case of a multi-sector fishery where each sector cor-

responds to a sub-industry defined on regional or state basis.


Fishing Effort and Equilibrium Yield


 Before pursuing these extensions, a brief digression on the concept

of fishing effort and equilibrium versus non-equilibrium production

functions will be useful. Prior to this discussion, a specific defini-

tion of fishing effort has been omitted, being defined only as some

measure of fishing activity. Traditionally, this measure has been

defined to be a composite of physical inputs in the fishery. Gulland

(1965) and Rothchild (1977) have noted that the notion of fishing effort

to the biologist and economist are different, especially in the long run.

This difference can be seen by comparing the effects of doubling effort

under the biological definition of effort as opposed to that of the

economist. Biological definitions of fishing effort are generally

couched in terms of catch. This results in the conclusion that a doubl-

ing of effort, other things being equal, must necessarily result in a

doubling of catch. In contrast, the economic definition of effort is

independent of catch. Under this definition a doubling of effort does

not necessitate a doubling of catch. Thus, it can be seen that the

concept of fishing effort can indeed be quite different to different

disciplines.