to protect their livelihood. Thus, the complexity of the scientific terminology and
issues and the usually strained economics of fishing (next) have become overlain by
the historical arcana rife in our legal system.
Fishery Economics
(^) Fishery biology interacts profoundly with fishery economics. If we have a well-
behaved and well-understood fishery, we can control it to any of several ends:
(^)
(^) for fishers to make lots of money;
(^) to get lots of nutritious, tasty food;
(^) to protect the stock as fully as possible while still exploiting it at a useful rate.
(^) Usually we don’t achieve control, for a variety of reasons. Perhaps the most
important is that most fisheries are free, unowned resources. Anyone who can obtain a
boat can go fishing. Thus, so long as there is a dollar, yen, or krone to be made in a
fishery, more fishers will show up to attempt to earn it. Therefore, in most of the
world’s fisheries, the average profit is very close to nothing. This comes about as
follows. The dollar (or yen, ¥) return to a fishery is roughly proportional to yield
(although large yield will depress prices). That is, $ = kY. Yield has a parabolic
relationship to effort, or at least varies as some curve showing diminishing returns.
So, dollar return must also be parabolic with effort. Cost of effort, on the other hand,
increases roughly linearly with effort: each additional boat costs about the same as the
one before it. These two relationships are shown together as follows:
So long as the fishery is below the break-even point, new entrants (buying boats and
starting to fish) can make a profit. Approaching the break-even point there is still a
profit, but it is divided between more and more boats. At the break-even point, the
mean profit is zero. In fact, many or most fisheries move about their break-even point
with year-to-year variations in catch and effort. On average, the return to investment