Fishery bulletin of the Fish and Wildlife Service - NOAA

58 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE
abundance of striped bass, the problem is to see how overfishing affects the stock.
Theoretically this factor may act in two ways—first, by the removal of too high a
proportion of undersized and immature fish so that there are too few spawning individuals,
and second, by failing to take the members of the available population at
the most efficient size.
In regard to the removal of too great a number of striped bass before they have
been given a single chance to spawn, evidence has already been presented to show
that the fishery for the smaller size-categories of bass, 2- and 3-year-olds, is highly
intensive, and that a large percentage of each successive year-class is caught before
its members attain maturity. Yet there is no reason to believe that an additional
supply of spawning individuals would result in an increased production, with the one
possible exception noted below. Thus it has been emphasized in the section on
fluctuations in abundance of the striped bass that the dominant 1934 year-class was
apparently produced by as small a parental stock as there has ever been. This means
that in southern waters the production of dominant year-classes is not completely
dependent—at least down to a certain limit—on the quantity of spawning individuals.
In other words, there appears to be no need for concern over the size of the spawning
population in the south as long as it is at least as large as it was in 1934. If such a
hypothesis be granted, there can be little good in raising the legal-length limit solely
for the purpose of increasing the number of spawning fish—especially since we know
that under the conditions of the present fishery the number of striped bass along the
Atlantic coast is sufficient to produce a year-class of enormous proportions, such as
the one that originated in 1934.
There is, however, one way in which an increased number of spawning adults
may possibly bolster the supply in northern waters, for this supply has apparently
declined in some cases to such an extent that the population has been practically
wiped out. It has been shown before that in certain years striped bass from the south
migrate north of Cape Cod. Since it has been well established that some of these
migratory fish remain in northern waters through the winter, it is a reasonable expectation,
if they were mature fish, that they would repopulate some of those areas
which formerly supported small populations in northern waters and are still suitable
for spawning purposes. Thus the striped bass has been virtually an unknown quantity
north of Cape Cod for the past 30 years or more; that is, until the members of the
dominant 1934 year-class came north of Cape Cod in huge quantities in 1936 and 1937
and provided a renewed sporting and commercial fishery of considerable size in those
waters. It is certainly not unreasonable to predict that if a sufficient number of
mature fish repopulate the spawning areas that still remain north of Cape Cod, the
stock in northern waters can be replenished and the supply increased and maintained
if the fish are given the proper protection.
It may therefore be said that measures designed to increase the supply of striped
bass along the Atlantic coast by providing a greater number of spawning fish might
quite possibly prove ineffective in the more southern waters of the Middle Atlantic
Bight, for it is known that there are now a sufficient number of mature individuals
to produce huge quantities of fish if the environmental factors are right; witness the
dominant 1934 year-class. On the other hand, such measures would probably renew,
at least partially, the supply north of Cape Cod where the stocks have been practically
exhausted in many instances.
The other aspect of overfishing to be considered is whether or not the present
fishery along the Atlantic coast takes the available members of the population at the
most efficient size, or, whether or not the fishery makes the best possible use of the
supply each year. Thompson and Bell (1934), Graham (1935), Thompson (1937),
and others, have all discussed the theory of the effect of fishing on various stocks of
fish, and have studied the problem of the most efficient utilization of the stock in
different species. These papers have laid the foundation for future studies along this
line, and it is possible to apply many of the principles set forth in them to the striped
bass fishery of the Atlantic coast. Those who are critically interested in this whole
subject should refer to the work of these authors.
The first problem in connection with the striped bass is to get some measure of
the yield from the stock under the existing conditions of the fishery at the present time.
Having attained this, it is possible to compare it with the yield from the stock under