In the regular fishery for mussels the beds are continually dragged
over with rakes, tongs, crowfoot hooks, or dredges. It is inevitable
that the young mussels will suffer to some extent from this process. It
is quite unnecessary, however, for the "infant" mussels, many of them
too small for any use at all and many more too small for any economical
or proper use in manufacture, to be entirely removed from the beds.
Mussels are thus uselessly destroyed that might be left to grow to a
size at which they would be both commercially valuable and properly
usable; meantime, too, they might take their natural part in the
reproduction of the species.
Furthermore, it would be desirable to leave portions of the rivers
entirely undisturbed by the operations of shelling during periods of
some years. This would accomplish a double object--it would leave the
best conditions for the natural reproduction of the remnant of the old
stock and for the growth of the young mussels and at the same time it
would create a series of reserves in which artificial propagation could
be carried on with the best conditions for maximum results. In such
closed regions the young mussels would have to contend against only the
normal unfavorable conditions which all mussels have ever had to
withstand, without an added toll of destruction being taken by the
direct and indirect effect of the operations of men.
The simple "closing" of a depleted region, if the exhaustion has not
proceeded too far, may be expected to lead to sure betterment, and even
in time, if the closure were for a very long period, to a restoration
of the former condition when mussels were so richly abundant. It will
be advisable, however, to supplement natural processes by the methods
of artificial propagation in order that the replenishment may be
hastened and a greater result gained in a shorter time. We have to
contemplate that the beds that may be closed will have to be reopened
after a definite period, for the fishermen can not afford to work
indefinitely on restricted and depleted areas, and the supply of
available shells must be maintained. A proper solution as fair as
possible to all will be found in a plan of rotation which will give
rest periods to the different portions of a river in succession. Let
this measure be supplemented as far as may be by Government or State
propagation of mussels in the resting regions.
It is apparent that artificial propagation and protection are
intimately related. Restrictive measures alone will yield benefits, but
these will be greater if the protection is followed up by well-directed
propagation. Artificial propagation pursued independently may be
expected to bring results, but the advantages will be considerably
diminished if no steps are taken to lessen the unnecessary destruction
of the young mussels thus given a start upon life.