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.