We therefore plan to work in such a way that, even with the liberal discount that nature will surely apply to our returns, there may be left a real measure of benefit gained without undue cost. Many of the young will be lost from falling upon unsuitable bottoms and from many other unfavorable conditions, such as confront every young mussel in nature with more or less frequency. We would like to remove all of the unfortunate conditions productive of loss, both to the mussels that we put out and to those that are propagated entirely by natural means; but this, of course, is not possible. There are, however, artificial conditions which do injury to the younger mussels, and it is both desirable and practicable to prevent such damage as far as can be done reasonably.
[RESULTS DEPENDENT UPON PROTECTION.]
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 [9]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.
[PROTECTION.]
[ESSENTIAL CONSIDERATIONS FOR EFFECTIVE LEGISLATION.]
Although at least 20 States participate directly in the mussel fishery for the shell trade, only 2 or 3 of these have taken any action of any kind for the protection of the resources. In some others measures have been proposed at various times, but without receiving favorable consideration by the legislative bodies. Indeed, it is probably well that this is the case, in view of the fact that there has been no general presentation of the case from all sides to aid in a just consideration of the matter. The Bureau is prompted to make this report in the hope that suggestions based upon a long-continued investigation of the shelling industry in all its phases may be of material aid to the responsible bodies concerned in the determination of how best to perpetuate the mussel resources, giving due regard to the local conditions involved.