FRESH-WATER MUSSELS AND MUSSEL INDUSTRIES. 45 
sized shells of the best quality. In the last stages the larger shells constitute a gradually 
decreasing proportion, while the smallest shells, the very infants, indeed, form a steadily 
increasing proportion. Here is a fatal defect of the present manner of fishery. The 
rate of depletion is automatically accelerated, since the fishermen are taking two or three 
for one. Where formerly from 5,000 to 10,000 mussels, more or less, constituted a ton, 
at a Jater time, when small shells prevail, each ton may represent some 30,000 mussels, 
as has been determined by repeated counts made by the writer in localities where the 
small shells are being marketed. The fact that the sheller can now take but a few hun- 
dred pounds a day, as against the former catches of half a ton or more, might lead one 
upon first thought to suppose that the beds thus automatically receive a measure of 
protection. The very contrary, however, may in practice be the case. ‘The continued 
rise in price stimulates the sheller to save everything, and the last stages of impoverished 
fishery are thus the more exhaustive. 
When shelling in a depleted locality becomes quite unremunerative, it may be 
practically entirely abandoned and almost forgotten, until after some years, it is found 
that the growth and natural reproduction of the mussels have so replenished the bed that 
it has again become a profitable one, and general shelling is resumed. Usually, however, 
the local shellers keep engaged, though irregularly, upon the same bed, or more exhaustive 
methods are employed, and the cases of natural recuperation are therefore conspicuous 
by their rarity. 
In view of the conditions just described, the Bureau has advocated the compulsory 
closing of portions of rivers for periods of years, in order that the mussel beds might 
have such a condition of rest and freedom from all injurious disturbances that the process . 
of replenishment would be assured. It has also urged the adoption of size-limit regula- 
tions which would prevent the needless destruction of the small mussels. With such 
reasonable protective legislation, supplemented, preferably, by artificial propagation, 
the depleted regions generally might be aided to recuperate. Several States have in 
recent years enacted comprehensive mussel laws whose effective enforcement will go 
far to insure the perpetuation of the mussel resources and thereby the permanence of 
the mussel fishery and its dependent manufacturing industries. 
There is no question that all of the better mussel streams are capable of supporting 
mussel resources many times as abundant as they do now, for they did so a score or less 
of years ago. For each stream, therefore, it is merely a question of whether common- 
sense measures will be applied to restore the abundance of mussels for the benefit of 
all or whether they will always exist only as scattering survivals of an over zealous 
fishery. 
The conditions and the measures for protection have been fully discussed in other 
publications of this Bureau? and need not be enlarged upon here. It may be said, 
however, that there is no important stream in which the mussel resources now exist 
in anything like their former abundance. There have been published photographs 
showing fishing through the ice in the Mississippi River in the early days, where the 
persons are grouped closely, each one with a considerable pile of shells about the hole 
2 Coker, Robert E.: The protection of fresh-water mussels, U.S, Bureau of Fisheries Document No. 793, 23 p., 2 pl. 
Washington, 1914. 
Coker, Robert E.: The utilization and preservation of fresh-water mussels. Transactions American Fisheries Society, 
Vol. XLVI, No. 1, New York, 1916. 
Smith, Hugh M.: Fresh-water mussels, Economic Circular No. 43, U. S. Bureau of Fisheries, 5 p. Washington, 1919. 
110307°—21—_4. 
