[B] At the time of making this table only a few of the larger-sized shells were available, so the estimates of blanks are less accurate.
It may be seen from the table that a marketable ton of niggerheads could be composed of the shells of 3,200 or of 33,000 mussels, according as the shells were 4 inches in length or only 1½ inches. As a matter of fact, no marketed ton is ever composed of mussels of an exactly uniform size; furthermore, the extremely large niggerhead shells are very rare and generally not very desirable on account of inferior quality and disproportionate waste. A ton of shells from a region of depletion will also include a number of the smallest and not strictly marketable shells.
Now, let us take a concrete illustration: Several counts of mussels gathered by shellers in the white River near Clarendon, Ark., were made in October, 1913; from these an average was taken that fairly represents the catches being made at that time in that region. It was found that 60 per cent by number of the shells taken were of a size less than 2 inches in greatest dimension; also that a ton of shells comprised 20,500 pairs, of which 12,300 were less than 2 inches. Now, it is evident that if these smaller shells were returned to the bed we would be depleting the bed less than one-half as fast as at present. This would be the substantial advantage that such a size limit would have to the mussel beds; and any advantage to the mussel beds is an ultimate advantage to the fishermen, manufacturers, and all others in any way dependent upon the perpetuation of the mussels. Under the working of a 2-inch size limit, 60 shells out of every 100 then being taken on the niggerhead beds of that vicinity would have been thrown back. This seems to be asking a good deal, but not so much as at first appears, for the undersized shells constitute only 38 per cent of the weight or selling value of the shells taken.
On the other hand, both sheller and manufacturer would be saved the trouble of handling over and over again an unnecessarily large number of shells. A ton of shells (from the same locality) comprising only those above 2 inches in greatest dimension would contain about 13,000 pairs, or 37 per cent less than the number now found in a ton (20,500), while these shells, the smallest ones being eliminated, would produce at least 10 per cent more buttons of corresponding sizes.