44 



BULLETIN O^ THE BUREAU OF FISHERIES. 



strictly comparable to those in the preceding table, since the preceding table is based 

 upon the shells taken from the river, and many of the smallest shells are lost before 

 reaching the factory. 



species. 



Blue-point , 



Do 



Butterfly 



Lake Pepin tnucket . 



Maple-leaf 



Monkey-face 



Mucket 



Do 



Do 



Niggerhead 



Do 



Do 



Pig-toe 



Pimple-back 



Pocketbook 



Do 



Three-ridge 



Washboard 



Do 



Yellow sand-shell . . . 



Do 



Locality 



Mississippi River, Grafton, 111 



Sunflower River, Miss 



White River, Ark 



Mississippi River, Lake City, Minn 



White River, Ark 



Mississippi River, Fairport, Iowa . . 



Fox River, Wis 



Mississippi River, Fairport, Iowa . . 



Wapsie River, Waverly, Iowa 



Mississippi River, Fairport, Iowa . . 



Sunflower River, Miss 



White River, Ark 



....do 



do 



Fox River, Wis 



Wapsie River, Waverly, Iowa 



Fox River, Wis 



Mississippi River, Fairport, Iowa . . 



Mississippi River, Grafton, 111 



Mississippi River, Fairport, Iowa . . 

 do 



Average size. 





Length. 



Width. 



Inches. 



Inches. 



3-82 



2.81 



3-5° 



2 



56 



3.00 



2 



44 



3- 17 



I 



92 



2-54 



2 



00 



3.00 



2 



43 



4.67 



2 



80 



4-47 



2 



60 



4.93 



2 



9-; 



3-56 



2 



81 



2-95 



2 



20 



2.58 



2 



14 



2. 23 



2 



00 



2. 10 



2 



00 



4.90 



3 



35 



5- 10 



3 



29 



4-33 



3 



33 



5- 75 



4 



12 



4.40 



3 



10 



4.72 



2 



33 



4-23 



2 



CMD 



Pairs of 



shells 



per ton. 



Number. 

 4>5oo 

 5.500 

 9,000 

 10,000 

 I I , 000 

 8,000 

 6,800 

 5,000 

 5) 500 

 4,000 

 6,500 

 9,000 

 13,000 • 

 16,000 

 5,000 

 4,000 

 4,800 

 2,000 

 4»500 

 6,000 

 9,000 



Many of the shellers are nomadic and therefore move readily with their launches 

 from a region of poor fishery to a better locality. It is often the case, however, that in 

 times of low water, when the mussels are easily obtained, the farm hands, miscellaneous 

 laborers, and others engage temporarily in shelling, using any kind of available 

 equipment or collecting by hand. It is in such cases that good beds are often rapidly and 

 seriously depleted. 



A noteworthy difficulty encountered in some places where the quality of shells is 

 good is the high cost of transportation. In regions remote from manufacturing centers 

 it is therefore advisable to have cutting plants, so that the expense of shipping the waste 

 portions of the shell may be obviated. A cutting machine costs about $16. The cost 

 of a plant of 12 machines, complete, with all equipment except power, was about $400, 

 as computed in 19 14. In 191 9 a cutting machine of improved type sells for $28 and a 

 i2-machine outfit is estimated at $725.^ 



DEPLETION OF THE MUSSEL RESOURCES. 



It has been mentioned that the extension of the fishery has been directed by the 

 depletion of the mussel beds in the regions first worked. Generally speaking, it may be 

 said that no stream or region has been entirely exhausted, but wherever a mussel fishery 

 has once existed it has continued in operation tg this time, although in reduced activity 

 and with much irregularity. 



The history of a shell bed in typical cases may be described. When first fished, 

 there is usually a large proportion of very old shells which are coarse and heavy and often 

 much eroded. After the first year or two the yield of the bed is chiefly the medium- 



o In referring to values and costs the writer feels obUged throughout this paper to give figures, when available, for both the 

 years 1914 and 1919. While it can not be asstuned that prices of 1919 are normal, it seems reasonably sure that prices will not 

 return to the level of 1914. 



