60 BEPORT OF THE COMMISSIONER OF FISHERIES. 



water for keeping the fish aHvc. In the live-carp trade, fish weigh- 

 ing from 2 to 3 pounds are preferred. In the fresh (dead) carp trade, 

 fish weighing from 3 to 5 pounds, and for smoking still larger fish, 

 are preferred. 



DEVELOPMENT OF AQUATIC SOURCES OF LEATHER. 



There is a growing scarcity of mammal hides used in the manufac- 

 ture of leather. The fishermen have no established market for fish- 

 skins. A smaU demand for certain fishskins for special purposes 

 exists, but difficulty is experienced by those using these products to 

 get in touch with sources of supply. These facts have led the 

 Bureau to investigate the possibilities of making satisfactory leathers 

 from fishskins and estabhshing a market for these products. The 

 tasks confronting it are to induce tanners to develop processes suitable 

 for converting fishskins into high-grade leathers and thus create a 

 market for the raw hides, to instruct the fishermen in preparing the 

 hides properly for the tanner, to encourage them to save and market 

 the skins, to ascertq-in to what uses the leathers are best suited, and 

 to determine the extent and sources of demand for fishskins for other 

 purposes. 



The Bureau has distributed several hundred skins of sharks and 

 other fishes, including cod, hake, grouper, gar, ray, catfish, and wolf- 

 fish, among tanners for experimentation. A number of tanners are 

 interested in the project and are developing processes capable of pro- 

 ducing some very creditable leathers. The larger samples have been 

 submitted to the Bureau of Standards for testing as to tensile strength. 

 The average tensile strength of one of the shark skins examined was 

 3,479. pounds per square inch. Such data are being used for com- 

 parison with other leathers. Of the skins tanned, those of the various 

 sharks are the most promising. 



Present methods of skinning sharks are slow and tedious. Special 

 instruments have been made and are being tried out for the purpose 

 of overcoming these difficulties. Instructions have been furnished 

 fishermen regarding the curing and packing of skins for shipment, 

 and the names of tanners desirous of obtaining raw materials have 

 been supplied. 



Formerly large quantities of shark skins, cleaned but not tanned, 

 were used for pohshing wood, ivory, and the like. Because of the 

 roughness, hardness, and durability of the outer surface, they were 

 especially serviceable for this purpose. Although sandpaper and 

 emery preparations have largely replaced such materials, there is 

 still a small demand among cabinetmakers for certain of these hides. 

 It remains to ascertain what hides are best suited to the needs of the 

 various trades and arrange for supplies of these materials. In the 

 past, shark-skin leathers have been used to a very limited extent for 

 various ornamental and novelty purposes. The results of experi- 

 ments recently made in the tanning of these skins indicate that they 

 can be used on a commercial basis for bag, belt, and similar purposes, 

 and this information is being brought to the attention of manufac- 

 turers of such articles. The Bureau is also endeavoring to ascertain 

 whether an industry can be built up which wiU utilize the skins of 

 smaller fishes, such as cod, hake, grouper, burbot, rays, catfish, etc., 

 on a commercial basis. These and other problems have received 



