NET PRESERVATIVE TREATMENTS 



By W. T. Conn 

 Technologist, United States Bureau of Fisheries 



INTRODUCTION 



Of the commercial catch of fish in the United States and Alaska, 

 about $75,000,000 worth is taken by means of textile webbing which, 

 when combined with other materials, is commonly referred to as 

 nets. The size, form, and quality of these vary with the size and 

 species of fish sought. The investment in fishing nets in the United 

 States and Alaska amounts to about $16,000,000 w^hen the value of 

 the rope, floats, leads, and other accessories are added to the value 

 of the webbing. From this it can be seen that the value of nets 

 alone constitutes about 20 per cent of the value of the catch made 

 by them annually. 



The factor}^ value of textile webbing used for replacement of nets 

 annually is about $5,400,000. This figure would be increased con- 

 siderably if the cost of merchandising, labor, and transportation 

 were added. Thus, the maintenance of replacement of nets repre- 

 sents a considerable proportion of the cost of fish landed, and pre- 

 servative treatments wliich will prolong the life of these nets are of 

 economic importance, not only to the fisherman or producer, but 

 also to the consumer of fishery products. 



Replacement of textile fishing gear is necessary, due largely to 

 deterioration wliich is partly controllable. When the best preserva- 

 tives are used the loss of tensile strength and losses due to storm 

 damage are minimized, with the result that more fish can be taken 

 with a certain quantity of gear. Fishermen can not eliminate dam- 

 age from driftwood, violent storms, and possibly from destruction 

 of nets by sharks, but it is generally recognized that a clean net is 

 less liable to storm damage, as it ofiers a minimum resistance to the 

 motion of the water. Preservatives are available which, when ap- 

 plied to certain types of textile webbing, impart to it a high 

 resistance to mechanical abrasion. 



Members of the technological staff of the Bureau of Fisheries 

 have devoted the past several years to a study of net preservatives. 

 They have tested many formulas over a long period of time under 

 actual fishing conditions. It is the purpose of this paper to discuss 

 those treatments which it is believed will have the greatest promise 

 of efficient preservatives. As a result of the investigations it has 

 been found that the quantity and quality by fouling of textile 

 fishing gear varies widely in different waters. Bacterial decomposi- 

 tion of nets has been proved in certain localities, and it is suspected 

 in others. In certain types of nets, contamination of the webbing 



1 Appendix III to the Report of the U. S. Commissioner of Fisheries for 1930. B. F, 

 Doc. 1075. 



03238°— 30 41 



