INVESTIGATIONS IN THE PRESERVATION OF FISH 

 NETS AND LINES. ^ 



By Harden F. Taylor 

 Chief Technologist 



and 



Arthur W. Weixs 



Assistant Technologist, Bureau of Fisheries, Washington, D. C, 



INTRODUCTION. 



In a paper by one ^ of us, the literature dealing with the pres- 

 ervation of fish nets was reviewed and summarized. The method 

 which appeared best where tar could not be used was that of Bull, 

 which consisted of a bark extract applied hot, and mordanted with 

 potassium bichromate and a small amount of copper sulphate. Ref- 

 erence may here be made to a series of papers which escaped notice 

 in compiling that review, namely the Dutch investigations carried 

 out in the years from 1915 to 1920 by Van Dorp, Tombrock and 

 Olie. 



The Dutch papers deal principally with tanning materials for 

 use in net preserving, and also with the use of aniline dyes for gjiv- 

 ing a desirable color to fishing nets and lines. They contain data 

 on a great variety of tanning materials obtained from many lo- 

 calities in various parts of the world. Perhaps the most importan'; 

 result of these investigations is the demonstration that if an aro - 

 moniacal solution of copper sulphate is used instead of potassium 

 bichromate to mordant or fix the tanning material in the line, much 

 better results are to be had. The chemical reason assigned for 

 this superiority is that the presence of ammonia prevents any in- 

 jury from acid that would otherwise be set free, and also that 

 copper has a preservative effect on the line. This method of treat- 

 ing lines, recommended by the Dutch Fishery Experiment Station, 

 is hereinafter referred to as the Dutch method. 



The significant fact is that while some investigations have 

 been made, and valuable results obtained, the preservation of nets 

 is still crude; extensive and thorough study is much needed, espe- 



1 This paper was awarded a prize of $100 for the best contribution dealing 

 with problems of the commercial fisheries. 



* Taylor, Harden F. Preservation of Fish Nets. Report of the U. S. Com- 

 missioner of BMsheries for 1920, Appendix IV, 35 p. Separately printed as Doc. 

 M8, U. S. Bureau of Fisheries, Washington, D. C, 1921. 



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