100 U. S. BUREAU OF FISHERIES 



From these data indices of abundance have been made, which indi- 

 cates the relative abundance of chinook salmon in this river system 

 from year to year and during short periods of time for each individual 

 year. In this way not only the fluctuations in abundance of the 

 entire population of chinook of the Columbia River have been fol- 

 lowed from one year to the next, but also indices of abundance for 

 portions of the migrating salmon population called "runs," which are 

 probably biologically distinct and self-maiutaining, have been com- 

 puted. 



The investigations of 1931 consisted of a detailed consideration of 

 the data available, and show that from 1909 to 1925, inclusive, the 

 chinook salmon of the Columbia River appeared to withstand the 

 straiQ of fishing to which they were subjected mthout any noticeable 

 decline in total numbers. However, from 1926 to 1930, the catch per 

 unit of effort and gear, which is a measure of abundance, has declined 

 noticeably. Also, it appears that certain of the "runs" or races are 

 suffering a more pronounced decline in numbers than others. 



TECHNOLOGICAL INVESTIGATIONS 



It has been said that the application of science is useful to indus- 

 try during booms, is indispensable when times are normal, and vital 

 when they become hard. Possibly this appHes to the fishing industry 

 with greater force than to any other of our basic food industries. 

 During the past year the fisheries have passed through a most trying 

 period. Producers and wholesalers experienced difficulty in market- 

 ing fresh and canned fishery products. The market for fish meals and 

 oils was depressed. Some of the important fisheries have shown 

 signs of depletion, and competition with other food products has 

 become keener. At times like these, in order to operate successfully, 

 it is important that losses be minimized, and that the products avail- 

 able be utilized to the fullest extent. The technological research of 

 the bureau has been aimed toward this end, and where the industry 

 has appHed the results of this research to its commercial procedure 

 it has been benefited according to the effort expended. As a result, 

 research by the bureau has shown ways for lengthening the life of 

 certain types of textile fishing gear; various types of fishing gear have 

 been developed which have a greater selectivity, thereby allowing 

 small and immature fish to escape; methods have been developed for 

 preventing rusting and shrinkage of frozen fish in cold storage, and 

 undue losses and food value of fresh fish shipped with ice as a refrig- 

 erant; methods also have been developed for manufacturing fish 

 meals and oils of higher nutritional value, and chemical and biochemi- 

 cal studies have demonstrated the richness of some fish, shellfish, and 

 their products in protein, minerals, and vitamins. This work has 

 had a stabilizing influence on the fisheries, and has enabled them to 

 carry on in a more efficient and successful manner than would other- 

 wise have been possible. 



RESEARCHfASSOCIATE 



In the above lines of technological research the bureau has attacked 

 those fundamental problems which promise to be of greatest value 

 to the largest number and which are possible with the funds and per- 



