BRISTOL BAY AND ALASKA PENINSULA SALMON STATISTICS 57 



Table 2. — Salmon caught and fishing appliances used in Bristol Bay, 1S93 to 1927, by districts — Con. 



' Includes 520 chums, 312 kings, and 194,045 reds not given above. 



We may now examine these data in an attempt to answer several important 

 and more or less interrelated questions: 1. Do the trends of the four districts vary 

 independently or together? In other words, has the development of the fishery in 

 the four districts been parallel? 2. Do the deviations from the trends, the yearly 

 fluctuations in abundance, vary independently or together? 3. What is the present 

 state of the fishery in each of the four districts? We shall consider the catches of 

 the various species separately, and as the red salmon is by far the most important 

 species in Bristol Bay we shall discuss it first. 

 • 



RED SALMON 



Figures 3 to 6 present graphically the data for red salmon given in Table 2 

 and in addition the trends of the catches. These trends are five-year moving aver- 

 ages and were calculated in the usual manner. The value of such a trend for any 

 given year is determined as the average of the catch for that year, the two preceding 

 years, and the two succeeding years.' The trends alone are sho\vn in Figure 7 on 

 a proportional (logarithmic) scale, so that the relative changes in the four districts 

 may be more readily compared. 



' Principles and Metliods of Statistics. By R. E. Chaddock. Pace 310 and following. Hougiiton Mifflin To.. 1925. 



