damaged by high water, and the escapement was 

 inaccurately assessed. Because it was desirable to have a 

 continuous record of past escapements, estimates were 

 used for missing data (Table 4). The estimates for 1924, 

 1931, and 1933 were made by U.S. Bureau of Fisheries 

 personnel stationed at Chignik in these years; the esti- 

 mate for 1951 represents the total of weekly estimates of 

 escapement made by the management agent, U.S. Fish 

 amd Wildlife Service, at Chignik in that yeeu-. 



Table 4. — Estimated escapements of sockeye salmon at Chignik, 

 Alaska, for those years in which weir counts either were not avail- 

 able or were unreliable (Dahlberg 1968). 



'Source: Alaska Fishery and Fur-Seal Industries (1938, 1940-48). 



Providing estimates of the escapement for 1938 and the 

 period 1940-48 was more complex since daily or weekly 

 estimates of the escapement were not available. In these 

 cases, the ratio of escapement to catch was calculated 

 from data obtained immediately before and after the pe- 

 riod, and escapement in the period was estimated by tak- 

 ing the product of the catch and the calculated ratio of 

 escapement to catch. Rounsefell (1958) used a similar 

 method for estimating the escapement to Karluk Lake 

 prior to 1921; however, I attempted to correct for an ap- 

 parent trend in the ratio (Fig. 7). 



The predicted ratios were estimated by linear interpo- 

 lation: 



yo + ^ - V (^ -*o) 



where x„ = 1936, 



>„ = average ratio of escapement to catch for the 



period 1933-37 and 1939, 

 X, = 1951, 

 y , = average ratio of escapement to catch for the 



period 1949-53, 



Figure 7. — Trend in the ratio of escapement to catch for Chignik 

 sockeye salmon. 1922-66. Ratios read from the straight line were 

 used where data were missing, 1940-4S. 



X = year in which an estimate of escapement to 



catch was desired, 

 y = estimated ratio of escapement to catch. 



The predicted ratios were calculated from: 



1.03 + 



(2.10 



1.03) 



(1951 - 1936) 



(x - 1936). 



The estimates were calculated from the ratio and catch 

 for each of the years and compared with qualitative de- 

 scriptions of the yearly runs (Alaska Fishery and Fur- 

 Seal Industries 1938, 1940-48) (Table 4). The estimate for 

 1938 is in close agreement with the figures shown in 

 Alaska Fishery and Fur-Seal Industries (1938). The esti- 

 mate of the escapement for 1940 is far from that shown in 

 Alaska Fishery and Fur-Seal Industries (1949); however, 

 since no rationale is given for the published figure, the 

 one calculated from the ratio of escapement to catch was 

 used. Although the quantitative estimates and quali- 

 tative descriptions in Table 4 are not directly compar- 

 able, they do seem to agree in magnitude. 



Catches, Escapements, and 

 Total Runs by Stock 



Estimated migration times and delays between 

 fishery, lagoon, and weir. — Regulation of the Chignik 

 fishery requires knowledge of the daily total run, which is 

 the total of the daily catch and daily escapement. 

 Escapement was counted at the weir in Chignik River. 

 The daily catch could not be added to the escapement for 

 the same day because of the migration time between the 

 fishing area and weir. In addition, until 1966, Chignik 

 fish were caught in significant numbers only in one near- 

 by fishing area that was within the management dis- 

 trict. Migration times must be considered before catch 

 and escapement data can be combined. 



