gradually increased as the fishery developed, leveled off 

 until the White Act took effect in 1924 at which time they 

 decreased, remained at an intermediate level for several 

 years (1925-48), and then dropped shtirply after 1949 to a 

 low level. The catch data for the Nushagak district of 

 Bristol Bay (Mathisen 1971), show a unique similarity in 

 trend (Fig. 6) except for the timing of the fall from ini- 

 tial high production. The decline of sockeye salmon pro- 

 duction in the Nushagak district preceded that at 

 Chignik by a few years. It is noteworthy that these two 

 independent sockeye salmon systems exhibit the same 

 historical development and both show a decline in re- 

 turn per spawner. 



I/I 7.2 



Z 



SS.6 



u. 3-2 

 O 



|l.6 

 z 0.8 



Figure 6.— Commercial catches of sockeye salmon in the Nushagak 

 district. Bristol Bay, 1893-1966 (after Mathisen 1967); unsmoothed 

 curve (broken line) and cur^■e smoothed by a moving average of .5 

 (solid line). 



CATCHES AND ESCAPEMENTS OF THE 

 CHIGNIK SOCKEYE SALMON RUNS, 



1888-1966 



Catch and escapement, age and size composition, sex 

 ratio, timing of the run, and distribution of the escape- 

 ment on the spawning grounds Eire among the important 

 required statistics for setting management regulations 

 for the establishment and maintenance of maximum sus- 

 tained yield. 



Catches and Escapements 



Elscapement records began accumulating after 

 erection of a weir in Chignik River in 1922. Catch 



statistics have been recorded from the beginning of the 

 fishery in 1888; more detailed records have been kept 

 since the Chignik canners joined the Alaska Packers As- 

 sociation in 1893 (Moser 1899). The long-term changes in 

 abundance of Chignik sockeye salmon have been about 

 twofold (Table 3). 



Catch records. — Several sources of information were 

 used to compile a complete record of the annual catches 

 of Chignik sockeye salmon since 1888 (Moser 1899, 1902; 

 Rich and Ball 1929, 1930; Alaska Fishery and Fur-Seal 

 Industries 1917-50; Kasahara 1963; Pacific Fisherman 

 Yearbook 1915-67; Pacific Salmon Inter-Agency Council 

 1966; Roos", see footnotes 5, 7; Calkins'''). The two most 

 valuable sources were 1) annual reports of the Chignik 

 cannery superintendents, Alaska Packers Association, 

 over the years 1895-1955; and 2) vfirious reports of the 

 management agents for the U.S. Bureau of Fisheries 

 (1922-39), the U.S. Fish and Wildlife Service (1940-59), 

 and the Alaska Department of Fish and Game (1960-66) 

 (microfilms of these documents are on file in the archives 

 of the FRI). I resolved inconsistencies in the reports com- 

 piled and issued by veirious agencies and individuals by 

 cross-checking several sources; in the event of a major 

 disagreement, 1 accepted the daily catch figures com- 

 piled by either the management agency or canning in- 

 dustry. Many arithmetical errors were discovered in the 

 historical records; in these instances, I used the summa- 

 tion of the daily catch figures (Dahlberg'^). Catch records 

 were complete for all the years covered in this study 

 (1888-1966). 



Escapement records. — Daily weir counts were used to 

 compile annual escapement records for those years in 

 which a weir was operated in the Chignik River. The 

 counting weir was not maintained in Chignik River dur- 

 ing 1938, from 1940 through 1948, and in 1951. More- 

 over, in some years (1924, 1931, 1933) the weir was 



"Rocs, J. F. 1957. Report on Chignik adult red salmon studies, 

 19.55-1956. Unpubl. manuscr., 58 p. Fish. Res. Inst., Univ. Washing- 

 ton. Seattle. 



"Calkins, T. P. 1958. Report on Chignik adult red salmon studies, 

 1957. Unpubl. manuscr., 59 p. Fish. Res. Inst., Univ. Washington, Seat- 

 tle. 



'^Dahlberg, M. L. 1967. Chignik catch-escapement analysis. Fish. 

 Res. Inst., Comput. Program FRD 295, Univ. Washington. Seattle, 4 p. 



Table 3. — Long-term changes in abundance of Chignik sockeye salmon (Dahlberg 1968). 



Chignik Lake 



Black Lake 



Total run 



Escape- Rate of Escape- Rate of Escape- Rate of 



Catch ment Total exploi- Catch ment Total exploi- Catch ment Total exploi- 

 1.(XX)'3 l.CXM's l.CKXJ's tation' 1,(X)0'9 1,000's 1,000's tation' 1,000's l,(XX)'s l,(XX)'s tation' 



Mean 



1922-39 504 563 



Mean 



1949-66 240 326 



Percent 



change- -52.5 -42.1 



1,06' 



0.472 



290 



787 0.368 794 1,060 1,854 0.428 



346 0.419 385 527 912 0.422 



47.0 -10.4 -49.8 -59.5 -55.9 ■H3.9 -51.5 -50.2 -50.8 -3.8 



566 0.423 



201 



'Rate of exploitation as defined by Ricker (1958:20). 

 -Expressed as a percentage of the mean for the period 1922-39. 



