Table 8. — Proportions of Black River spawners in the early sockeye 

 salmon escapements. 1960-66 (Dahlberg 1968). 



ADJUSTED DATE OF TACCINC 



Figure 11.— Patterns of time of entry for tagged Black Lake and 

 Chignik Lake sockeye salmon, 1962-66 (Dahlberg 1968). 



Table 7. — Estimates of d, 6. and spji for tagging 

 studies of time of entry of Chignik sockeye salmon. 

 1962-66. after the formula of Moore and Zeigler 

 (1967). see text. 



To precisely regulate the escapement to the Chignik 

 system, it is imperative to know where the progeny of the 

 various spawning groups are reared, because manage- 

 ment is based on the nursery area carrying capacity of 

 each lake. A knowledge of the time of entry of early- and 

 late-season spawners is not adequate in itself, because all 

 the progeny of the Black River tributary spawners (early 

 season and late season) are reared in Chignik Lake 

 (Narver 1966). About 13' r of the early spawners use the 

 river (Table 8).'^ The progeny of the remainder of the 

 early spawners (which utilize the Black Lake tributar- 

 ies) are reared in Black Lake; whereas, all the progeny of 



'^he percentage of early spawners in the Black Lake tributaries is 

 determined from aerial surveys of the spawning grounds in each year. The 

 total number of spawners in Black River tributaries divided by the total 

 number of spawners counted on all early spawning areas is the propor- 

 tion u.sed. For the years before 1960 the geometric mean ratio for the years 

 1960-66 was used. The proportion of Black River spawners observed each 

 year from 1960 to 1966 is shown in Table 8. .\ test of the consistency of us- 

 ing aerial survey data to calculate the Black River proportions of the early 

 escapement was conducted in 1965. .-Xn Alaska Department of Fish and 

 Game management biologist aerially surveyed the early spawning 

 grounds and from his counts determined a proportion of 0.0308 Black 

 River spawners; he accounted for 76' r of the early escapement. On the 

 same day. I made the same survey using the same airplane with the same 

 pilot. 1 calculated a proportion of 0.0312 Black River spawners and ac- 

 counted for 53' r of the early escapement. Thus, although the total counts 

 were quite different, both observed the same relative proportion of 

 spawners in Black River tributaries. 



the late spawners are reared in Chignik Lake. On the 

 average, the portion of the escapement for a given date 

 whose progeny will be reared in Black Lake is the value 

 read from the entry curve for the year in question (Fig. 

 11) minus 13'; , the part of the escapement whose pro- 

 geny is reared in Chignik Lake. This relationship implies 

 that all Black Lake fry remain in Black Lake; this condi- 

 tion may not hold true in every year. 



Calculation of catches and escapements by stock. — 



The information on catches and escapements was pro- 

 cessed by computer program after the records had been 

 compiled and estimated portions collated with the 

 observed data (Dahlberg see footnote 15). The daily 

 catches and escapements were divided into Chignik Lake 

 and Black Lake stocks on the basis of the time of entry 

 relationship. Time of entry was determined from tagging 

 studies and the distribution of spawners on the spawning 

 grounds. For years in which these data were not avail- 

 able, the average relationship was used. Catches were ad- 

 justed to allow for migration time from Cape Kumlik to 

 Chignik Lagoon and the migration time between the 

 lagoon and counting weir. Escapements of the two stocks 

 were corrected for weir leakage (Lechner"") and the pro- 

 portion of Black River spawners in the early escape- 

 ments. 



Estimates of the total catches by stock for the years 

 1888-1921 were produced from the computer program 

 (Table 9). Table 10 presents the catches, escapements,"' 

 and runs by stock for the years 1922-66. Table 11 pre- 

 sents ratios of escapement to catch, rates of exploita- 

 tion, and percentages of escapement for each stock. Fig- 

 ures 12 through 15 show the data in graphical form. 



Beginning in 1967, summaries of the annual catch and 

 escapement of the runs of sockeye salmon to Chignik 

 have been reported by either FRI (Dahlberg and Phin- 

 ney see footnote 18; Parr and Pedersen;'" Wells and 

 Parr") or the Alaska Department of Fish and Game 

 (Phinney and Lechner;-^ Pedersen and Seibel;^' 



-".Jack Lechner. Area .Management Biologist, Alaska Department of 

 Fish and Game, pers. commun., .August 1965. 



■'Includes estimates of missing data for certain years as described pre- 

 viously. See also Table 6. 



•Parr. \V. H.. .Jr.. and P. C. Pedersen. 1969. Studies of adult sock- 

 eye salmon at Chignik in 1968. Univ. Washington, Fish. Res. Inst. Circ. 

 69-16. 40 p. 



-'Wells, J. W.. and W H. Parr. 1971. Studies of adult sockeye 

 salmon (Oncorhynchus nerka) at Chignik, Alaska, in 1969 and 

 1970. Univ. Washington. Fish. Res. Inst. Circ. 71-7. 61 p. 



-'Phinney, D. E.. and .J. Lechner. 1969. Studies of adult Chignik 

 sockeye salmon in 1967. Alaska Dep. Fish Game Inf. Leafl. 130, 43 p. 



■'Pedersen. P. C, and M. C. Seibel. 1970. Forecast of the 1970 

 Chignik system red salmon run. Alaska Dep. Fish Game Inf. Leafl. 144, 

 24 p. 



11 



