1961 escapement. This escapement was relatively small 

 (351,000), but about two-thirds of the spawners went to 

 the uppermost spawning grounds of the system — Amer- 

 ican Creek. As a consequence most of the progeny of the 

 escapement had to run the gamut of predators to reach 

 the ocean. Even so, the number of smolts produced per 

 adult in the parent escapement was about 32, the high- 

 est rate recorded between 1956 and 1963. Thus, a large 

 rate of production can occur in this system despite maxi- 

 mum exposure to predation. 



RATIONALE FOR INCREASING 

 PRODUCTION OF SMOLTS 



It appears that significantly more sockeye salmon 

 smolts could be produced in the Naknek system if pro- 

 duction of fry in the three external basins (Brooks Lake, 

 North Arm, and Northwest Basin), which now support 

 relatively few juveniles, could be increased. Brooks lake 

 has an intermediate ratio of spawning ground to lake 

 area, but the only way of increasing the escapement to 

 Headwater Creek (the major spawning ground) is by 

 selectively protecting its stock from the fishery. Since the 

 run into Naknek River occurs over a short period (Straty 

 1966), it may not be feasible to protect one stock with- 

 out a closure of the entire fishery. Even if selective pro- 

 tection of stocks were possible, increasing the escape- 

 ment of spawners to North Arm and Northwest Basin 

 would probably not increase their fry production be- 

 cause of limited spawning grounds. Therefore, the need 

 for other methods of increasing production of juveniles 

 seems obvious — i.e., a selective increase in survival of 

 some stocks from egg to fry via a hatchery system or ar- 

 tificial spawning channels. Rationale for an enhance- 

 ment program will now be developed. 



Spawning Populations and Sex Ratios 



Our best estimates of the capacities of the Naknek 

 system and of the three external basins in particular to 

 produce fry can be determined from past escapement 

 data. The annual escapements of adult sockeye salmon 

 to the Naknek system averaged about 994,000 fish for the 

 years 1956-69 (Parker 1974). For Brooks Lake, unpub- 

 lished observations by the National Marine Fisheries 

 Service for the years 1957-67 ' reveal that an average of 

 about 21,000 adults spawned annually in the lake or its 

 tributaries (Table 6). For North Arm the average number 

 of spawning adults is assumed to be about 2% of the total 

 escapement to the Naknek system (an average of 20,000 

 fish), and for Northwest Basin the number is assumed to 

 be about 0.2'c (an average of 2,000 fish). These assumed 

 percentages are based on the respective percentages of 

 the total spawning area in each basin. 



Table (». — Number (»f a(!ult siickexe 

 salmon spawning;' in liruuks Lake 

 and tributaries and tbe pereentaKe 

 of females. l!).'>7-(>7. 



'1\)tal count of adults passed into 

 Brooks Lake at Brooks River weir less 

 number counted back downstream 

 (data derived from Dewey et al. see 

 text footnote 3). 



Although stocks of sockeye salmon spawning in the 

 Naknek system exhibit variable sex ratios from year to 

 year, males generally predominate. Some stocks, such as 

 Brooks Lake, have a strong dominance of males in most 

 years (Table 6), whereas others, as illustrated by Amer- 

 ican Creek (which flows into Coville Lake), exhibit a 

 weak dominance of males (Table 7). On the basis of these 

 data, we assumed a sex ratio of 40 females/100 spawners 

 in estimating various factors related to the production of 

 sockeye salmon in the Naknek system. 



Table 7.— Number of adult sockeye 

 salmon entering American Creek 

 (Coville Lake) and the percentage 

 of females, iy(il-72. (Data from 

 Dahlberg see text footnote 4). 



Fecundity 



The fecundity of sockeye salmon in the Naknek system 

 appears to vary around an approximate average of 4,000 

 eggs/female. For example, Dewey et al. (see footnote 3) 

 counted an average of 3,950 eggs/female (range 3,668- 

 4,336 eggs) from Brooks Lake samples from 1957 through 

 1967. Dahlberg reported an average of 4,651 eggs/fe- 



'Dewey, R. D., S. Tsunoda, and W. L. Hartman. 1971. Naknek system 

 red salmon investigations. 1966-67. Unpubl. manuscr., 44 p. Northwest & 

 Alaska Fisheries Center Auke Bay Laboratory, Natl. Mar. Fish. Ser\., 

 NOAA. P.O. Box 155, Auke Bay, AK 99821. 



'Dahlberg, M. L. 1972. Studies of sockeye salmon m the Naknek River 

 system. 1972. Unpubl. manuscr.. 114 p. Northwest & Alaska Fisheries 

 Center Auke Bay Fisheries Laboratory. Natl. Mar. Fish. Serv., NOAA, 

 P.O. Box 155, Auke Bay. AK 99821. 



