FISHERY BULLETIN: VOL. 71. NO. 3 



estimated returns. Walker (1956)'" attempted 

 to check the age readings made from Karluk 

 sockeye salmon using the objective technique 

 developed by Koo (1962). Walker (see footnote 

 10) presented the results of a comparison of 

 age readings he had made with the U.S. Fish 

 and Wildlife Service on the same fish as follows: 



The year 1952 offered the only data that were com- 

 parable. The escapement was sampled by both research 

 groups; actually the same fish were handled by each. 

 The catch data taken by the Fisheries Research Institute 

 were shared, and hence the sampling was identical. 

 The discrepancy in the final results (table 6) [Walker's 

 Table 6 is reproduced as our Table 2.] must be due to 

 the method of age interpretation and calculation. 



From this study and a review of 1947 and 1948 Fish 

 and Wildlife Service Karluk smolt samples, it is sug- 

 gested that the Fish and Wildlife Service favors the 

 older age classes, particularly in the fresh-water ages. 

 Two policies may account for this: (1) The recording of 

 an annulus on the outside of plus growth, and (2) re- 

 cording an annulus wherever there is a departure from 

 a uniform circulus. 



This attempt to reconcile the age readings of 

 two organizations was given up for Karluk fish, 

 but has been pursued later for other stocks of 

 salmon under the International North Pacific 

 Fisheries Commission. However, so far as we 

 can determine, this coordination has not been 

 extended to the Karluk data and in particular 

 has not been used to review the age determina- 



which requires separate interpretation. We do 

 not know if the ages of Karluk sockeye salmon 

 have been checked by the Koo technique since 

 1952. 



The relative importance of the Karluk River 

 as a spawning ground is further emphasized 

 by the estimated number of potential redd sites 

 shown in Table 13 of Burgner et al. (1969:424), 

 which is partially reproduced below as Table 3. 

 The spawning capacity of the Karluk system is 

 given as follows on page 425: 



Karluk syswin. — Estimates of the size of a redd 

 site for several tributaries in the Karluk system are 

 about 2 m.2, and because estimates are not available for 

 other areas, 2 m.- is used for all. The estimated number 

 of redd sites for streams and lake beaches is 174,000 

 (table 13), and (assuming a 1:1 sex ratio) the capacity 

 is 348,000 adults. This estimate is only approximate — 

 the situation in the Karluk system is complicated by 

 the occurrence of successive waves of spawners in most 

 streams and incomplete information on the amount of 

 potential spawning ground, especially orr lake beaches. 

 Escapements to Karluk neared or exceeded 1 million 

 fish for many years during the early 1900's. 



The conclusion is inescapable that the Karluk 

 River must have been the most important spawn- 

 ing area in the Karluk system but the only 

 data directly substantiating this conclusion is 

 found in the report by Bevan (1962) on the 

 sockeye salmon tag recoveries in 1948 and 1949. 



Table 2. — ["Table 6 Comparison of 1952 Adult Age Analysis"] 



Year of 

 return 



4-2 52 43 53 63 



64 74 2 SW 3 SW 



Percent of total run 

 Percent of total run 



0.3 0.5 



0.2 



F.R.I, figures for the year 1952 

 1.8 52.3 5.2 3.1 12.0 22.1 64.6 27.8 



F.W.S. figures for the year 1952 

 1.8 28.0 10.2 1.0 18.9 38.7 46.9 49.1 



tions prior to 1950, which were the basis for 

 Rounsefell's estimates of the numbers of fish 

 which returned from different spawning years. 

 The process of reconciling age readings on sock- 

 eye salmon scales is particularly difficult be- 

 cause of the distinct fields of freshwater and 

 saltwater growth found in each scale, each of 



•" Walker, C. E. 1956. Age analysis of the Karluk red 

 salmon runs. Unpubl. manuscr. Univ. Wash. Fish. Res. 

 Inst., Seattle, WA 98195. 



Table 3. — Estimated numbers of potential redd sites in 

 various types of spawning grounds of the Karluk system 

 (from Burgner et al., 1969). 



' Does not take into consideration successive waves of spawners. 



636 



