VAN CLEVE and BEVAN: DECLINE OF KARLUK SALMON RUNS 



While these recoveries were not designed to 

 identify the times and areas of spawning, they 

 indicate that sockeye salmon which spawn in 

 late August and early September use the Kar- 

 luk River. These fish would have optimum con- 

 ditions for survival in the Karluk River in the 

 fall where the eggs would have excellent condi- 

 tions for development, with both temperature 

 and floods moderated by the lake so that pro- 

 ductivity of the spawn deposited late in the 

 season in this area should be high. 



Why then has this part of the Karluk run 

 continued to decline? 



The decline in earlier periods, i.e., before 1940, 

 must have been due to overfishing as indicated 

 by Thompson (1950). However, the decrease 

 has continued in later years even when the en- 

 tire run has been given protection. This is seen 

 in the spawner-recruit relationship shown in 

 Figure 2. Different symbols are used to identify 

 the returns from different j^eriods in the Karluk 

 history which correspond to 1) before 1921, i.e., 

 before a weir was installed at the lower end of 

 the Karluk River, 2) 1921 to 1941, when the 

 weir was located at the lower end of the Karluk 

 River, 3) 1942 to 1944, a brief period during 

 which the weir was located at the portage oppo- 

 site the head of Larsen Bay, and 4) 1945 and 

 later, when the weir was located just below the 

 outlet of Karluk Lake. 



Interest in the location of the weir was 

 aroused by Schaefer's (1951) reports of attempts 

 in the Birkenhead River, to hold sockeye salmon 

 for spawning, by the effects of delays of sock- 

 eye salmon in their migration up the Fraser 

 River as reported by Thompson (1945) and Tal- 

 bot (1950), and by Walker's reports (Walker, 

 see footnote 7, 1954, ''-'^ 1959'3) of the effects of 

 the weir of sockeye salmon fry migrating up 

 the Karluk River to the lake. Walker also indi- 

 cated that the smolts migrating downstream 

 were delayed and he and Bevan replaced the 



" Walker. C. E. 1954b. The red salmon smolt migra- 

 tion at Karluk Lake, 1954. Unpubl. manuscr. Univ. 

 Wash., Fish. Res. Inst., SeaUle, WA 98195. 



'2 Walker, C. E. 1954c. Size and age analysis of the 

 red smolt migration — Part II of the red salmon smolt 

 migration at Karluk Lake. 1954. Unpubl. manuscr. 

 Univ. Wash., Fish. Res. Inst. 



13 Walker, C. E. 1959. The enumeration of the 

 Karluk red salmon smolt run in 1954. Unpubl. manuscr. 

 Univ. Wash., Fish. Res. Inst. 



500 1000 1500 2000 2500 3000 



NUMBER OF SPAWNERS 



Figure 2. — Spawner-recruit relationship for Karluk sock- 

 eye salmon 1887 to 1961. 



wooden weir pickets with round metal bars to 

 increase flows and thereby to induce the smolts 

 to move through the weir. 



The loss of over 50% of the adult sockeye salm- 

 on held for spawning in the Karluk hatchery is 

 recorded by Bower (1912:75). Lest this be con- 

 sidered to be the result of rough handling, we 

 must recall the history of the hatchery opera- 

 tion on the Birkenhead River above Harrison 

 Lake in the Fraser River system. This history 

 is briefly recounted by Schaefer (1951) as fol- 

 lows: 



The Birkenhead River is frequented by sockeye as 

 far up as Poole Creek. During the period of our studies. 



637 



