VAN CLEVE and BEVAN: DECLINE OF KARLUK SALMON RUNS 



Walker and Bevan (IDSS)** noted that the largest 

 spawning population of sockeye salmon in the 

 Karluk watershed was found in the Karluk 

 River. They also observed that the decline in 

 size of the Karluk River race could explain the 

 decrease in size of smolts observed by Barnaby 

 (1944) who was later quoted by Rounsefell. 

 They also maintained that the decrease in Kar- 

 luk River spawning could explain the increase 

 ill relative numbers of 4-yr smolts, since the 

 river spawners were predominantly of 53 age. 

 Barnaby interpreted these events as evidence 

 of a decline in productivity of the lake, but 

 Walker and Bevan maintained that since fry 

 from the Karluk River are largest at the time 

 of emergence, they should also be largest at the 

 time of seaward migration if they retain their 

 size difference during lake residence. Moreover, 

 the second migration of fingerlings up the Kar- 

 luk River into the lake which extended through 

 late July and August consisted of fish ranging 

 from 39 to 72 mm long with a mode at 51 mm. 

 They were not certain where these fish came 

 from, but said that some no doubt were from 

 the Karluk River spawners and after emerging 

 from the gravel in May had remained in the 

 river to feed and grow before migrating up- 

 stream to Karluk Lake (Walker and Bevan, 

 see footnote 8, page 16). 



The slow-moving section of the river just 

 above the portage which appears in all the de- 

 scriptions of the Karluk River, would be an 

 ideal location for a sockeye nursery area com- 

 parable to those areas in the Chilko, South 

 Thompson Rivers, and Little Shuswap Lake, 

 which are used for the same purpose by differ- 

 ent races of Fraser River sockeye salmon fry. 



Bevan (1951)." in his notes on the Karluk 

 Lake stream surveys made in 1948 through 

 1951. said that in the Karluk River sockeye 

 salmon spawn almost exclusively in the first 

 mile below the outlet where the current is 

 moderate and the water shallow. He recorded 

 that large numbers of fry migrate upstream 



8 Walker, C. E., and D. E. Bevan. 1955. Observations 

 on the biology of the red salmon in the Karluk watershed. 

 Unpubl. manuscr. Univ. Wash.. Fish. Res. Inst., Seattle, 

 WA 98195. 



« Bevan, D. E. 1951. Karluk Lake stream surveys, 

 1948-1951. Unpubl. manuscr. Kodiak Isl. Res. Group, 

 Univ. Wash., Fish. Res. Inst., Seattle, WA 98195. 



into the lake and are most noticeable behind 

 the weir and 1 mile below where they are 

 blocked by fast water. In 1951, large numbers 

 of fry were seen as far downstream as "Barnaby 

 Ridge." He also stated that between Barnaby 

 Ridge and Larsen Bay Portage the current is 

 slow and the water is choked with Poiamogetan 

 and Ranunculus in the summer. The sockeye 

 salmon spawn in the river in the second or 

 third week of September. 



The upstream movement of the fry was also 

 noted by Burgner et al. (1969:427). 



Recently emerged fry behave in such a way in the 

 Karluk system that the total escapement is assignable 

 to Karluk Lake for consideration of rearing areas. The 

 progeny of spawners that use the outlet (Karluk River) 

 move upstream into the lake, and progeny of spawners 

 from areas above O'Malley and Thumb Lakes move 

 down into Karluk Lake early in their first summer of 

 life. 



This upstream movement of fry and small fin- 

 gerlings into the nursery lake was also ob- 

 served by the senior author in several rivers in 

 the Fraser River system, i.e., the South Thomp- 

 son River, Little River, and the Chilko River. 

 Fry and fingerlings from the South Thompson 

 move upstream into Little Shuswap Lake and 

 then with the fry already accumulated in that 

 lake from spawning in Little River and Adams 

 River they move up Little River into Big Shu- 

 swap Lake, Little Shuswap Lake and slowly 

 flowing sections of the South Thompson River 

 provide shelter for the fry until they gain suf- 

 ficient strength to swim upstream. The same 

 function is performed by the slower section of 

 the Chilko River near Canoe Cross. Th6 slow 

 section of the Karluk River near the portage 

 opposite the head of Larsen Bay must serve the 

 same i)urpose for many of the Karluk River fry. 



Although Rounsefell's (1958) demonstration 

 of a negative effect of the even-year pink salmon, 

 O. gorbuscJia, runs on the sockeye salmon re- 

 turns is of marginal significance, competition 

 between the two species for spawning room in 

 even years would emphasize the importance of 

 the sockeye salmon race which si)awns in the 

 Karluk River. 



Further study of this relationship would re- 

 quire a restudy of the ages assigned to the Kar- 

 luk sockeye salmon to improve the accuracy of 



635 



