ROGERS: JUVENILE SOCKEYE SALMON 



150 



100 



50 

 K 



UJ 



CD 



z 



3 



50 



50 



25 





 20 



July 9 



n = 553 



July 16 



o = 719 



July i3 



n = 412 



August 4 



n . 193 



^-'■^^^A^^ 



IV\^\ 1 I I 



30 40 50 60 70 80 90 100 110 



LENGTH 



Figure 3. — Length-frequency distributions (mm) of sock- 

 eye salmon, 1966. 



Richardson; and Arctic char fry, Salvelinus 

 (dpiiiKH Linnaeus. Of primary value in the beach 

 seine statistics are the annual estimates, since 

 our main concern is with the source of the 

 observed annual variation in adult sockeye 

 salmon abundance. Geographical and temporal 

 variations were examined and are discussed 

 here to the extent necessary for procurement of 

 valid annual estimates of abundance, growth 

 and size. 



Sockeye Salmon 



Length -frequency distributions for juvenile 

 sockeye salmon are shown in Figures 3 and 4 

 for a year in which growth was below average 

 (1966) and a year in which growth was above 

 average (1968). The length frequencies are based 

 on number offish measured and thus do not re- 



flect variation in abundance among time periods 

 and years. The apparent abundance of sockeye 

 salmon fingerlings in comparison to fry is exag- 

 gerated since usually the entire sample of finger- 

 lings, but often a subsample of fry, was mea- 

 sured. 



Sockeye salmon fingerlings (primarily age I) 

 ranged in length from approximately 45 to 118 

 mm. Many presumably originated in the upper 

 lakes of the Wood River system and had been in 

 Lake Aleknagik by early summer as smolts to 

 migrate out of the lake system. Catches were 

 significantly higher toward the lake outlet (area 

 C) than elsewhere (Tables 3 and 4). 



Sockeye salmon fry (age 0) ranged in length 

 from approximately 25 to 60 mm. The length 

 frequencies are symmetric and may be modeled 



25 



50 



25 





 30 

 K 



UJ 20 

 OS 



£ 10 



z> 



Z 

 30 



20 



10 











20 



10 



-^^^\A. 



-^ ^ ^ 



June 30 



n - 534 



July 23 



 ^-^^^^A^AAA^ .^y^ 



AugusI 2 



n - 221 



30 40 50 60 70 80 90 100 110 



LENGTH 



Figure 4. — Length-frequency distributions (mm) of sock- 

 eye salmon, 1968. 



1065 



