BEACHAM ET AL : VIKON RIVER CHUM SALMON POPILATION" 



cates within families (all P < 0.05). Significant inter- 

 actions between temperature and family were also 

 observed for all alevin size characters (all P < 0.05), 

 again illustrating that alevin size characters did not 

 respond consistently among families to changes in 

 incubation temperature. 



The effect of different incubation temperatures 

 on fry size characters was similar to that for the 

 alevin size characters. Significant differences in fry 

 length, total weight, and tissue weight were ob- 

 served among temperatures, among families, and 

 between replicates. The amount of yolk remaining 

 at the time of fry emergence was similar at all in- 

 cubation temperatures (P > 0.05) (Table 6). In- 

 teractions between family and incubation temper- 

 ature were present for all fry size characters (all P 

 < 0.05). 



Biochemical Genetics 



Regional differentiation of allelic frequencies for 

 chum salmon stocks in Alaska and the Yukon Terri- 

 tory was observed. Chum salmon from Alaska 

 generally had a lower frequency of Idh-1"^'^ and a 

 higher frequency of Tapep (Lgg)'^'^ than those from 

 the Yukon Territory (Table 7). Regional differen- 

 tiation in allelic frequencies was also observed for 

 the other loci examined. The Delta and Toklat River 

 populations, both tributaries of the Tanana River, 

 had higher frequencies of Idh-3'*"' than all other 

 populations except the Teslin River population. Only 

 one genotypic frequency was not in Hardy- Weinberg 

 equilibrium, that being Pgdh in the Toklat River 

 population. The disequilibrium was due to a hetero- 

 zygote deficiency. 



Variation in allelic frequencies among populations 



Table 6.— Fork length, total weight, yolk weight, and tissue weight 

 for Kluane River chum salmon alevins and fry maintained at con- 

 stant 4°, 8°, and 12°C water temperatures. N is the number of 

 alevins and fry measured and weighed for all families combined. 

 Standard deviations are in parentheses. 



within a region was greater than annual variation 

 in allelic frequencies within a population (Fgy 43 = 

 4.00, P < 0.01) (Table 8). Annual stability of allelic 

 frequencies was examined for the loci for which two 

 years of data was available in each population. Of 

 39 comparisons made, 3 (8%) were significant (Table 

 8). 



Heterozygosity of populations from Alaska was 

 generally higher than that from the Yukon Terri- 

 tory. Mean heterozygosities were 0.156 (SD = 

 0.009) and 0.138 (SD = 0.019), respectively, for the 

 loci outlined in Table 7. Heterozygosity values are 

 dependent upon the number of polymorphic and 

 monomorphic loci included in the calculations, and 

 thus will vary among studies. 



The analysis of genetic distance for all pairwise 

 combinations of the 10 populations sampled ranged 

 from 0.0000 to 0.0072. A dendogram based upon the 

 unweighted pair group mean analysis (UPGMA) 

 illustrated two main clusters of populations (Fig. 2). 



Figure 2.— Dendogram produced from cluster analysis using Nei's 

 (1978) genetic distance value. Codes are C = Canadian and US 

 = United States. 



KLUANE C 

 KOIDERN C 

 SHEENJEK US 

 MINTO C 

 PORCUPINE C 

 CHANDALAR US 

 L FISHING BRANCH 

 TESLIN C 

 TOKLAT US 

 DELTA US 



1 1 1 1 1 1 1 1 1 



0.0032 0.0028 0.0024 0.0020 O.OO16 0.0012 0.0008 0.0004 0.0000 



GENETIC DISTANCE 



669 



