FISHERY Bl'l.LETIN: VOL. 8(;, NO. 4 



Table 7.— Observed allelic frequencies at polymorphic loci for 10 Yukon River drainage 



and other alleles were assigned numbers 



Table 8.— Analysis of heterogeneity of allelic frequencies between countries, among 



sampled during 



The Toklat and Delta River populations were dis- 

 tinctive from other populations surveyed. The popu- 

 lation from Chandalar River, a tributary of the Por- 

 cupine River, was similar to the Porcupine River 

 population (sampled at the Old Crow fishery) and 

 to the Fishing Branch River population, also a trib- 

 utary of the Porcupine River. The populations from 

 Kluane and Koidern Rivers, tributaries of the White 

 River, were also similar to each other, as well as to 

 the Sheenjek River population in Alaska. 



DISCUSSION 



Yukon River fall chum salmon undertake the long- 

 est freshwater spawning migration of chum salmon 

 in North America and spawn in locations where 

 winter environmental conditions are very severe. 

 They are also relatively abundant, with an average 

 of almost 450,000 chum salmon harvested annually 

 during 1974-83 (Buklis and Barton 1984). Their 

 abundance indicates that they have adapted success- 



670 



