GENETIC DIFFERENTIATION OF SUBPOPULATIONS OF SOCKEYE-SALMON (ONCORHYNCHUS-NERKA) WITHIN LAKES OF ALASKA, BRITISH-COLUMBIA, AND KAMCHATKA, RUSSIA

Genetic differentiation among subpopulations of sockeye salmon (Oncorh ynchus nerka) was investigated within nine intensively sampled lake sy stems located throughout the species' range using allozyme allelic fre quency data collected by researchers in Canada, Russia, and the United States. Allelic frequencies at up to nine highly polymorphic loci wer e used to examine genetic diversity among 163 samples collected from 6 8 distinct spawning sites and to identify subpopulation structure with in lakes. Significant heterogeneity was detected among sites within al l lakes. The greatest differentiation was evident among subpopulations exhibiting different run timing (earlier vs. later) or utilizing diff erent spawning habitat (tributary vs. littoral). These findings indica te that sockeye home precisely to natal streams, not just to lake syst ems, and underscore the importance of conserving individual spawning s ites within sockeye populations.