Environmental Biology of Fishes

, Volume 69, Issue 1, pp 51–62

Smaller Effective Population Sizes Evidenced by Loss of Microsatellite Alleles in Tributary-Spawning Populations of Sockeye Salmon from the Kvichak River, Alaska drainage

  • Christopher Habicht
  • Jeffrey B. Olsen
  • Lowell Fair
  • James E. Seeb
Article

DOI: 10.1023/B:EBFI.0000022887.62009.54

Cite this article as:
Habicht, C., Olsen, J.B., Fair, L. et al. Environmental Biology of Fishes (2004) 69: 51. doi:10.1023/B:EBFI.0000022887.62009.54

Abstract

We tested signals of historical reductions in effective population size within populations of sockeye salmon Oncorhynchus nerka returning to Bristol Bay, Alaska, to examine the roles that ecotype, migration obstacles, and drainage might play in the highly variable production of the Kvichak River drainage. We collected data for eight microsatellite loci from ∼100 fish at each of 16 locations within the Kvichak River drainage and five locations within the more productively stable Naknek River drainage. Pair-wise exact tests were used to group similar collections within ecotype, within drainage, and above and below migration obstacles. After grouping, collections represented independent populations for further analyses. We examined the number of alleles per locus, mean ratio of the number of alleles to the range in allele size, heterozygosity excess, and gametic disequilibrium as measures of reduction-in-population-size events. Number of alleles per locus revealed the largest number of significant differences. Tributary populations showed a stronger signal consistent with reduced effective population size than did beach populations within the Kvichak River drainage. Kvichak River drainage populations showed a stronger signal consistent with reduced effective population size than did the Naknek River drainage populations. Populations above migration obstacles showed signals consistent with reduction in historical population sizes in multiple measures indicating some of these reductions may be severe enough to qualify as demographic bottlenecks.

bottleneckNaknek RiverBristol BayAlaskaOncorhynchus nerkacommercial fisheryecotypeMheterozygosity excessgametic disequilibriumstrayingmigration obstaclesbeach spawners

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Christopher Habicht
    • 1
  • Jeffrey B. Olsen
    • 1
    • 2
  • Lowell Fair
    • 1
  • James E. Seeb
    • 1
  1. 1.Commercial Fisheries DivisionAlaska Department of Fish and GameAnchorageU.S.A.
  2. 2.U.S. Fish and Wildlife ServiceAnchorageU.S.A.