The impact of supplementation in winter-run chinook salmon on effective population size

Phil W. Hedrick, D. Hedgecock, S. Hamelberg, S. J. Croci

Research output: Contribution to journalArticlepeer-review

62 Scopus citations


Supplementation of young raised at a protected site, such as a hatchery, may influence the effective population size of an endangered species. A supplementation program for the endangered winter-run chinook salmon from the Sacramento River, California, has been releasing fish since 1991. A breeding protocol, instituted in 1992, seeks to maximize the effective population size from the captive spawners by equaling their contributions to the released progeny. As a results the releases in 1994 and 1995 appear not to have decreased the overall effective population size and may have increased it somewhat. However, mistaken use of non-winter-run chinook spawners resulted in artificial crosses between runs with a potential reduction in effective population size, and imprinting of the released fish on Battle Creek, the site of the hatchery, resulted in limiting the contribution of the released fish to the target mainstem population. Rapid genetic analysis of captured spawners and a new rearing facility on the Sacramento River should alleviate these problems and their negative effect on the effective population size in future years.

Original languageEnglish (US)
Pages (from-to)112-116
Number of pages5
JournalJournal of Heredity
Issue number2
StatePublished - 2000

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Biology
  • Genetics
  • Genetics(clinical)


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