Rapid Evolution of Egg Size in Captive Salmon

See allHide authors and affiliations

Science  14 Mar 2003:
Vol. 299, Issue 5613, pp. 1738-1740
DOI: 10.1126/science.1079707

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution


Captive breeding and release programs, widely used to supplement populations of declining species, minimize juvenile mortality to achieve rapid population growth. However, raising animals in benign environments may promote traits that are adaptive in captivity but maladaptive in nature. In chinook salmon, hatchery rearing relaxes natural selection favoring large eggs, allowing fecundity selection to drive exceptionally rapid evolution of small eggs. Trends toward small eggs are also evident in natural populations heavily supplemented by hatcheries, but not in minimally supplemented populations. Unintentional selection in captivity can lead to rapid changes in critical life-history traits that may reduce the success of supplementation or reintroduction programs.

  • * To whom correspondence should be addressed. E-mail: dheath{at}

View Full Text

Stay Connected to Science