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Box 4. Genetic risks, hatchery activities causing such risks, and genetic <br />processes related to these risks (expressed ad changes from natural <br />patterns). Modified from Kapuscinski et al. (1993). <br />Genetic risk Hatchery activity causing risk Genetic process <br />Extinction Excessive numbers of adults removed from Increases in <br />wild stock or population for development genetic drift <br />of broodstocks. and inbreeding <br />Loss of genetic Low number of parents mated. Increases in <br />diversity with- genetic drift <br />in stocks or Inappropriate breeding design. and inbreeding <br />populations <br />Inappropriate fertilization method. <br />Captive breeding changes the natural <br />genetic variation in families. <br />Founders for broodstocks differ from wild <br />or supplemented stocks or populations in <br />genetic diversity, life history patterns, <br />or adaptability to the environment of the <br />wild stock or population. <br />Loss of genetic Broodstock collected from stocks or Immigration: <br />diversity among populations that are genetically Changes in <br />stocks or popu- unrelated to wild or supplemented genetic <br />tions interbreeding stocks or populations. patterns: <br />Outbreeding <br />depression <br />Inadvertent Broodstock not collected throughout Artificial <br />artificial the spawning season. selection: <br />selection Disrupted <br />Mated adults are from a nonrandom patterns of <br />sample of their cohort with respect natural <br />to genetic performance traits because selection: <br />of nonrandom mortality during incuba- Changes in <br />tion, rearing, or holding. amounts of <br />natural <br />Genetic swamping of wild stocks through selection <br />stocking of large numbers of closely <br />related individuals or unequal family lots. <br />16