ABSTRACT
As concern over erosion of genetic diversity in fish stocks has increased over the years, so has concern about the role of hatcheries in influencing genetic change. Whereas past genetic concerns regarding hatchery operations have tended to emphasize effective population size or hatchery broodstocks, now hatchery managers need to consider a more comprehensive view of genetic risk. In this paper we present some basic concepts and associated issues in such a broad view. We recognize four fundamentally different types of genetic hazard: (1) extinction, (2) loss of within-population variability, (3) loss of among-population variability, and (4) domestication. The importance of type-2 hazards in hatchery operations has long been realized, but types 3 and 4 are controversial because of a scarcity of empirical data and because consideration of them has great ramifications for hatchery operations. Precise quantification of genetic impacts in terms of fitness depression is likely to remain a difficult if not impossible task. Ultimately, incorporation of genetic concerns into hatchery operations and other aspects of fisheries management will require managers to shift their perspective from one of managing fitness to one of managing genetic diversity.