Definitions

Broodstock-the pool of captured adult salmon a hatchery has available for artificial spawning. This pool can be made up of wild and/or returning hatchery salmon.

Carrying capacity- is a measure of the amount of a population (like the amount of salmon) that can be supported by an ecosystem. Carrying capacity changes over time with the abundance of predators and resources like food and habitat.

Inbreeding- occurs when there is mating between close relatives. It can affect growth, survival, and reproduction. Inbreeding is high in small populations because most individuals are related. Hatcheries that use only a portion of a population for broodstock can increase the level of inbreeding.

Straying- when salmon do not return to their stream or hatchery of birth. Straying ensures that salmon colonize new areas. However, straying can have negative genetic consequences when hatchery fish stray into streams inhabited by natural populations. Some hatchery stocks have stray rates that are much higher than natural stray rates. In addition, some hatchery stocks use nonindigenous broodstock, that is fish from other locations, which can have negative genetic consequences for local wild populations.

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last modified 03/09/2006
Web site owner: Northwest Fisheries Science Center