Originally Posted By: Salmo g.
Big Jim,

When Chambers Creek hatchery steelhead spawn in the wild, either with themselves or mixing with wild steelhead, the resulting offspring lack sufficient fitness to survive and return as a future generation of adult fish. The number of survivors that return is statistically zero. Is that clear enough? That's why it's a bad thing when a hatchery steelhead spawns with a wild one. It removes the reproductive potential of that wild fish from the spawning population.

Sg


Your example is an isolated one. In other populations hatchery fish have been shown to keep *wild* fish populations at elevated levels. In some cases hatchery fish have been successful in implementing reintroductions of extirpated populations.

Granted, hatchery fish are not always capable of carrying all of the genes needed to keep populations afloat and adapt to a changing environment.

FYI, the word fitness is not the correct one to use here. Fitness in ecological or biological terms applies only to the capability to produce viable offspring, not their overall success at survival.