A highly productive hatchery can support harvest rates of 90%. If the fisheries affecting this hatchery population are being managed for natural production, they can never generated harvest rates that high, so in most cases, unmarked fish that would be released in selective fisheries are not needed to support hatchery programs. In less productive hatcheries, or where you have small hatchery programs that export eggs to larger programs, like Skykomish coho (used to support the larger release program at Tulalip Bay as well as the smaller release in the Sky), releasing some unmarked fish may be necessary to assure that hatchery escapement is always made.