Blackmouth is a Puget Sound term for a juvenile or feeder chinook. In Puget Sound as elsewhere there are basically two types of chinook, "ocean type" chinook which smolt or go out of the rivers to the marine environment about three months after they emerge as fry from the gravel (90 day wonders) they then spend some time in the esturary then go out to the Pacific to grow to adulthood, this is typical of fall run chinook. Then there are the "river type" chinook which spend up to a year or more in the river before going out to the marine environment, blasting through the estuary and growing to adulthood within Puget Sound, San Juans and Pacific Ocean, this is typical of spring or summer chinook. Hatchery managers found when they delayed the release "ocean type" chinook fry/smolts for a year they changed their behavior to emulate "river type" chinook, these fish then stayed closer to home or residualized in Puget Sound and the San Juans thus being available for harvest year round. The term blackmouth refers to a technique for distinguishing between small chinook and coho, chinook have black gumlines whereas coho have white gumlines. This is kind of a generalization.

Beezer