RT, When our club was raising steelhead smolt ,we would refer to the smolt that wasn't released in the right time frame and just stay in the river as being residualized.
They never would go out the ocean. Some reason the state biologist had a certain day(which I can't remember) to open the raceways. We wanted to let them out when they were trying to jump out at the bottom of the raceway. Have a great time fishing ,Duck