Very fishy.......there is no such thing as an adult SH <18". WDFW uses 20" as to differentiate between rainbow trout and SH. This is done because they are relatively confident that an fish that has been to salt and back would attain a length of 20". Most habitat biologist with WDFW spend very little time conducting stream surveys. It's likely that this has not been confirmed by a WDFW fish biologists?