Just a couple of clarifications I can make. Salmon do have female jacks. They are called jennies, and I've seen them in the fishtrap that I used to work at. Grilse are a term I've only heard applied to the equivalent of a jack in Atlantic Salmon. Being from the south coast of Oregon, we called them half pounders, sure are a kick in the pants on light fly gear, I did catch one on the trask this year, and another on the salmon the year before. Hope this helps.