I suspect that Josephine has no creeks where trout can spawn and the fish must be periodically stocked. Old trout develop the appearance of spawning salmon; humped backs and hooked jaws, they also appear markedly thin, the head being the deepest part of the profile. I remember seeing a slide show put on by a member of the Trailblazers (a volunteer group that stocks mountain lakes that have no self-sustaining populations of trout); the lake in question had been stocked, by air, eight years earlier with rainbows and, assuming they all died of old age by now, the Trailblazers were packing in cutthroat fry. When the first cutthroat were released, the gaunt, hook-jawed rainbows appeared, seemingly from nowhere, to gobble them down. According to the slideshow presenter, they had quite a time, lashing pocket knives to sticks and spearing the rainbows, before they could safely release their cargo of cutthroat fry. He had slides of the rainbows and they appeared very much like your description.
