I fish the Youghiogheny (mostly stocked fish, some holdovers) here in southwestern PA with a couple buddies from work and one always checks the stomach content of those that he keeps. He says he often finds small pebbles and moss (stringy algae) in the stomachs and we have gone back and forth between those are probably the disoriented, newly stocked fish dining on anything that moves or resembles their normal trout pellets diet. Then I started thinking that perhaps the trout are learning to catch insects on the bottom and the pebbles and algae are sort of the by-catch of doing so. And maybe they digest the bugs but the rocks and algae take longer to get through their digestive tracts. Perhaps that is just wishful thinking as I don't know how long it takes for the fish to learn to catch bugs.

Perhaps I should come up with a pebble/algae fly pattern?