"Mint, sorrel, and wild onions - all of which can often be found near mountain streams - are other tasty additions, especially if you steam or foil-bake your fish."
I don't know about mint or sorrel in the Sierra but wild onions, often found in boggy areas along the outlets of streams up to ~10,000', are excellent stuffed in the body cavity of trout before roasting/steaming in foil on a bed of coals.
For those of you who fry your fish, mix up a batch of instant mashed potatoes beforehand, season to taste(chopped wild onions are a nice addition here), and then fry the mashed potatoes as a big potato pancake in the oil you used to fry the fish. When it's brown on one side flip it and fry until brown on the other side. A tasty way to get your carbs plus the extra calories in the fish frying oil that might otherwise go to waste.