Cecil -- we see a few snails in perch diets, but not many (to best of my knowledge; I'm at home without any reference materials).
Now I'm going to not look knowledgeable: we're having a big problem with yellow grubs in one of our perch ponds. It has plenty of vegetation and snails, and plenty of herons and cormorants. The perch are infested with the grubs, while the walleyes and smallmouth bass have very darn few. We haven't looked at perch diets in that pond, but you gotta wonder.
