When predator and prey frequently interact, it is highly likely the predator is feeding on numerous nearby prey. However I do not know of any published research on this topic of HSB eating a lot of small pelagic stage crappie. Ewest our Pond Boss librarian can search his resources for this or a similar topic. IMO probably the best way to determine this information would be to do gut analyses of open water HSB when crappie are in the pelagic stage of life. This to me sounds like a very good college level research topic for MS or PhD students.