I think tilapia take predation pressure off of bluegill, but that doesn't necessary ensure improved bluegill spawning and recruitment, because tilapia will compete for bed-sites. Best if you are stocking tilapia is to feed your standing crop of bluegill and get what reproduction you can from them in addition to what tilapia will naturally do. I've seen coppernose spawn in early april on very warm days, which would be great if you haven't already stocked tilapia by that time.
