I have a reproduction pond dedicated to raising BG/RES hybrids the last two years. Year one had minimal success as a female BG slipped in from another pond and I was having a hard time making positive ID on YOY BG and hybrids. Last year I had much more success, but am waiting until Spring to seine because I neglected to stay on top of vegetation issues and it prevented good collection efforts this Fall. I remain hopeful though as during net sampling I was finding hundreds of YOY BG/RES in a few swipes. Not sure if they will have survived the winter or not. I have kept it largely ice free and full of flowing water to hopefully mitigate the mortality rate. I think mortality on fish that size isn't so much about temps, but lack of forage. This year I think my collective experience should prove to yield another strong crop of SMB and finally BG/RES hybrids. If you stock Male BG and Female RES they will hybridize and create one cool fish. I love them.