L.W.J,
One of the key aspects to Tilapia as a forage is that they do not reproduce at temps below 68 degrees and have significantly reduced reproduction below 80 degrees. Hence, for my ponds in East Texas, which I manage for high catch rates on medium sized LMB (3 to 6 pounds) (trophy LMB 10 pounds+ have been a welcome bonus), it is important to have other forage available for those approximately 4 or 5 months during the year in which no young Tilapia are produced.
IMO, you will have the same problem, and perhaps even more so. Tilapia that overwinter are not going to provide much if any reproduction in your 65 degree water temps and during the time those temps are falling to those levels. They survive, but that is about all. They don't even eat much at all, based on my experience with them in a temp controlled indoor facility. In addition, you will not benefit from the die off in which huge amounts of Tilapia are consumed by LMB just before when winter metabolism slows down the LMB feeding rates. In your case, the LMB metabolism will remain relatively high through winter in comparison to mine hence, further adding to the need for additional forage.
It will be interesting to read the stocking rates and the results you get with your plan of using Tilapia as the only forage. In my way of thinking, a Tilapia only forage pond in S. Texas will see results very comparable to a standard LMB/BG pond in more northern latitudes. In both instances, limited forage availability through the winter months curtails LMB growth independent of winter metabolism. My experience tells me that year-around forage separates the average pond from the above average and spectacular ponds.
If I were in S. Texas, I would contact Texas715 (Greg) for his experience. He has overwintering Tilapia and a successful LMB fishery.
