Redear I snorkeled with in southern streams appear to eat a lot of hard-shelled mollusces. Those in northern lakes (ancestors came via hatcheries from same southern streams) are more Bluegill like and typically do not have anything tougher than Rams Horn Snails to eat seasonally. It is my guess that my location is north of where Redear would occur naturally without periodic infusions from stocked reservoirs.
I think Shorty described some pretty large amounts of winter kill in his RES last year in Nebraska. So cold water stress would go along with that argument for need of periodic infusions. With just one year in say ten where a bad winter would knock populations back, it could be hard for the RES to continue to compete and prosper along side other fish species that were better adapted to their local environment.
I know I put 175 RES and 100 CNBG in my sediment pond and based on the fingerlings I got out of it I could have put 25 CNBG and still had more BG recruitment than I did RES.
