I have crossed WM with GSF, NBG, RE and Redspotted Sunfish. F1's of the first three failed to produce fry even when ponds were stocked only with them for two growing season. I could sex fish, but could not get gametes to express using socially acceptable degrees of stripping pressure.
I am confident of my ability to keep other species / crosses out and ponds were 1/10 acre and otherwise suitable for breeding sunfishes.
