Also from and old, old research paper where ponds were stocked with RES/GSF hybrids it was found that a GSF female X RES male was a very easy and reliable in-pond cross that could be made. They were unsuccessful at producing GSF male X RES female in a natural environment. It could be done in the lab artificially, but not in pond natural conditions.
So if this old research holds true, your hybrids are likely from a GSF female and RES male.
As I recall, this natural cross produces about as many females hybrids as male hybrids (unlike GSF female X BG male which produces a high number of males and few females)
Just an FYI. Experts correct me if my memory fails on this subject.
Last edited by snrub; 07/28/15 03:12 PM.
