At least one of the early studies on sex ratios on BG X GSF crosses is/has been questioned due to possible GSF component genetics. It is possible that the 66% male figure was off due to the GSF genetics not being pure. So a little off can make a big difference in results.
Even pures can be off within a brood. If number of broods small, then it is very easy to come away away with conclusion sex ratio is skewed. Lack of proper replication plagues much of the data I see looking at sex ratios in sunfish.
Aquaculture Cooperative Research / Extension Lincoln University of Missouri
Ok so I should not expect to be able to calculate the gender ratio. Is it ok to assume that the smaller less aggressive fish are female? Or should this be decided based on color, or physical features?
Final update on the project. Released the fish today. Pond water temp was about 65 degrees. 11 fish were released with the largest at 6 inches. Conclusion from experiment is that GSF do not do well enough together to keep groups in a tank. The largest was separated for protection and it did the best. This might work if fish were separated into groups of 1 or 2 but I lacked that many tanks. I would like to try this with 1 or 2 LMB fry but not sunfish again.
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