Bruce -- the "definitive" study on the skewed sex ratio came from a "famous" [in the fisheries world only, of course :-)] study done by W. F. Childers of the Illinois Natural History Survey [Bulletin Volume 29, Article 3, 1967; Hybridization of four species of sunfishes (Centrarchidae)]. He found that 7 of 10 crosses were mostly male, two were near 50-50, and one was predominantly female.
This will probably get long, but I suspect others might be interested in this topic.
Here are the sex ratios (percent male) that he got with various hybrid crosses. The male parent is listed first. When he had more than one trial, I put the number in parentheses following the average.
Redear X Bluegill 97 (3)
Bluegill X Redear 97
Redear X Green 69
Green X Redear 48
Bluegill X Green 97
Green X Bluegill 68 (2)
Redear X Warmouth 55
Bluegill X Warmouth 69 (2)
Green X Warmouth 16
Warmouth X Green 84
A few interesting tidbits, if these percentages are reliable!
As everybody probably knows, these high percentages of males only occur when very "pure" parents are used (no hybridization in their backgrounds).
