SRAC
https://srac.tamu.edu/serveFactSheet/252

Hybrid fertility
The strains of channel catfish female and blue catfish male used to produce first generation (F1) C�B hybrids affects whether or not they can reproduce. Some F1 C�B hybrids can spawn and produce large numbers of second generation (F2) hybrids; other types of F1 C�B hybrids have low fertility or are essentially sterile. With difficulty, F1 C�B hybrids can be crossed with a pure strain of chan�nels or blues to produce backcross hybrids. However, the performance of these F2 and backcross hybrids is inferior to that of F1 hybrids and channel catfish. Therefore, pro�ducing fry from C�B hybrid parents is not recommended. To obtain genetic improvement and hybrid vigor, chan�nel catfish females must be mated with blue catfish males each year to produce F1 C�B hybrids for production.