Comparative morphological analysis and body weight prediction of hormone-induced YY pseudofemale channel catfish, Ictalurus punctatus (Actinopterygii, Siluriformes, Ictaluridae)

To advance the efficient all-male breeding of channel catfish, Ictalurus punctatus (Rafinesque, 1818), this study utilized YY pseudofemales obtained through hormone-induced sex reversal. Morphological traits and body weight were systematically compared among YY pseudofemales ( n = 50), XX females ( n = 50), XY males ( n = 50), YY supermales ( n = 50), and XY pseudofemales ( n = 50) at 6 months of age. Using correlation analysis, path analysis, and multiple regression, the relationships between morphological traits and body weight were elucidated. The results showed that YY pseudofemales exhibited significantly lower values for several morphological indicators than males, but no significant differences were observed relative to females or XY pseudofemales. This provides key phenotypic evidence supporting the feasibility of using YY pseudofemales as female broodstock in the “YY supermale × YY pseudofemale” breeding system. The analysis revealed strong correlations between morphological traits and body weight; however, the key traits affecting body weight showed significant population-specific patterns. Specifically, weight gain in pseudofemale channel catfish primarily depended on increased body depth at the anus, exhibiting a “body depth-dominant” pattern, whereas male channel catfish showed a “standard length-dominant” or “total length-dominant” pattern. This finding offers direct theoretical guidance for implementing precise population-differentiated selection strategies tailored to distinct breeding objectives. Furthermore, a reliable predictive model for body weight in YY pseudofemales was established based on key morphological traits. This model may facilitate early screening of broodstock and accelerate genetic progress in all-male breeding, although its broader applicability requires validation across independent populations and rearing systems.