Effect of Genetics on Body Weight Variability in Channel Catfish (Ictalurus punctatus) Female X Blue Catfish (I. furcatus) Hybirds

Abstract

Hybrid catfish have become common in the catfish production industry in the United States accounting for 50-70% of all catfish produced. Variable body weight of hybrid catfish can create production and marketing problems and economic loss for farmers due to undersized fingerlings and food fish and oversized food fish. Genetic effects on body weight variability in channel catfish (Ictalurus punctatus) female x blue catfish (I. furcatus) male hybrids were examined. Coefficient of variation (CV) for body weight of hybrid catfish and channel catfish fingerlings were similar and the environment had strong and equal effects on the variability of each genetic type. When evaluating hybrids produced from different strains of channel catfish and blue catfish, sire and dam affected variability both in terms of CV for body weight and population distribution. Contradictorily, crossbred channel catfish dams and crossbred blue catfish sires increased the CV for body weight, but resulted in hybrid progeny that were not extreme distances from the population mean in regards to the standard deviations. This could have major impact on the variability problem. Various families of hybrid catfish were grown in aquaria and then transferred to a split-pond. The correlation of the family CVs between hybrids grown in aquaria and a split-pond was 0.05, indicating genotype-environment or genotype-age interactions. When the families were pooled by sire genetic type or dam genetic type, the interactions decreased as the correlations were 0.51 and 0.39, respectively.