|dc.description.abstract||Two strains of channel catfish (Ictalurus punctatus, HS-5 channel and NWAC 103 channel catfish), one strain of blue catfish (I. furcatus, D&B blue catfish) and their hybrids (HS-5 channel ? × D&B blue ?, NWAC 103 channel ? × D&B blue ?) were compared for their production characteristics in twenty-five 0.04-ha earthen ponds at a density of 12,500 fish/ha. Mean survival (88.9%) was not significantly different among the five fish groups. HS-5 channel catfish and its hybrid started at larger sizes (56.5 g) and ended up with larger animals (850.5 g) than the other three fish groups (29.4 g and 638.6 g, respectively). D&B blue catfish (CV=29.9) was more uniform than NWAC 103 channel (CV=38.6) and NWAC 103 hybrid (CV=41.8), but it was not significantly different from HS-5 channel (CV=35.4) and HS-5 hybrid (CV=30.3). Better average growth rates were observed on the HS-5 channel catfish (2.76 g/day) and its hybrid (2.87 g/day) than those of the NWAC 103 channel (2.31 g/day), NWAC 103 hybrid (2.30 g/day), and D&B blue (2.03 g/day). The NWAC 103 channel (1.12%) and its hybrid (1.06%) had better mean specific growth rates than those for the HS-5 channel (0.97%), HS-5 hybrid (0.96%), and D&B blue (1.01%). No significant differences were detected among the five fish groups based on the growth rate index (a) evaluation, and the overall average growth rate index (a) was 1.89. Mean net production among NWAC 103 hybrid catfish (6953 kg/ha), HS-5 channel catfish (8396 kg/ha) and its hybrid (8480 kg/ha) was not significantly different, and they were greater than those of the NWAC 103 channel catfish (5791 kg/ha) and the D&B blue catfish (5774 kg/ha). Mean feed conversions (1.62) were not significantly different among treatments. D&B blue catfish (94%) was the easiest to seine as measured as percentage harvested within the first seine haul. HS-5 channel × D&B blue hybrid catfish (61%) was easier to seine than its parent HS-5 channel catfish (31%).
Processing revealed some differences among fishes. Both the mean head percentages of HS-5 channel × D&B blue hybrid (17.0%) and NWAC 103 channel × D&B blue hybrid (16.5%) were less than those of their parent channel catfish (20.8% and 19.1%, respectively). Both hybrid catfishes had better mean dress-out percentages (HS-5 channel × D&B blue hybrid 72.1% and NWAC 103 channel × D&B blue hybrid 71.8%, deheaded and gutted with skin) than those of their parent channel catfish (67.4% and 69.6%, respectively) and blue catfish (70.2%). No significant differences were detected on the mean skin-on fillet percentages (50.6%) among the five treatments.
The success in the hybrid catfish artificial spawning techniques made the commercial production of hybrid catfish possible. According to the results of the present study, hybrids from different parental stocks performed differently. Further studies on the selection of hybrid catfish and mechanism of heterosis are needed for the commercial production of hybrid catfish.||en_US