Pond culture of female green sunfish ( Lepomis cyanellus) × male bluegill ( L. macrochirus) hybrids stocked at two sizes and densities

Abstract

The hybrid produced by crossing the female green sunfish ( Lepomis cyanellus) and male bluegill ( L. macrochirus) was evaluated under production conditions for 1 year. Juveniles were stocked at two initial sizes (38 and 66 g) and two densities (6175 and 12350/ha) into twelve 0.04-ha ponds and fed a diet containing 36% protein for 371 days. Fish stocked at 6175/ha had significantly higher ( P < 0.05) final weights and average total and summer gains than fish stocked at 12350/ha. Although fish stocked at 38 g were significantly smaller ( P < 0.05) at harvest, percentage weight gain and feed conversion efficiencies were significantly higher ( P < 0.05) than for fish stocked at 66 g. There was a significant interaction ( P < 0.05) between stocking density and stocking size on net yield and gross yield which ranged from 838 and 1315 kg/ha, respectively for small fish stocked at low density to 1925 and 3565 kg, respectively for large fish stocked at high density. There were no significant differences ( P > 0.05) in percent protein, fat, and moisture of whole bodies of fish stocked in the different treatments. Stocking of large juveniles at high density produced more harvestable-size fish (> 110 g) per ha. Effects of higher stocking densities on feed utilization and improved feeding regimes should be investigated.