Production Methods for Food‐Sized Bluegills

Abstract

AbstractGrowth of selected crosses (P1♀ × F1♂, F1♀ × P1♂, and F1♀ × F1♂) of Lincoln University bluegill stocks were evaluated. The purpose was to test the commercial potential for reaching marketable size (227–340 g) within 2 years in an indoor water‐recycle system and grow‐out in ponds. Pond hatched young‐of‐year bluegill were reared in a 12‐tank (719 L/tank) indoor water‐recycle system. Fish were fed to satiation three times daily. Fish were weighed and measured for total length (TL), for a 120‐d growth trial. Initial mean fish weight and TL were 28.0 ± 15.8 g and 106 ± 16 mm, respectively. Final mean weight was 119.4 ± 54.9 g, and mean TL was 161 ± 19 mm. Crosses were significantly different (P ≤ 0.05). Initial female weight averaged 82.1 ± 32.5 g, and male weight averaged 158.6 ± 45.5 g. Feed conversion ratio was 1.26, and survival was 99.4%. Specific growth rate (SGR) averaged 1.21%/d with a mean length increase of 0.5 mm/d. Fish were then marked by specific crosses with colored visible implant elastromer tags. Fish were stocked in four 0.04‐ha ponds (N = 600 fish/pond; density = 15,000 fish/ha) for 129 d. Final mean weight of fish in the pond study was 228.3 ± 71.7 g; mean TL was 200 ± 15 mm. Crosses were not significantly different from each other (P > 0.05). Sexual dimorphism was more pronounced after pond rearing; females averaged 175.4 ± 41.7 g and males averaged 284.0 ± 54.4 g. Results indicate bluegill grown in indoor recycle systems may reach target weights of 227–340 g within 2 years with the use of out‐of‐season spawning and selective breeding. Forty‐eight percent reached or exceeded the minimum target weight (227–340 grams). This study also suggests that removing females could increase the number of fish reaching target weight by 33%.