Heritability of Swimbladder Inflation in Striped Bass

Abstract

Lack of swim bladder (gas bladder) inflation can be a serious problem in the culture of striped bass Morone saxatilis, resulting in high mortalities and skeletal anomalies. We undertook a heritability study to examine the genetic basis for this trait. A 7 × 10 (female × male) factorial mating study resulted in 70 full-sibling families. Each full-sibling family was reared individually for 10 d posthatch, and sampled surviving larvae were microscopically examined for swim bladder inflation. Full-sibling and dam half-sibling heritability estimates were 0.35 and 0.04, respectively. Low half-sibling heritabilities indicate that there is little additive genetic variance that can be exploited for selection purposes. The higher full-sibling estimates suggest swim bladder inflation is predominantly influenced by dominance, epistatis, or environmental factors.