Effect of Photoperiod on the Growth and Survival in the Early Stage of Snubnose Pompano Trachinotus blochii

This chapter aimed to compare the effects of the natural photoperiod (12 hL: 12 hD) with those of continuous illumination (500 Lx) on feeding, growth, and survival of the early-stage snubnose pompano (Trachinotus blochii) larvae from 1 to 10 days post-hatch (DPH). Providing continuous or prolonged exposure to light had an impact on the fish larvae. Studies have shown photoperiod manipulation significantly influences fish feeding, growth, and development. Newly hatched larvae were stocked at a density of 15 ind L-1 and fed with enriched rotifers (Brachionus plicatilis; 50-250 µm) at 30 ind mL-1 starting from 2 DPH. The number of rotifers in the digestive organ, feeding incidence, and total length of larvae was examined at 3-h intervals from 0400H to 2200H at 3 DPH, 6-h intervals from 4 to 5 DPH, and once at 8 DPH. Final growth and survival were also determined at the end of the experiment. Results showed that T. blochii larvae were visual feeders and exhibited diel rhythm under 24 h light. In contrast, larvae under natural photoperiod (12 hL: 12 hD) normally underwent diurnal rhythms. In conclusion, better larval feeding, growth, and survival were obtained under continuous illumination.