Effects of different light qualities on embryonic development of Sepia pharaonis

Abstract

To investigate the impact of different light qualities (red, blue, green, yellow, and white light) on the embryonic development of Sepia pharaonis, this experiment studied the effects of different light qualities on the timing of embryonic development, incubation period, hatching rate, malformation rate, weight of hatchlings, and survival rate on the 7th day after hatching. The findings demonstrated a significant influence of different light qualities on the embryonic development of S. pharaonis (P<0.05). Specifically, red and blue light led to increased occurrences of phenomena such as yolk surface cracking, cell autolysis, coagulation of cells in the animal pole, yolk sac edema, malformations in endoskeleton development, and decreased pigmentation and whitening of the body surface compared to the control group (white light). Conversely, green light showed a tendency to reduce these phenomena. The hatching rate and hatching cuttlefish weight were highest under green and yellow light conditions, with significantly greater survival rate on the 7th day after hatching compared to red, blue, and white light conditions. Furthermore, the malformation rate was notably lower under green light conditions compared to other light groups. Red and blue light conditions exhibited the shortest hatching periods, significantly outpacing other light groups. In conclusion, green light appears advantageous for enhancing hatching rate, the quality and health of hatched larvae, reducing malformation occurrences and embryonic mortality, and improving overall hatching quality.