Effects of light colour and intensity on stress responses in the Pacific white shrimp (Penaeus vannamei). (2025)

Pichon, C., Kersante, P., Le Reste, G. et al.

Abstract

Stress is a natural defence mechanism that can negatively impact the outcome of experiments and increase interindividual variability. Among environmental parameters, light colour and intensity are known to impact stress responses in numerous species. The Pacific white shrimp Penaeus vannamei is one of the most bred shrimp species worldwide, although knowledge about the environmental factors influencing its feeding behaviour is lacking. The aim of this study was to determine which light colour and intensity induce less stress responses and promote feeding behaviour of P. vannamei shrimp. In a first experiment, we analysed the stress responses of shrimp to purple, blue, green, yellow, orange and red lights of 83 Lux. We found that orange and red lights induced fewer stress responses, especially fewer number of loops. In a separate experiment, we found that infrared light lowered the thigmotaxis level in comparison with white and red lights. Finally, we analysed the stress responses and feeding behaviour of shrimp to orange light at intensities of 17, 64, 170 and 430 Lux. We found no effect of orange light intensity on stress responses and feeding behaviour. These findings suggest that orange light can be used in behavioural experiments for P. vannamei, even at high intensity, as it will not stress the animals while ensuring good visibility for the observer (in comparison with infrared light). Optimising testing conditions in P. vannamei’s behavioural experiments is the starting point for reducing interindividual variability and ensuring more reliable interpretation of their behaviour.