Group dynamics of Plecoglossus altivelis under different light environments

Abstract

Collective behavior in nature exemplifies self-organization through local interactions, with fish schooling being a compelling case. While illuminance affects both individual physiological traits and group dynamics, light wavelength has been shown to influence individual physiological traits, such as growth and endocrine secretion. However, its role in shaping collective behavior remains unclear. In this study, we used Plecoglossus altivelis to investigate schooling behavior under three light conditions: darkness, blue light, and red light. The key findings included: (1) fish formed fewer groups in darkness, with larger inter-individual distances and lower orientation alignment and (2) under blue light, fish exhibited tighter, more aligned schools than the fluid and variable group formations under red light. These results suggest that light wavelengths significantly impact schooling behavior and have potential applications in aquaculture and fish guidance systems.