Abstract:Light is one of the main factors affecting fish activity, feeding, and growth, and has thus been an active focus of marine research. The aim of this study was to investigate the selectivity of light spectra and intensity in Schizothorax wangchiachii using wild and cultured fishes. The study investigated the effects of light on the growth performance and physiological characteristics of S. wangchiachii. S. wangchiachii were cultured in a 12-replicated recirculating aquaculture system with four different lighting conditions (natural light, blue light, green light, and yellow light) for 8 weeks. The results showed that S. wangchiachii were attracted to the yellow, red, and green light, with blue light having a negative effect on species. No significant differences were found (P<0.05) between the phototaxis behaviors of S. wangchiachii in response to different light intensities (22.6~64.7 lx) under green and yellow light. The results showed that light colors have a notable impact on the growth rate and survival rate of S. wangchiachii (P<0.05). The yellow light showed better trapping ability but did not improve the growth and survival rate of S. wangchiachii, however, the survival rate of S. wangchiachii was only 46.7% in the blue light treatment group. In addition, there was no significant difference between cortisol levels of the natural light and yellow light treatment groups, but they were significantly lower than those of the blue light treatment group. In conclusion, better growth performance was obtained with yellow and natural light treatments, and the survival rate of S. wangchiachii was more than 85%, both faring significantly better than the blue light treatment. Blue light increased the stress levels of S. wangchiachii and led to a decreased survival rate. These results can provide scientific basis for the wild harvest of fish, solutions for fish passage around hydraulic engineering construction, and in the selective breeding of S. wangchiachii.
