In order to meet the demand of salmon market, Chinese scientists and entrepreneur are working on salmon mariculture far offshore in the Yellow Sea, China. Light is one of the most dominant environmental regulating the growth of salmonids. Optimal light regulation technology is vital for far offshore salmon mariculture, especially in a full-submersible cage in China. The objective of this study is to explore the effect of different light spectrum and light intensity on growth and high-temperature tolerance of juvenile rainbow trout Oncorhynchus mykiss. Eight treatments were designed as two light intensities of 150 lx and 1500 lx and four light spectrums of white (full-spectrum), red (615 nm), blue (455 nm) and green (518 nm). The photoperiod was 12 L: 12 D.
Juvenile rainbow trout (N=4; 73.85 g initial weight) were fed diets for nine weeks and subsequently underwent the high temperature acclimation. This study has eight treatments at a stocking density of 20 fish per tank (400 L). The fish were fed satiation twice daily (8:00 and 16:00) and fed consumption was recorded daily. At the end of the growth trial, there were no significant differences in final mean weight (231.09-256.56 g), percent weight gain (313.45-347.04%), survival (97.5%-100%) and FCR (0.93-1.07) (Table 1). On days 1, 7 and 14 after high temperature acclimation as well as at the end of the growth trial, enzyme activities such as (liver superoxide dismutase (SOD) activity, liver catalase (CAT) activity), malondialdehyde (MDA), immunoglobulin M and heat shock protein 70 (HSP70) will be determined.