Flow-regime Conditioning for Wild-adaptation in Juvenile Sebastes schlegelii

Abstract

Sebastes schlegelii is an economically important fish distributed in northern China, but its populations are declining. To support stock enhancement and assess the effects of swim-conditioning on juveniles' wild-adaptation, we conducted swim-training on juvenile Sebastes schlegelii (total length 3.05 ± 0.10 cm, body weight 0.58 g) to improve their preparedness for the natural environment. Constant-flow swim training was applied at three speeds (2BL s^-1, 4BL s^-1, and 6BL s^-1) for 30 days. After the training, the following parameters were measured: survival rate, terminal body mass, weight gain efficiency, visceral somatic index, condition factor, specific growth rate; as well as the activity of alkaline phosphatase, catalase, glutamate oxaloacetate transaminase, lysozyme, and total amino acids. The results showed that after swim training, the 2BL s^-1 flow rate affected juveniles’ growth performance and biochemical parameters by significantly increasing terminal body mass, weight gain efficiency, specific growth rate and condition factor. The 4BL s^-1 flow rate produced no significant differences compared with the control. The 6BL s^-1 flow rate caused significant negative effects relative to the control. The research indicates that moderate swimming exercise training can enhance the growth performance and biochemical indicators and improve the muscle quality, increase the antioxidant capacity, and regulate the functions in juvenile Sebastes schlegelii, thereby promoting the healthy growth and helping them adapt to the complex conditions of the wild.