*2.1. Experimental Animals*

Small green *A. japonicus* (~1 g of wet body weight) were transported from Yinhaima Aquatic Products Co., Ltd. (121◦54 E, 39◦38 N) to the Key Laboratory of Mariculture and Stock Enhancement in the North China's Sea and Ministry of Agriculture and Rural Affairs at Dalian Ocean University (121◦56 E, 38◦87 N) on 2 March 2022. Small sea cucumbers were cultured in fiberglass tanks (length × width × height: 115 cm × 75 cm × 60 cm) at a density of 400 g/m2 [22,23] and with aeration. Water temperature was increased 1 ◦C each day from 8 ◦C to 25 ◦C (ambient temperature) by using a temperature-controlled system (Huixin Co., Dalian, China). Sea cucumbers were maintained at 25 ◦C for two weeks to be acclimatized to the experimental conditions. Sand-filtered seawater was replaced every three days with feces and uneaten food removed. Salinity, pH, and dissolved oxygen were tested weekly using a water quality detector (YSI Incorporated, Yellow Springs, OH, USA). The results were 31.36 ± 0.19, 8.01 ± 0.03 and 9.34 ± 0.21 mg/L, respectively. Small sea cucumbers were fed *ad libitum* with sea mud and commercial feed (Anyuan Industrial Co., Ltd., Yantai, China) at a ratio of 1:4 until the experiments started in April 2022.
