acute heat and hypo-salinity stresses on sea cucumber Apostichopus japonicus

The 120 individuals were randomly and equally divided into four experimental groups: negative control group, C (16 ?, 30 psu); heat group, HT(30 ?, 30 psu); hypo-salinity group, LS (16 ?, 20 psu); and heat plus hypo-salinity group, HL (30 ?, 20 psu). In the HT group, seawater was gradually heated to 30 ? at a rate of 0.5 ?/h using a temperature-controlled heating rod. In the LS group, salinity was adjusted with tap water that had been aerated for 48 h and lowered by 2 psu every 2 h until the target 20 psu was reached. In the HL group, the same procedures were applied to obtain the target temperature and salinity. The experiment was run for 48 h, with samples taken at the end of the experiment