2.1 Sea bass husbandry and treatment
European sea bass juveniles were reared at Ifremer Station at
Palavas-les-flots (Hérault, France) in recirculating seawater (SW;
osmolality: 1208 mOsm.kg−1, Na+: 515
mmol.L−1, Cl−: 737
mmol.L−1) under a 12/12 h light/dark photoperiod at 20
°C. At the age of 8 months (13.59 ± 0.12 cm, 32.19 ± 2.62 g), half of
the fish were transferred to brackish water (BW; osmolality: 475 mOsm
kg−1) for 24 h and then transferred to dechlorinated
tap fresh water (FW; osmolality: 8 mOsm.kg−1,
Na+: 2 mmol.L−1,
Cl−: 3.5 mmol.L−1) for two weeks.
The remaining fish were transferred from SW to SW as controls. Pellet
food (Le Gouessant, France) was proposed daily to fish. After the 2-week
salinity challenge, 5 fish per condition were killed using a 100 ppm
lethal dose of benzocaine before immediate tissue sampling.