Fig. 1. Time course of changes in osmoregulatory parameters in plasma osmolality (A,B) and Na⁺,K⁺-ATPase activity in gills (C,D) and kidney (E,F) of gilthead sea bream acclimated to hyperosmotic (A,C,E) or hypo-osmotic (B,D,F) conditions. Fish were transferred for 14 days from seawater (SW) to (A,C,E) hypersaline water (HSW; closed circles) or (B,D,F) low salinity water (LSW; closed circles). Open circles indicate control fish transferred from SW to SW. Each value is the mean ± S.E.M. of N=8 fish per group and sampling time. ^*Significantly different (P<0.05) from SW group at the same sampling time. Different letters indicate significant differences (P<0.05) among sampling times (0, 1, 3, 7 and 14 days) in fish acclimated to HSW or LSW.