Fig. 5. Effects of a rapid decrease in environmental salinity (from 26 p.p.t., 758 mOsm kg^–1 to FW, 22 mOsm kg^–1) on river lampreys. Blood samples were collected from a group of lampreys prior to transfer and further groups at 2 h, 4 h, 8 h and 24 h after transfer. Data for (A) plasma osmolality (mOsm kg^–1; N=8 at each time point), (B) haematocrit (%; N=10 at 0h, 8 at all other time points) and (C) plasma angiotensin concentration (pmol l^–1; N=9 at 0 h, N=8 at 2 h and 24 h, N=7 at 4 h and 8 h) are shown). Groups with different letters above error bars differed significantly (ANOVA and post-hoc multiple comparison tests).