A technique using 51 chromium‐labelled erythrocytes was used to measure blood volume in Scyliorhinus canicula following long‐term and acute salinity transfers. Basal whole‐blood volume was 5·6 ± 0·2 ml 100 g −1 (mean ± s . e .), this increased (6·3 ± 0·2 ml 100 g −1 ) following +14 day acclimation to 80% sea water (SW) and decreased (4·6 ± 0·2 ml 100 g −1 ) following acclimation to 120% SW. These changes were shown to be prima...

To compare rectal gland morphology of bull sharks Carcharhinus leucas , animals captured in the freshwater reaches of the Brisbane River, Australia, were acclimated to sea water over 17 days with 1 week in the final salinity. A control group was left in fresh water for 17 days. Animals in fresh water and sea water were strongly hyper‐ and hypo‐ionic with respect to plasma Na + and Cl – , respectively. This difference necessita...

The existence of an intrarenal renin‐angiotensin system (RAS) in a perfused European lesser‐spotted dogfish Scyliorhinus canicula trunk preparation was examined by the inhibition of angiotensin‐converting enzyme by captopril. This resulted in a glomerular diuresis, an increase in urea and chloride clearance and excretion, and an increase in transport maxima for glucose. It is proposed that these results suggest the presence of...

In the European lesser‐spotted dogfish Scyliorhinus canicula , rectal gland mass in mg ( M Rg ) followed the allometric relationship: M Rg = 1·15 M 0·68 , where M is body mass (g). The concept of allometric scaling is an important consideration in studies investigating the function of osmoregulatory organs.

Chloride secretion rates of rectal glands taken from the European lesser‐spotted dogfish Scyliorhinus canicula adapting to 70% and 120% sea water (SW) were significantly greater and less than, respectively, those in the control 100% SW group. C‐type natriuretic peptide (CNP) significantly increased chloride secretion rates above basal values in 100% SW although angiotenisn II (ANG II) had no effect. Perfusion of the secretory...

Drinking rates in glass eels and elvers of the European eel increased with environmental acclimation salinity from 0·07±0·02 (FW) to 0·70±0·09 μl g‐ 1 h‐ 1 (SW) at month 1 and from 1·12±0·42 (FW) to 12·85±1·05 ± l g‐ 1 h‐ 1 (SW) at month 5. Drinking rates increased with time in both FW and SW groups. FW acclimated eels when challenged acutely with SW increased drinking rate rapidly immediately upon transfer (0–15 min) and the...