Drinking Rate and Oxygen Consumption in the Euryhaline Teleost Aphanius Dispar in Waters of High Salinity
1. The drinking rate and the oxygen consumption were measured in Aphanius in sea water (SW) at 17, 20 and 24.5 °C and at 20 °C in 2-fold and 3½-fold SW. Both untrained (shocked) and trained fish were used. In this species shock was observed to reduce the drinking rate. 2. In trained fish the drinking rate was 11.0±1.0 µl/g.h (mean±S.E.) in SW at 20 °C. The oxygen comsumption was 346±16 µl O2/g. h. These parameters were not significantly changed in 2 SW and 3½ SW. 3. At 17 °C both drinking rate and oxygen consumption were reduced, and at 24.5 °C were increased. 4. The results suggest that adaptation to waters of high salinity primarily involves a reduced effective osmotic permeability of the integument (the gills) and an increase in the transport rate of NaCl by the intestine, roughly proportional to the salinity.