Influence of water temperature on gill sodium, potassium-stimulated ATPase activity in juvenile coho salmon (Oncorhynchus kisutch)

Abstract

1. 1. Gill sodium, potassium-stimulated ATPase activity was determined from December to July in gills of yearling coho salmon (Oncorhynchus kisutch) maintained at four temperatures, 6, 10, 15 and 20°C. 2. 2. Compared to fish held at 6°C, elevation in ATPase activity and the associated parr-smolt transformation were accelerated in fish at 10 and 15°C whereas animals at 20°C experienced at best only a transitory elevation in activity. 3. 3. Fish transferred from one temperature to another developed ATPase activities characteristic of fish residing at temperatures to which they were transferred. 4. 4. Cold water (6°C) tended to preserve the elevated ATPase activity while higher temperatures (10 and 15°C) caused decreases after an initial accelerated increase. © 1976.