|Document Type:||Journal Article|
|Title:||Inhibition of salt water survival and Na+-K+-ATPase elevation in steelhead trout (Salmo gairdneri) by moderate water temperatures|
|Author:||B. L. Adams, Waldo S. Zaugg, Lynn R. McLain|
|Journal:||Transactions of the American Fisheries Society|
We evaluated the steelhead trout metamorphosis from a freshwater parr to a seawater–tolerant smolt possessing the migration tendency at six different growth temperatures ranging from 6 to 15°C during January through July. The highest temperature where a transformation was indicated was 11.3°C. By April, fish reared at 6°C had elevated ATPase levels typical of smolts or migratory animals and showed 92% survival in sea water. Fish reared at 10 and 11.3°C showed a short–lived elevation in ATPase in mid–April alone concurrently with 100% sea water survival at that time. Only in animals reared at 6°C did the salt water survivability continue into May. High ATPase levels likewise were prolonged into May and June only in the group reared at 6°C. The data indicated that metamorphosis (and therefore successful migration) of juvenile steelhead trout was directly controlled by water temperature.