Temperature Studies

Salmonids are coldwater fish with defined water temperature requirements during their upstream migration, spawning, incubation, and rearing. The metabolism, behavior, reproductive success and/or mortality at each life stage of the salmon can be strongly affected by water temperatures ¾ not so cold as to slow metabolic process nor so warm that excess body resources must be used for maintenance. Water temperatures play an important role in moderating migration behaviors and migration success, potentially blocking or delaying migration at temperature extremes.  Moreover, many distinct salmon populations have evolved in response to the specific temperatures of their natal streams and migration corridors.  FERL has several ongoing temperature studies in the Columbia and Snake Rivers. They include:

·         A white paper review of literature related to the effects of warm water temperatures on salmon in the Snake River thermal hydro-regimes.

·         A study of altered temperature regimes on migration, survival and reproductive success of adult salmon and steelhead in the Columbia River Basin.

·         A study of the probability of adult Chinook salmon and steelhead passing through the Hydrosystem and successfully spawning in the Snake River drainage, given exposure to variable temperature regimes during migration from the ocean. 

·         An evaluation of the effects of the quantity and timing of cool water releases from Dworshak Reservoir on passage, vertical and horizontal distribution, and body temperature on adult Chinook salmon migrating through Lower Granite Dam and Reservoir. 

·         A study of the effects of water temperatures in ladders on salmon and steelhead passage at McNary Dam and the lower Snake River dams.