Guidance for evaluating and recommending temperature regimes to protect fish

Procedures are presented for evaluating temperature regimes for fish. Although examples pertain to spring chinook salmon (Oncorhynchus tshawytscha), the principles apply to other species. Basic temperature tolerance relationships for fish are explained and three options are described for comparing alternative temperature regimes. The options are to base comparisons on experimental temperature tolerance results, suitability of a simulated temperature regime for key life stages, or population statistics and predicated responses to simulated temperatures.