Mean Annual Discharge and Chinook Salmon
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Species Common Name
Chinook Salmon
Latin Name (Genus species)
Oncorhynchus tshawytscha
Stressor Name
Flow
Specific Stressor Metric
Mean Annual Discharge (MAD)
Stressor Units
%
Vital Rate (Process)
Egg-smolt survival
Life Stage
Season
Fall-Early Summer
Geography
Lehmi River, Washington, USA
Detailed SR Function Description
Arthaud et al. (2010) used a time series of adult returns from the Lemhi River and Marsh Creek populations of Chinook salmon to estimate the effects of tributary stream flow in the brood year on returning adults four to five years later.
The SR function was derived only the relationship for August flows as minimize pseudo replication from including 2 months (both May and August) with similar underlying flow-ecology mechanisms. Similarly, only one of egg-trap transition rate and egg-smolt survival responses was used because they were highly correlated responses.
Implicit pathway of flow effect: passage/migration
The SR function was derived only the relationship for August flows as minimize pseudo replication from including 2 months (both May and August) with similar underlying flow-ecology mechanisms. Similarly, only one of egg-trap transition rate and egg-smolt survival responses was used because they were highly correlated responses.
Implicit pathway of flow effect: passage/migration
Function Derivation
Observational data and expert elucidation
Transferability of Function
Appropriate for late-summer stream flow impacts on chinook salmon juveniles and egg-to-smolt. General transferability to other stocks in unclear, but likely appropriate for other fall-spawning salmonids (i.e., regions with similar hydrology to the Lehmi River).
The relationship may be unreliable if extrapolated to a flow range outside the original data (see the Average Salmonid flow-ecology SR function entry based on Rosenfeld and Enright (2025) for a more generalizable function across a wider range of flows).
The relationship may be unreliable if extrapolated to a flow range outside the original data (see the Average Salmonid flow-ecology SR function entry based on Rosenfeld and Enright (2025) for a more generalizable function across a wider range of flows).
Source of stressor Data
Stressor data reflects direct field measurements. The Lemhi River has multiple gaging stations, and the authors used the McFarland gage (river km 58) because it was the one of the "most reflective of local rearing conditions".
Function Type
continuous
Stressor Scale
linear
References Cited
Arthaud, D.L., Greene, C.M., Guilbault, K., and Morrow, J.V. Jr. 2010. Contrasting life-cycle impacts of stream flow on two Chinook salmon populations. Hydrobiologia 655: 171-188.
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Stressor Response csv data
Data_Chinook_Flow_Lehmi_0.csv
(368 bytes)
| PERCENT_MAD | Mean System Capacity (%) | SD | low.limit | up.limit |
|---|---|---|---|---|
| 32.01639344 | 11.6932787 | 0 | 0 | 100 |
| 32.48688525 | 12.3613771 | 0 | 0 | 100 |
| 33.73934426 | 14.1398688 | 0 | 0 | 100 |
| 34.05245902 | 14.5844918 | 0 | 0 | 100 |
| 36.56065574 | 18.1461312 | 0 | 0 | 100 |
| 37.42459016 | 19.372918 | 0 | 0 | 100 |
| 40.16721311 | 23.2674426 | 0 | 0 | 100 |
| 41.5 | 25.16 | 0 | 0 | 100 |
| 64.08196721 | 57.2263934 | 0 | 0 | 100 |
| 78.59180328 | 77.8303607 | 0 | 0 | 100 |
Stressor Response Chart
Mean Response
±1 Standard Deviation
Upper/Lower Limits