The Efficacy of Reservoir Flow Regulation for Cooling Migration Temperature for Sockeye Salmon in the Nechako River Watershed of British Columbia
Bibliographic record
Abstract
Abstract Since the early 1980s, a water temperature management program has been in existence on the Nechako River system in central British Columbia, Canada. The program releases water based on anticipated meteorological conditions in an attempt to prevent temperature from exceeding a specified threshold of 20°C downstream during a period when spawning migrations of sockeye salmon Oncorhynchus nerka are in the Nechako River. Since the inception of the program, this threshold has been exceeded only rarely; however, the variables that influence water temperature and that are used to manage water releases in the Nechako River watershed have not been subject to an independent analysis. Increasing demand for water at other times of year and a desire to restore a more natural hydrograph to the river to meet other ecological demands have impelled this analysis. A principal components analysis that examined the factors contributing to river temperature demonstrated that the summer controlled flow releases accounted for 24% of the temperature variability and were probably a factor in maintaining compliance with the program's temperature threshold. Furthermore, during most summers, the Nechako River provided a cooling influence to input from the Stuart River tributary in a downstream reach that is used by the majority of the migrating sockeye salmon. Water temperature has a modest influence on prespawning mortality (up to 22% of the variability), suggesting that attempts to reduce summer water temperatures through releases in the upper Nechako River watershed can mitigate against poor spawning success of sockeye salmon populations that migrate through the lower reaches of the system. Received April 19, 2011; accepted December 9, 2011
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".