Response of Out-Migrating Adult American Shad Guided by Spill and Ultrasound as They Approach Rivière-des-Prairies Hydroelectric Generating Station (Québec, Canada)
Bibliographic record
Abstract
Abstract Fish entrainment and mortality at hydropower generating stations constitute a major concern for power producers and government agencies. The American Shad Alosa sapidissima is particularly at risk at higher latitudes because of the large percentage of repeat spawners and the vulnerability of many populations. Total or partial turbine shutdowns at powerhouses and concurrent increased spillage are generally considered an effective way to enable fish to bypass the turbines and to reduce associated mortality, but this strategy is unappealing to hydropower producers because of the loss of power generation revenue. Two approaches were tested to repel out-migrating adult American Shad from the turbine intakes of the Rivière-des-Prairies Generating Station powerhouse and guide them toward the adjacent spillway. The first approach consisted of shutting down the powerhouse and increasing spillage. The second approach consisted of testing the effectiveness of an ultrasonic field to deter American Shad from getting close to turbine intakes and to guide them toward the partially opened spillway. On average, fish density observed in front of the 54-MW powerhouse was reduced by 93% as a result of a powerhouse shutdown lasting about 1 h and a concurrent spillage increase. Similarly, our results showed a decrease in shad abundance of 78–90% in front of the turbine intakes when a pulsed ultrasonic field (125 kHz) was activated. Measurements of sound pressure levels (SPLs) in the forebay suggested that the deterrent effect could be perceived by American Shad more than 100 m away, before they could sense higher water velocities near the powerhouse intakes. These results indicate that the combination of high-SPL pulsed ultrasounds (125 kHz) and the concurrent opening of adjacent spillway gates could guide postspawn American Shad away from powerhouse intakes.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".