Effect of Approach Velocity on Impingement of Juvenile Northern Pike at Water Intake Screens
Bibliographic record
Abstract
Abstract Current guidelines with respect to the use of irrigation intakes limit Canadian operators to approach velocities (at the screen) of 3.8 cm/s; however, this value is based on relatively little data. To address this issue, I examined the ability of juvenile (2.3–7.4-cm fork length) northern pike Esox lucius to avoid impingement on irrigation intake screens under ambient environmental conditions in a swim tunnel (where water velocity was constant and uniform) and in a simulated intake where water velocity declined with distance from the test screen (as in real structures). The effects of impingement duration (in swim tunnel tests) and approach velocity (in both tests) on feeding and physical condition (abrasions, bruising, and scale loss) were also examined. Juvenile northern pike in the swim tunnel became impinged at speeds ranging from 10 to 28 cm/s. Injuries and mortalities from impingement up to 10 min in duration were nonexistent, although some short-term feeding disruptions were observed. Northern pike tested in the intake simulation apparatus never became impinged when the approach velocity was 15 cm/s; however, some impingement (but no feeding disruptions, injuries, or mortalities) was observed at an approach velocity of 25 cm/s. At higher velocities, impingement, feeding disruptions, injuries, and mortalities occurred. Environmental regulations pertaining to approach velocity at irrigation intake screens can be set as high as 15 cm/s without adversely affecting juvenile northern pike.
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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 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".