The role of fish physiology, behaviour, and water discharge on the attraction and passage of adult sockeye salmon (Oncorhynchus nerka) at the Seton River dam fishway, British Columbia
Bibliographic record
Abstract
In many rivers, dams have interrupted the connectivity of migration routes for fish. While fishways can provide access between downstream and upstream habitats, it is important that passage can occur with minimal delay, energy expenditure, and physiological stress. The research presented here is based on investigations into fishway attraction and passage for the Gates Creek sockeye salmon (Oncorhynchus nerka, Walbaum) stock at the Seton River dam in British Columbia. The first part of this thesis examined the effect of changes in water discharge from the dam on the relationship between the physiological condition of sockeye and their behaviour in approaching the fishway entrance. Fish were caught and non-lethally biopsied under three normal operating discharge conditions at Seton River dam, and subsets of sampled fish were implanted with radio transmitters and released downstream of the dam. Indices of physiological stress and exhaustive exercise (e.g. plasma cortisol, glucose, lactate, osmolality and hematocrit) did not differ among the water discharge levels that were examined. Fish delayed in the tailrace below the fishway entrance significantly longer under intermediate discharge (19.9 h @ 12.7 m³s‾¹) than either the high discharge (9.3 h @ 15.8 m³s‾¹), or the low discharge (7.0 h @11.0 m³s‾¹;) conditions (P = 0.022, and P = 0.015, respectively). Delay time was similar under high and low discharge conditions (P = 0.617), and passage success was found to be independent of discharge (P = 0.356). The second part of this thesis investigated how prior physiological condition and subsequent swimming energetics and behaviours effected fishway passage success. Fish were captured and biopsied, before being implanted with electromyogram (EMG) transmitters and released near the downstream entrance of the fishway. Very few differences existed between successful and unsuccessful fish in body size, initial plasma physiology and energy state, and mean swim speed and energy use during passage. However, plasma Na+ concentration was significantly lower in unsuccessful fish (P = 0.022), which is suggestive of a depressed ionic state for unsuccessful fish. Generally, fish did not employ burst swimming during successful or failed attempts at passage, indicating that failure was probably not related to metabolic acidosis.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".