The Effect of Food Deprivation on the Cortisol Response to Crowding in Juvenile Steelhead
Bibliographic record
Abstract
Abstract Routine salmonid hatchery procedures include food deprivation, handling, and crowding of fish before sorting, transporting, or stocking. Although several studies have examined the effects of food deprivation or husbandry stressors on salmonid physiology, few have examined the effects of food deprivation and standard hatchery procedures, such as handling and crowding. The objective of this study was to determine whether food deprivation of juvenile steelhead (anadromous rainbow trout Oncorhynchus mykiss) affects the cortisol response to stress from low-water crowding. Plasma cortisol levels of fish held in circular fiberglass tanks at 8°C under normal daily feeding conditions were compared with levels in fish subjected to 3 d of food deprivation; both groups were held at 3.8 kg/m3 (control density). Additionally, these groups were compared with fed and food-deprived fish held at a density of 12.8 kg/m3 for 3 h (low-water crowding stressor). There was a significant increase in plasma cortisol levels of fish subjected to low-water crowding (129.9 ng/mL) relative to fish held at the control density (14.7 ng/mL), regardless of previous feeding treatment. However, for fish at a given density (control or crowded), there was no difference in cortisol levels between fed and food-deprived groups. We conclude that depriving juvenile steelhead of food does not significantly alter their cortisol response to low-water crowding. Consequently, the standard hatchery practice of withholding food before performing stressful husbandry procedures does not appear to cause additional stress or exacerbate physiological responses typically observed in steelhead after they are subjected to physical stressors.
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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 | 0.000 | 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) | 0.001 | 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".