Differences in egg quantity and quality among hatchery- and wild-origin Chinook salmon (Oncorhynchus tshawytscha)
Bibliographic record
Abstract
Each year, millions of hatchery-raised juvenile salmon are released into the wild to help bolster salmon populations all over North America. These fish often differ from their wild-origin conspecifics in terms of survival and reproductive success after release, but our understanding of their reproductive investment is limited. We examined differences in egg number (gonad mass and fecundity) and quality (mass, lipids, fatty acids) between spawning hatchery- and wild-origin Chinook salmon (Oncorhynchus tshawytscha) from Lake Ontario. Hatchery-origin females were found to not differ significantly in body size, age, egg total lipids, and fatty acid content of eggs relative to wild-origin females, but hatchery-origin females allocated significantly less body mass and neutral lipids into egg and gonadal development compared with wild-origin females. We also examined diets of both groups of females using stable isotopes and found that carbon and nitrogen stable isotopes suggested limited differences in the diet between hatchery- and wild-origin adult females. The results from the present study provide evidence that the differing environmental conditions and associated selection pressures of captive environments during early life in hatchery settings can alter certain life-history traits later in adult development, namely gonad mass and egg size, and could contribute to differences in their performance in the wild.
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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".