Otolith sulfur isotope method to reconstruct salmon (<i>Oncorhynchus tshawytscha</i>) life history
Bibliographic record
Abstract
We report a new ion microprobe method to reconstruct aspects of fish life history based on sulfur isotopes (34S/32S, expressed as δ34S). Selected hatchery raised and naturally spawned juvenile chinook salmon (Oncorhynchus tshawytscha) are shown to have a 12.96 ± 0.27 (mean ± 2 standard errors) difference in muscle δ34S values, corresponding to δ34S differences between the hatchery and freshwater diets. Isotopic microanalyses of otoliths demonstrate that this 13 difference is preserved in the otoliths. We interpret the otolith δ34S record to be a chronology of dietary δ34S, with approximately one-week temporal resolution, preserved in these banded calcium carbonate structures. Potential applications of this method include identifying hatchery raised fish and reconstructing nutrition sources, migration, and other aspects of fish life history.
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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 | 0.001 | 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".