Stable isotopic composition of otoliths in identification of spawning stocks of Pacific herring (<i>Clupea pallasi</i>) in Puget Sound
Bibliographic record
Abstract
Otoliths of Pacific herring (Clupea pallasi) were collected from Puget Sound, Washington, and were analysed for oxygen and carbon isotope ratios (δ18O and δ13C). It was expected that if adult herring spawn at different localities with different δ18O and δ13C values, these isotope variations would constitute a natural tag that can be used to distinguish the herring spawning stocks. For a test project, we took aragonite powder samples from the surface of otolith nuclei and the second summer otolith rings, respectively. Isotopic composition of otolith nuclei from the Georgia Strait had lowest isotope values (from 8.2 to 2.0 VPDB (Vienna Peedee belemnite) in δ18O and 6.8 to 3.9 VPDB in δ13C), significantly different from those collected from two southern Puget Sound spawning grounds (from 3.9 to 0.9 VPDB in δ18O and 5.6 to 2.0 VPDB in δ13C). This isotopic identification is consistent with the biological observation and the actual sample collection. Stable isotopic information extracted from the summer otolith rings, in contrast, showed two types of herring in 1999 corresponding to the migratory and non-migratory stocks in Puget Sound. The rate of the two types of herring was about 70% versus 30%.
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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) | 0.000 | 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".