Oceanic Water Temperatures Less Than 20°C May Partly Account for Bias in American Eel Elver Otolith Age Estimates
Bibliographic record
Abstract
Abstract The mystery of the discrepancy between American Eel Anguilla rostrata larval, glass, and elver ages derived from otolith examination and from observed spawning and recruitment dates is long standing. A variety of solutions have been proposed but none have been validated. Japanese Eels Anguilla japonica do not deposit daily otolith growth rings at water temperatures ≤10°C and have less than daily deposition at temperatures 10–20°C, which may apply to American Eels. Oceanic water temperatures ≤10°C between continental sites and the Gulf Stream during glass and elver eel migration periods have little effect on ages imputed from otolith ring counts of eels migrating to sites south of Cape Hatteras because coastal water temperatures infrequently, and usually only for a few days, decline below 10°C between Cape Hatteras and South Carolina. Coastal and estuarine water temperatures of 10–20°C may have more effect. North of Cape Hatteras, the temperature effect on otolith ages increased with distances north of and from the Gulf Stream. Adjustment to otolith ages for low estuarine/freshwater temperatures may more fully account for the difference between otolith and observed ages over the recruitment period at sites north and south of Cape Hatteras. The effect of recent higher oceanic water temperatures north of Cape Hatteras on otolith daily growth increments remains to be learned but may increase otolith age estimates. Otolith ages for glass and elver American Eels should be used with caution unless adjusted for seasonal low oceanic, estuarine, and freshwater temperatures; even then otolith aging issues remain. A greater understanding of oceanic migratory paths and durations is needed for American Eels.
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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 | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".