Transatlantic movements of juvenile Atlantic bluefin tuna inferred from analyses of organochlorine tracers
Bibliographic record
Abstract
Ratios of certain organochlorine pollutants in fish tissues are significantly different between the eastern and western North Atlantic and have been used to identify recent (<1 year) transatlantic migrants of Atlantic bluefin tuna (Thunnus thynnus). In this study we observed limited variation of organochlorine pollutant ratios across collections of young-of-the-year (YOY) bluefin tuna from the western North Atlantic (WNA) and eastern North Atlantic (ENA) in different years and highly significant differences between WNA and ENA YOY samples each year and for all years combined. A significant increase in organochlorine ratios was noted between YOY and age-1 ENA bluefin tuna, consistent with the movement of YOY out of the Mediterranean Sea and into the ENA. Using baseline organochlorine ratios from WNA YOY to identify recent eastern migrants, 29% of age-2, 33% of age-3, and 24% of age-4 juvenile bluefin tuna in the WNA were identified as recent migrants from the east during 2011 and 2012. Applying baseline ratios from age-1 ENA bluefin tuna to identify recent migrants from the WNA, 14.3% of age-2, 9.5% of age-3, and 0% of age-4 juvenile bluefin tuna caught in the Bay of Biscay fishery were identified as recent western migrants during 2010 and 2011. These data reveal substantial connectivity of juvenile bluefin tuna across the North Atlantic and demonstrate that WNA juveniles are heavily subsidized by eastern fish.
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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".