Otolith elemental fingerprints reveal source-sink dynamics between two Greenland halibut nurseries in the St. Lawrence Estuary and Gulf
Bibliographic record
Abstract
In fisheries science, it is important to understand the population dynamics of commercial species and also their movements from the nursery to the population, especially for juvenile individuals, to avoid overfishing. To determine their migration patterns among nurseries, we collected juvenile Greenland halibut Reinhardtius hippoglossoides from 2 nurseries inside our study area, the Estuary and Gulf of St. Lawrence, in the summer of 2016. We measured the concentrations of chemical elements in their otoliths along a margin-core transect and used the margin elemental fingerprints of Mg, Mn, Sr, and Ba to infer migratory behaviour between 2 sample sites, the Estuary and North Anticosti nurseries. Using a random-forest analysis, we achieved an overall reclassification success of margin elemental fingerprints to their capture site of 77%. Most fish sampled from both sample sites originated from the estuary (82.5%), suggesting an important asymmetry in the source-sink dynamics between these nurseries. Juvenile Greenland halibut migrate towards the North Anticosti nursery at a smaller-than-expected size (approximately 26 cm) corresponding to 2.5-3 yr old fish. Despite sexual dimorphism in growth, sex does not affect migratory behaviour or timing of migration before sexual maturation. Our study highlights the recruitment dynamics of Greenland halibut and confirms the estuary as the main nursery in the St. Lawrence system.
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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 | 0.001 |
| Science and technology studies | 0.001 | 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".