Genetic analysis of the exploited snow crab (<i>Chionoecetes opilio</i>) in the Barents Sea—possibilities of origin
Bibliographic record
Abstract
Abstract After the initial opening of the Bering Strait 5.5–-5.0 My ago, there occurred several periods with exchange of marine species between the Pacific and Atlantic Oceans. The snow crab ( Chionoecetes opilio) was first reported in the Barents Sea (BAR) in 1996, presumably following introduction via Ballast water. Since then, the population has increased in size and distribution and has become self-reproducing and of economic importance. We implemented genetic analysis to identify the origin and pathway of introduction of BAR snow crab. Samples from BAR, Alaska, eastern Canada, and west Greenland were genotyped with 12 microsatellite loci. Pairwise FST between 15 samples showed three geographic clusters, each significantly different from one another. Unexpectedly, the largest genetic distance was between the BAR and Greenland clusters. This clustering may be the result of dispersals through Bering Strait from the North Pacific Ocean and passage through the Arctic Ocean. The BAR samples did not show signs of a bottleneck in population size, as would be expected after introduction of small numbers of individuals. Presence of snow crab in the BAR may thus be the result of recent natural range expansion from around Alaska.
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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".