Low tolerance of salt water in a marine fish: new and historical evidence for surprising local adaption in the well-studied commercially exploited capelin
Bibliographic record
Abstract
Intraspecific biodiversity among populations is ecologically and evolutionarily notable. Substantial adaptations in well-studied commercial species should be obvious and ought to have been uncovered. The tenet of marine stability posits relatively little local adaptation in the sea, except for temperature responses to latitude for widespread species. However, aquatic reproduction is tightly constrained by water chemistry, which may lead to abstruse adaptations. Capelin (Mallotus villosus) reproduction has been studied for over a century, occurring within pebble substrate on beaches or the seafloor of continental shelves. Offshore spawners (Iceland/Barents Sea) have embryos with tolerance of high salinity. I provide new and historical data on beach spawners from several areas indicating that their embryos perform well from ∼2 to 28 psu, but at higher salinities indicative of coastal seawater, there is poor hatch success, larvae take longer to hatch, hatch at a smaller size, and starve more quickly. The body of evidence supports the hypothesis that beach spawning evolved from anadromy, with offshore spawning a derived state, enabled by increased salinity tolerance. The results have recovery implications for depleted Newfoundland stocks, which have been spawning seasonally late under relatively high salinity for over 25 years.
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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 | 0.001 |
| 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 | 0.002 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".