Photoperiod at emergence regulates early life history plasticity in fall Chinook salmon
Bibliographic record
Abstract
Early life history pathways for Chinook salmon are directly related to environmental variation, which can shift phenotypic traits expressed by a population. Fall Chinook salmon in the upper Columbia River Basin historically timed migration downstream (smolted) as subyearlings; however, some wild and hatchery-reared fall Chinook salmon also express a successful yearling smolt life history strategy. Previous research suggests that this shift to yearling smoltification represents evolution—a genetic change due to an increase in fitness and improved downstream survival. Alternatively, the shift in smolt timing could be a phenotypically plastic response that optimizes life history traits for current environmental conditions. We raised hatchery-origin fall Chinook salmon from the Umatilla River (Oregon, USA) in a controlled laboratory experiment to explore environmental drivers of early life history. We found smolt timing to be age/size dependent for subyearlings, and photoperiod dependent for yearlings. We found the propensity for precocious male maturation at age-1 (microjack) to be primarily photoperiod dependent and for age-2 (minijack) to be primarily growth dependent. The resulting adaptable life history portfolio may provide this population with some baseline capacity to cope with future environmental change.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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".