Canadian‐Origin Chinook Salmon Rearing in Nonnatal U.S. Tributary Streams of the Yukon River, Alaska
Bibliographic record
Abstract
Abstract Yukon River Chinook salmonOncorhynchus tshawytschaare described as having a “stream‐type” life history strategy. After emergence from river gravel, juveniles typically feed and grow in tributary streams of the Yukon River throughout their first summer, overwinter in freshwater, and usually leave their rearing areas for marine waters during the second spring or summer. Nonnatal rearing has been described in the upper Canadian portion of the drainage, but information is lacking for downstream U.S. waters. In 2006–2007, a study was conducted to document nonnatal rearing and the genetic origin of Chinook salmon in U.S. tributary streams of the Yukon River. Eight nonspawning streams were selected for study, seven located in a 260‐km segment between the U.S.–Canada border and Circle, Alaska, and one located 742 km downstream from the border. Age‐0 juveniles were captured in all eight streams. Genetic stock composition analyses using 13 standardized microsatellite loci assigned the fish to Canadian source populations. The Carmacks region (over 460 km upstream from the border) contributed 91% to the mixtures in 2006 and 82% in 2007. Canadian stocks nearest the border and from large river systems were underrepresented in the collections. Simulation and known‐origin mixture analyses demonstrated that stock composition and individual assignment estimates derived from the genetic baseline were accurate and precise. Some juveniles may have traveled over 1,200 km to reach rearing areas in U.S. waters. Future studies would help define the importance of this life history strategy to the overall health and productivity of Yukon River Chinook salmon.
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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 | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".