Dispersal of stream salmonids from nests and stocking sites: patterns, variability, and sampling bias
Bibliographic record
Abstract
To reconcile divergent views about the direction and distance that salmonids disperse from nests or release sites, we conducted a systematic search and synthesis of existing data that included 154 data points from 58 papers. After correcting for a sampling bias in the downstream direction, 56.6% of fish dispersed downstream, significantly greater than 50%, but much less than expected. The best generalized linear mixed model explaining the percentage of fish moving downstream included a positive effect of the percentage of sampling effort downstream, a negative effect of body size, and differences among species; brown trout ( Salmo trutta) tended to disperse upstream more than other species. Dispersal distance increased with body size; median dispersal distances for age 0+ and older fish were 167 and 908 m, respectively, implying much greater mobility than expected. As predicted, median dispersal distance was greater downstream (715 m) than upstream (602 m). Our analyses indicated that many of our perceptions about salmonid dispersal are based on biased sampling—too much effort that is too close to, and downstream of, the release site.
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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 | 0.034 | 0.097 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.010 | 0.010 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".