Levels of Introgression in Westslope Cutthroat Trout Populations Nine Years after Changes to Rainbow Trout Stocking Programs in Southeastern British Columbia
Bibliographic record
Abstract
Abstract Introgressive hybridization (introgression) between native westslope cutthroat trout Oncorhynchus clarkii lewisi and introduced rainbow trout O. mykiss in the upper Kootenay River, British Columbia, appears to be recent and is partly attributed to rainbow trout stocking in Koocanusa Reservoir starting in 1988. In 1998, rainbow trout stocking was stopped or replaced with the stocking of triploids throughout the watershed. The goal of this research was to determine the effect of the change in stocking practices on the level of introgression between westslope cutthroat trout and rainbow trout. We monitored 14 sites from 1999 to 2007 using four co-dominant, diagnostic nuclear markers. Sample sites were categorized as (1) open if no fish migration barriers existed between the site and the reservoir or (2) closed if migration barriers were present between the site and the reservoir. We classified fish as pure westslope cutthroat trout if no rainbow trout alleles were detected; fish were classified as hybrids if they had at least one rainbow trout allele present. We also classified fish into parental and hybrid types based on their multilocus genotypes. Open sites had more hybrids (15.8%) than closed sites (4.8%; χ2 = 23.38, df = 1, P < 0.0001). Westslope cutthroat trout backcrosses were the most common hybrid genotype at both open and closed sites. At open sites near the reservoir, introgression levels stayed relatively high (20–30%) and pure rainbow trout and rainbow trout backcross individuals were common. Introgression significantly increased at two of three sites surveyed at intermediate distances upstream from the reservoir (i.e., 27–87 km). The new stocking program does not appear to have reduced introgression or prevented the spread of hybrid individuals in the upper Kootenay River, and more active management strategies will be required to prevent further introgression and loss of unique westslope cutthroat trout populations.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".