Minimal Introgression but Restricted Gene Flow: How Stocking and Dams Influence Wild Brook Trout (<scp><i>Salvelinus fontinalis</i></scp>) Genetics and Morphology
Bibliographic record
Abstract
ABSTRACT Anthropogenic activities are increasingly influencing eco‐evolutionary processes across spatial, temporal, and biological scales. Freshwater ecosystems, harbouring species that are important for subsistence, recreational, and commercial fisheries, are particularly vulnerable. In North America, brook trout ( Salvelinus fontinalis ) populations have experienced widespread declines due to factors including habitat fragmentation and angling. To increase population densities and meet fishing demands, thousands of captive‐bred individuals are released annually. Stocking, however, could lead to introgression of maladaptive genes into the wild population and, in combination with the presence of dams restricting gene flow, may reduce their evolutionary potential. Here, we sampled 495 fish from 14 inland and two coastal sites in the state of Rhode Island, USA and from two hatchery strains. We used quaddRAD to develop single nucleotide polymorphism (SNP) markers and combined genetic and geometric‐morphometric analyses to evaluate intraspecific variation, the consequences of stocking, and test hypotheses, in a riverscape framework, on how dams influence gene flow. We found moderate genetic structure within streams with low levels of genetic diversity and effective population sizes but higher than the two hatchery strains. Importantly, we found no significant introgression from captive‐bred individuals. However, we did detect isolation‐by‐distance and ‐by‐resistance (due to dams) with evidence for upstream and downstream gene flow occurring mainly within catchments. Phenotypic differentiation also was apparent both between wild and hatchery brook trout and even among streams, correlating with genetic distances. Our findings highlight the importance of fine‐scale analyses in evaluating anthropogenic impacts and uncovering hidden intraspecific variation. Conservation efforts for wild brook trout populations, which harbour distinct genetic and phenotypic variation, will require careful attention, and our results will help inform management strategies across the species' range.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 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 teacher head, 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".