No Evidence for Long-Term Carryover Effects in a Wild Salmonid Fish
Bibliographic record
Abstract
Early-life experiences can shape life histories and population dynamics of wild animals. To examine whether stressful stimuli experienced in early life resulted in carryover effects in later life stages, we conducted several experimental manipulations and then monitored wild fish with passive integrated transponder tags during juvenile out-migration and adult return migration. In total, 3,217 juvenile brown trout (Salmo trutta) were subjected to one of six manipulations: chase to exhaustion, thermal challenge, food deprivation, low-concentration cortisol injection, high-concentration cortisol injection, and sham injection, plus a control group. Cortisol and food deprivation treatments were previously shown to have short-term effects on juveniles, such as lower survival to out-migration and changes in migration timing. However, it remained unknown whether any of the six manipulations had effects that carried over into the adult phase. We therefore investigated whether these extrinsic manipulations, as well as intrinsic factors (size and condition), affected probability of return as adults and time spent at sea. Of the 1,273 fish that out-migrated, 146 returned as adults. We failed to detect any effect of treatments on return rates, while high-concentration cortisol weakly affected time spent at sea in one tagging event. We also found that juvenile condition was positively correlated to likelihood of adult return in only one tagging event. Overall, our findings did not identify either intrinsic factors or extrinsic stressful early-life experiences that have strong effects on fish that survive to adulthood. This suggests that some species may be more resilient than others to stressful stimuli encountered early in life.
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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 | 0.001 | 0.001 |
| 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 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".