A fish-mediated trophic cascade on freshwater calanoid copepod abundance is concealed by food web fatty acid availability, functional traits and population sex ratio
Bibliographic record
Abstract
We applied essential fatty acids as a biomarker to experimentally test the effects of a fish-mediated trophic cascade on calanoid copepod nutritional state and functional traits in north-temperate freshwater ponds. A whole-pond experiment was conducted where young-of-the-year brook trout (Salvelinus fontinalis) were introduced into three natural, fishless ponds with no previous history of fish introduction, and compared with four similar naturally fishless ponds. We unexpectedly found no effect of the fish-mediated trophic cascade on copepod population nutritional state and abundance, despite enhanced phytoplankton resources in fish-stocked ponds. While salmonids increased individual female copepod fecundity, the fish also reduced gravid copepod female abundance and altered copepod population sex ratios in favour of males. Fish predation likely influenced the overall nutritional state of calanoid copepod populations by expenditure of key lipids in male copepods through increased activity linked to female mate limitation, and selective predation on gravid female copepods. Therefore, the positive effects of the fish in enhancing the essential fatty acid content of phytoplankton communities via nutrient additions were not sufficient to over-ride the negative effects of fish predation on copepod population nutritional state and abundance.
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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 | 0.002 | 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 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 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".