Resource use, niche width, and trophic position reveal diverse trophic structure in a tidal freshwater zone fish community
Bibliographic record
Abstract
Abstract The tidal freshwater zone is an aquatic transition zone that links a river to its estuary and provides an important habitat used in the life cycle of resident and migratory fishes. Yet, information on the trophic structure of fishes in this habitat is scarce. To address this gap, we characterize the trophic structure of a fish community in the tidal freshwater zone of the Northwest Miramichi River (New Brunswick, Canada). Stable isotope analyses (δ 13 C, δ 15 N, and δ 34 S) of 17 fish species revealed diverse feeding strategies. Resource use varied across species; some fish relied on either marine or freshwater resources, whereas others integrated resources from both habitats. Fishes varied in their trophic position (range 3.1–4.2) which increased with reliance on marine‐derived resources. Species isotopic niche widths varied widely (range 20.4 to 1015.3). Species with intermediate marine resource use (~0.50) had a mix of wide and narrow isotopic niche widths, contrary to wide niches predicted by current literature. Our findings indicate that these narrow‐niched species may either act as a sort of tidal freshwater transition zone specialist or assimilate equal proportions of marine and freshwater resources on average. Trophic information from the tidal freshwater zone improves the understanding of fish communities and food web structure where freshwater rivers and marine ecosystems meet.
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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 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".