Compound‐Specific Stable Isotope Analysis Reveals Population‐Specific Differences in Chinook Salmon Trophic Level and Basal Resource Use in the Northeast Pacific
Bibliographic record
Abstract
ABSTRACT Chinook salmon exhibit far‐flung and disparate population‐specific marine migrations that have made it difficult to assess their trophic ecology. In this study, we collected returning and resident subadult Fraser River Chinook salmon in 2018 and 2019 from population groups with different known run‐timings (spring, summer, and fall) and marine distributions relative to the Fraser River (local/south, north, offshore) and processed them for carbon and nitrogen CSIA‐AA. We investigated population‐specific differences in trophic level using δ 15 N AA , and used δ 13 C AA with published taxon‐specific fingerprints of phytoplankton groups to investigate differences in the primary producer base that underpinned the food web they experienced. The south/local Fraser Fall 4 1 population exhibited distinct δ 13 C AA values from the north and offshore Summer 4 1 , Spring 5 2 , and Summer 5 2 populations, likely due to their different geographic distributions and corresponding differences in primary producer communities. Chinook salmon trophic level was variable, with evidence for more omnivory and lower trophic levels in the southern distributing populations (TL = 3.7 ± 0.2) relative to the northern ones (TL = 3.9 ± 0.1), although there was interannual variability in the trophic level of the southern distributing population. This analysis builds on previous investigations of Chinook salmon marine ecology, linking distribution to basal food web resources to trophic level, and highlights the importance of population‐specific marine distributions in structuring Chinook salmon trophic ecology. Knowledge of their food web ecology is necessary to understand how this species is and will respond to changing climate and ocean conditions and support management and conservation efforts.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.003 |
| 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) | 0.000 | 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".