The Hunger Games: Stable Isotopes Indicate Winter Inter‐Guild Competition for Resources by Marine Meso‐Predators in the Sub‐Arctic North Pacific
Bibliographic record
Abstract
ABSTRACT Interspecific competition can significantly impact marine ecosystems by affecting species distributions and abundances. Understanding how sympatric species utilize available food helps identify potential competition and its effects when resources are limited. Here, we applied a suite of analytical methods (diet analysis, stable isotopes, and biomass estimates) to identify potential competitive interactions among North Pacific pelagic predators. Samples were collected in the Gulf of Alaska during the winter of 2019. Environmental conditions and food web structure (prey consumption, species biomass, and isotopic niche overlap) varied across the region. Several squid and myctophid species occupied similar trophic positions and had high isotopic nice overlap with Pacific salmon. The intensity of these interactions differed between the northwest and southeast Gulf of Alaska. For example, there was a substantial isotopic niche overlap between sockeye salmon and the squid Onychyoteuthis borealijaponica in the southeast, while chum salmon exhibited considerable niche overlap with various species in both areas. Our results demonstrate that, as the biomass of non‐salmonid competitors may exceed that of Pacific salmon, these interactions must be considered when assessing salmon production on the high seas. Regional differences in trophic interactions demonstrate that the open ocean northeast Pacific is more dynamic than previously proposed, and knowledge of salmon rearing locations could improve production estimates. Further research on regional ocean properties and their effects on trophic ecology is needed to understand how salmon will respond to climate‐driven changes in ocean conditions. This study provides the first analysis of pelagic food webs in the North Pacific high seas during winter, highlighting significant intra‐guild competition among meso‐predators. The effects of this competition on production are difficult to assess using empirical approaches due to the inaccessibility of the region. We propose the application of the trophic interactions identified here to explore these effects using food web models.
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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 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".