Pacific herring (Clupea pallasii) trophodynamics and fisheries in the Northeast Pacific Ocean
Bibliographic record
Abstract
Pacific herring is a common North Pacific forage fish targeted by commercial, aboriginal, and subsistence fisheries. Recent declines in several Northeast Pacific herring stocks have caused concern among scientists, management agencies, and aboriginal peoples. This dissertation investigates the trophodynamics of herring in Northeast Pacific ecosystems and their effects on fisheries management. Its main hypothesis is that herring interacts strongly with both predators and prey, with some interactions governed by top- down and others by bottom-up control. Chapter 1 presents a set of high-resolution, mass- balanced ecosystem models representing waters surrounding Haida Gwaii, an archipelago off northern British Columbia, Canada. These three models provide a dynamic simulation platform and indicate strong interactions between herring and its predators and prey, as well as notable changes in local ecosystem structure across the 20th century, largely due to fishing and whaling. Chapter 2 reveals whale depletion and recovery trajectories off Haida Gwaii, and the historical and current role of whales as consumers, using surplus production and ecosystem models, respectively. Dynamic ecosystem simulations suggest that whale recovery could exert top-down effects on herring and other prey, with indirect trophic impacts on competing predators and ecosystem composition. Chapter 3 employs management strategy evaluation, combined with ecosystem simulations, to comparatively evaluate potential impacts of herring depletion and fisheries management strategies on dependent predators and ecosystem structure. The results suggest sharp tradeoffs between herring and many predator biomasses on the one hand and high, stable herring catches on the other, as well as potential compromise solutions. Chapter 4 investigates the potential positive effects of high adult herring energy content on the trophic role of herring using energy-balanced ecosystem models, reformulated from their mass-balanced counterparts using a novel methodology. Both static and dynamic analyses conducted in these models indicate that elevated energy content increases the dependence of numerous predators on herring. It may thus be concluded that herring, while belonging to a diverse forage fish guild, nevertheless exercises a key role in Northeast Pacific ecosystems as a trophic node connecting zooplankton to higher predators. Many of these depend on herring to support healthy populations, stimulating management tradeoffs for commercial herring fisheries.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".