Explaining diet composition of North Sea cod (<i>Gadus morhua</i>): prey size preference vs. prey availability
Bibliographic record
Abstract
The nature and significance of size preference for fish prey in the diet selection of North Sea cod (Gadus morhua L.) was analysed. The analysis combined information on size-specific abundance derived from bottom trawl surveys with prey size frequencies in cod stomachs from the International North Sea Stomach Database. To estimate the abundance of all potential fish prey in the sea, a length-based number spectrum was calculated, corrected for gear efficiency by the application of a species-specific correction factor, and weighted by local predator abundance to take the spatialtemporal overlap between cod and its prey into consideration. A prey size preference model for cod feeding on fish is presented. Results showed that the preferred predator-to-prey weight ratio is an exponentially increasing function of predator size and an exponentially decreasing function of the slope of the number spectrum. More than 75% of fish found in the stomachs of North Sea cod originated from the least preferred quartile of the prey size range, indicating that prey abundance is the main determinant of the diet composition.
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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".