Diel vertical migration and shoaling heterogeneity in Atlantic redfish: effects on acoustic and bottom-trawl surveys
Bibliographic record
Abstract
Abstract A series of experiments comparing acoustic and bottom-trawl surveys was conducted on Atlantic redfish (Sebastes spp.) on the edge of the Green and Grand Banks of Newfoundland, Canada. Redfish were on or near bottom by day and migrated vertically in the water column at night. In an attempt to account for biases attributable to the presence of fish in the near-bottom dead zone (DZ), a correction factor was applied based on density values measured within the first few metres above the detected bottom. Acoustic densities within increasing range increments above the bottom were compared with densities estimated from the trawl catch. Swept area was calculated using both the trawl's wing spread and door spread as proxies for the minimum and maximum fishing widths. Uncorrected acoustic densities were significantly higher during the night than during the day. No significant day/night differences for the entire water column were observed after DZ corrections. Close agreement between acoustic and trawl densities was obtained by integrating within the first 10 to 20 m off the bottom, with or without the DZ corrections, for both day and night experiments, but regression slopes differed. Trawl catchability appeared to be density-dependent at night, being higher at lower fish densities. Daytime acoustic estimates were more variable than those made at night, as indicated by consecutive passes of several transects and CVs of density (means of 131% during day, 35% at night). We conclude that acoustic measurements made at night provide the most reliable and least variable density estimates, and make recommendations for surveys.
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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 | 0.001 | 0.002 |
| 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".