Abundance estimates for Beluga (Delphinapterus leucas) in James Bay and the Belcher Islands-Eastern Hudson Bay area in Summer 2021
Bibliographic record
Abstract
Systematic line-transect surveys were flown in James Bay and the Belcher Islands-eastern Hudson Bay area from July 22 to August 23, 2021. A total of 357 groups of belugas were detected by primary observers, but only 330 groups remained after the left truncation of groups closer than 120 m from the track line to account for the reduction in detection probability near and underneath the plane. A single hazard-rate detection function was selected to model the probability of detection in both surveyed areas from the ungrouped distribution of perpendicular distances, which estimated an average effective strip half-width of 771 m (CV = 4%). A total of 249 groups with an average size of 1.78 (CV = 7%) animals were detected in James Bay over 4,272 km of survey lines, resulting in a surface abundance estimate of 5,043 (95% CI: 3,494–7,279) belugas. The Belcher Islands-eastern Hudson Bay area was split into a high coverage stratum, surveyed twice, and two low-coverage strata located to the north and in Richmond Gulf. On the first and second survey of the high coverage area, 72 and 35 groups with average sizes of 1.86 (CV = 12%) and 3.31 (CV = 26%) detected over 8,897 km and 8,828 km of transects, respectively. These produced respective surface abundance indices of 766 (95% CI: 413–1,423) and 669 (95% CI: 244–1,832). In the northern low-coverage stratum, only one individual was detected over 1,030 km of survey lines resulting in a surface abundance index of 12 (95% CI: 2–63). No beluga were observed in Richmond Gulf. New correction factors for availability and perception biases were calculated to account for the proportion of belugas visible at the surface and to account for animals at the surface but missed by observers. For the 2021 survey in James Bay, an availability correction factor of 0.590 (CV = 7.7%) and a perception bias correction factor of 0.601 (CV = 10.5%) resulted in a corrected abundance estimate of 14,213 (95% CI: 9,208–21,938). For the 2021 survey in Belcher Islands-eastern Hudson Bay, an availability correction factor of 0.549 (CV = 7.7%), a perception bias correction factor of 0.601 (CV = 10.5%), and the addition of 289 belugas observed in the Little Whale River Estuary, resulted in a corrected abundance index of 2501 (95% CI: 1,439–4,344). New correction factors were also estimated from and applied to the previous surveys (1985–2015) conducted in the James Bay and Belcher Islands-eastern Hudson Bay area.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".