Stock Assessment of Belcher Islands-Eastern Hudson Bay and James Bay Beluga in 2024
Bibliographic record
Abstract
Total harvest in Nunavik has ranged between 366 and 681 beluga per year during 2021- 2024. In Sanikiluaq (Belcher Islands, Nunavut), harvest has ranged from 20 to 51 beluga per year. Based on genetic analysis and season- and area-specific distribution of the beluga hunt, on average, 126 and 23 beluga from the BEL-EHB stock were harvested by Nunavik and Sanikiluaq hunters between 2021-2024, respectively. For the JAM stock, the Nunavik and Sanikiluaq harvest levels are estimated at 27 and 6 beluga over the same period. The spatial- and seasonal distribution of the harvest under the current management plan results in 3.8 beluga being harvested for each BEL-EHB landed. Alternate scenarios would increase or decrease this ratio. The 2024 survey abundance estimate, corrected to account for the proportion of animals missed at the surface or underwater during the aircraft overpass, was 1,500 (95% CI= 900- 2,400) (rounded to the nearest 100) for the BEL-EHB stock. This 2024 estimate is the lowest and most precise in the time series of comparable surveys flown since 1985. The 2024 corrected survey abundance estimate for the JAM stock was 11,500 (95% CI=7,300-17,900). A Bayesian Integrated Population model was developed for the BEL-EHB stock using six sources of information (aerial surveys, harvest levels, genetic composition of the harvest, reproductive rates, age and sex structure, and proportion of lactating females) to estimate abundance trends and the impact of various harvest scenarios. For the BEL-EHB stock, the model estimated carrying capacity at 8,100 (95% CrI = [6,800; 10,300]) and a 2024 abundance of 2,200 (95% CrI = [1,800; 2,500]) beluga. Following a period of apparent stability (2001-2013), the stock is estimated to have been declining, with an average rate of decline of 5.1% per year (95% CrI = [3.6; 7.2]) since 2021. The 2021-2026 management plan objective for the BEL-EHB stock is to ensure a 50% probability that the stock will be at or above 3,400 animals after 5 years. Based on the 2024 estimate of stock abundance and trend, no harvest level of BEL-EHB beluga would respect this objective. The maximum number of BEL-EHB beluga that could be harvested annually to ensure 50%, 80% and 95% probabilities that the stock remains stable to its 2024 abundance are 50, 43, and 35 BEL-EHB beluga, respectively. Under the Maximum Sustainable Yield (DFO-MSY) Precautionary Approach framework, the Limit Reference Point (LRP) for the BEL-EHB stock is estimated at 1,900 beluga and the Precautionary Reference Point (PRP) at 3,900 beluga. Considering the 2024 estimate, there is a 100% probability that it is below the PRP and a 89% probability that the stock is above the LRP. Therefore, the stock is considered in the Cautious Zone. Model projections indicate that if current BEL-EHB beluga harvest levels are maintained, the stock is expected to decrease to a state of quasi-extinction (i.e., less than 50 mature females) with 50% to 95% probabilities by 2037 to 2039. Annual harvest levels not exceeding 88, 66, and 55 BEL-EHB beluga would allow the BEL EHB stock to reach or surpass the LRP with a 50% probability in 5, 10 and 25 years. The potential biological removal (PBR) for the BEL-EHB beluga stock was estimated at 4 beluga per year. The IPM approach was applied to the JAM beluga stock. Two sources of information (aerial surveys, harvest levels) were used to fit the model and estimate abundance and demographic trends. The model estimated a carrying capacity of 18,300 and a population abundance in 2024 of 16,000 (95% CrI = [12,300; 20,600]) beluga for the JAM stock. Following a period of increase, the stock is estimated to have remained stable close to carrying capacity since 2010. Under the DFO-MSY Precautionary Approach framework and considering the 2024 estimate, there is a 100% probability that the JAM stock is above the PRP (8,800 beluga), i.e., in the Healthy Zone. The PBR for JAM was estimated at 245 beluga per year. Harvest levels exert a large influence on the IPM results for the BEL-EHB stock. However, there remains a high level of uncertainty in the number of animals struck and killed but not recovered or non-reported, and in how these may have varied over time.
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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 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".