Stock Assessment of Belcher Islands-Eastern Hudson Bay and James Bay Beluga in 2024
Notice bibliographique
Résumé
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.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».