Estimation de l'abondance et impact de la chasse pour le béluga des îles Belcher-est de la baie d'Hudson et de la baie James : mise à jour 2024

Abstract

Stock assessment for Nunavik beluga is based on population models. A new population model was recently developed for the Belcher Islands-Eastern Hudson Bay (BEL-EHB) beluga stock. The new model is a Bayesian Integrated Population Model (IPM) informed by several sources of information (abundance estimates from aerial surveys, pregnancy rates, age, sex and reproductive state structure, harvest levels, as well as stock-specific genetic representation in the harvest). In 2024, a new aerial survey was flown to assess the abundance of the BEL-EHB and James Bay (JAM) beluga stocks. Here, we used the IPM fitted to the new 2024 survey estimate and updated data from all sources to assess the abundance, trend, and status of the BEL-EHB and JAM stocks. In addition, we present advice on potential harvest levels for the BEL-EHB beluga stock based on the current management objective and alternative management scenarios. Based on the IPM, abundance of the BEL-EHB stock in 2024 was 2,200 (95% CrI = [1,800; 2,500]) beluga and has been declining at a rate of 5.1% (95% CrI = [3.6; 7.2]) per year since 2021. Since 2021, an estimated average of 140 BEL-EHB beluga have been harvested annually. Under the DFO maximum sustainable yield framework, the Lower Reference Point (LRP) was estimated at 1,900 beluga and the Precautionary Reference Point (PRP) at 3,900 beluga for the BEL-EHB stock. No harvest level of BEL-EHB beluga would respect the current management plan of ensuring a 50% probability that the stock reaches or surpasses 3,400 animals in the next five to ten years, and no harvest levels would allow the stock to reach or surpass the PRP over a period of 5 to 10 years with > 50% probability. Simulations indicate that the stock would reach a state of quasi-extinction (i.e., less than 50 mature females) within the next 15 years should current harvest levels be perpetuated. Alternative management scenarios were also explored, and harvest levels allowing to meet the corresponding objectives are presented. Based on the 2024 model estimate, the annual PBR for BEL-EHB is 4 beluga. Based on the IPM, the abundance of the JAM stock in 2024 was estimated at 16,000 (95% CrI = [12,300; 20,600]) beluga, with apparent stability since 2021. An estimated average of 31 JAM beluga are being harvested annually since 2021. The PRP for the JAM stock is estimated at 8,800 and the LRP at 4,400. The annual PBR for JAM is 245 beluga.