Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, British Columbia, Canada.
Ocean Wise Research Institute, Marine Mammals Research Program, Vancouver, British Columbia, Canada.
PLoS One. 2022 Jun 27;17(6):e0270523. doi: 10.1371/journal.pone.0270523. eCollection 2022.
The salmon-eating Southern Resident killer whale (SRKW) (Orcinus orca) population currently comprises only 73 individuals, and is listed as 'endangered' under the Species at Risk Act in Canada. Recent evidence suggests that the growth of this population may be limited by food resources, especially Chinook salmon (Oncorhynchus tshawytscha). We present spatio-temporal bioenergetics model for SRKW in the Salish Sea and the West Coast of Vancouver Island from 1979-2020 with the objective of evaluating how changes in the abundance, age-structure, and length-at-age of Chinook salmon populations has influenced the daily food consumption of the SRKW population. Our model showed that the SRKW population has been in energetic deficit for six of the last 40 years. Our results also suggested that the abundance of age-4 and age-5 Chinook salmon are significant predictors of energy intake for SRKW. We estimated that the annual consumption (April-October) of Chinook salmon by the whales between 1979 and 2020 ranged from 166,000 216,300. Over the past 40 years, the model estimated that the contribution in the predicted SRKW diet of Chinook salmon originating from the Columbia River has increased by about 34%, and decreased by about 15% for Chinook salmon stocks originating from Puget Sound. Overall, our study provides an overview of the requirements and availability of prey for SRKW over the last 40 years, while supporting the hypothesis that SRKW were limited by prey abundance in the study period.
摄食大麻哈鱼的南方居留地虎鲸（SRKW）（Orcinus orca）种群目前仅由 73 头个体组成，在加拿大的《濒危物种法》下被列为“濒危”物种。最近的证据表明，该种群的增长可能受到食物资源的限制，尤其是奇努克鲑（Oncorhynchus tshawytscha）。我们提出了 1979 年至 2020 年期间在萨利希海和温哥华岛西海岸的 SRKW 的时空生物能量学模型，目的是评估奇努克鲑种群数量、年龄结构和年龄长度的变化如何影响 SRKW 种群的每日食物消耗。我们的模型表明，在过去的 40 年中，有六年 SRKW 种群处于能量不足状态。我们的研究结果还表明，年龄为 4 岁和 5 岁的奇努克鲑的丰度是 SRKW 能量摄入的重要预测因子。我们估计，1979 年至 2020 年间，鲸鱼每年（4 月至 10 月）食用的奇努克鲑鱼数量在 166,000 到 216,300 之间。在过去的 40 年里，该模型估计，源自哥伦比亚河的奇努克鲑在预测的 SRKW 饮食中的贡献增加了约 34%，而源自普吉特湾的奇努克鲑种群的贡献减少了约 15%。总体而言，我们的研究提供了过去 40 年来 SRKW 对猎物的需求和可利用性的概述，同时支持了在研究期间 SRKW 受到猎物丰度限制的假设。
