Significance of whale predation on natural mortality rate of Pacific herring in Prince William Sound, Alaska: 2006 - 2009, 2011-2012

Pacific herring (Clupea pallasi) in Prince William Sound (PWS) have been classified as "not-recovered" by the Exxon Valdez Oil Spill Trustee Council. Predation by marine mammals has been cited as a factor in the failure of this population to rebound. We will assess the significance of humpback whale predation on herring in PWS, particularly in winter. Specifically we will estimate the number of whales foraging in winter, determine when and if there is a prey switch to herring, and how long whales focus on herring as prey. Year one was funded, small in scale with an intense monitoring strategy; year 2 would expand the scale up in area significantly. Year 3 will verify the impact on herring of the high numbers of humpback whales we observed in PWS during year 2. These data will be combined in a bioenergetic model to determine numbers of herring consumed (and energy content consumed). Lastly, the estimated numbers of herring consumed would be included in an age-structured model so that the significance of whale predation on herring recovery can be evaluated. Year 4 (2010) will close out the project with the completion of analysis, reports, and manuscripts. This data set focuses on the humpback whale surveys including survey effort, whale identification, photo quality, whale behavior, prey items and tissue samples.威廉王子湾（Prince William Sound, PWS）内的太平洋鲱（Clupea pallasi）被埃克森·瓦尔迪兹溢油事故受托人委员会列为"未恢复"种群。海洋哺乳动物捕食被认为是该种群未能实现种群回弹的关键影响因素之一。本研究旨在评估威廉王子湾内座头鲸捕食鲱鱼的生态重要性，尤其聚焦冬季捕食行为。具体研究内容包括：估算冬季觅食座头鲸的种群数量，确定座头鲸是否会转向捕食鲱鱼，以及其以鲱鱼为主要捕食对象的持续时长。项目第一年已获得资助，采用小尺度高强度监测策略；第二年将大幅扩大监测覆盖范围；第三年将验证第二年在威廉王子湾观测到的大量座头鲸对鲱鱼种群造成的影响。上述观测数据将整合至生物能学模型中，以计算被捕食鲱鱼的总数量及消耗的能量总量。此外，估算的被捕食鲱鱼数量将被纳入年龄结构模型，从而评估鲸类捕食对鲱鱼种群恢复的显著性影响。第四年（2010年）将完成项目收尾工作，包括数据分析、研究报告撰写及学术论文发表。本数据集聚焦座头鲸调查工作，涵盖调查作业强度、鲸类个体识别、照片质量、鲸类行为、捕食猎物种类及组织样本采集等内容。