<b>Shaped by their environment: variation in blue whale morphology across three productive coastal ecosystems</b>

<b>Shaped by their environment: variation in blue whale morphology across three productive coastal ecosystems</b>Dawn R. Barlow¹*, K.C. Bierlich¹, William K. Oestreich², Gustavo Chiang³, John W. Durban⁴, Jeremy A. Goldbogen⁵, David W. Johnston⁶, Matthew S. Leslie⁷, Michael Moore⁸, John P. Ryan², Leigh G. Torres¹¹Geospatial Ecology of Marine Megafauna Lab, Marine Mammal Institute, Department of Fisheries, Wildlife, and Conservation Sciences, Oregon State University, Newport, Oregon USA²Monterey Bay Aquarium Research Institute, Moss Landing, California, USA³Centro de Investigación para la Sustentabilidad (CIS) &amp; Departamento de Ecología y Biodiversidad, Universidad Andrés Bello, Santiago, Chile⁴Marine Mammal Institute, Oregon State University, Newport, Oregon, USA⁵Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, California, USA⁶Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University Marine Laboratory, Beaufort, North Carolina, USA⁷ National Climate Adaptation Science Center, United States Geological Survey, Reston, Virginia, USA⁸Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA*[e-mail]<b>Abstract: </b>Species ecology and life history patterns are often reflected in animal morphology. Blue whales are globally distributed, with distinct populations that feed in different productive coastal regions worldwide. Thus, they provide an opportunity to investigate how regional ecosystem characteristics may drive morphological differences within a species. Here, we compare physical and biological oceanography of three different blue whale foraging grounds: (1) Monterey Bay, California, USA, (2) the South Taranaki Bight (STB), New Zealand, and (3) the Corcovado Gulf, Chile. Additionally, we compare the morphology of blue whales from these regions using unoccupied aircraft imagery. Monterey Bay and the Corcovado Gulf are seasonally productive and support the migratory life history strategy of the Eastern North Pacific (ENP) and Chilean blue whale populations, respectively. In contrast, the New Zealand blue whale population remains in the less productive STB year-round. All three populations were indistinguishable in total body length. However, New Zealand blue whales were in significantly higher body condition despite lower regional productivity, potentially attributable to their non-migratory strategy that facilitates lower risk of spatiotemporal misalignment with more consistently available foraging opportunities. Alternatively, the migratory strategy of the ENP and Chilean populations may be successful when their presence on the foraging grounds temporally aligns with abundant prey availability. We document differences in skull and fluke morphology between populations, which may relate to different feeding behaviors adapted to region-specific prey and habitat characteristics. These morphological features may represent a trade-off between maneuverability for prey capture and efficient long-distance migration. As oceanographic patterns shift relative to long-term means under climate change, these blue whale populations may show different vulnerabilities due to differences in migratory phenology and feeding behavior between regions. <br>**受环境塑造：三类高生产力沿海生态系统中蓝鲸（blue whale）的形态变异** Dawn R. Barlow¹*, K.C. Bierlich¹, William K. Oestreich², Gustavo Chiang³, John W. Durban⁴, Jeremy A. Goldbogen⁵, David W. Johnston⁶, Matthew S. Leslie⁷, Michael Moore⁸, John P. Ryan², Leigh G. Torres¹ ¹ 海洋巨型动物地理生态学实验室，海洋哺乳动物研究所，渔业、野生动物与保护科学系，俄勒冈州立大学，美国俄勒冈州纽波特 ² 蒙特雷湾水族馆研究所，美国加利福尼亚州莫斯兰丁 ³ 可持续发展研究中心（Centro de Investigación para la Sustentabilidad, CIS）& 生态与生物多样性系，安德烈斯·贝略大学，智利圣地亚哥 ⁴ 海洋哺乳动物研究所，俄勒冈州立大学，美国俄勒冈州纽波特 ⁵ 霍普金斯海洋站，生物学系，斯坦福大学，美国加利福尼亚州太平洋丛林镇 ⁶ 海洋科学与保护系，尼古拉斯环境学院，杜克大学海洋实验室，美国北卡罗来纳州博福特 ⁷ 国家气候适应科学中心，美国地质调查局，美国弗吉尼亚州雷斯顿 ⁸ 生物学系，伍兹霍尔海洋研究所，美国马萨诸塞州伍兹霍尔 * [e-mail] **摘要：** 物种的生态学特征与生活史模式往往体现在动物的形态特征中。蓝鲸（blue whale）为全球广布物种，拥有在全球不同高生产力沿海区域觅食的独特种群，因此为探究区域生态系统特征如何推动物种内部的形态差异提供了绝佳的研究契机。本研究对比了三处不同蓝鲸觅食地的物理与生物海洋学特征：（1）美国加利福尼亚州蒙特雷湾；（2）新西兰塔拉纳基湾南部（South Taranaki Bight, STB）；（3）智利科科瓦多湾。同时，本研究利用无人航空器影像对比了来自上述区域的蓝鲸形态。 蒙特雷湾与科科瓦多湾为季节性高生产力海域，分别支撑东北太平洋（Eastern North Pacific, ENP）蓝鲸种群与智利蓝鲸种群的洄游生活史策略。与之相对，新西兰蓝鲸种群全年栖息于生产力较低的塔拉纳基湾南部。三处种群的总体体长无显著差异，但新西兰蓝鲸的体况显著更优，尽管其所在区域生产力更低，这一现象可能归因于其非洄游策略：该策略降低了其与稳定持续的觅食机会在时空上错配的风险。另外，东北太平洋与智利种群的洄游策略仅在其抵达觅食地的时间与猎物大量富集的时段相匹配时才能取得成功。 本研究记录了不同种群间头骨与尾鳍的形态差异，这可能与适应区域特有猎物与生境特征的不同摄食行为相关。这些形态特征可能代表了猎物捕获机动性与高效长距离洄游之间的权衡。随着气候变化下海洋格局相对于长期均值发生改变，这些蓝鲸种群可能因区域间洄游物候与摄食行为的差异而表现出不同的脆弱性。