Effects of Climate Change on the Seasonal Diets, Energy Requirements, Abundances and Distributions of Marine Mammals in the North Pacific Ocean

人们越来越担心气候变化将对海洋哺乳动物和其他海洋物种产生影响。据推测，海洋哺乳动物的极地物种将受到冰盖减少的负面影响，一些温带哺乳动物的分布可能会因其猎物分布的北移而向两极转移。然而，这些假设从未得到检验。量化气候变化对海洋哺乳动物影响的一种方法是利用生物能量学模型和海洋哺乳动物的食物、数量和分布的历史数据来确定制约它们的生物能量学限制。在接下来的5年里，我建议与研究生一起制定生物能量学模型，并建立北太平洋47种海洋哺乳动物的丰度和饮食数据库。我还将利用PICES成员国(日本、韩国、中国、俄罗斯、加拿大和美国)提供的数据，建立一个关于猎物数量、质量、组成和分布的补充数据库。将根据单个物种的能量需求(由能量模型确定)、食物、猎物的能量密度和种群大小来计算1º单元(~100x100千米)的猎物消耗量。对气候变化对海洋哺乳动物消费和分布的空间和时间影响的预测将基于对猎物数量和质量的预测变化(来自对鱼类的气候影响的独立模型)，以及我相信可以利用食物和种群丰度数据库建立海洋哺乳动物与其偏爱的猎物物种之间的营养联系和依赖关系，以及关于身体大小、游泳能力和生理的额外信息。我还建议评估随时间变化的饮食变化、被捕食物种的能量密度、海洋哺乳动物生理和海洋哺乳动物种群趋势之间的生理联系，以测试垃圾食品假说作为北太平洋海洋哺乳动物种群动态的主要驱动力的适用性。这项研究支持的研究生将发展编程、数据分析以及渔业和海洋哺乳动物研究方面的技能；并将参加为支持这一倡议而在PICES年会上组织的讲习班和专题讨论会。这项研究的结果将提供1)参数化生态系统模型所需的饮食数据，2)食物消耗量的估计，3)海洋哺乳动物对气候变化的反应的预测，以及4)海洋哺乳动物与其猎物之间的相互依赖和营养联系的新见解。

There is growing concern about the effects that climate change will have on marine mammals and other marine species. It has been assumed that polar species of marine mammals will be negatively affected by reduced ice coverage, and that the distribution of some temperate mammals may shift towards the poles in response to northward shifts in the distribution of their prey. However, these assumptions have never been tested. One means of quantifying the effects of climate change on marine mammals is to use bioenergetic models and historical data on diets, numbers and distributions of marine mammals to determine the bioenergetic limitations that constrain them. For the next 5 years, I propose to work with graduate students to formulate bioenergetic models and build databases of abundances and diets for 47 species of marine mammals in the North Pacific. I will also establish a complementary database on prey quantity, quality, composition, and distribution using data provided by PICES member countries (Japan, Korea, China, Russia, Canada and the United States). Prey consumption will be calculated for 1º cells (~100x100 km) based on energetic requirements of the individual species (determined by the energetic models), diets, energy densities of prey, and population sizes. Predictions of spatial and temporal effects of climate change on consumption and distribution of marine mammals will be based on projected changes in the quantities and qualities of prey (derived from independent models of climate effects on fish) and from the trophic linkages and dependences I believe can be established between marine mammals and their preferred prey species using the database of diets and population abundances, along with additional information about body sizes, swimming performance and physiologies. I also propose to evaluate the physiological linkages between dietary shifts over time, energy density of prey species, marine mammal physiologies, and population trends of marine mammals to test the applicability of the junk-food hypothesis as the major driver of marine mammal population dynamics in the North Pacific. The graduate students supported by this study will develop skills in programming, data analysis, and fisheries and marine mammal research; and will take part in workshops and symposiums organized at PICES annual meetings to support this initiative. Results from this research will provide 1) dietary data needed to parameterize ecosystem models, 2) estimates of food consumption, 3) predictions of marine mammal responses to climate change, and 4) new insights into the interdependencies and trophic linkages between marine mammals and their prey.