Apex Predators in the Pelagic Zone

远洋区域的顶级掠食者

• 批准号: 9731531
• 负责人: James Kitchell
• 金额: $ 54.23万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9731531&HistoricalAwards=false
• 关键词: Apex; Predators; Pelagic; Zone

Exploitation of apex predators in pelagic food webs should result in a set of ecological changes at several scales. We will determine the dynamics of compensatory responses by apex predators (large tunas, billfishes and sharks) and some of their primary prey (squids, small tunas and juvenile mahimahi) in the pelagic food webs of the Central North Pacific (CNP). We will test for fishery-induced changes in growth rates, predator-prey interactions (diets), life history characteristics such as size or age at maturity, and species composition of the fish community. Analyses of food web dynamics will be used to evaluate the ecological consequences of changes in exploitation. We will use retrospective analyses of long-term data sets provided by collaboration with the Honolulu Laboratory, National Marine Fisheries Service. Responses to `pulse` manipulations will derive from analyses of recent evidence for major, rapid changes in exploitation effects, prey availability, and environmental effects (oceanic regime shifts). Responses to `press` manipulations of apex predator populations will derive from the 35-50 year records of basic biological data, life history studies and catch data maintained by NMFS. Contemporary data on growth rates, diets, life history characteristics, and species composition will be compared with those collected since 1948. This effort will employ three classes of analytical tools. Time-series methods and Bayesian models will be used to discern signal from noise and to identify the interactions of causative variables. Bioenergetics models will provide quantitative estimates of the changes in food web linkages for individual predators, their prey and the cumulative change for all members of the apex trophic guild. A new simulation model (Ecosim II) creates the food web context of an entire ecosystem and will be used to explore responses to changing mortality rates, different life history strategies and the role of a habitat refuge created around the Northwest Hawaiian Islands. The recent rise of conservationist concern for large predatory fishes is based on their unknown role in sustaining the ecological integrity of pelagic ecosystems. It is imperative that we better understand the effects of these migratory predators and their interactions with habitats encompassed by current and future refuges for pelagic fishes. That understanding must be set in the context of environmental changes that dampen or amplify food web effects.

开发中上层食物网中的顶端捕食者应导致一系列不同尺度的生态变化。 我们将确定的动态补偿反应的顶端捕食者（大金枪鱼，长嘴鱼和鲨鱼）和他们的一些主要猎物（鱿鱼，小金枪鱼和少年mahimahi）在中上层食物网的中北部太平洋（CNP）。 我们将测试渔业引起的增长率，捕食者-猎物相互作用（饮食），生活史特征，如大小或年龄成熟，鱼类群落的物种组成的变化。 对食物网动态的分析将用于评价开发变化的生态后果。 我们将使用与国家海洋渔业局檀香山实验室合作提供的长期数据集的回顾性分析。 对“脉冲”操纵的反应将来自于对开发效应、猎物可获性和环境效应（海洋状况变化）方面的重大、快速变化的最新证据的分析。 对顶端捕食者种群的“新闻”操纵的反应将来自国家海洋渔业局保存的35-50年的基本生物数据记录、生活史研究和渔获量数据。当代的增长率，饮食，生活史特征和物种组成的数据将与1948年以来收集的数据进行比较。 这项工作将采用三类分析工具。 时间序列方法和贝叶斯模型将用于区分信号和噪声，并确定因果变量的相互作用。 生物能量学模型将提供定量估计的变化，在食物网的联系，为个人的捕食者，他们的猎物和累积变化的所有成员的顶端营养集团。 一个新的模拟模型（Ecosim II）创建了整个生态系统的食物网环境，并将用于探索对不断变化的死亡率，不同的生活史策略和在夏威夷西北群岛周围创建的栖息地避难所的作用的反应。 最近，环保主义者对大型掠食性鱼类的关注有所增加，这是基于它们在维持远洋生态系统的生态完整性方面的未知作用。 我们必须更好地了解这些洄游捕食者的影响及其与目前和未来的中上层鱼类避难所涵盖的生境的相互作用。 这种理解必须以环境变化为背景，因为环境变化会减弱或扩大食物网的影响。