Modeling interactions between top predators and fishing vessels: implications for fisheries management in a wider ecosystem

2002年在约翰内斯堡举行的可持续发展世界首脑会议（WSSD）上，签署国同意在2012年前制定和实施渔业生态系统方法（EAF）。EAF的一个核心原则是，管理优先事项应从生态系统而不是目标物种开始，必须将人类视为所管理的生态系统的组成部分。然而，实施EAF带来了一系列所谓的邪恶问题，因为很难找到一个对生态系统的所有组成部分都公平的解决方案。但是，如果能够制定一个共同框架，在这个框架内对系统所有组成部分的风险进行评估和比较，就有可能找到一种解决办法。该项目将通过开发一个空间上明确的数学和统计模型来促进这一框架，该模型描述了在北海开发具有商业重要性的鱼类种群的“捕食者”（灰海豹和斑海豹以及不同的捕鱼船队）之间的相互作用。该模型将用于研究不同管理方案对个体捕食者和生态系统的影响。特别是，我们将重点关注拟议海洋法案的白色文件中概述的海洋环境管理变化的影响。我们将使用一个操作模型的方法来描述三组不同的过程：底层生物系统的运作方式;管理该系统的方式;以及收集和分析系统数据的方式。我们将扩展这种方法，通过应用计算机密集型统计方法，以适应渔业上岸量和海豹状况和数量的数据，提供更多的深入了解潜在的生物和经济过程。由于运营模型可以明确考虑到我们对系统的了解中的主要不确定性来源，因此它们对于评估与不同管理方案相关的风险特别有用。运营模式将分两个阶段开发。一套功能反应将被用来预测消费/捕获鳕鱼，黑线鳕，鳕鱼和鲱鱼和它们的丰度在一个特定的空间位置之间的关系。一套综合反应将被用来预测分布的捕捞努力和海豹觅食的空间。建模过程将促进捕食者的觅食策略和收集其行为信息的方式之间的相似性。它们都能从猎物中获得相对明确的净收益，这取决于它们捕获物的价值和获得猎物的成本之间的平衡。我们将重点讨论捕食者的一个子集，它们的觅食受到限制，需要定期返回相对较少的明确地点进行捕捞和繁殖，就海豹而言，或者降落捕获物并补充燃料，在渔业方面。我们将在一个共同的经济框架中评估其收益和成本，该框架使用捕鱼/觅食行程作为基本时间单位。我们将这些模型的基础上收集的大量数据的海豹运动的海洋哺乳动物研究单位，以及广泛的数据库在北海捕捞努力下收集的欧洲委员会的MAFCONS项目。我们将把这些组合模型与北海主要繁殖地的渔业上岸量数据和海豹身体状况数据相匹配。最后，我们将示范如何实施Defra提出的新的海洋资源管理制度，如一系列保护区和更加强调区域管理。然后，我们将使用情景分析来预测这些制度对渔船队和捕食者的空间分布，对他们的登陆和身体状况，以及对他们的猎物资源可能产生的影响。

At the 2002 World Summit on Sustainable Development (WSSD) in Johannesburg, signatory nations agreed to develop and implement an ecosystem approach to fisheries (EAF) by 2012. A central tenet of EAF is that management priorities should start with the ecosystem rather than the target species, and that humans must be considered as an integral part of the ecosystems that are being managed. However, implementing an EAF poses a range of so-called wicked problems, because it is difficult to find a solution that is equitable for all components of the ecosystem. A solution may, however, be possible if a common framework can be developed within which the risks to all components of the system can be evaluated and compared. This project will contribute to that framework by developing a spatially-explicit mathematical and statistical model of the interactions between the 'predators' (grey and harbour seals, and different fishing fleets) that exploit commercially-important fish stocks in the North Sea. This model will be used to investigate the impacts of different management options on the individual predators and on the ecosystem. In particular, we will focus on the implications of changes in the management of the marine environment that are outlined in the White Paper on the proposed Marine Bill. We will use an operating model approach that describes three different sets of processes: the way in which the underlying biological system operates; the way in which this system is managed; and the way in which data from the system are collected and analysed. We will extend this approach to provide additional insight into the underlying biological and economic processes by applying computer-intensive statistical methods to fit the to data on fisheries landings and seal condition and numbers. Because operating models can take explicit account of the major sources of uncertainty in our knowledge of the system, they are therefore particularly useful for evaluating the risks associated with different management scenarios. The operating model will be developed in two phases. A set of functional responses will be used to predict the relationship between the consumption/catch of cod, haddock, whiting and herring and their abundance at a particular spatial location. A set of aggregative responses will be used to predict the distribution of fishing effort and seal foraging over space. The modelling process will be facilitated by similarities between the foraging strategies of the predators and the ways in which information on their behaviour is collected. They all derive relatively well-defined net benefits from their prey that are determined by the balance between the value of what they catch and the cost of obtaining it. We will focus on a subset of the predators whose foraging is constrained by the need to return at regular intervals to a relatively small number of well-defined locations to haul out and breed, in the case of seals, or to land their catch and refuel, in the case of the fisheries. We will evaluate their benefits and costs in a common economic framework that uses the fishing/foraging trip as the basic time unit. We will base these models on the large body of data on seal movements collected by the Sea Mammal Research Unit, and the extensive database on fishing effort in the North Sea collected under the European Commission's MAFCONS project. We will fit these combined models to data on fisheries landings and data on the body condition of seals at the major breeding colony in the North Sea. Finally, we will model the way in which new management regimes for marine resources, such as a range of protected areas and a greater emphasis on regional management, proposed by Defra are likely to be implemented. We will then use scenario analysis to predict the likely impacts of these regimes on the spatial distribution of fishing fleets and predators, on their landings and body condition, and on their prey resources.