CNH: Fishscape: Complex Dynamics of the Eastern Pacific Tuna Fishery

作为全球共有的资源，许多高度洄游鱼类种群被过度捕捞，因此渔民必须越来越努力地捕捞越来越少的鱼。这场国际公地悲剧的一个结果是，曾经丰富的种群，如太平洋鳕鱼和北大西洋鳕鱼，以及它们所支持的渔业沿着突然崩溃。另一方面，对于一些过度捕捞的种群，如北方大西洋箭鱼和东太平洋大眼金枪鱼，各国进行了合作和投资，以减少捕捞量，使种群有机会重建，渔业有时间恢复。 我们的项目将确定稳定性和不稳定性的主要来源，导致这种广泛的变化，否则类似的系统。我们将通过创建、验证和探索“鱼景”来实现这一目标，这是一个针对东太平洋（EPO）热带金枪鱼的国际渔业的完全集成的地理空间模型。将人类和自然元素--海洋、鱼类、渔民、市场，甚至政治政策--结合在这个复杂系统中，是充分理解所观察到的恢复力和崩溃动态的唯一途径。通过连接海洋条件，鱼类种群动态和渔民行为的现实模型，Fishscape将揭示仍然没有答案的关键生态问题，例如营养物质可用性，洋流和远洋环境中繁殖成功之间的关系。关于渔民偏见和捷径的现实假设也将被纳入Fishscape，产生船长技能，技术变革和市场力量等因素对国家捕鱼船队相对收益的影响的措施。一旦该模型得到交叉验证，该项目将使用强大的决策方法，通过模拟广泛的社会和生态因素来探索，以发现是什么使系统具有弹性，是什么导致不稳定。具体来说，我们将测试三个元情景：（1）气候变化，（2）油价上涨，（3）技术进步，以确定系统内稳定和不稳定的来源。像金枪鱼这样的顶级捕食者对海洋生态系统、全球粮食供应和国际产业至关重要。确定这些系统的恢复力或崩溃的来源可以防止在其他渔业中看到的大部分痛苦。Fishscape提供了一个探索相对和绝对收益的工具。它将打破合作的障碍，将焦点从谁得到什么的冲突--以及相关的无法防止种群下降的问题--转移到可以改善每个人（甚至是鱼）条件的管理协议上。参与鱼景教育计划应该引导人们以不同的方式思考环境权衡：作为日常生活中复杂但可理解的一部分，而不是绝望地寻找单一的次优解决方案。

As global common-pool resources, many highly migratory fish stocks are overexploited and so fishers must work harder and harder to catch fewer and fewer fish. One result of this international tragedy of the commons is the sudden collapse of once-abundant stocks, such as the Pacific anchovetta and the North Atlantic cod, along with the fisheries they supported. On the other hand, for some overfished stocks such as northern Atlantic swordfish and eastern Pacific bigeye tuna, countries have cooperated and invested to reduce harvests, giving the stocks a chance to rebuild and the fisheries time to recover. Our project will identify the major sources of stability and instability that lead to such wide variation across otherwise similar systems. We will do this by creating, validating, and exploring 'Fishscape', a fully integrated, geo-spatial model of the international fishery targeting tropical tunas in the eastern Pacific Ocean (EPO). Coupling the human and natural elements in this complex system - the oceans, the fish, the fishers, the markets, and even the political policies - is the only way to fully understand the observed dynamics of resilience and collapse. By connecting realistic models of oceanographic conditions, fish population dynamics, and fisher behavior, Fishscape will shed light on still-unanswered key ecological questions, such as the relationships among nutrient availability, ocean currents, and reproductive success in a pelagic environment. Realistic assumptions about fishers' biases and shortcuts will also be integrated into Fishscape, yielding measures of the effects of factors like skipper skill, technological change, and market forces on relative gains among national fishing fleets. Once the model is cross-validated, the project will use robust decision making methods to explore through simulation over a wide range of social and ecological factors to discover what makes the system resilient and what leads to instability. Specifically, we will test three meta-scenarios: (1) climate change, (2) increasing price of oil, and (3) technological improvements, in order to identify sources of stability and instability within the system. Top predators like tuna are critical to marine ecosystems, global food supplies, and international industries. Identifying sources of resilience or collapse in these systems could prevent much of the suffering that has been seen in other fisheries. Fishscape provides a tool that explores relative and absolute gains. It will break down barriers to cooperation by moving focus away from conflict over who gets what - and the related inability to prevent the decline of stocks - to agreement on management that can improve conditions for everyone, even the fish. Participation in the Fishscape education program should lead people to think about environmental trade-offs differently: as a complex but comprehensible part of daily life, rather than as a desperate search for a single sub-optimal solution.