Small pelagics, or forage fish, link lower and higher trophic levels in marine food webs. Recently, attention has been given to the management of forage fish, including anadromous river herring (Alewife Alosa pseudoharengus, blueback herring A. aestivalis) and American shad (A. sapidissima) due to their current depleted status and historically important ecological and economic roles. Little is known about the impact of changes in their biomass on marine food webs and what management practices will promote their recovery. Estimated historical riverine productivity was utilized to evaluate potential ecosystem impacts of the increasing river to ocean connectivity to resemble 19th-century conditions. The Ecopath with Ecosim modeling framework was used to simulate management strategies, focused on anadromous forage fish, by creating scenarios of fisheries reduction (mixed fishery effort reduction) and river to ocean habitat connectivity (75% of historical connectivity achieved). Sixty-year simulations covered the entire time series including a 36-year forecast period to evaluate the ecosystem impacts of management strategies. Results suggest nonlinear relationships and large changes in biomass flows from forage fish to upper trophic levels in the Gulf of Maine ecosystem. Increases in biomass were observed for pelagic sharks, demersal piscivores, and species of conservation concern such as pinnipeds and seabirds, although overall results were strongly influenced by indirect trophic effects. Promoting anadromous forage fish recovery through increased connectivity resulted in the redundancy of marine ecosystem niches that would increase resilience to climate, fisheries, and other perturbations. This study highlights the value of employing ecosystem models for testing management scenarios to contrast different approaches to recover anadromous forage fish towards its former ecological prominence.

中文翻译：

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对比减少捕捞努力和栖息地连通性作为使用生态系统模型促进 alewife (Alosa pseudoharengus) 恢复的管理策略

小型中上层鱼类或饲料鱼将海洋食物网中较低和较高的营养水平联系起来。最近，饲料鱼的管理受到关注，包括溯河鲱（Alewife Alosa pseudoharengus，蓝背鲱A. aestivalis）和美洲鲱（A. sapidissima ）) 由于它们目前的枯竭状态和历史上重要的生态和经济作用。人们对它们的生物量变化对海洋食物网的影响以及哪些管理措施将促进它们的恢复知之甚少。估计的历史河流生产力被用来评估河流与海洋的连通性增加对生态系统的潜在影响，以类似于 19 世纪的情况。Ecopath 与 Ecosim 建模框架用于模拟管理策略，重点关注溯河性饲料鱼，通过创建渔业减少（混合渔业努力减少）和河流与海洋栖息地连通性（实现 75% 的历史连通性）的情景。60 年的模拟涵盖了整个时间序列，包括 36 年的预测期，以评估管理策略对生态系统的影响。结果表明，在缅因湾生态系统中，从饲料鱼到上层营养水平的生物量流动存在非线性关系和巨大变化。尽管总体结果受到间接营养效应的强烈影响，但观察到远洋鲨鱼、底栖鱼类以及鳍足类和海鸟等受保护物种的生物量增加。通过增加连通性来促进溯河性饲料鱼的恢复导致海洋生态系统生态位的冗余，这将增加对气候、渔业和其他扰动的恢复能力。本研究强调了使用生态系统模型来测试管理方案的价值，以对比不同的方法来恢复溯河的饲料鱼以恢复其以前的生态突出地位。