Conservation of marine ecosystems is important for the sustainable utilization of marine resources under environmental changes and anthropogenic impacts. In Japan, fishery management has been based on single-species stock assessments and little attempts have been made to assess and manage the impacts of multi-species multi-gear fisheries except for a few local case studies. In this study, we analyzed two local Ecopath food-web models constructed for Japanese waters (Northeastern Japan and Seto Inland Sea). We adopted a comparative approach to assess the ecosystem characteristics and fishery impacts through a comparison of these models with other published Ecopath models for various periods and regions of the world ocean. Among the metrics derived from Ecopath outputs, total biomass and total productivity represented the gross metabolic activities of the systems, and trophic level fractionation of biomass and catch reflected the trophic structure of the food webs and fishery removals. Loss of food for top predators, primary production required, and mean and variance of trophic level of catch were good indicators of the impacts and patterns of fishery removals. Our results illustrate the characteristics of food webs and fisheries in Japanese local ecosystems: The Northeastern Japan model showed the moderate productivity of the ecosystem, and fishery removals from lower and wider trophic levels. The Seto Inland Sea model indicated large impacts of fisheries on the low productivity neritic system. Such profiling of ecosystems and fisheries provides good overviews that will help initiate stakeholder discussion toward the set-up phase of ecosystem-based fishery management in Japan.

保护海洋生态系统对于在环境变化和人为影响下可持续利用海洋资源至关重要。在日本，渔业管理一直以单物种种群评估为基础，除少数本地案例研究外，几乎没有尝试评估和管理多物种多齿轮渔业的影响。在这项研究中，我们分析了为日本水域建造的两个本地Ecopath食物网模型（日本东北和濑户内海）。通过将这些模型与其他已发布的针对世界海洋不同时期和地区的Ecopath模型进行比较，我们采用了一种比较方法来评估生态系统特征和渔业影响。在从Ecopath输出得出的指标中，总生物量和总生产力代表了系统的总代谢活动，生物量和捕获量的营养级分反映了食物网和渔业清除的营养结构。顶级捕食者的食物损失，所需的初级生产以及营养捕获水平的均值和方差是渔业捕捞影响和模式的良好指标。我们的结果说明了日本当地生态系统中食物网和渔业的特征：日本东北部模型显示了该生态系统的中等生产力，以及在较低和较宽的营养级别上的渔业捕捞。濑户内海模型表明，渔业对低生产力的尖沙咀系统有很大影响。