The Norwegian and Barents Seas host large commercial fish populations that interact with each other, as well as marine mammal populations that feed on plankton and fish. Quantifying the past dynamics of these interacting species, and of the associated fisheries in the Norwegian and Barents Sea is of high relevance to support ecosystem-based management. The purpose of this work is to develop a food-web model of intermediate complexity and perform a quantitative assessment of the Norwegian and Barents Sea ecosystems in the period 1988–2021 in a manner that is consistent with existing data and expert knowledge, and that is internally coherent. For this purpose, we use the modelling framework of chance and necessity (CaN). The model construction follows an iterative process that allows to confront, discuss, and resolve multiple issues as well as to recognise uncertainties in expert knowledge, data, and input parameters. We show that it is possible to reconstruct the past dynamics of the food-web only if recognising that some data and assumptions are more uncertain than originally thought. According to this assessment, consumption by commercial fish and catch by fisheries jointly increased until the early 2010s, after which consumption by fish declined and catches by fisheries stabilised. On an annual basis, fish have consumed an average of 135.5 million tonnes of resources (including 9.5 million tonnes of fish), marine mammals have consumed an average of 22 million tonnes of which 50 % (11 million tonnes) were fish. Fisheries and hunting have captured an average of 4.4 million tonnes of fish and 7 thousand tonnes of marine mammals.

中文翻译：

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挪威海和巴伦支海海洋哺乳动物、鱼类和渔业的食物网评估模型


挪威海和巴伦支海拥有大量相互影响的商业鱼类种群，以及以浮游生物和鱼类为食的海洋哺乳动物种群。量化这些相互作用的物种以及挪威和巴伦支海相关渔业的过去动态，对于支持基于生态系统的管理具有高度相关性。这项工作的目的是开发一个中等复杂度的食物网模型，并以与现有数据和专业知识一致且内部连贯的方式对 1988 年至 2021 年期间的挪威和巴伦支海生态系统进行定量评估。为此，我们使用了机会和必然性 （CaN） 的建模框架。模型构建遵循一个迭代过程，允许面对、讨论和解决多个问题，以及识别专业知识、数据和输入参数中的不确定性。我们表明，只有当认识到某些数据和假设比最初认为的更不确定时，才有可能重建食物网的过去动态。根据这项评估，直到 2010 年代初，商业鱼类消费量和渔业渔获量共同增加，此后鱼类消费量下降，渔业渔获量趋于稳定。每年，鱼类平均消耗 1.355 亿吨资源（包括 950 万吨鱼类），海洋哺乳动物平均消耗 2200 万吨，其中 50%（1100 万吨）是鱼类。渔业和狩猎平均捕获了 440 万吨鱼类和 7000 吨海洋哺乳动物。