Abstract Investigating the drivers of fish assemblage trophic structure is a critical question, in order to better understand ecosystem functioning, predict the effects of perturbations and implement integrated management of exploited marine ecosystems. Ecosystemic surveys enabled the determination of the trophic structure of the fish assemblages in three French marine ecosystems, namely the Eastern English Channel, the Bay of Biscay and the Gulf of Lions, through the simultaneous collection of qualitative (stable isotopes and energy content) and quantitative (biomass) data. In the Bay of Biscay and in the Gulf of Lions, pelagic primary production supported at least 80% of the fish biomass production, and explained the dominance of pelagic species, but with differences resulting from the different productivity. The lower productivity in the oligotrophic Gulf of Lions led to a lower total biomass, energy density as well as the predominance of zooplankton-feeders. In contrast, fluxes in the Bay of Biscay were sufficient to support a higher biomass of pelagic piscivores, and of species with higher energy content. In the shallow Eastern English Channel, the respective contributions of pelagic and benthic sources were similar. Bentho-demersal species of higher trophic level dominated this assemblage, because of their ability to exploit both pathways. Results of the present study confirmed that fisheries-focused surveys can be used as efficient platforms to address questions about ecosystem functioning. Here, it confirmed the expected differences between ecosystems and the importance of primary production and environment as drivers of fish assemblage structure and functioning. Future studies should nevertheless develop new methods to better assess the paramount role of low trophic level consumers.

中文翻译：

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初级生产和深度驱动法国海洋生态系统中鱼类组合的不同营养结构和功能

摘要 调查鱼类组合营养结构的驱动因素是一个关键问题，以更好地了解生态系统功能，预测扰动的影响并实施已开发的海洋生态系统的综合管理。通过同时收集定性（稳定同位素和能量含量）和定量数据，生态系统调查能够确定三个法国海洋生态系统中鱼类群落的营养结构，即东英吉利海峡、比斯开湾和狮子湾（生物量）数据。在比斯开湾和狮子湾，中上层初级生产支持至少 80% 的鱼类生物量生产，并解释了中上层物种的优势，但由于生产力不同而导致差异。低营养狮子湾的生产力较低导致总生物量、能量密度以及浮游动物饲养者的优势较低。相比之下，比斯开湾的通量足以支持中上层食鱼动物和能量含量更高的物种的更高生物量。在浅东英吉利海峡，远洋和底栖来源各自的贡献相似。较高营养水平的底栖物种在这种组合中占主导地位，因为它们能够利用这两种途径。本研究的结果证实，以渔业为重点的调查可以作为解决生态系统功能问题的有效平台。这里，它确认了生态系统之间的预期差异以及初级生产和环境作为鱼类组合结构和功能驱动因素的重要性。然而，未来的研究应该开发新的方法来更好地评估低营养级消费者的重要作用。