Abstract The dietary preferences of 61 Western Mediterranean species of fish belonging to different trophic levels were studied. Specimens were collected during the annual bottom trawl survey MEDITS for the period 2011–2018, with a total of 16,588 stomach contents analyzed, providing a highly valuable raw dataset for advanced studies in trophic ecology. The software EstimateS 9.1 was used, for the first time in a study of Mediterranean fish species, to estimate cumulative prey curves in order to determine the adequacy of the sample size for each species in representing the species diet. The main findings revealed the existence of nine well-identified feeding strategies, or trophic guilds, based on food preferences. Indicators, namely the Shannon diversity index, biomass estimated from standard surveys, mean trophic level and fish community composition, were used to categorize the structure of the fish community in Western Mediterranean marine food webs. In addition, the effects of latitude, depth and habitat type on fish community structure were investigated. Results show all these environmental factors investigated drove fish composition structure. Regarding the three variables investigated, depth had the greatest impact on the fish community structure, particularly affecting diversity and fish community composition. Latitudinal gradient only seemed to affect fish community composition, showing consistency along a latitudinal north-south axis. Habitat type was found to be significant in fish community structure. Mean trophic level was the only indicator that was not affected significantly by environmental variables. The present study shows the relevance of environmental forcing in fish community structure. These findings highlight the need of ecosystem studies, since information about the trophic networks in the study area is still scarce, jeopardizing the development of ecosystem models. The present work aims to fill this gap for the effective implementation of an ecosystem approach to fisheries management in the Western Mediterranean Sea.

中文翻译：

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揭示西地中海附近鱼类群落不同营养类群的环境强迫

摘要 研究了61种不同营养级别的西地中海鱼类的饮食偏好。在 2011 年至 2018 年期间的年度底拖网调查 MEDITS 期间收集了标本，共分析了 16,588 份胃内容物，为营养生态学的高级研究提供了非常有价值的原始数据集。在地中海鱼类研究中首次使用软件 EstimateS 9.1 来估计累积猎物曲线，以确定每个物种的样本量是否足以代表物种饮食。主要发现揭示了基于食物偏好的九种明确的喂养策略或营养行会的存在。指标，即香农多样性指数，根据标准调查估计的生物量，平均营养水平和鱼类群落组成，用于对西地中海海洋食物网中鱼类群落的结构进行分类。此外，研究了纬度、深度和栖息地类型对鱼类群落结构的影响。结果表明，所有这些调查的环境因素都推动了鱼类的组成结构。关于调查的三个变量，深度对鱼类群落结构的影响最大，特别是影响多样性和鱼类群落组成。纬度梯度似乎只影响鱼类群落组成，显示出沿纬度南北轴的一致性。发现栖息地类型在鱼类群落结构中很重要。平均营养水平是唯一不受环境变量显着影响的指标。本研究表明环境强迫与鱼类群落结构的相关性。这些发现强调了生态系统研究的必要性，因为有关研究区域营养网络的信息仍然稀缺，危及生态系统模型的发展。目前的工作旨在填补这一空白，以有效实施西地中海渔业管理生态系统方法。