In the North-Western Mediterranean Sea (NWMS), changes in size and taxonomic composition of zooplankton have been hypothesized to underlie observed changes in populations of Sardina pilchardus, one of the main small pelagic fish species. The present study was undertaken to better understand the link between the temporal variability of zooplankton and the diet of adult sardine in the Bay of Marseille over a period of 16 months by comparing the taxonomic and prey size composition of sardine stomach content with net-collected zooplankton samples from a fixed station. A greater similarity was found between sardine stomach content and 80-μm mesh size net samples than with the traditionally used 200-μm net samples. Sardine showed a high diet plasticity over the entire study period, covering a broad diversity of prey species and a wide prey size range (ranging from 400 to 1000 μm in measured total length), including a lot of small copepods (Microsetella/Macrosetella spp., Corycaeidae and Oncaeidae). The most consumed prey groups were not necessarily the most abundant in the zooplankton sampled with nets, suggesting potential prey selection. Sardine showed most often an opportunistic selective predation on larger individuals for most taxonomic prey groups. Results highlighted the diet flexibility of sardine between months and showed seasonal variation in prey size, suggesting a continuous filter-feeding mode on relatively small prey when prey densities were high and more frequent selective particulate-feeding on larger prey when prey densities were low. Sardines were able to feed on a wide diversity of prey and size range and thus to shift their diet between months. This ability probably allows them to adapt to high spatial and temporal variability of the zooplankton community in a context of both human-induced and climatic changes.

在西北地中海 (NWMS)，浮游动物的大小和分类组成的变化被假设为观察到的沙丁鱼种群变化的基础，主要的小型中上层鱼类之一。本研究旨在通过比较沙丁鱼胃内容物的分类和猎物大小组成与净收集的浮游动物，更好地了解马赛湾 16 个月内浮游动物的时间变化与成年沙丁鱼饮食之间的联系。来自固定站的样品。与传统使用的 200 微米网状样品相比，沙丁鱼胃内容物和 80 微米网目尺寸的网状样品之间的相似性更大。沙丁鱼在整个研究期间表现出很高的饮食可塑性，涵盖了广泛多样的猎物物种和广泛的猎物尺寸范围（测量总长度从 400 到 1000 微米），包括许多小型桡足类（Microsetella/Macrosetellaspp., Corycaeidae 和 Oncaeidae)。在用网采样的浮游动物中，消耗最多的猎物群体不一定是最丰富的，这表明潜在的猎物选择。对于大多数分类猎物群体，沙丁鱼最常表现出对较大个体的机会主义选择性捕食。结果强调了沙丁鱼在几个月之间的饮食灵活性，并显示出猎物大小的季节性变化，表明当猎物密度高时，对相对较小的猎物采用连续滤食模式，而当猎物密度低时，对较大猎物的选择性颗粒喂养更频繁。沙丁鱼能够以各种各样的猎物和大小范围为食，因此可以在几个月之间改变它们的饮食。