Global change projections predict significant impacts on the aquaculture sector leading to a substantial interest in the study of species' ecophysiological responses to increased temperature and shifting salinities. Here, we experimentally evaluated shifts on the fatty acid (FA) profiles of the ragworm Hediste diversicolor under global and local ocean change drivers. This polychaete is a suitable extractive organism for integrated multi-trophic aquaculture (IMTA) designs, as it maximizes the use of otherwise wasted nutrients present in particulate organic matter of farm effluents. Ragworms were collected from intertidal mudflats and subjected to an experimental trial of 28 days under control (24 °C), warming (27 °C) and heatwave (30 °C) scenarios combined with salinity variations (20 and 30) in a full factorial design. Individuals were sampled after 14 and 28 days of exposure (D14 and D28 respectively) for FA profile analysis. Interactions between temperature x day and salinity x day modulated ragworms' fatty acid profiles. Overall, an increase in different FA classes, as well as in ∑n-3 UFA, ∑n-6 UFA and essential fatty acids (EFA) was detected over time in polychaetes exposed to salinity 30, contrary to what was observed in salinity 20. This suggests that salinity 30 is an optimal condition for H. diversicolor FA enrichment. At this salinity, fatty acids from n-3 and n-6 families remained stable at 24 °C and 27 °C, with a decrease being detected at 30 °C (after 14 days of exposure), possibly related to changes in the lipid composition of cell membranes to maintain homeostasis. However, after 28 days, no differences were detected, suggesting that polychaetes can acclimate to elevated temperatures when they are in optimal salinity conditions. In contrast, if an extreme warm event (30 °C) is combined with low salinity (20), all FA classes increase at day 14 and HUFA class remain elevated after 28 days, while ∑n-3 UFA, ∑n-6 UFA, ARA, EPA and DHA decrease, suggesting their potential role in osmotic balance and membrane fluidity. Still, if ragworms are grown at low salinity and the increase in temperature is only moderate, ∑n-3 UFA, ∑n-6 UFA, ARA, EPA and DHA increase. This study shows that heatwaves can have an impact on H. diversicolor aquaculture, especially under low salinity conditions, by decreasing EFA. Risk assessment and adaptation strategies need to be implemented into aquaculture practices to mitigate the impacts of global change on the nutritional profile of farmed species and their overall commercial value.

全球变化预测预测将对水产养殖业产生重大影响，从而引起人们对研究物种对温度升高和盐度变化的生态生理反应的浓厚兴趣。在这里，我们通过实验评估了沙蚕Hediste diversicolor的脂肪酸（FA）谱的变化受全球和当地海洋变化驱动因素的影响。这种多毛鱼类是适合综合多营养水产养殖（IMTA）设计的合适提取生物，因为它可以最大程度地利用农场污水中颗粒有机物中原本浪费的养分。从潮间带滩涂收集g，并在控制下（24°C），变暖（27°C）和热浪（30°C）以及盐度变化（20和30）的情况下进行28天的实验设计。在暴露14天和28天后（分别为D14和D28）对个体进行采样，以进行FA谱分析。温度x天和盐度x天之间的相互作用调节了worm虫的脂肪酸谱。总体而言，不同FA类别以及∑ n -3 UFA，∑ n的增加随着时间的推移，在暴露于盐度30的多毛狗中检测到-6 UFA和必需脂肪酸（EFA），这与在盐度20中观察到的相反。这表明盐度30是杂色嗜血杆菌富集的最佳条件。在此盐度下，n -3和n的脂肪酸-6个家族在24°C和27°C下保持稳定，在30°C（暴露14天后）检测到下降，这可能与维持体内稳态的细胞膜脂质组成的变化有关。但是，在28天后，没有发现任何差异，这表明多壳鸭在最佳盐度条件下可以适应高温。相反，如果将极端高温事件（30°C）与低盐度（20）结合使用，则所有FA类在第14天均增加，而HUFA类在28天后仍保持升高，而∑ n -3 UFA，∑ n -6 UFA ，ARA，EPA和DHA降低，表明它们在渗透平衡和膜流动性方面的潜在作用。但是，如果虫在低盐度下生长且温度仅适度升高，∑ n-3 UFA，∑ n -6 UFA，ARA，EPA和DHA增加。这项研究表明，热浪可以通过降低EFA来影响杂色嗜水种的养殖，特别是在低盐度条件下。需要在水产养殖实践中实施风险评估和适应战略，以减轻全球变化对养殖物种营养状况及其总体商业价值的影响。