The Gulf of Nicoya is a large tropical estuary located on the Pacific coast of Costa Rica and accounts for the country’s main fish production. It is increasingly impacted not only by its fisheries, but also by urbanization, tourism developments, the input of pollutants from urban centers and agriculture activities in the catchment areas of large rivers entering the gulf. Similar to other coastal ecosystems, the gulf is particularly sensitive to short- and long-term changes in the climate, such as the precipitation rate, Sea Surface Temperature, wind speed and current regimes. While the gulf has been studied for decades, until now no attempt has been made to combine the analysis of the impacts of fishing and environmental changes on the ecosystem. By following a holistic approach that uses fisheries and environmental time series data from collaborative research and simulation models, this study aims at identifying the main drivers of the observed changes in the Gulf of Nicoya ecosystem. While the model simulations indicate that variations in the catch of some target species (e.g., cephalopods and shrimps) are mainly driven by the fisheries’ exploitation rates, several other species (e.g., corvina, snook, small pelagics, and crabs) are also substantially affected by climate variations, particularly during El Niño periods of high Sea Surface Temperature extremes and increased precipitation. During these periods, phytoplankton productivity and zooplankton biomass deceases with bottom–up effects on the entire food chain. Indicators of the environmental state of the system thus have to be considered along with regulations of the fishing pressure to form the basis for the development of appropriate management strategies.

中文翻译：

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确定尼科亚湾生态系统变化的驱动因素（哥斯达黎加）

尼科亚湾是位于哥斯达黎加太平洋沿岸的一个大型热带河口，是该国主要的鱼类生产地。它不仅受到渔业的影响，而且受到城市化、旅游发展、城市中心污染物的输入以及进入海湾的大河流集水区的农业活动的影响越来越大。与其他沿海生态系统类似，海湾对气候的短期和长期变化特别敏感，例如降水率、海面温度、风速和水流状况。虽然对海湾的研究已经有几十年了，但直到现在还没有尝试将捕鱼和环境变化对生态系统影响的分析结合起来。通过使用来自协作研究和模拟模型的渔业和环境时间序列数据的整体方法，本研究旨在确定观察到的尼科亚湾生态系统变化的主要驱动因素。虽然模型模拟表明某些目标物种（例如头足类和虾）的捕获量变化主要由渔业的开发率驱动，但其他几个物种（例如，corvina、snook、小中上层鱼类和螃蟹）也有很大的差异受气候变化的影响，特别是在厄尔尼诺现象期间，海面温度极端升高和降水增加。在这些时期，浮游植物生产力和浮游动物生物量下降，对整个食物链产生自下而上的影响。