Eutrophication occurs due to domestic, industrial and agricultural pollution entering aquatic ecosystems, increasing the availability of nutrients such as nitrogen and phosphorus. This results in the accumulation of macroalgae and excessive phytoplankton growth, negatively affecting marine metabolism and causing significant ecological and socioeconomic impacts. This project seeks to understand how eutrophication affects the nutritional quality of tropical marine organisms. To achieve this objective, we will analyze different marine and coastal ecosystems affected by eutrophication. We will use stable isotopes to track the transfer of essential components, such as carbon and omega-3 and omega-6 fatty acids, from the base of the food chain to the fish. With this, we will be able to understand the sources of these components and the changes in nutritional quality throughout the food chain. This research will contribute to understanding the impacts of eutrophication on marine food webs and help improve the management of tropical ecosystems.