Catches come from fish stocks which normally have high, but not unlimited, reproductive capacity. If fisheries are not controlled, stocks will be exhausted and fishing will no longer be economically viable. It is in the general interest to implement a fisheries management system which: Ensures the reproduction of stocks for long-term high yields, (b) lays the foundations for the creation of a profitable sector, (c) guarantees a fair distribution of fishing opportunities, and (d) ensures the conservation of water resources and biodiversity. At the same time, Greece as a member state of the European Union (EU) must implement the EU Framework Directives and the policies adopted, notably the Common Fisheries Policy, the Maritime Strategy, the Water Directive, the Habitats Directive, etc.According to the DG MARE, the basis of the fisheries management systems is (a) the continuous collection of biological and other data on an annual basis and (b) the ad hoc plans to produce the necessary scientific advice (and the necessary scientific advice). However, long-term data series often do not provide a complete picture of the state of an ecosystem or fish stock, while not allowing scientists and administrators to assess the future impacts of any parameters on them. This proposal contributes to technological progress in terms of the quality and type of scientific information available for fisheries management, using innovative technological methods aimed at creating a platform for the holistic study of lakes and marine ecosystems, based on the Ecopath/Ecosim/Ecospace models describing the nutritional relationships between organisms, fishing activities and the structure and functioning of ecosystems. This platform aims to clearly capture the marine and lake ecosystem as it is today, taking into account not only biological data as before, but also a large volume of parameters such as climate, anthropogenic impacts on the ecosystem and the social and economic data of those involved in fisheries and fisheries management, as well as the relations between them. In addition to this platform’s operation, its important innovation is that it exists in software form and therefore has great capacity to transfer and apply to other systems, while allowing modifications of individual parameters or elements in order to study the future results of current hypothetical scenarios (what-if-style scenarios). An example of such scenarios is the future impact on commercial stocks of a particular increase or reduction in fishing effort or the impact on stocks and ecosystems of the temperature change. In order to establish the value of the Ecopath/Ecosim/Ecospace platform, this proposal provides for the application of these models in two lakes (Wolbe and Trichonis) and two marine areas (Saronic and Thracian/Strymonian) of particularly high importance in terms of fishing activity. In the same context, the results will be disseminated extensively for the maximum possible information and ultimately benefit to all stakeholders (fishing cooperatives, management bodies and other local and scientific bodies). The proper management of fisheries, which the proposal aims at, is aimed at restoring and sustainable exploitation of catches, together with the simultaneous conservation of ecosystems and biodiversity.