In the face of the acceleration of ecological imbalances in the Mediterranean, the Greece mission of the Monaco Explorations combined scientific observation, field experimentation, and citizen involvement. Seaweed forests, plankton, invasive species, and maritime uses were studied through reproducible protocols. The challenge is clear: to produce useful data, strengthen monitoring tools, and transform knowledge into levers for action for marine protection policies.
During the holiday season, 22-med cross-references and contextualizes solutions that have been the subject of articles in the French media Marcelle with articles on the same theme published in 22-med.
Summary of articles by journalist Olivier Martocq published in 22-med on November 6 and 13, 2025
Launched in the fall, between Volos, Alonissos, and Syros, the Greece mission returns fifteen years after an initial scientific campaign at these same sites, which aimed to measure the rapid changes in Mediterranean ecosystems and test tools capable of transforming observation into action. Seaweed forests, plankton, invasive species, and citizen participation formed the foundation of this scientific and political approach.
The Mediterranean remains one of the richest reservoirs of biodiversity in the world. It concentrates a significant portion of global marine fauna over a small area. However, this richness is subjected to multiple pressures related to accelerated warming, overfishing, tourist saturation of coastlines, and chronic pollution. The Greece mission is part of this reality, with the ambition to produce useful data for public decisions and managers of Marine Protected Areas.
A simple and mobile scientific platform
The mission relied on a next-generation catamaran designed to limit its environmental impact. Equipped with inflatable wings, photovoltaic panels, hydrogen generators, and electric motors, the vessel served as an agile scientific platform. Quiet and economical, it allowed work close to the coasts and within Marine Protected Areas without disturbing the observed environments.
Onboard, scientists deployed lightweight and reproducible methods. Visual counts while diving, sediment sampling, plankton nets, and measurements of temperature, salinity, pH, and oxygen were carried out throughout the journey. Near-daily imaging of plankton complemented these devices, providing a detailed understanding of the health of the waters traversed. The vessel thus became both a research tool and a means of mediation, demonstrating that cleaner navigation is compatible with scientific demands.
Seaweed forests and ecological imbalances
The MAR4PAST project allowed for a comparison of the current state of seaweed forests with that observed fifteen years earlier. The findings are clear at several sites: these ecosystems have regressed. The disappearance or scarcity of large predators has favored the proliferation of herbivores that graze unchecked, permanently weakening algal habitats.
However, one exception stands out within the Marine Protected Area of Alonissos, at the Piperi site. There, the seaweed forests are maintained thanks to a still functional trophic balance. Groupers and monk seals play their role as predators, limiting herbivores and allowing for the regeneration of algae. This contrast concretely illustrates the effectiveness of protection measures when they are strict and monitored over time.
Invasive species and pragmatic responses
The spread of exotic species is one of the most concerning signals observed during the mission. The participatory science program EXOFISHMED mobilized volunteer divers trained in standardized protocols. The results show a clear increase in the number of exotic species moving southward in the Greek Mediterranean.
Among them, the rabbitfish and lionfish pose major problems. The former destroys seaweed forests, while the latter, a voracious carnivore, decimates small fish without any identified natural predator. Their expansion is favored by the warming of the sea and the opening of the Suez Canal. In response to this situation, scientists advocate for pragmatic responses. Targeted fishing of lionfish, which can be valued in cooking, appears to be one of the most immediately actionable solutions, provided that a supply chain is structured and the public is informed.
Plankton as a central indicator
With the PlanctoMed program, the mission highlighted the central role of plankton, the true pulse of the Mediterranean. Daily samples revealed a great diversity of plankton, sometimes unexpected, in certain well-preserved areas. Conversely, near ports and heavily anthropized zones, the impoverishment is immediate and visible.
Monitoring plankton is part of a long-term strategy led by the Plankton Planet consortium. It aims to structure a sustainable observation network, involving scientists and citizens. This approach allows for a direct link between the state of plankton and the pressures exerted on the environment, anticipating the vulnerabilities of the entire food chain. In parallel, sediment sampling has allowed for the assessment of microplastics, highlighting the persistence of diffuse pollution even in the seabed.
Participatory science and political direction
Beyond ecological findings, the Greece mission tested tools aimed at directly involving field actors. The SailingBox, an onboard laboratory continuously measuring essential water parameters, paves the way for massive data collection by recreational boaters, fishermen, or commercial vessels. Each trip can thus become a line of useful information for monitoring marine climate change.
Participatory bathymetry addresses another major issue: the lack of knowledge about Mediterranean seabeds. By sharing depth data from echo sounders, navigators contribute to filling a mapping deficit that still affects the majority of the seabeds. This knowledge is essential for understanding water circulation, nutrient upwelling zones, and ecological corridors.
The mission also placed a central emphasis on mediation with the general public, especially children. Workshops, traveling exhibitions, plankton observations, and immersive devices have made often abstract phenomena visible. For the project leaders, this dimension is inseparable from scientific action. Without social engagement, tools and data remain ineffective.
All of this work is part of a clear political objective supported by Monaco and its partners: to increase Marine Protected Areas in the Mediterranean by thirty percent by 2030, with effective monitoring plans and operational tools. The Greece mission is not limited to diagnosing the situation. It outlines a method to move from observation to decision and transform ecological vulnerabilities into levers for collective action.
Cover photo: Prince Sovereign Albert II of Monaco aboard MODX ©Maeva Bardy