In 1976, Monaco became home to the world's first urban marine protected area in the Larvotto district.

Half a century later, this initiative has expanded to other regions along the principality's coastline.

Marine protected areas (MPAs) are now critical for researchers striving to understand marine biodiversity and the ecological dynamics of Monaco's waters.

Monaco, with a daily influx of over 60,000 workers and a bustling economic landscape characterized by construction and maritime activities, conceals an intricate underwater ecosystem.

At a depth of 25 meters, hundreds of fish navigate around a 300-ton artificial reef, made of natural boulders, deployed in 1977 as the first artificial reef in the principality's waters.

Since then, the MPA network has evolved significantly, with new artificial reefs installed approximately every decade since 1977.

The latest artificial reefs were introduced in 2017, featuring six 2.5-ton structures designed through 3D printing techniques.

These modern reefs are noted for their complexity, which provides enhanced habitats for marine species.

Jacqueline Gautier-Debernardi, the director of the Association Monégasque pour la Protection de la Nature (AMPN), asserts that the intricate design facilitates the establishment of various marine species, which have shown a preference for more complex structures.

Since their deployment, 36 different fish species have been observed inhabiting these new reefs, indicating an encouraging trend in marine biodiversity.

Another focal point of the AMPN’s efforts is the conservation of the Posidonia oceanica seagrass beds, which play a crucial ecological role in carbon storage, organic matter production, coastal erosion reduction, and as a food source for numerous marine organisms.

Recognized as a vital component of the Mediterranean ecosystem, these seagrass beds have been scientifically monitored since their protection by the French government in 1988. The AMPN has initiated an experimental propagation program since 2021, resulting in a reported 20% increase in Posidonia coverage within the Larvotto MPA over the past four years.

The impact of climate change poses significant challenges for the preservation of these marine areas.

Issues such as increased sedimentation from coastal development and rising sea temperatures are of particular concern.

The Mareterra project, a recent large-scale construction effort near the Larvotto MPA, raised alarms about the dredging process and its effects on marine life.

The director of AMPN noted short-term disruptions in marine ecosystems during this period; however, she emphasized that marine life often recovers over time.

Eugenio Di Franco, a project lead at AMPN, highlighted alarming observations regarding rising temperatures in Monaco's waters, reaching 30 degrees Celsius at depths of 30 meters.

Such temperatures are atypical and lead to the mortality of species that are unable to adapt quickly.

Additionally, the warming waters have facilitated the northward migration of species from southern Mediterranean regions, threatening local species that may not survive the encroaching competitors.

Researchers caution that if current trends continue, significant species loss could occur in the following decades, altering the ecological landscape of Monaco’s marine environment.