The considerable naturalistic features of Cinque Terre seabed, and in particular of places like Punta Mesco, has justified the establishment of a Marine Protected Area in December 1997, created to safeguard and manage the natural resources in a better way, without totally excluding human activities.
The submerged morphology of the marine protected area is as varied as the morphology characterizing the surfacing land. Sometimes the cliffs continue for dozens of meters of depth, as in Punta Mesco and, even if less evidently, in Capo Montenero. In other cases the rock ends at a few meters of depth, where sandy areas begin.
The most superficial part of the submerged cliffs is characterized by the photophile associations characterizing the west Mediterranean. When the walls reach a considerable depth, they are colonized by photophile and sciaphilous species until they reach the coralligenous area. Moreover, there are some small grasslands and scattered spots of Posidonia oceanica.
As far as richness in biological formations, the areas of greatest interest are in Punta Mesco and Capo Montenero, and they include Coralligenous formations, Semi-Dark Caves, and Coastal Debris. The facies consisting of Paramuricea clavata and Lophogorgia ceratophyta are well represented, as well as Parazoanthus axinellae and others. In front of the beach of Corniglia there are amphioxus sands. The first meters of the "infralittoral area" are colonized by photophile seaweed biocenosis, differentiating in various aspects according to depth and exposure, while at greater depths, in conditions of reduced light and hydrodynamism, the presence of sciaphilous seaweed becomes gradually more important, leading to the typical coralligenous population as you draw near to the circalittoral plane.
On the eastern side of the Promontory of Mesco, between the point and Monterosso, there is a grassland of Posidonia oceanica, which is not well preserved because of the consequences deriving from the human action along the coast.
Cinque Terre seabed is considered among the most varied and rich in marine fauna of Liguria. In a relatively limited seabed characterizing Cinque Terre, there are a number of different species, some of them not so frequent in the Mediterranean Sea, each of them represented by a great number of specimens.
The rocky coastal seabed, which characterizes almost the whole Protected Area except the beaches of Monterosso and Corniglia, favors the settlement of many seaweed species. At different levels of depth, you can notice a considerable presence of these organisms which, thanks to their ability to produce nourishment from the solar energy, create the first ring of the alimentary chain.