Paramuricea Clavata is a marine species with a branching structure and it is found in the Mediterranean Sea. Populations of Paramuricea Clavata create real submarine forests, which – like the terrestrial ones – give protection to a rich variety of species, by helping to strengthen the local biodiversity.

Paramuricea Clavata forests can be found in most of Mediterranean Marine Protected Areas. They are sessile organisms, growing with their bases buried in the substrate, unable to move. The only possibility of movement is through reproduction, when larvae disperse into the water column. Some of the larvae are drifted by the current and they keep a connection with the distant colonies, some others stay in the genia madre to contribute to the original colony.

As part of the IMPACT project, LECOB – Laboratoire d’Ecogequimie des Environnements Benthiques researchers measure the retention rate of Paramuricea Clavata larvae.

The results make it possible to estimate the indicator of local persistence of population, which means the capacity for renewal, thanks to new individuals.

In May 2019, two researchers and two LECOB divers accomplished a mission of sampling in Port-Cros National Park, near the port of Toulon.

The purpose of the mission was to describe the density and the structure of size of the Paramuricea Clavata population; they also took samples for a genetic study aimed at understanding the degree of connectivity between the studied populations.

For 15 days, the researchers dived twice a day between 30 and 50 metres deep. During the diving, demographic parameters of the Paramuricea Clavata – size and density – were measured and samples were taken for genetic analysis.

The sampling was made by cutting small pieces from the apex of the Paramuricea Clavata – less than 3 cm – and by placing them in alcohol.

Density measurements were made by square-shaped frames, with 1 meter long side.

Size measurements were made by using a “gorgoniometro”, a tool with a graduated bar, invented by LECOB researchers to measure the size of Paramuricea Clavata.