The Mediterranean mussel (Mytilus galloprovincialis) is a species of bivalve, a marine mollusc in the family Mytilidae. It is an invasive species in many parts of the world, and also an object of aquaculture. Mytilus galloprovincialis is one of the three principal, closely related species in the Mytilus edulis complex.

Neopycnodonte cochlear is a species of marine bivalve molluscs belonging to the family Gryphaeidae.This species can be found in the North Atlantic Ocean (Azores) and in the Mediterranean Sea. The peculiarity we want to point out is that it is a small oyster that plays the same role as corals. That is, it forms aggregations as they grow and multiply, create agglomerations of more or less large dimensions comparable to corals.