Asian green mussel shell. The Asian green mussel (Perna viridis) is large saltwater mussel, a bivalve mollusc belonging to the family Mytilidae. Shells of bivalve molluscs such as mussels consist of two articulating parts, or valves. This species is found in the Asia-Pacific but has been introduced elsewhere. It is harvested for food, but it can be invasive, or toxic due to substances produced by the dinoflagellates that it feeds upon. It can be used as an indicator of pollution caused by heavy metals, organochlorides and petroleum products.