Common name: green mussel
Identification: Young mussels are a brilliant green while the adults are darker green to brown. Peak spawning activities normally occur once a year. Eggs and sperm are released into the water. Fertilized eggs develop into free-swimming larvae within a day. They remain free-swimming for 2-3 weeks, after which they settle onto a hard substrate and attach to the surface using a cluster of thread-like structures called a byssus. At 2-3 months of age or approximately 20 mm in length, they are sexually mature. Life spans is about 3 years. Densities as high as 35,200/m2 have been reported near Hong Kong.
Size: 160 mm (6 inches)
Native Range: Tropical marine and estuarine waters of the Indo-Pacific region of Asia, from the Persian Gulf to the South China Sea. This sessile bivalve naturally inhabits estuarine waters where the salinity ranges from 27-33 PSU, lower limit is about 16 ppt. Optimal temperature range is 26-32oC but some can survive for short periods from 10-35oC. They feed on phytoplankton, zooplankton, and detritus filtered from the water.
Hydrologic Unit Codes (HUCs) Explained
Puerto Rico &
Interactive maps: Point Distribution Maps
This species has been intensively cultured as a protein source for human consumption and has been distributed to many islands outside its native range in the South Pacific over the past several decades. Green mussels were first found outside their native range in waters surrounding the Caribbean island of Trinidad in 1990 (Agard et al. 1992) and later along the nearby coast of Venezuela in 1993 (Rylander et al. 1996). The first known occurrence of the green mussel in the United States was in Tampa Bay, Florida, during the summer of 1999 where they were discovered clogging the inside of cooling water intake tunnels at several power plants. Their current known distribution is limited to Florida, including Tampa Bay (Hillsborough and Old Tampa bays) and from Clearwater south to Boca Grande in the Gulf of Mexico (Benson et al. 2001). Most likely, currents in the Gulf will continue to spread the green mussel along the coast, south of Tampa Bay towards the Florida Keys. Early in 2003, green mussels were collected on the Atlantic Coast for the first time at Crescent Beach and later in New Smyrna, St. Augustine, and Jacksonville, Florida. In October of 2003, single specimens were collected off both Brunswick and Savannah, Georgia. Green mussels have been found in Charleston Harbor, South Carolina in 2006 (S. Crickenberger, pers. comm.). Also in 2006, a single specimen was collected in Puget Sound, Edmonds, Washington (O. Caddy, pers. comm.). In December 2008, two small specimens were collected in the waters adjacent to Panama City, Florida, a first for the panhandle region (S. Geiger, pers. comm.).
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Perna viridis are found here.
Table last updated 6/13/2021
† Populations may not be currently present.
Means of Introduction: Possible ways of introduction include ballast water dumping from ocean-going vessels carrying planktonic larvae, ship hull fouling, and intentional release. There are no known commercial aquaculture operations in the United States.
Status: It is established on both the east and west coasts of Florida.
Impact of Introduction: Green mussels are biofoulers of power plants in India and have already impacted several power plants in Florida by fouling the surface of intake condenser tunnels. They are also notorious for fouling navigation buoys in China where biomass has reached up to 72 kg/m2. Potential negative impacts include competition with the oyster fishery, displacement of native mussels, and carriers of diseases and parasites harmful to native species.
References: (click for full references)
Agard, J., R. Kishore, and B. Bayne. 1992. Perna viridis
(Linneaus 1758): first record of the Indo-Pacific green mussel (Mollusca: Bivalvia) in the Caribbean. Caribbean Marine Studies 3:59-60.
Benson, A. J., D. C. Marelli, M. E. Frischer, J. M. Danforth, and J. D. Williams. 2001. Establishment of the green mussel, Perna viridis (Linneaus 1758) (Mollusca: Mytilidae) on the west coast of Florida. J. Shellfish Res. 20(1):21-29.
Rylander, K., J. Perez, and J. A. Gomez. 1996. Status of the green mussel, Perna viridis (Linneaus 1758) (Mollusca: Mytilidae), in north-eastern Venezuela. Caribbean Marine Studies 5:86-87.
Revision Date: 5/26/2020
Benson, A.J., 2021, Perna viridis Linneaus, 1758: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=110, Revision Date: 5/26/2020, Access Date: 6/18/2021
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.