''Perna viridis'', known as the Asian green mussel, is an economically important

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which ...

, a

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of marine and freshwater Mollusca, molluscs that have laterally compressed bodies enclosed by a shell consisting of two hing ...

belonging to the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Mytilidae Mytilidae are a family of small to large marine and brackish-water bivalve molluscs in the order Mytilida. One of the genera, '' Limnoperna'', even inhabits freshwater environments. The order has only this one family which contains some 52 gener ...

. It is harvested for food but is also known to harbor toxins and cause damage to submerged structures such as drainage pipes. It is native in the

Asia-Pacific Asia-Pacific (APAC) is the part of the world near the western Pacific Ocean. The Asia-Pacific region varies in area depending on context, but it generally includes East Asia, Russian Far East, South Asia, Southeast Asia, Australia and Paci ...

region but has been introduced in the

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean ...

, and in the waters around

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...

, and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

Description

''Perna viridis'' ranges from in length and may occasionally reach . Its shell ends in a downward-pointing beak. The smooth

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods ...

is dark green, becoming increasingly brownish towards its point of attachment ( umbo), where it is lighter. Younger mussels are bright green and that becomes darker as it ages. The shell's interior has a pale-blue sheen. The mussel has a large mobile foot which it uses to climb vertically should it be covered by sediments. It also produces

byssus A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells ( Pinnidae), true mussels (Mytili ...

to help it attach to its substrate. ''

Perna canaliculus ''Perna canaliculus'', the New Zealand green-lipped mussel, also known as the New Zealand mussel, the greenshell mussel, ''kuku'', and ''kutai'', is a bivalve mollusc in the family Mytilidae (the true mussels). ''P. canaliculus'' has economic im ...

'' and ''

Perna perna ''Perna perna'', the brown mussel, is an economically important mussel, a bivalve mollusc belonging to the family Mytilidae. It is harvested as a food source but is also known to harbor toxins and cause damage to marine structures. It is nativ ...

'' are two similar species, native to the waters of

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island coun ...

and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

respectively. File:Perna viridis 01.jpg, Left valve File:Perna viridis 02.jpg, Right valve

Habitat and distribution

The Asian green mussel is found in the coastal waters of the Indo-Pacific region. However the mussels are introduced to other areas as an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

via boat hulls and water ballasts. The mussel inhabits

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

habitats and is found in densities as high as 35,000 individuals per square meter on any submerged marine object. Although vivid green in appearance, the mussels are shrouded with overgrowth and are often hard to find. The mussels live in waters that are with a wide-ranging

salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...

of about 18-33 ppt. ''P. viridis'' grows fastest at below the surface, in high salinity and a high concentration of

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. ...

, although it can tolerate a range of salinity and turbid water.

Ecology and life history

The Asian green mussel has separate sexes and fertilizes externally. There are a very few functional

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have ...

s (<0.1%). The mussel's sexual development was shown to be affected by temperature. Spawning ordinarily occurs twice a year between early spring and late autumn; however, the mussels found in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

and

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...

are known to spawn all year round. The zygote transforms to a larva 7–8 hours after fertilization. The larvae stay in the water column for 10–12 days before undergoing

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...

into a juvenile and settling onto a surface. The juveniles become sexually mature when they are in length, a size reached within 2–3 months. Growth is influenced by the availability of food, temperature, water movement, the mussel's age, and caging. Cage culturing can prevent entry of predators and barnacles increases marketability but slows down the mussel's growth rate. The adult can live to up 2–3 years. Due to its fast growth, it can outcompete other fouling organisms and cause changes in marine ecological relationships. This mussel is a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

that feeds on phytoplankton,

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and suspended organic materials. They are eaten by fishes,

crustaceans Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean g ...

, seastars, octopuses and humans.

Importance to humans

''P. viridis'' is harvested in the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region as a food source due to its fast growth. However, it can harbor deadly

Saxitoxin Saxitoxin (STX) is a potent neurotoxin and the best-known paralytic shellfish toxin (PST). Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralyti ...

produced by the

dinoflagellate The dinoflagellates ( Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s that it feeds upon. It can also be used as a

biomonitor A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sma ...

to indicate pollution caused by heavy metals, organochlorides and petroleum products. Mussels that are in contaminated areas have labile lysosomal membranes due to metal-induced stress. This mussel is also notorious for clogging water pipes used by industrial complexes and fouling marine equipment. It has fouled the intake condenser tunnels of power plants in India and

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and ...

and navigational buoys in China where their biomass has grown to up to . Chlorination of pipes and using high velocity water was shown to decrease or remove ''P. viridis'' population. However, the mussel excretes ammonia which reacts with the chlorine to form

monochloramine Monochloramine, often called chloramine, is the chemical compound with the formula NH2Cl. Together with dichloramine (NHCl2) and nitrogen trichloride (NCl3), it is one of the three chloramines of ammonia. It is a colorless liquid at its melting p ...

, a weaker disinfectant than chlorine. Ammonia can also accelerate the corrosion of copper-based alloys found in the water pipes. Heat treatment is also being considered as an alternative to chlorination due to the safety and environmental concerns raised by the latter method. As an

, the mollusk is viewed as threat to oyster fisheries in several nations where it has been introduced. It might also displace native mussels by introducing harmful parasites and diseases. The green mussel is edible and used widely in several Asian cuisines.

References

{{Taxonbar, from=Q3271979 Commercial molluscs Mytilidae Bivalves of Asia Molluscs described in 1758 Taxa named by Carl Linnaeus