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

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

, a

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Mytilidae The Mytilidae are a family (biology), family of small to large Marine life, marine and Brackish water, brackish-water bivalve molluscs in the order (biology), order Mytilida. One of the genera, ''Limnoperna fortunei, Limnoperna'', even inhabits f ...

, or the "true mussels". 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 region but has been introduced in the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

, and in the waters around Japan, North America, and South America.

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 an ...

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'' are two similar species, native to the waters of New Zealand and Africa 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 is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...

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 environm ...

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 Aquatic ecosystem, ecosystems. The name comes from the Greek language, Greek words (), meaning 'plant', and (), mea ...

, 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 A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

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, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

and

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

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 transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...

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 aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a s ...

that feeds on phytoplankton,

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

and suspended organic materials. They are eaten by fishes,

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

, 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. Ingestion of saxitoxin by humans, usually by consumption of shellfish contaminated by toxic algal blooms, is responsible for the illness known as paralytic she ...

produced by the

dinoflagellate The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also commo ...

s that it feeds upon. It can also be used as a biomonitor to indicate pollution caused by heavy metals,

organochloride Organochlorine chemistry is concerned with the properties of organochlorine compounds, or organochlorides, organic compounds that contain one or more carbon–chlorine bonds. The chloroalkane class (alkanes with one or more hydrogens substituted ...

s and petroleum products. Mussels that are in contaminated areas have

labile Lability refers to the degree that something is likely to undergo change. It is the opposite ( antonym) of stability. Biochemistry In reference to biochemistry, this is an important concept as far as kinetics is concerned in metalloprotein ...

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 U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

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, 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. In

Thai cuisine Thai cuisine (, , ) is the national cuisine of Thailand. Thai cooking places emphasis on lightly prepared dishes with aromatics and spicy heat. The Australian chef David Thompson (chef), David Thompson, an expert on Thai food, observes that ...

, it is popularly baked in a pot with basil and kaffir lime leaves with lemongrass stems, eaten with a spicy and sour dipping sauce, just like other

seafood Seafood is any form of Marine life, sea life regarded as food by humans, prominently including Fish as food, fish and shellfish. Shellfish include various species of Mollusca, molluscs (e.g., bivalve molluscs such as clams, oysters, and mussel ...

dishes.

References

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