The blue mussel (''Mytilus edulis''), also known as the common mussel, is a medium-sized edible
marine bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biv ...
mollusc in 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 ge ...
, the mussels. Blue mussels are subject to commercial use and intensive
aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lotus ...
. A species with a large range, empty shells are commonly found on beaches around the world.
Systematics and distribution
The ''Mytilus edulis'' complex
Systematically blue mussel consists of a group of (at least) three closely related taxa of mussels, known as the ''Mytilus edulis'' complex. Collectively they occupy both coasts of the North Atlantic (including the
Mediterranean
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on th ...
) and of the North
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
in temperate to polar waters, as well as coasts of similar nature in the
Southern Hemisphere. The distribution of the component taxa has been recently modified as a result of human activity. The taxa can hybridise with each other, if present at the same locality.
*''Mytilus edulis''
sensu stricto
''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular c ...
: Native to the North Atlantic.
*''
Mytilus galloprovincialis'', the Mediterranean mussel: Native in the Mediterranean, the Black Sea and Western Europe. Introduced in the temperate North Pacific,
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring count ...
and elsewhere in the Southern Hemisphere.
*''Mytilus planulatus'', the New Zealand blue mussel, a distinct lineage native to the Southern Hemisphere along the southern coast of Australia, Tasmania and New Zealand
*''
'' (junior synonym ''M. chilensis''), the Chilean mussel: Temperate and sub-Antarctic waters of South America and the
Kerguelen Islands
The Kerguelen Islands ( or ; in French commonly ' but officially ', ), also known as the Desolation Islands (' in French), are a group of islands in the sub-Antarctic constituting one of the two exposed parts of the Kerguelen Plateau, a l ...
.
*''
Mytilus trossulus'': North Pacific, northern parts of the
North Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Africa, Europe and ...
,
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain.
The sea stretches from 53°N to 66°N latitude and fr ...
.
''Mytilus edulis'', strict sense
The Atlantic blue mussel is native on the North American Atlantic coast, but is found intermixed with ''M. trossulus'' north of
Maine
Maine () is a U.S. state, state in the New England and Northeastern United States, Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Provinces and territories of Canad ...
. In Atlantic Canada, ''M. trossulus'' was found to have smaller shell growth values than ''M. edulis'' and contain less meat than ''M. edulis.''
Keeping this in mind, ''M. edulis,'' under raft culture conditions, is estimated to have an economic value of 1.7 times ''M. trossulus.''
In Europe it is found from French Atlantic coast northwards to
Novaya Zemlya
Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island ...
and
Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...
, but not in the
Baltic Sea
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain.
The sea stretches from 53°N to 66°N latitude and fr ...
. In France and in the
British Isles
The British Isles are a group of islands in the North Atlantic Ocean off the north-western coast of continental Europe, consisting of the islands of Great Britain, Ireland, the Isle of Man, the Inner and Outer Hebrides, the Northern Isles (O ...
, it makes
hybrid zone
A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. Hybrid zones can form ''in situ'' due to the evolution of a new lineage but generally they result from secondary cont ...
s with ''M. galloprovincialis'', and also is sometimes intermixed with ''M. trossulus''.
The genetically distinct lineage of ''M. edulis'' present in the Southern Hemisphere has been attributed to subspecies ''
Mytilus edulis platensis'' (now ''
'').
[
]
Habitat
Blue mussels are boreo-temperate invertebrates that live in intertidal
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...
areas attached to rocks and other hard substrates by strong (and somewhat elastic) thread-like structures called byssal threads, secreted by byssal glands located in the foot of the mussel.
Description
The shape of the shell is triangular and elongated with rounded edges. The shell is smooth with a sculpturing of fine concentric growth lines but no radiating ribs. The shells of this species are purple, blue or sometimes brown in color, occasionally with radial stripes. The outer surface of the shell is covered by the 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 a ...
which as eroded, exposes the colored prismatic calcitic layer. Blue Mussels are semi-sessile, having the ability to detach and reattach to a surface allowing the mollusk to reposition itself relative to the water position.
Right and left valve of the same specimen:
File:Mytilus edulis 001.jpg, Right valve
File:Mytilus edulis 002.jpg, Left valve
var. ''flavida''
File:Mytilus edulis var. flavida 01.jpg, Right valve
File:Mytilus edulis var. flavida 02.jpg, Left valve
Reproduction
Mussels have separate sexes. Once the sperm and eggs are fully developed they are released into the water column for fertilization. Although there are about 10,000 sperm per egg, large proportions of eggs deposited by blue mussels are never fertilized. As few as 1% of larvae that do mature ever reach adulthood. The majority are eaten by predators before completing metamorphosis.
The reproductive strategy seen in blue mussels is characteristic of planktotrophs. By minimizing nutrients in egg production to the bare minimum they are able to maximize the number of gametes produced. If the adult mussels are stressed during the beginning of gametogenesis, the process is terminated. When stressed while fresh gametes are present, adult mussels reabsorb gametes. Larvae viability is also affected by the condition of parents: high water temperatures, pollutants and scarcity of food, during gamete production. The reduction in viability is probably due to the lack of lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids incl ...
reserves distributed to the eggs.
Larval development
Larval development can last from 15 to 35 days depending environmental conditions including salinity and temperature, as well as location. Larvae originating from Connecticut
Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its cap ...
mature normally at , though at normal development occurs at salinities between 15 and 35 ppt and at 35 ppt at .
The first stage of development is the ciliated embryo, which in 24-hours for fertilization form the trochophore. At this point although mobile, it is still reliant on the yolk for nutrients. Characterized by a functional mouth and alimentary canal the veliger stage also has cilia which are used for filtering food as well as propulsion. A thin translucent shell is secreted by the shell gland forming the notable straight hinge of the prodissoconch I shell. The veliger continues to mature forming the prodissoconch II shell. In the end stage of veliger development photosensitive eye spots and elongated foot with a byssal gland are formed.
Once the pediveliger is fully developed, its foot extends and makes contact with substrate. The initial contact with the substrate is loose. If the substrate is suitable, the larva will metamorphoses into the juvenile form, plantigrade, and attach byssus threads. The mussel will remain in that state until reaching 1-1.5mm in length. This attachment is the prerequisite for the foundation for the blue mussel population. In sheltered environments large masses sometimes form beds which offer shelter and food for other invertebrates. Byssal thread are secreted by byssal glands located in the foot of the mussel, and are made up of polyphenolic proteins which serve as a bioadhesive.
Aggregation and mussel bed formation
Blue mussels often form aggregations, where they attach to each other using byssus threads. These are collagenous protein strands used for attachment. The type of aggregation depends on population densities. When densities are low, for example in mussel fields – short-lived mussel populations – clumped distribution patterns are seen. The rate of aggregation is aided by the presence of predator cues.
Several explanations for aggregate formation have been offered, such as increase of reproductive success in low density populations, resisting of wave action
In fluid dynamics, a wind wave, water wave, or wind-generated water wave, is a surface wave that occurs on the free surface of bodies of water as a result from the wind blowing over the water surface. The contact distance in the direction ...
, and defence against predators. It is, however, still unclear what the main purpose is and aggregation might have different purposes under different circumstances.
Mussel beds are persistent, dense mussel populations. Beds generally form from fields that persist long enough to establish a dense population. In high density aggregations, growth of blue mussels at the centre of the aggregation is reduced, likely due to a reduction in food availability. When possible, mussels will thus migrate to lower densities on larger scales (>7.5 cm), but aggregate on small scales (<2.0 cm). In areas where blue mussels are threatened, such as the Wadden Sea
The Wadden Sea ( nl, Waddenzee ; german: Wattenmeer; nds, Wattensee or ; da, Vadehavet; fy, Waadsee, longname=yes; frr, di Heef) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern cont ...
, it is of great importance to enhance the survival of mussel fields, of which mussel aggregates are the primary component.
Predators
Predation of blue mussels is greatest during the three weeks it spends as a planktonic larva. During this stage it is susceptible to jellyfish
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...
and fish larva
Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the ...
e through adults. Once it metamorphoses the mussel is still restricted by predation, with smaller mussels with thinner, weaker shells most affected. Once the shells becomes stronger, blue mussels are preyed upon by sea stars
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish a ...
such as '' Asterias vulgaris'' as well as by several species of sea gulls
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...
. The capability of shell thickening by mussels has become a very effective defense mechanism. In the presence of predators a mussel is able to increase shell thickness 5 to 10 percent, which in turn makes opening the shell take 50 percent more time. Small mussels are also eaten by the dog whelk, '' Nucella lapillus''. The blue mussel is host to a wide range of parasites, but these parasites usually do not cause much damage.
Blue Mussels are able to fight off one species of predator at a time such as sea star(''Asterias Rubens (=Asterias Vulgaris'')) or green crabs (''Carcinus maenas''). They use their inducible defenses to strengthen their adductor muscle or grow thicker shells. When faced with two species at a time, they are no longer able to use their defenses and can be killed more easily.
Uses and ecosystem services
Blue mussels are filter feeders and play a vital role in estuaries by removing bacteria and toxins.
''Mytilus edulis'' is commonly harvested for food throughout the world, from both wild and farmed sources. Mussels are a staple of many seafood dishes in various cuisines including Spanish
Spanish might refer to:
* Items from or related to Spain:
** Spaniards are a nation and ethnic group indigenous to Spain
**Spanish language, spoken in Spain and many Latin American countries
**Spanish cuisine
Other places
* Spanish, Ontario, Ca ...
(especially Galician), Portuguese, French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
, Dutch, Belgian, Italian and Turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
as midye dolma. They are also commonly used as lab animals. Blue mussels were also harvested by the indigenous peoples of North America.
Blue mussels are starting to decline in areas such as the Gulf of Maine. Historical references have shown a decrease of about 40 percent in the last fifty years. This can cause a future problem because mussels are foundation species providing homes and protecting other small animals in the intertidal zone like small fish as well as filtering the water. Mussels filter out bacteria, metals, and toxins, that would increase significantly without mussels around. Ocean acidification
Ocean acidification is the reduction in the pH value of the Earth’s ocean. Between 1751 and 2021, the average pH value of the ocean surface has decreased from approximately 8.25 to 8.14. The root cause of ocean acidification is carbon dioxi ...
due to increasing atmospheric carbon dioxide is projected to reduce the growth and survival of blue mussels; in turn, this could drastically reduce their positive impact on coastal water quality.
Gallery
File:Blue mussel Mytilus edulis.jpg, Live blue mussels on a rocky substrate
File:Mussels-on-beach-20030601.jpg, Numerous empty blue mussel shells on a beach in Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its ...
File:Mytilus edulis (live).jpg, Live blue mussels
File:Gegratineerde mosselen.jpg, Mussels and cheese gratin
File:Mussel_Sculpture_Conwy_North_Wales_by_Graeme_Mitcheson_photo_6_by_Darren_W_Rees.jpg, Blue mussel sculpture at Conwy
Conwy (, ), previously known in English as Conway, is a walled market town, community and the administrative centre of Conwy County Borough in North Wales. The walled town and castle stand on the west bank of the River Conwy, facing Deganwy o ...
, North Wales near Conwy Castle
Conwy Castle ( cy, Castell Conwy; ) is a fortification in Conwy, located in North Wales. It was built by Edward I, during his conquest of Wales, between 1283 and 1287. Constructed as part of a wider project to create the walled town of Conw ...
References
External links
The blue mussel in Maine
Maine Department of Marine Resources
*Newell, R.I.E. (1989)
Species profiles: life histories and environmental requirements of coastal fishes and invertebrates (North and Mid-Atlantic) - blue mussel.
U.S. Fish. Wildl. Serv. Biol. Rep. 82(11. 102 ). U.S. Army Corps of Engineers, TR El-82-4. 25 pp.
The common mussel ''Mytilus edulis''
MarLIN - The Marine Life Information Network The Marine Life Information Network (MarLIN) is an information system for marine biodiversity for Great Britain and Ireland.
MarLIN was established in 1998 by the Marine Biological Association together with the environmental protection agencie ...
*Robert Nordsieck
The Blue or Common Mussel (''Mytilus edulis'')
The Living World of Molluscs www.molluscs.at
*
{{Authority control
Mytilus (bivalve)
Commercial molluscs
Bivalves described in 1758
Taxa named by Carl Linnaeus
Molluscs of the Atlantic Ocean
Fauna of the North Sea
Seafood in Native American cuisine
Marine molluscs of Europe
Bivalves of Europe
Bivalves of North America