Animal Diversity Web

Ge­o­graphic Range

Mytilus edulis is found in coastal areas of the north­ern At­lantic Ocean, in­clud­ing North Amer­ica, Eu­rope, and the north­ern Palearc­tic. They are found from the White Sea in Rus­sia to south­ern France, through­out the British Isles, with large com­mer­cial beds in the Wash, More­cambe Bay, Con­way Bay and south­west Eng­land, north Wales, and west Scot­land. In the west At­lantic, M. edulis oc­cu­pies the south­ern Cana­dian Mar­itime provinces to North Car­olina. ("Fish­eries Global In­for­ma­tion Sys­tem (FIGIS)", 2006; "Fish­eries Global In­for­ma­tion Sys­tem (FIGIS)", 2006)

• Biogeographic Regions
• nearctic
  • native
• atlantic ocean
  • native
• pacific ocean
  • introduced

Habi­tat

Mytilus edulis is eu­ry­ther­mal and are able to with­stand freez­ing con­di­tions for sev­eral months. Blue mus­sels are well ac­cli­mated to a 5 to 20 °C tem­per­a­ture range, with an upper sus­tained ther­mal tol­er­ance limit of about 29 °C for adults. Blue mus­sels do not thrive in salin­i­ties of less than 15%, but can with­stand wide en­vi­ron­men­tal fluc­tu­a­tions. Their depth ranges from 5 to 10 me­ters. Usu­ally, M. edulis is found in sub­ti­dal and in­ter­tidal beds on rocky shores, and re­main per­ma­nently at­tached there. The range of Mytilus edulis is lim­ited by the move­ment of drift­ing lar­val and ju­ve­nile stages. ("Fish­eries Global In­for­ma­tion Sys­tem (FIGIS)", 2006; Tyler-Wal­ters and Seed, 2006)

• Habitat Regions
• temperate
• polar
• saltwater or marine

• Aquatic Biomes
• coastal
• brackish water

• Other Habitat Features
• estuarine
• intertidal or littoral

• Range depth

  1 to 10 m

  3.28 to 32.81 ft

Phys­i­cal De­scrip­tion

Mytilus edulis is char­ac­ter­ized by a smooth in­equi­lat­eral shell, usu­ally pur­ple, blue, or dark brown, which fea­tures con­cen­tric growth lines em­a­nat­ing from the hinge. The in­te­rior of the shell is pearl-white. In­ter­nally the man­tle has a whitish/yel­low color, with a pos­te­rior ad­duc­tor scar sig­nif­i­cantly larger than its an­te­rior ad­duc­tor scar. Ex­tend­ing from the closed shell are fi­brous brown byssal threads for at­tach­ment to a sur­face. (Tyler-Wal­ters and Seed, 2006)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

• Range mass

  1.4 to 6.5 g

  0.05 to 0.23 oz

• Range length

  2 to 20 cm

  0.79 to 7.87 in

• Average length

  5-10 cm

  in

De­vel­op­ment

After the egg is fer­til­ized it turns into a cil­i­ated tro­cophore larva. The tro­chophore larva then be­comes a veliger, which per­sists 1 to 1.5 months. In this phase, the larva bears cil­i­ated fan-like pro­tru­sions and fil­ter feeds be­fore be­com­ing a ju­ve­nile and find­ing a pri­mary set­tle­ment lo­ca­tion. The pri­mary set­tle­ment lo­ca­tion is often lo­cated in open­ings in the sub­strata, or amongst bry­ozoans or other fil­a­men­tous struc­tures and often sit­u­ated away from ma­ture mus­sels, pre­sum­ably to de­crease com­pe­ti­tion. After weeks there, the ju­ve­nile has dou­bled in size and de­taches to drift again and find a per­ma­nent sub­strate to which to at­tach. The young adult will at­tach to the sea floor with a byssus thread or, if such open sub­strate is not sta­ble, may at­tach to an­other mus­sel, cre­at­ing a mus­sel bed. (Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Development - Life Cycle
• metamorphosis
• colonial growth
• indeterminate growth

Re­pro­duc­tion

Mytilus edulis sexes are sep­a­rate and ga­metes are shed into the water where fer­til­iza­tion oc­curs. (Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Mating System
• polygynandrous (promiscuous)

Mytilus edulis spawns from April to Sep­tem­ber, de­pend­ing on water tem­per­a­ture, cur­rents, and other en­vi­ron­men­tal fac­tors. In most pop­u­la­tions, rest­ing go­nads begin to de­velop from Oc­to­ber to No­vem­ber, with ga­me­to­ge­n­e­sis oc­cur­ring through­out win­ter so that go­nads are ma­ture in early spring. A par­tial spawn­ing in spring is fol­lowed by rapid ga­me­to­ge­n­e­sis, with go­nads ma­tur­ing by early sum­mer, re­sult­ing in a less in­ten­sive sec­ondary spawn­ing in late Au­gust or Sep­tem­ber. Lar­vae spawned in spring can take ad­van­tage of phy­to­plank­ton blooms. Oc­cur­rence of the sec­ondary spawn­ing is op­por­tunis­tic, de­pend­ing on fa­vor­able en­vi­ron­men­tal con­di­tions and food avail­abil­ity. Ga­me­to­ge­n­e­sis, spawn­ing, and re­pro­duc­tive strate­gies vary with ge­o­graphic lo­ca­tion. An in­di­vid­ual fe­male can pro­duce 5 to 8 mil­lion eggs, larger in­di­vid­u­als may pro­duce as many as 40 mil­lion eggs. In op­ti­mal con­di­tions, lar­val de­vel­op­ment may be com­plete in less than 20 days but lar­val growth and meta­mor­pho­sis be­tween spring and early sum­mer, at 10 °C, usu­ally takes 1 month. Pe­di­veligers can delay meta­mor­pho­sis for up to 40 days at 10 °C or for up to 6 months in some cases. (Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• fertilization
  • external
• broadcast (group) spawning

• Breeding interval

  Reproductive output is influenced by temperature, food availability, and tidal exposure and can therefore vary from year to year and from place to place.

• Breeding season

  Blue mussels generally breed during the spring to late summer.

• Range number of offspring

  5000000 to 40000000

• Average number of offspring

  7000000

• Range age at sexual or reproductive maturity (female)

  1 to 2 years

• Range age at sexual or reproductive maturity (male)

  1 to 2 years

There is no parental care after fer­til­iza­tion.

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female

Lifes­pan/Longevity

The lifes­pan of Mytilus edulis may vary con­sid­er­ably de­pend­ing on at­tach­ment lo­ca­tion. Set­tline in more ex­posed coastal areas make in­di­vid­u­als sig­nif­i­cantly more vul­ner­a­ble to pre­da­tion, in large part avian. Qual­ity and sta­bil­ity of the sub­strate also plays a role in the lifes­pan. Mus­sels that set­tle in ex­posed lo­ca­tions can ex­pe­ri­ence mor­tal­ity up to 98% per year. Drift­ing lar­val and ju­ve­nile stages suf­fer the high­est mor­tal­ity rates. (Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Range lifespan
  Status: wild

  18 to 24 years

Be­hav­ior

Mytilus edulis is a ses­sile species, per­ma­nently set­tling on sub­strates as adults. In loose sub­strates blue mus­sels set­tle to­gether in beds, with younger in­di­vid­u­als smoth­er­ing the older in­di­vid­u­als on which they set­tle. (Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Key Behaviors
• sessile
• sedentary
• colonial

Com­mu­ni­ca­tion and Per­cep­tion

Blue mus­sels have sta­to­cysts to aid in geo-po­si­tion­ing and ori­en­ta­tion. Blue mus­sels have chemore­cep­tors ca­pa­ble of de­tect­ing the re­lease of ga­metes. These chemore­cep­tors also help ju­ve­nile blue mus­sels avoid set­tling tem­porar­ily on sub­strata near ma­ture blue mus­sle, pre­sum­ably to de­crease com­pe­ti­tion for food. (Con­ser­va­tion Man­age­ment In­sti­tute, 2001; Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Communication Channels
• chemical

• Perception Channels
• tactile
• chemical

Food Habits

The diet of Mytilus edulis con­sists of phy­to­plank­ton, di­nofla­gel­lates, small di­atoms, zoospores, fla­gel­lates, other pro­to­zoans, var­i­ous uni­cel­lu­lar algae, and de­tri­tus fil­tered from the sur­round­ing water. Blue mus­sels are sus­pen­sion fil­ter feed­ers and are con­sid­ered scav­engers, col­lect­ing any­thing in the water col­umn that is small enough to in­gest. (Con­ser­va­tion Man­age­ment In­sti­tute, 2001; Tyler-Wal­ters and Seed, 2006)

• Primary Diet
• planktivore
• detritivore

• Animal Foods
• eggs
• zooplankton

• Plant Foods
• algae
• phytoplankton

• Other Foods
• detritus
• microbes

• Foraging Behavior
• filter-feeding

Pre­da­tion

Blue mus­sels are most often found in large mus­sel beds, where they are some­what pro­tected from pre­da­tion by virtue of their num­bers. The shell of Mytilus edulis acts as a pro­tec­tive layer, though some preda­tor species are able to crush the shell. (Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

Some preda­tors of M. edulis wait until the mus­sel is forced to open its valves to breathe. The preda­tor then pushes the mus­sel's siphon into the gap, wedg­ing the mus­sel open so it can be eaten. (Nord­sieck, 2006)

• Known Predators

  • flounders (Pleuronectiformes)
  • sandpipers (Scolopacidae)
  • gulls (Larus)
  • crows (Corvus)
  • dogwhelks (Nucella lapillus)
  • common starfish (Asterias rubens)
  • Strongylocentrotus droebachiensis

Ecosys­tem Roles

Mytilus edulis has a high tol­er­ance for in­creased sed­i­ment lev­els and help to re­move sed­i­ments from the water col­umn. Large blue mus­sel beds pro­vide habi­tat and prey for other an­i­mals and act as a sub­strate for algal at­tach­ment, in­creas­ing local di­ver­sity. Blue mus­sel lar­vae are an im­por­tant food source for plan­tiv­o­rous an­i­mals as well. ("Fish­eries Global In­for­ma­tion Sys­tem (FIGIS)", 2006; Tyler-Wal­ters and Seed, 2006)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Peo­ple har­vest blue mus­sels as food and they are used in com­mer­cial aqua­cul­ture. Blue mus­sels are con­sid­ered an im­por­tant food source in some coastal areas and the shells are used in jew­elry man­u­fac­tur­ing. Blue mus­sels also help limit algae growth, which has be­come prob­lem­atic in the Mediter­ranean Sea and else­where. (Con­ser­va­tion Man­age­ment In­sti­tute, 2001; Nord­sieck, 2006; Tyler-Wal­ters and Seed, 2006)

• Positive Impacts
• food
• research and education

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Mytilus edulis on hu­mans.

Con­ser­va­tion Sta­tus

Mytilus edulis is fairly com­mon and is abun­dant in many coastal areas and has there­fore not been placed on any con­ser­va­tion list or given any spe­cial sta­tus.

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

Craig Za­gata (au­thor), Rut­gers Uni­ver­sity, Christy Young (au­thor), Rut­gers Uni­ver­sity, Joanne Soun­tis (au­thor), Rut­gers Uni­ver­sity, Melanie Kuehl (au­thor), Rut­gers Uni­ver­sity, David Howe (ed­i­tor, in­struc­tor), Rut­gers Uni­ver­sity .

Ref­er­ences

FAO In­land Water Re­sources and Aqua­cul­ture Ser­vice (FIRI). 2006. "Fish­eries Global In­for­ma­tion Sys­tem (FIGIS)" (On-line). Cul­tured Aquatic Species In­for­ma­tion Pro­gramme - Mytilus edulis. Ac­cessed De­cem­ber 12, 2006 at http://​www.​fao.​org/​figis/​servlet/​static?​dom=culturespecies&​xml=Mytilus_​edulis.​xml.

Con­ser­va­tion Man­age­ment In­sti­tute, 2001. "Fish and Wildlife In­for­ma­tion Ex­change (FWIE)" (On-line). Ma­rine and Coastal Species In­for­ma­tion Sys­tem. Ac­cessed De­cem­ber 12, 2006 at http://​fwie.​fw.​vt.​edu/​WWW/​macsis/​lists/​M060008.​htm.

Nord­sieck, R. 2006. "The Liv­ing World of Mol­luscs" (On-line). The Com­mon Mus­sel (Mytilus edulis). Ac­cessed De­cem­ber 12, 2006 at http://​www.​weichtiere.​at/​Mollusks/​Muscheln/​miesmuschel.​html.

Tyler-Wal­ters, H., R. Seed. 2006. "The Ma­rine Life In­for­ma­tion Net­work" (On-line). Ac­cessed De­cem­ber 01, 2006 at http://​www.​marlin.​ac.​uk/​species/​Mytilusedulis.​htm.