Common mussel

from Wikipedia, the free encyclopedia
Common mussel
Common blue mussel (Mytilus edulis)

Common blue mussel ( Mytilus edulis )

Systematics
Order : Mytilida
Superfamily : Mytiloidea
Family : Blue mussels (Mytilidae)
Subfamily : Mytilinae
Genre : Mytilus
Type : Common mussel
Scientific name
Mytilus edulis
Linnaeus , 1758
Mussel beds in Booby's Bay, Cornwall, UK

The common mussel or edible mussel ( Mytilus edulis ) (Latin edulis = edible) is a type of mussel from the family of mussels (Mytilidae). It is the type species of the genus Mytilus and one of the three very closely related species of the Mytilus edulis group, together with the Mediterranean blue mussel ( Mytilus galloprovincialis ) and the Pacific blue mussel ( Mytilus trossulus ). The three types can hardly be distinguished from the morphological point of view of the housing and can therefore only be reliably determined by allozyme electrophoresis studies or molecular biological methods.

features

The front, strongly bulbous, equally-folded housing is elongated-triangular, trapezoidal or wedge-shaped ("mytiliform") with a length of up to 15 centimeters. The length to thickness ratio of both flaps (L / D index) is around 2.6. It is significantly longer than it is high (L / H index = 2). The vertebra sits at the front end. The edge of the housing with the ligament ("dorsal edge") is long and straight to slightly curved. The rear edge is initially straight to slightly curved, the rear end is more narrowly curved. The ventral margin is straight, convex to slightly concave. The front end (= vertebra) is tightly curved; however, the housing does not form a "hook". The inner edge of the case is smooth. The ligament is external, but sunk, and extends over two thirds of the "dorsal margin". The lock is essentially smooth; only in the area of ​​the front end are a few notches and projections perpendicular to the outer line. Housing shape and size are very variable and also heavily dependent on ecological factors.

The ornamentation on the outside of the case consists of concentric growth strips and somewhat coarser lines that were formed during interruptions in growth. The skin is thin and brittle. The thicker outer layer of the mineral shell consists of prismatic calcite . The thinner inner layer is made up of aragonitic mother-of-pearl leaves .

The thin periostracum adheres firmly to the mineral skin and does not flake off. It is colored blue-black to dark brown. Juvenile specimens are often horn-colored with dark blue rays emanating from the vertebra.

The two sphincters are very unequal in size. The anterior sphincter sits immediately on the anterior margin below the anterior end. It is very small and the point of attachment can only be seen indistinctly. The posterior sphincter, on the other hand, is very large and, together with the byssus retractor muscle, forms a very large, uniform muscle impression directly within the surface line.

Similar species

The Pacific mussel ( Mytilus trossulus ) cannot be distinguished from the common mussel by its external shell characteristics. In the White Sea , where both species occur sympatric , about 80% of the specimens of the Pacific mussel have a distinct, uninterrupted dark prismatic stripe under the ligament, while 97% of the specimens of the common mussel do not show this feature. Otherwise they can only be reliably differentiated by allozyme electrophoresis and molecular biological investigations. Although it had been known since the 1980s that the morpho species Mytilus edulis concealed two different species ( crypto species ), no distinction was made between them, especially in ecological studies. Therefore, the range of the two species and that of the very similar Mediterranean mussel is still not known with certainty. The two species probably separated from each other as early as the Pliocene .

The Mediterranean mussel ( Mytilus galloprovincialis ) cannot be clearly distinguished from the common mussel and the Pacific mussel with its external shell features. On average, it differs in the slimmer habit of the case; it is significantly longer than it is high. The front end is tightly rounded; however, the casing does not form a "hook" as is the case with the Mediterranean mussel.

Geographical distribution and way of life

The common blue mussel was originally limited to the coastal waters of the eastern North Atlantic from about the Aquitaine to northern Norway, the White Sea and Svalbard. In the western North Atlantic it occurs from to about Maine. From Nova Scotia northwards, it is replaced by the Pacific mussel. In contrast, the common blue mussel has been found in southern Greenland and Iceland. Today it also occurs in the North Pacific through displacement and targeted settlement in aquacultures.

The common blue mussel prefers to live in tidal areas and in shallow water up to a depth of about 50 meters, where it is attached with its byssus threads. They occur from rocky coasts to near the estuaries. In mussel beds they can form very dense populations of up to 2,000 animals per square meter. The attachment is not permanent, the clam can loosen the attachment, move a little with the help of the foot and attach itself again in another place. It needs water temperatures of at least 4 ° C in summer.

development

The sexes of the common mussel are separate. The females can release 5 to 12 million eggs up to three times a year. The fertilization is external. The fertilized eggs measure an average of 67 µm. From them a planktotrophic Veliger larva develops over the trochophora with a clear apical flagellum , which drifts in the open water for up to four weeks before it changes to soil life and initiates a metamorphosis. The first housing of the Veliger larva is D-shaped with a straight lock line (Prodissoconch I). The length is about 95 µm, the height 70 µm, and the lock line is 70 µm long. While the length of the lock line remains almost constant, the housing grows in length and height. The umbo appears at a length of 140 to 150 µm. With a length of 210 to 230 µm, the umbo rises above the lock line or its shoulders. Eye spots mostly appeared at a length of 220 to 230 µm, rarely even at 205 µm. The foot develops when the larvae are about 195 to 210 µm long. Active movement begins in larvae that have reached around 215 to 240 µm. Only a little later the larva changes to soil life and metamorphosis. The service life is strongly dependent on the temperature. In cold conditions, the animals grow very slowly and can reach an age of over ten years. They are sexually mature after 1½ to 3 years.

Taxonomy

The taxon was introduced into scientific literature by Carl von Linné in the still used form Mytilus edulis in 1758 . It is the type species of the genus Mytilus Linné, 1758 by later definition.

Due to the great variability in the housing shape, there are numerous synonyms for this species: Mytilus abbreviatus Lamarck, 1819, Mytilus angulatus Williamson, 1834, Mytilus borealis Lamarck, 1819, Mytilus elegans Brown, 1827, Mytilus grunerianus Dunker, 1853, Mytilus minganensis Mighels, Mytilus notatus DeKay, 1843, Mytilus pellucidus Pennant, 1777, Mytilus petasunculinus Locard, 1886, Mytilus retusus Lamarck, 1819, Mytilus retusus var. acrocyrta Locard, 1889, Mytilus solitary Williamson, 1834, Mytilus spathulinus Locard, 1889, Mytilus subsaxatilis Williamson, 1834 , Mytilus trigonus Locard, 1889, Mytilus ungulatus Linnaeus, 1758, Mytilus variabilis Fischer von Waldheim, 1807, Mytilus vulgaris da Costa, 1778 and Perna ungulina Philipsson, 1788.

Śmietanka et al. refer to the three species in the text as subspecies, but continue to treat them formally as species.

Economical meaning

The common mussel is an important seafood: around 200,000 tons are currently harvested in aquaculture every year.

Anthropogenic pollution

Due to the contamination of the water with microplastic made of polyethylene (PE) , the common mussel forms fewer byssus threads and the bond strength is reduced by around 50 percent. With microplastics made of polyethylene and also made of polylactide (PLA) , a protein metabolism disorder occurs - a change in the hemolymph proteome . This shows that even biodegradable plastic can alter the health of the common mussel.

literature

Web links

Commons : Edible mussel ( Mytilus edulis )  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Fritz Gosselck, Alexander Darr, Jürgen HJ Jungbluth, Michael Zettler: Trivial names for mollusks of the sea and brackish water in Germany. Mollusca, 27 (1): 3-32, 2009 PDF
  2. ↑ Paul C. Dalbeck: Crystallography, stable isotope and trace element analysis of Mytilus edulis shells in the context of ontogeny. PhD thesis, University of Glasgow, 2008. Abstract
  3. ↑ a b Marina Katolikova, Vadim Khaitov, Risto Väinölä, Michael Gantsevich, Petr Strelkov (2016) Genetic, Ecological and Morphological Distinctness of the Blue Mussels Mytilus trossulus Gould and M. edulis L. in the White Sea. PLoS ONE 11 (4): e0152963. doi : 10.1371 / journal.pone.0152963
  4. ^ Sofie Smedegaard Mathiesen, Jakob Thyrring, Jakob Hemmer-Hansen, Jørgen Berge, Alexey Sukhotin: Genetic diversity and connectivity within Mytilus spp. in the subarctic and Arctic . In: Evolutionary Applications . tape 10 , no. 1 , January 1, 2017, ISSN  1752-4571 , p. 39-55 , doi : 10.1111 / eva.12415 , PMID 28035234 , PMC 5192891 (free full text) - ( wiley.com [accessed February 13, 2017]).
  5. ^ R. Wenne, L. Bach, M. Zbawicka, J. Strand, JH McDonald: A first report on coexistence and hybridization of Mytilus trossulus and M. edulis mussels in Greenland. Polar Biology 39: 343-355, 2016 doi : 10.1007 / s00300-015-1785-x
  6. ↑ Elizabeth H. de Schweinitz and Richard A. Lutz: Larval Development of the Northern Horse Mussel, Modiolus modiolus (L.), Including a Comparison with the Larvae of Mytilus edulis L. as an Aid in Planktonic Identification. Biological Bulletin, 150 (3): 348-360, Chicago 1976.
  7. ^ Carl von Linné: Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Pp. 1–824, Holmiae / Stockholm, Salvius, 1758. Online at Göttinger Digitization Center (p. 705).
  8. ↑ a b MolluscaBase: Mytilus edulis Linnaeus , 1758
  9. ↑ B. Śmietanka, A. Burzyński, H. Hummel, R. Wenne: Glacial history of the European marine mussels Mytilus, inferred from distribution of mitochondrial DNA lineages. Heredity, 113: 250-258, 2014 doi : 10.1038 / hdy.2014.23
  10. ↑ Cultured Aquatic Species Information Program Mytilus edulis (Linnaeus, 1758)
  11. ↑ Dannielle S. Green, Thomas J. Colgan, Richard C. Thompson, James C. Carolan: Exposure to microplastics reduces attachment strength and alters the haemolymph proteome of blue mussels (Mytilus edulis). In: Environmental Pollution. 246, 2019, p. 423, doi : 10.1016 / j.envpol.2018.12.017 .