''Mytilus trossulus'', the Pacific blue mussel, bay mussel or foolish mussel, is a medium-sized edible marine

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 ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in 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 ...

. ''Mytilus trossulus'' is one of the three principal, closely related taxa in the ''

Mytilus edulis The blue mussel (''Mytilus edulis''), also known as the common mussel, is a medium-sized edible marine (ocean), marine bivalve mollusc in the family (biology), family Mytilidae, the only extant family in the order (biology), order Mytilida, known ...

'' complex of blue mussels, which collectively are widely distributed on the temperate to

subarctic The subarctic zone is a region in the Northern Hemisphere immediately south of the true Arctic, north of hemiboreal regions and covering much of Alaska, Canada, Iceland, the north of Fennoscandia, Northwestern Russia, Siberia, and the Cair ...

coasts the Northern Hemisphere, and often are dominant inhabitants on hard substrates of the intertidal and nearshore habitats.

Distribution

''Mytilus trossulus'' is the main native intertidal mussel in the Northern

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 the definition, to Antarctica in the south, and is bounded by the cont ...

. In North America it is found from

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

, and in Asia from

Hokkaido is the list of islands of Japan by area, second-largest island of Japan and comprises the largest and northernmost prefectures of Japan, prefecture, making up its own list of regions of Japan, region. The Tsugaru Strait separates Hokkaidō fr ...

northwards. At its southern limits, it hybridizes with '' Mytilus galloprovincialis'' (the Mediterranean mussel), which has been introduced to the Pacific by human activity. In the

North Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for ...

, ''M. trossulus'' is found on the U.S. coast of

Maine Maine ( ) is a U.S. state, state in the New England region of the United States, and the northeasternmost state in the Contiguous United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Provinces and ...

and northwards to Canada, as well as in scattered localities on North European coasts. In these regions it often coexists and hybridizes with ''Mytilus edulis''. The entire

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

is inhabited by a peculiar population of ''Mytilus trossulus'', which shows some genetic

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introg ...

from ''M. edulis'' and whose

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

has been replaced by ''M. edulis'' mtDNA. In the Arctic, ''Mytilus trossulus'' is found in northwest Greenland where they are found scattered in the intertidal zone from 71°N to 77°N

References

trossulus Molluscs of the Atlantic Ocean Molluscs of the Pacific Ocean Marine molluscs of Asia Marine molluscs of North America Molluscs of Japan Molluscs of the United States Western North American coastal fauna Fauna of California Fauna of the Baltic Sea Bivalves of Asia Fauna of the Northwestern United States Bivalves described in 1850 Taxa named by Augustus Addison Gould {{Mytilidae-stub