Endangered
Freshwater pearl mussel
Margaritifera margaritifera
Freshwater pearl mussel is a bivalve in the family Margaritiferidae (order Unionida) — Margaritifera margaritifera, recorded as Endangered.
Appearance
Like all bivalve molluscs, the freshwater pearl mussel has a shell consisting of two parts that are hinged together, that can be closed to protect the animal's soft body within. The shell is large, heavy and elongated, typically yellowish-brown in colour when young and becoming darker with age. Older parts of the shell often appear corroded, an identifying feature of this mussel species.
Range and habitat
The native distribution of this species is Holarctic. The freshwater pearl mussel can be found on both sides of the Atlantic, from the Arctic and temperate regions of western Russia, through Europe to northeastern North America. Clean, fast-flowing streams and rivers are required for the freshwater pearl mussel, where it lives buried or partly buried in fine gravel and coarse sand, generally in water at depths between 0.5 and 2 metres, but sometimes at greater depths.
The goal of the hatchery improvements is to breed more than 4,000 juveniles for release. Release 3,000 of the 4,000 as juveniles, and retain 1,000 for reintroduction to the SAC once they have grown to a larger size.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Breeding
Freshwater mussels bury in the bed and live for decades if the river still runs and the host fish still spawn.
In crisis
Zyuganov have been corroborated by multiple observations of 250 year old individuals in Finland. Once the most abundant bivalve mollusc in ancient rivers around the world, numbers of the freshwater pearl mussel are now declining in all countries and this species is nearly extinct in many areas. Introduced species are also directly affecting the freshwater pearl mussel. The invasion of the zebra mussel (Dreissena polymorpha), that has been spread to new locations by being transported on the bottom of boats or in ballast waters, has affected freshwater pearl mussel populations in all countries it has invaded.
Measures have included the transfer of adult mussels to areas where it had gone extinct, the culture of juvenile mussels, and the release of juvenile trout, that have been infected with glochidia, into small rivers, but mainly the freshwater pearl mussel has benefited from habitat restoration projects in some areas. Due to the essential role salmonid fish play in the life of the freshwater pearl mussel, the conservation of salmon and trout is also central in the survival of this endangered freshwater mussel.
Freshwater pearl mussel is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Freshwater pearl mussel, Wikidata item Q772012. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
