Description and characteristics
The painter's mussel (Unio pictorum) is a bivalve mollusc with an elongated, oval shell of brown-green or yellowish colour. The two valves are joined by a hinge, and the interior has a nacreous sheen.
Habitat and distribution
It lives on sandy or muddy bottoms of fresh, flowing and standing waters — the Danube, branches and lakes of the Danube Delta. It is a semi-buried species in the bottom.
Diet and behaviour
It feeds by filtering water, capturing plankton and organic particles. It is a sedentary species that filters large volumes of water, helping to purify it.
Reproduction
Reproduction occurs via larvae (glochidia) that attach to the gills of fish, where they parasitise temporarily, then fall to the bottom and become adults.
Economic and ecological importance
It has an important ecological role as a natural filter-feeder, contributing to water quality. It can form pearls, and its shells were historically used.
Threats and conservation
It is sensitive to pollution and habitat loss. Protection of water quality is essential for its survival.
Fishing and legal minimum size
It is collected from the bottom. In the table of minimum legal sizes, the painter's mussel (Unio pictorum) has a minimum size of 8 cm.
Conclusion
The painter's mussel is a valuable natural filter-feeder, important for the quality of the fresh waters of the Danube Delta.