Unio crassus
Unio crassus, the thick shelled river mussel, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.Ecology
As part of newly discovered reproductive behaviour, this mollusc crawls up to the edge of the water, exposing its excurrent aperture, and then lets loose a stream of water. The fountain of water often contains glochidia, and it is suggested that this spurting behavior may facilitate dispersal of mussel larvae.Decline
The thick shelled river mussel declined during the 20th century everywhere in Europe due to deteriorating water quality, habitat fragmentation and host fish limitation.Distribution
Its native distribution is Europe and Western Asia.
