- It feeds on small organic particles.
- It requires stable cobble and gravel substrates with little fine material.
- Growth rings can be seen on the shells.
- Maturity is reached after 10-15 years.
- After maturity, it can have a reproductive life span of about 75 years.
- It has two sexes. Females can become self-fertile hermaphrodites.
- It is a Holarctic species, found in North America and Europe.
- The hosts of its parasitic larvae are salmonids. In Europe, these are the brown trout and Atlantic salmon.
- Population declined over 90 % in Europe in the last 90 years.
- The loss of habitats and host fish contributed to its population decline.
- It is assessed as Endangered globally and Critically Endangered in Europe on the IUCN Red List.
It can reach about 16 cm in length, but is usually smaller. It can live for up to 280 years, but its life span is often shorter. It can produce 200 million larvae, called glochidia, during its reproductive life span. It can filter up to 50 litres of water per day.
It feeds on small organic particles. Growth rings can be seen on the shells. Population declined over 90 % in Europe in the last 90 years. It has two sexes. Females can become self-fertile hermaphrodites.
