Mya truncata (Linnaeus, 1758), Blunt Soft-shell clam, Blunt gaper (Molluscs)

Compiled by: Fritz Gosselck, Germany

1. Description / Ecological demands / Autecology

M. truncata needs a salinity above 20 psu. This marine species is rare in the Belt Sea with maximum densities of 1-10 ind./m². Reproduction takes place from October to January; pelagic larvae. Tolerates temporary oxygen deficiency.

2. Distribution

Blunt gaper is retricted to muddy and sandy mud substrata in deep (10-30 m) and cold basins in the Kattegat and the Belt Sea (Kiel Bay and Mecklenburg Bay).

3. Importance

M. truncata is an example of a migrated marine species to the Baltic Sea, living in the bottom water layer with high salinity and cold temperature. It is a characteristic species for the basins of the Belt Sea.

4. Status of threat

M. truncata is red-listed in the Mecklenburg Bay as “endangered”.

5. Threat factors

Reasons for threat are oxygen deficiency often caused by eutrophication in combination with poor water exchange.