| Reference no. | Winkler, H.M., K. Skora, R. Repecka, M. Ploks, A. Neelov, L. Urho, A. Gushin and H. Jespersen, 2000 |
| Ecosystem | Baltic Sea |
| Status | native |
| Abundance | common (usually seen) |
| Lifestage | adults |
| Regional database | |
| Remarks | Threatened due to target fisheries, eutrophication/pollution, construction/weirs in rivers, and habitat loss (Ref. 83294). Also Ref. 6114. HELCOM: critically endangered; considered a high priority species (Ref. 83294). |