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[4] (video).[5]
Decline
The thick shelled river mussel declined during the 20th century everywhere in Europe due to deteriorating water quality,[6]habitat fragmentation and host fish limitation.[7]
Denmark – believed to have been extirpated until rediscovered in Odense River in 2003. The Odense River population is estimated to number c. 3000 individuals and subsequently it has been rediscovered from Suså River where the population size is unknown (might also survive in a couple of other rivers, but this remains unconfirmed).[21][22]
^Douda, Karel (2010). "Effects of nitrate nitrogen pollution on Central European unionid bivalves revealed by distributional data and acute toxicity testing". Aquatic Conservation: Marine and Freshwater Ecosystems. 20 (2): 189–197. Bibcode:2010ACMFE..20..189D. doi:10.1002/aqc.1076.
^Douda, Karel; Horký, P.; Bílý, M.; Gompper, Matthew; Johnson, Jerald (2012). "Host limitation of the thick-shelled river mussel: identifying the threats to declining affiliate species". Animal Conservation. 15 (5): 536–544. Bibcode:2012AnCon..15..536D. doi:10.1111/j.1469-1795.2012.00546.x.
^"Unio crassus Philipson, 1788". Fauna Europaea. Fauna Europaea Secretariat, Museum für Naturkunde, Berlin. Retrieved 13 July 2017.
^(in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. (2010). "Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]". Malacologica Bohemoslovaca, Suppl. 1: 1-37. PDF.
^Juřičková L., Horsák M. & Beran L., 2001: Check-list of the molluscs (Mollusca) of the Czech Republic. Acta Soc. Zool. Bohem., 65: 25-40.
^Dušek J., Hošek M. & Kolářová J. (2007) Hodnotící zpráva o stavu z hlediska ochrany evropsky významných druhů a typů přírodních stanovišť v České republice za rok 2004-2006. - Ochrana přírody, 62(5): appendix 5:I-IV. (in Czech)
^Glöer P. & Meier-Brook C. (2003) Süsswassermollusken. DJN, pp. 134, strana 109, ISBN3-923376-02-2
^"Bataafse stroommossel (Unio crassus)". Beschermde natuur in Nederland: soorten en gebieden in wetgeving en beleid (in Dutch). Ministerie van Landbouw, Natuur en Voedselkwaliteit (Dutch Ministry of Agriculture, Nature and Food Quality). Retrieved 6 June 2024.