Captive breeding of European freshwater mussels as a conservation tool: A review

• Published in: Aquatic conservation Vol. 33; no. 11; pp. 1321 - 1359
• Main Authors: Geist, Juergen, Thielen, Frankie, Lavictoire, Louise, Hoess, Rebecca, Altmueller, Reinhard, Baudrimont, Magalie, Blaize, Christine, Campos, Miquel, Carroll, Paul, Daill, Daniel, Degelmann, Wolfgang, Dettmer, Rainer, Denic, Marco, Dury, Pierrick, de Eyto, Elvira, Grunicke, Felix, Gumpinger, Clemens, Jakobsen, Per J., Kaldma, Katrin, Klaas, Kunnar, Legeay, Alexia, Mageroy, Jon Hamner, Moorkens, Evelyn A., Motte, Grégory, Nakamura, Keiko, Ondina, Paz, Österling, Martin, Pichler‐Scheder, Christian, Spisar, Ondřej, Reis, Joaquim, Schneider, Lea D., Schwarzer, Arno, Selheim, Heidi, Soler, Joaquín, Taskinen, Jouni, Taylor, John, Strachan, Ben, Wengström, Niklas, Zając, Tadeusz
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01-11-2023
• Subjects: aquaculture; Biologi; Biology; Breeding; Cages; Captive breeding; Conservation; conservation translocation; Ecological function; Environmental restoration; Freshwater; Freshwater molluscs; freshwater mussel culturing; Individual rearing; Inland water environment; Margaritifera margaritifera; Mollusks; Mussels; Natural populations; propagation; reintroduction; Streams; Survival; Unio crassus; Water quality
• DOI: 10.1002/aqc.4018
• EISSN: 1099-0755
• ISSN: 1052-7613; 1099-0755

Abstract
Freshwater mussels are declining throughout their range. Their important ecological functions along with insufficient levels of natural recruitment have prompted captive breeding for population augmentation and questions about the usefulness and applicability of such measures.
This article reviews the current state of captive breeding and rearing programmes for freshwater mussels in Europe. It considers the various species, strategies, and techniques of propagation, as well as the different levels of effort required according to rearing method, highlighting the key factors of success.
Within the last 30 years, 46 breeding activities in 16 European countries have been reported, mainly of
Margaritifera margaritifera
and
Unio crassus
. Some facilities propagate species that are in a very critical situation, such as
Pseudunio auricularius
,
Unio mancus
, and
Unio ravoisieri
, or multiple species concurrently. In some streams, the number of released captive‐bred mussels already exceeds the size of the remaining natural population.
Rearing efforts range from highly intensive laboratory incubation to lower intensity methods using in‐river mussel cages or silos. Most breeding efforts are funded by national and EU LIFE(+) grants, are well documented, and consider the genetic integrity of the propagated mussels. Limited long‐term funding perspectives, the availability of experienced staff, water quality, and feeding/survival during early life stages are seen as the most important challenges.
Successful captive breeding programmes need to be combined with restoration of the habitats into which the mussels are released. This work will benefit from an evidence‐based approach, knowledge exchange among facilities, and an overall breeding strategy comprising multiple countries and conservation units.