Culturing freshwater pearl mussel Margaritifera margaritifera: a breakthrough in the conservation of an endangered species

Abstract

ABSTRACT1. The freshwater pearl mussel Margaritifera margaritifera L. is globally endangered and is threatened by commercial exploitation, pollution and habitat loss throughout its range. Captive breeding would be a valuable tool in enhancing the status of M. margaritifera in the UK.2. We have developed a semi-natural system for successfully infecting juvenile brown trout with glochidial M. margaritifera, and culturing juvenile mussels in experimental tanks where glochidial M. margaritifera can excyst from fish gills and settle into sediment.3. Infected fish had less than 1% mortality. Levels of infection varied among fish. Two yearly cohorts of juvenile M. margaritifera were identified from samples of sediment taken from each experimental tank. Individuals range in size from 1.4 mm (2000 cohort) to >3 mm in length (1999 cohort).4. The number of juvenile M. margaritifera present in the two experimental tanks are estimated to be between 3600 (tank A) and 0 (tank B) for the putative 1999 cohort and between 6000 (tank A) and 13 000 (tank B) for the putative 2000 cohort.5. This pioneering method for large-scale cultivation of juvenile M. margaritifera is intermediate between the release of infected fish into rivers and the intensive cultivation systems developed in continental Europe and the USA for other species of unionid. This is the first time that large numbers of M. margaritifera have been cultured and represents a significant breakthrough in the conservation of this globally endangered Red Data List species. The method is straightforward and is most cost-effective when undertaken alongside established hatchery processes.

Valve gape and exhalant pumping in bivalves: optimization of measurement

“…Wilson et al 2005, Robson et al 2007. Given that the minimum appropriate sampling frequency has now been established for recording fine-scale Margaritifera margaritifera gape and, most probably, pumping behaviour, our ongoing research can test if the breakthrough in the ability to culture M. margaritifera (Preston et al 2007) can be further improved by conditioning broodstock and providing juveniles with additional food. Advances in the understanding of bivalve feeding and reproductive strategies may be gleaned by recording behaviour with high temporal and sensor resolution over a range of ecological circumstances (according to factors such as depth, light, temperature, particulate matter, food availability and predator interactions) and may aid long-term survival of endangered bivalves including freshwater pearl mussels.…”

Strategies for the conservation of endangered freshwater pearl mussels (Margaritifera margaritifera L.): a synthesis of Conservation Genetics and Ecology

“…In the case of pearl mussels, the availability of culturing techniques has been considered a breakthrough in their conservation (Preston et al, 2007). Preservation of genetic diversity requires robust genetic analyses of source populations.…”

Captive breeding of the endangered freshwater pearl mussel Margaritifera margaritifera

“…In flow-through systems, mussel broodstock can be maintained in salmonid hatchery troughs supplied with filtered river water (30 µm) to reduce sediment loads, and covered with sand and gravel (Hastie & Young 2003a, Preston et al 2007). Very little is known about the diet requirements of adult Margaritifera margaritifera, although information from other freshwater bivalves suggests that they probably feed on freshwater algae within the 15 to 40 µm range (Winkel & Davids 1982).…”

“…As an alternative to the cohabitation method, the outflow of tanks housing gravid mussels can be diverted into fish tanks housing hatchery-reared juvenile salmonids (Hastie & Young 2003a, Preston et al 2007). Hastie & Young (2001, 2003a showed that large numbers of Atlantic salmon and brown trout could be infected in this way, with glochidia loads ranging between 10 and 800 glochidia per fish.…”

“…The accelerated decline of many freshwater mussels has recently prompted a flurry of initiatives designed to propagate and restore the species in Europe (Buddensiek 1995, Beasley & Roberts 1999, Hastie & Young 2003a, Preston et al 2007) and elsewhere (Strayer et al 2004, Barnhart 2006. In the UK, unprecedented steps have recently been taken to safeguard entire Margaritifera margaritifera (L.) populations by collecting adults from the wild and bringing them into captivity in the hope of establishing living gene banks and aiding the recovery of self-sustaining populations (Taylor 2007).…”