The importance of population genetic information in formulatingex situconservation strategies for the freshwater pearl mussel (Margaritifera margaritiferaL.) inNorthernIreland

Abstract

Captive breeding is the last resort to protect a species that will become extinct because it is incapable of surviving in the wild without human intervention. The freshwater pearl mussel Margaritifera margaritifera is a prime candidate for such action: the species has experienced a recent range-wide decline, particularly in Europe. In Northern Ireland, M. margaritifera is now only found in six rivers and, because of a lack of natural recruitment in the wild, it has been predicted that these populations will become extinct within 80 years. Consequently, an ex situ breeding program was established with the aim of using a semi-natural method to propagate mussels for restocking. In the present study, we analysed the levels and patterns of genetic diversity in the captive-bred mussels, as well as their parent broodstock and remnant populations from their natal and other rivers in Northern Ireland where M. margaritifera is still found, to help develop best practice for the captive breeding program. Levels of genetic diversity were high, although there was a strong correlation between genetic diversity and census population sizes, as well as evidence of inbreeding in all populations. Small but significant levels of genetic differentiation were observed between both the captive-bred juveniles and their parent broodstock, and the samples from their source river, indicating a possible founder effect. In addition, three groups of genetically distinct clusters were observed among the remaining natural populations that could be used as the basis for defining conservation units. These findings allow us to make recommendations for efficient management of the captive breeding program, including rotation of the ex situ broodstock on a regular basis to avoid prolonged inbreeding, and the establishment of captive breeding of other populations to reflect genetic differences between putative conservation units in Northern Ireland and elsewhere. bs_bs_banner Animal Conservation. Print ISSN 1367-9430 Animal Conservation 15 (2012) 593-602

Comparison of population genetic patterns in two widespread freshwater mussels with contrasting life histories in western North America

“…We suggest that this pronounced population-level structuring is due to high levels of localized inbreeding, as evidenced by strongly positive inbreeding (F) coefficients, high rates of selfing (s) and a high incidence of identical genotypes despite a low overall probability of identity (Table 2). Both F and s varied dramatically among populations [a pattern also noted in European M. margaritifera (Bouza et al 2007;Geist 2010)], but were generally higher than values observed in European M. margaritifera by Geist & Kuehn (2005) and Wilson et al (2012). Inbreeding may be a function of small population sizes and/or hermaphroditism with self-fertilization.…”

“…; Geist )], but were generally higher than values observed in European M. margaritifera by Geist & Kuehn () and Wilson et al . (). Inbreeding may be a function of small population sizes and/or hermaphroditism with self‐fertilization.…”

Conservation status of the freshwater pearl mussel Margaritifera margaritifera in Portugal

“…Some successful captive breeding programs for M. margaritifera already exist in Europe, and so, these techniques are already available to be used in Portugal, taking in account the best practices that should include genetic information, careful determination of habitat requirements (from the macro to the microscale) and assessment of suitable food resources (e.g. Preston et al, 2007;Bolland et al, 2010;Gum et al, 2011;Wilson et al, 2012;Eybe et al, 2013;Scheder et al, 2014).…”

Genetic structure of Irish freshwater pearl mussels (Margaritifera margaritifera and Margaritifera durrovensis): Validity of subspecies, roles of host fish, and conservation implications

“…In contrast, the highest genetic diversity was found in eastern and northern parts of Europe (Geist et al, ; Geist & Kuehn, , ), as well as in North America (Zanatta et al, ). To date, the genetic constitution of freshwater pearl mussels in the north‐western European distribution range, particularly in Ireland, remains unknown, except for studies by Wilson et al () and Kyle, Beatty, Roberts, and Provan (), exclusively within Northern Ireland. Knowledge of the genetic structure of pearl mussel populations throughout the island of Ireland is important for several reasons.…”