Genetic and environmental implications of reintroducing laboratory-raised unionid mussels to the wild

Abstract

The reintroduction of endangered species is a potentially useful conservation strategy, which in the case of freshwater unionid mussels, must be preceded by the successful laboratory rearing of juvenile mussels on their host fishes. However, an understanding of the genetic and environmental implications of reintroductions of artificially propagated mussels is required. Unfortunately, there is a dearth of information on these issues with respect to freshwater mussels. In general, regarding the genetic effects of reintroductions, small founder populations may lead to low heterozygosity (reduced genetic variability) in the reintroduced populations, which can make them more susceptible to extinction. Captive breeding programs may also alter the genetic composition of species through artificial selection, whether intentional or unintentional. Captive breeding may also affect an individual’s interactions with conspecifics or predators by altering behaviour. Genetic problems in reintroduced populations also have the potential to affect wild populations, particularly by reducing variability among populations of the same species and eliminating local adaptation. There is also the possibility that diseases, parasites, or exotic species may be spread when populations are relocated or augmented. Recommendations related to the minimization of these impacts are presented for freshwater mussels, with the recognition that many of the issues will require additional study.

Captive breeding of the endangered freshwater pearl mussel Margaritifera margaritifera

“…The success of the programme will therefore ultimately depend on the ability of captive-bred individuals to survive and reproduce in the natural environment, not on the success of the rearing programme itself. However, it is unknown whether captive populations will adapt to the natural environment, and how juvenile mussels will fare compared to wild populations; this is an area where research is urgently needed (Hoftyzer et al 2008). …”

Essay: Making the most of recent advances in freshwater mussel propagation and restoration

“…Previous publications have addressed aspects of these issues (e.g., Haag, 2012;Hoftyzer, Ackerman, Morris, & Mackie, 2008;Jones, Hallerman, & Neves, 2006;McMurray & Roe, 2017;Patterson, Mair, et al, 2018), but have focused mostly on technical biological issues (e.g., production methods, genetic concerns). Previous publications have addressed aspects of these issues (e.g., Haag, 2012;Hoftyzer, Ackerman, Morris, & Mackie, 2008;Jones, Hallerman, & Neves, 2006;McMurray & Roe, 2017;Patterson, Mair, et al, 2018), but have focused mostly on technical biological issues (e.g., production methods, genetic concerns).…”

A multi‐basin approach determines variability in host fish suitability for unionids in tributaries of the Laurentian Great Lakes

“…One objective of host fish testing involves considering of the geographical source of fish and mussels. The majority of host fish suitability tests use allopatric fish and freshwater mussel populations with the objective of avoiding using fish that have developed immunity to glochidia or are currently infested with glochidia (Zale & Neves, ; Haag & Warren, ; Jones et al ., , ; Dodd et al ., ; Hoftyzer et al ., ; Taeubert et al ., ,b). In addition to allopatric host fish studies, there has been some research on the compatibility of sympatric fish and mussel populations.…”