Don't move a mussel? Parasite and disease risk in conservation action

Abstract

Freshwater mussels are one of the most endangered animal groups globally, making them a high conservation priority. Conservationists increasingly employ translocation or captive breeding procedures to support ailing populations, and the ecosystem engineering capabilities of mussels are being increasingly harnessed in bioremediation projects. However, there is little consideration of the risk of pathogen transmission when moving mussels from hatcheries or wild donor populations into new habitats. This is of significant concern as recent developments suggest parasites and diseases are highly prevalent and have contributed to several mass population-level die-offs. Here, we explicitly highlight the risks of pathogen spread in mussel translocations, explore how these risks are mediated, and provide recommendations for both research and action to avoid the inadvertent spread of virulent pathogens when conserving vulnerable mussel populations. While targeted at freshwater conservationists, this perspective has relevance for considering translocation-mediated disease and parasite spread in any study system.

Predicting climatic threats to an endangered freshwater mussel in Europe: The need to account for fish hosts

“…In this particular situation, possible multi‐species translocations (FPMs plus the suitable fish hosts) should be considered. Still, in the case of considering the translocation of individuals to more suitable northern latitudes, precautionary measures should be implemented to avoid the possible spread of parasites and diseases (see Brian et al, 2021). Increasing the number of individuals in suitable areas could also include propagation and artificial rearing and culturing of juveniles from local populations.…”

Evidence for multiple refugia and hotspots of genetic diversity for Westralunio carteri, a threatened freshwater mussel in south‐western Australia

“…Although some authors contend that the risk of outbreeding depression resulting from the mixing of ESUs has been overstated (Frankham et al, 2011) and that it is better to use source individuals from genetically diverse populations to augment genetic diversity in small, fragmented populations (Weeks et al, 2011), the mixing of distinct, putative species (MOTUs) through translocation programmes would be less desirable and potentially harmful owing to increased risk of outbreeding depression (Frankham et al, 2011). There is also concern over the increasing trend for unionid translocations because of the risk of transmitting parasites and diseases when introducing mussels from hatcheries or donor populations (Brian, Ollard & Aldridge, 2021).…”

Translocation as an ultimate conservation measure for the long-term survival of a critically endangered freshwater mussel

“…For example, there is a risk of co-dispersal of bacteria, viruses, fungi, or other pathogens with the translocated specimens. Brian et al (2021) mention that parasites and diseases in freshwater mussels are highly prevalent and may contribute to some of the massive mortalities that have been reported in recent years. Since 2013, when the high mortality of P. auricularius was detected in the CIA, the Aragón Government began to investigate the possible causes.…”

“…As a concept, translocation seems a relatively straightforward task to carry out but, in fact, it needs a rigorous planning of all the steps involved in the process, including appropriate collection, handling and transport methods, assessment of habitat stability and suitable environmental and biological conditions in the recipient site, among others (Cope et al, 2003;Dunn et al, 2000;Luzier & Miller 2009;Moorkens 2017;Pires et al, 2020). In addition, any translocation plan should include a careful evaluation of the tradeoffs between conservation benefits and the costs and risks for the target species, so as for other species present in the recipient community (Cope & Waller, 1995;IUCN/SSC, 2013;Tsakiris et al, 2017;Brian et al, 2021). Finally, it is also essential to establish a longterm monitoring plan to assess the success or failure of the action (Luzier & Miller, 2009;Germano et al, 2015;Jourdan et al, 2019).…”