A cautionary tale about translocating mussels and implications for conservation: A case study from two river basins in central Texas

Abstract

Translocation is used to conserve mussels, yet there remains a debate about its merit owing to poor understating of its effects on transported mussels. This study evaluated survivorship, body condition, and total glycogen and lipids for one common and widely distributed species (Cyclonaias pustulosa), two rare species (Cyclonaias petrina; Lampsilis bracteata), and one species complex (Fusconaia sp. – Fusconaia chunii and Fusconaia flava) from the East Fork of the Trinity River and the Llano River of Texas. Survivorship estimates for C. pustulosa and Fusconaia sp. using the Kaplan–Meier estimator were high in the East Fork. Body condition, glycogen, and total lipids varied for C. pustulosa and Fusconaia sp., which may have indicated a short‐term impact. For the Llano, survivorship of C. petrina and L. bracteata was high for the resident treatments but significantly reduced for the translocation treatments. The decline in survivorship for C. petrina was mirrored by decreases in the body condition, which may indicate inability to acclimate to novel environments. For L. bracteata, declines in survivorship were due to predation by Procyon lotor, racoon. A large flood of 3,766 m3 s−1 at the end of the study eliminated both study sites. The findings of this study show that translocating mussels can be successful; however, sublethal effects and mortality may still occur. These effects are rooted in species‐specific differences, which is not unexpected because mussel species vary in how they cope with environmental change based on their life‐history traits. However, these traits are rarely considered when translocating mussels. To complicate matters, most mussel species have yet to be evaluated on how they respond to translocation, and for species where such information is available, adults are the primary focus. Addressing these knowledge gaps is critical for determining the appropriateness of translocation and improving its efficacy.

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

“…However, where local population declines have the potential to put in danger the persistence of the species, as is the case in P. auricularius in the CIA, translocation should be planned and performed (Fig. 4; Hart et al, 2021).…”

“…When selecting localities for translocation, it is important to take into account the effects of large flood events (Fischer & Lindenmayer, 2000;Jourdan et al, 2019;Hart et al, 2021). The extraordinary flood that occurred in the Ebro River in spring (April 2018, Fig.…”

“…Stodola et al (2017) reported variable survival depending on species and site. In other cases, high mortalities have been related to predation by raccoons or to specimens being washed away by large floods (Sousa et al, 2012;Stodola et al, 2017;Zając et al, 2019;Hart et al, 2021). Besides survival, sub-lethal effects have also been reported, including losing body condition, which may indicate poor adaptation to the new habitat (Hart et al, 2021).…”

A systematic review of the global freshwater mussel restoration toolbox

“…Forming partnerships between restoration practitioners and research scientists is an essential next step in developing effective restoration measures (Table 5). Not only will partnerships aid in publishing restoration outcomes, but they appear to be the best approach to guide research on appropriate scales for implementation, to consider suitable combinations of restoration measures and to understand any effects of environmental or species context (Jarvis et al, 2020; Hart, Fisher & Randklev, 2021). In turn, understanding the reasons for restoration success or failure may help to address stressors, characterize suitable habitat and achieve sustainable populations (Freshwater Mollusk Conservation Society, 2016).…”

Inventory and Assemblage Classification of the Freshwater Mussels (Mollusca: Unionidae) of the Strawberry River, Arkansas, USA, with Implications for Conservation Planning

“…Where possible, using source populations from the same AES (e.g., Strawberry River upstream or downstream) as proposed conservation efforts could enhance the success of future augmentation, restoration, relocation and/or translocation activities [26,27]. Using source populations from the same assemblage should help minimize negative effects to species unable to acclimate to novel environments [28,29].…”