Survival and growth assessment after reintroduction of the pocketbook mussel, Lampsilis cardium Rafinesque, 1820 among three streams in Nebraska (USA)

Abstract

1. Freshwater mussels are a globally diverse and fundamental group in aquatic ecosystems. However, 65% of freshwater mussel species have become endangered over the past century and 10% of them are already extinct. Natural population preservation and restoration efforts have been expedited, but the complicated life history of this taxon presents many challenges since speciesspecific ecology involved in restoration projects is often poorly understood.2. Lampsilis cardium is an imperilled freshwater mussel in Nebraska, USA. A reintroduction project has been carried out to restore L. cardium populations among three streams in Nebraska, during autumn 2016 and summer 2017. A 2-year mark-recapture study was used to determine habitat, timing and size-atintroduction effects on mussel survival and growth following introduction. Water quality and habitat parameters were seasonally recorded from each site to assess potential effects on mussel growth and survival.3. The highest daily growth rates of L. cardium ranged between 145 and 185 μm d À1 , whereas the lowest daily growth rates observed were $88-107 μm d À1 , with the greater rate of shell growth always recorded for those individuals introduced in spring and lower for those individuals introduced in summer or autumn. Survival models indicated that mussels were most susceptible to mortality immediately following introduction in spring, whereas size at introduction had almost no effect on survival. At each site, habitat parameter measurements recorded during different seasons indicated that calcium availability, water temperatures, water depth and water quality may contribute to differences in growth and survival rates.4. Survival rate estimation and population growth predictions are essential knowledge to understand population dynamics; this study provides useful information and a framework for management decisions that may influence L. cardium population dynamics, such as identifying more suitable habitats and introduction times not only for this species but also other similar unionids.

Abundance of five sympatric stream dwelling mussels varies with physical habitat

“…Despite the complexity of freshwater mussel habitat, identifying species‐specific habitat is particularly important given stream modifications that may affect species differentially (Sousa et al, 2021), including dam removal and flow alteration from agricultural practices and urbanization (Bellmore et al, 2017; Kondolf & Micheli, 1995). Furthermore, interest in population reintroduction requires identifying suitable catchments (Montesanto et al, 2023) and river reaches (Zając et al, 2018) that can support the focal species. Combining approaches in this study, mainly information on substrate, with larger‐scale occupancy models that capture land use and flow over greater spatial scales, could improve predictions of high‐quality habitat for population restoration.…”

Population Reinforcement of the Endangered Freshwater Pearl Mussel (Margaritifera margaritifera): Lessons Learned

“…However, reporting on the outcomes of reintroductions/population reinforcements remains limited in the primary literature. Accurate survival/site retention data are critical for informing adaptive management activities to ensure effective population restoration strategies [9,21]. This current paper outlines systematic methods undertaken to assess available juvenile mussel habitats (suitability and condition), identify candidate release sites, undertake population reinforcements with ~2500 propagated juveniles, and monitor the short-term success of releases.…”

“…Recapture rates of released mussels can vary significantly between sites and years. For example, the survival rate of the plain pocketbook (Lampsilis cardium) varied between 0 and 63% two years post-release across 13 different sites in three rivers [21]. This highlights the need for ongoing and repeated monitoring in order to refine population estimates.…”

“…The use of PIT tags to monitor mussel populations is a powerful tool and one which has enabled us to estimate retention per site two years after releases with relatively few monitoring occasions. The regular monitoring of release sites and downstream areas should be continued so that site-specific retention (and migration during high-flow events) can be modelled in the future [21,33,36,41] to help inform the adaptive management of this population reinforcement project.…”