Scholarly Works, Freshwater Mollusk Conservation Center

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    Periodic growth and growth cessations in the federally endangered freshwater mussel Cumberlandian combshell using a hierarchical Bayesian approach
    Hua, Dan; Jiao, Yan; Neves, Richard; Jones, Jess W. (Inter-Research, 2016-12-29)
    Understanding and monitoring life history traits is often important in endangered species conservation. Populations of the endangered mussel Cumberlandian combshell Epioblasma brevidens have continued to decline in the Powell River, USA. Understanding and modeling mussel growth is critical for effective reintroduction of this endangered species. In this study, 2 yr old E. brevidens that were produced in our laboratory were released to the Powell River in 2009 to augment this declining population. A mark-recapture monitoring approach using passive integrated transponder (PIT) tags was used to assess the survival and growth of the released mussels. Hierarchical Bayesian growth models incorporating individual growth variations, periodic growth and growth cessations, along with multiple release occasions were developed and compared to the classic von Bertalanffy growth model. Our results showed that the hierarchical model that incorporated individual growth variation gave the best estimates of model parameters, yielding the lowest deviance information criterion value. Mussels exhibited different growth rates (K), including 0.015, 0.026, 0.110 and 0.050 (mo⁻¹), corresponding to the duration of laboratory culture (ages 2, 3 and 4 yr old) and a growth cessation (GC) for 5.98 mo, respectively. The other parameters of asymptotic length (L∞) and age at zero length (t₀) were 51.36 mm and −0.648 mo. The flexible structure of Bayesian hierarchical models allowed us to examine growth characteristics of E. brevidens in a changing environment to better understand the details of its growth and lifespan, thus providing useful data for conservation management.
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    Bat activity following repeated prescribed fire in the central Appalachians, USA
    Austin, Lauren V.; Silvis, Alexander; Muthersbaugh, Michael S.; Powers, Karen E.; Ford, W. Mark (2018-12-27)
    Background To restore and manage fire-adapted forest communities in the central Appalachians, USA, land managers are now increasingly prioritizing use of prescribed fire. However, it is unclear how the reintroduction of fire following decades of suppression will affect bat communities, particularly where white-nose syndrome-related population declines of many cave-hibernating bat species have occurred. To address this concern, we monitored and compared bat activity in burned and unburned habitat across a temporal gradient in western Virginia. Results We found evidence for slightly positive fire effects on activity levels of the northern long-eared bat (Myotis septentrionalis [Trouessart, 1897]), Indiana bat (Myotis sodalis [Miller and Allen, 1928]), little brown bat (Myotis lucifugus [Le Conte, 1831]), big brown bat (Eptesicus fuscus [Palisot de Beauvois, 1796])/silver-haired bat (Lasionycteris noctivagans [Le Conte, 1831]) group, all high-frequency bats, and all bat species combined. We observed temporal effects only for the big brown bat, with a negative relationship between activity and time since fire. Conclusions Because response of bat activity was neutral to weakly positive relative to burned forest condition, our results suggest that bats are not a resource that would impede the use of this management tool in the central Appalachians.
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    Restoring the endangered oyster mussel (Epioblasma capsaeformis) to the upper Clinch River, Virginia: An evaluation of population restoration techniques
    Carey, Caitlin; Jones, Jess W.; Butler, Robert S.; Hallerman, Eric M. (Restoration Ecology, 2015)
    From 2005 to 2011, the federally endangered freshwater mussel Epioblasma capsaeformis (oyster mussel) was reintroduced at three sites in the upper Clinch River, Virginia, using four release techniques. These release techniques were (1) translocation of adults (site 1, n=1418), (2) release of laboratory-propagated sub-adults (site 1, n=2851), (3) release of 8-week-old laboratory-propagated juveniles (site 2, n=9501), and (4) release of artificially infested host fishes (site 3, n=1116 host fishes). These restoration efforts provided a unique research opportunity to compare the effectiveness of techniques used to reestablish populations of extirpated and declining species. We evaluated the relative success of these four population restoration approaches via monitoring at each release site (2011–2012) using systematic 0.25-m2 quadrat sampling to estimate abundance and post-release survival. Abundances of translocated adult and laboratory-propagated sub-adult E. capsaeformis at site 1 ranged 577–645 and 1678–1700 individuals, respectively, signifying successful settlement and high post-release survival. Two untagged individuals (29.1 and 27.3mm) were observed, indicating that recruitment is occurring at site 1. No E. capsaeformis were found at sites where 8-week-old laboratory-propagated juveniles (site 2) and artificially infested host fishes (site 3) were released. Our results indicate that translocations of adults and releases of laboratory-propagated sub-adults were the most effective population restoration techniques for E. capsaeformis. We recommend that restoration efforts focus on the release of larger (>20mm) individuals to accelerate augmenting and reintroducing populations and increase the probability for recovery of imperiled mussels.
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    Factors Affecting Survival and Growth of Juvenile Freshwater Mussels Cultured in Recirculating Aquaculture Systems
    Jones, Jess W.; Mair, Rachel; Neves, Richard (North American Journal of Aquaculture, 2005)
    Seasonal differences in glochidial maturity, substrate, and diet were studied to determine how these factors affect the survival and growth of juvenile freshwater mussels. Comparisons were made between juveniles produced in the fall and spring of the year; cultured in sediment, sand, or without substrate; and fed either of two species of small (5–10-mm) green algae. The survival and growth of endangered juveniles of oyster mussel Epioblasma capsaeformis were compared with those of a common, seemingly more robust species, the rainbow mussel Villosa iris. The growth of rainbow mussel juveniles was significantly greater than that of oyster mussel juveniles (P , 0.001). The survival and growth of oyster mussel juveniles were significantly greater when propagated in the spring, that is, when glochidia were mature and would normally be released, than in fall (P , 0.001). Survival and growth of juveniles of both species were significantly greater when they were cultured in a sediment substratum rather than sand or no substratum (P , 0.001). No differences (P . 0.05) were observed in survival and growth of juveniles fed algal species Neochloris oleoabundans or Nannochloropsis oculata. In the spring of the year, juvenile oyster mussels achieved a survival of 29.6% and mean length of 664 micrometers at 60 d of age, whereas at the same age rainbow mussel juveniles exhibited a survival of 25.1% and a mean length of 1,447 micrometers.