Browsing by Author "Butler, Robert S."

Now showing 1 - 2 of 2
  • Thumbnail Image
    A Comparison of Systematic Quadrat and Capture-Mark-Recapture Sampling Designs for Assessing Freshwater Mussel Populations
    Carey, Caitlin; Jones, Jess W.; Butler, Robert S.; Kelly, Marcella J.; Hallerman, Eric M. (MDPI, 2019-08-07)
    Our study objective was to compare the relative effectiveness and efficiency of quadrat and capture-mark-recapture (CMR) sampling designs for monitoring mussels. We collected data on a recently reintroduced population of federally endangered Epioblasma capsaeformis and two nonlisted, naturally occurring species—Actinonaias pectorosa and Medionidus conradicus—in the Upper Clinch River, Virginia, over two years using systematic quadrat and CMR sampling. Both sampling approaches produced similar estimates of abundance; however, precision of estimates varied between approaches, years, and among species, and further, quadrat sampling efficiency of mussels detectable on the substrate surface varied among species. CMR modeling revealed that capture probabilities for all three study species varied by time and were positively associated with shell length, that E. capsaeformis detection was influenced by sex, and that year-to-year apparent survival was high (>96%) for reintroduced E. capsaeformis. We recommend that monitoring projects use systematic quadrat sampling when the objective is to estimate and detect trends in abundance for species of moderate to high densities (>0.2/m2), whereas a CMR component should be incorporated when objectives include assessing reintroduced populations, obtaining reliable estimates of survival and recruitment, or producing unbiased population estimates for species of low to moderate densities (≤0.2/m2).
  • Thumbnail Image
    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.