From 2006-2011, four population reintroduction techniques were applied to three sites within a reach of the upper Clinch River in Virginia designated suitable for population restoration of the federally endangered oyster mussel (Epioblasma capsaeformis). These techniques were: 1) translocation of adults (Site 1), 2) release of laboratory-propagated sub-adults (Site 1), 3) release of 8-week old laboratory-propagated juveniles (Site 2), and 4) release of stream-side infested host fishes (Site 3). Demographic data were collected in 2011 and 2012 by systematic quadrat and capture-mark-recapture sampling to assess reintroduction success, evaluate reintroduction techniques, and compare survey approaches for monitoring freshwater mussels. Estimates of abundance and density of translocated adults ranged from 450-577 individuals and 0.09-0.11/m2 in 2011, and 371-645 individuals and 0.07-0.13/m2 in 2012. Estimates of abundance and density of laboratory-propagated sub-adults ranged from 1,678-1,943 individuals and 0.33-0.38/m2 in 2011, and 1,389-1,700 individuals and 0.27-0.33/m2 in 2012. Additionally, three recruits were collected at Site 1. No E. capsaeformis were collected at Sites 2 and 3. Capture-mark-recapture sampling produced similar mean point estimates as systematic quadrat sampling, but with typically more precision. My results indicated that the release of larger individuals (>10 mm) is the most effective technique for restoring populations of E. capsaeformis, and that systematic quadrat and capture-mark-recapture sampling have useful applications in population monitoring that are dependent on project objectives. Systematic quadrat sampling is recommended when the objective is to simply estimate and detect trends in population size for species of moderate to larger densities (>0.2/m2). Capture-mark-recapture sampling should be used when objectives include assessing a reintroduced population of endangered species or at low density, obtaining precise estimates of population demographic parameters, or estimating population size for established species of low to moderate density (0.1-0.2/m2). The ability to grow endangered juveniles to larger sizes in captivity requires improving grow-out culture methods of laboratory-propagated individuals. A laboratory experiment was conducted to investigate the effects of temperature (20-28 C) on growth and survival of laboratory-propagated juveniles of the Cumberlandian combshell (Epioblasma brevidens), E. capsaeformis, and the wavyrayed lampmussel (Lampsilis fasciola) in captivity. Results indicated that 26 C is the optimum temperature to maximize growth of laboratory-propagated juveniles in small water-recirculating aquaculture systems. Growing endangered juveniles to larger sizes will improve survival in captivity and after release into the wild. As a result, hatcheries can reduce the time that juveniles spend in captivity and thus increase their overall production and enhance the likelihood of success of mussel population recovery efforts by federal and state agencies, and other partners. / Master of Science

Epioblasma capsaeformis, commonly named the oyster mussel, once occupied thousands of miles of stream reaches, but has now been reduced in range to small, isolated populations in a few river reaches. Due to this significant decline in population numbers, a study was conducted to develop a diet for propagating this endangered species under captive conditions. Oyster mussel juveniles were collected from several sites on the Clinch River and sacrificed for gut content and biochemical composition analyses in summer. Feces and pseudofeces from live river-collected juveniles were examined seasonally for algae, detritus, and bacteria to qualitatively determine diet of specimens. Two feeding trials also were conducted in this study to evaluate effect of diet (commercial and non-commercial diets), on growth and survival of oyster mussel juveniles. From examination of gut contents, fecal and pseudofecal samples, it was apparent that algae and a significant amount of detritus (~90%) composed wild juvenile diets. E. capsaeformis juveniles (1-3 y of age) could have fed on particles up to 20 µm in size and seemed they were mostly ingesting particles within the 1.5-12 µm size range. Protein content of sacrificed juveniles ranged from 313 to 884 mg/g and was highly variable. Glycogen content ranged from 49-171 mg/g. Caloric content of four juveniles ranged from 2,935.10 to 4,287.94 cal/g, providing a preliminary baseline range for future energetic studies on freshwater mussels. Growth was significantly higher in those juveniles fed the triple concentration algae-mix (62,076 cells/ml) than all other diets tested in trial 1. Results of both feeding trials indicated that survival of juvenile oyster mussels was enhanced when fed an algal diet supplemented by bioflocs. / Master of Science

Genetic variation was examined in two endangered mussel species, Epioblasma brevidens and E. capsaeformis, and a common species Lampsilis fasciola, in the Clinch River, TN, by screening mitochondrial DNA (mtDNA) sequences and nuclear DNA microsatellites. These species use fish hosts with varying dispersal capabilities, ranging from low, moderate, and high, respectively. Patterns of mtDNA polymorphism exhibited different trends for long-term population sizes for each species during the Holocene (~10,000 ya to present); namely, E. brevidens has declined over time, E. capsaeformis has remained stable, and L. fasciola has expanded. Long-term effective population size (Ne) was smallest in E. brevidens, intermediate in E. capsaeformis, and highest in L. fasciola. Moderately diverged mtDNA lineages, perhaps indicative of secondary contact, were observed in E. brevidens and E. capsaeformis. High levels of gene flow (Nm) were estimated among demes of L. fasciola using traditional F-statistics and likelihood estimates of Nm, whereas such metrics were lower in E. brevidens and E. capsaeformis. Data are consistent with population dynamics and life history traits of each species and their fish hosts. Age, shell growth, and population demography of Epioblasma brevidens, E. capsaeformis, and Lampsilis fasciola were studied from 2004-2007 in a 32-km reach of the Clinch River, TN. Observed maximum age and length of E. brevidens was 28 y and 71.5 mm for males and 11 y and 56.6 mm for females; of E. capsaeformis, 12 y and 54.6 mm for males and 9 y and 48.6 mm for females; and of L. fasciola, 45 y and 91.3 mm for males and 13 y and 62.6 mm for females. For all three species, observed maximum age and length was greater among males than females. Estimated population size in this river reach was approximately 43,000 individuals for E. brevidens, 579,000 individuals for E. capsaeformis, and 30,000 individuals for L. fasciola. Mean recruitment y-1 of 1 y-old E. brevidens ranged from 7.1% to 20%, of E. capsaeformis from 4.0% to 32.4%, and of L. fasciola from 5.8% to 25.6%. Population growth rate y-1 was 24.9% for E. brevidens, 34.6% for E. capsaeformis, and -22.4% for L. fasciola. Mortality rates of females were higher than for males of E. capsaeformis and L. fasciola, but not E. brevidens. Juvenile mussels were collected but temporally and spatially variable in occurrence, and a significant component of the age-class structure of all three species. Recruitment was very high during 2006-2007 for E. capsaeformis and other species, likely due to low river discharges in the spring-summer of 2005-2007. Surplus individuals of E. brevidens and E. capsaeformis are currently available to conduct translocations for restoration purposes. Population modeling of Epioblasma brevidens and E. capsaeformis in the Clinch River was conducted to determine suitable harvest levels for translocation of sub-adults and adults, and to determine quantitative criteria for evaluating performance and recovery of extant and reintroduced populations. For both species, the recommended annual harvest was <1% of local population size to minimize risk of decline. Reintroduction modeling indicated that size of the initial population created during a 5 y build-up phase greatly affected final population size at 25 y, being similar to size at the end of the build-up phase, especially when expected growth rate was low, (e.g., 1-2%). Excluding age-0 individuals, age-1 juveniles or recruits on average comprised approximately 11% and 15% of a stable population of each species, respectively. The age-class distribution of a stable or growing population was characterized by multiple cohorts, to include juvenile recruits, sub-adults, and adults. Molecular genetic and demographic data indicated that the ratio of Ne/Nc was ~5% for both species. Based on this ratio and predicted declines of genetic variation at different population sizes, target sizes for reintroduced or recovered populations of each species should be ≥5,000 individuals (Ne=250) and ≥10,000 individuals (Ne=500), respectively, and should be comprised of multiple smaller demes spread throughout a river. Populations of both species are currently large enough to sustain harvest for translocation and reintroduction purposes, offering an effective species recovery strategy. / Ph. D.