Augment and expand existing endangered and species of concern mussel populations in the upper Tennessee and Cumberland River systems, Tennessee

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.

Carey. C.S., J.W. Jones, E.M. Hallerman, and R.S. Butler. 2013. Determining optimum temperature for growth and survival of laboratory-progagated juvenile freshwater mussels.  North American Journal of Aquaculture. 75:532-542.

The effects of temperature on growth and survival of laboratory-propagated juvenile freshwater mussels of two federally endangered species, the Cumberlandian combshell Epioblasma brevidens and oyster mussel E. capsaeformis, and one nonlisted species, the wavy-rayed lampmussel Lampsilis fasciola, were investigated to determine optimum rearing temperatures for these species in small water-recirculating aquaculture systems. Juveniles 4–5 months old were held in downweller buckets at five temperatures. Growth and survival of juveniles were evaluated at 2-week intervals for 10 sampling events. At the end of the 20-week experiment, mean growth at 20, 22, 24, 26, and 28◦C was, respectively, 0.75, 2.22, 3.27, 4.23, and 4.08 mm for Cumberlandian combshell; 1.35, 3.73, 3.81, 4.90, and 4.70 mm for oyster mussel; and 2.09, 3.96, 4.99, 5.13, and 4.87 mm for wavy-rayed lampmussel juveniles. Generally, temperature was positively correlated with growth of juveniles. Finalmeanmaximum growth occurred at 26◦C for all three species, although no significant differences in growth were detected between 26◦C and 28◦C. The relationship between temperature and survival of juveniles was less clear. Final survival was 82.5, 89.0, 91.0, 89.5, and 93.5% for Cumberlandian combshell; 73.0, 83.5, 78.0, 78.0, and 68.1% for oyster mussel; and 75.0, 89.5, 87.0, 86.5, and 89.5% for wavy-rayed lampmussel juveniles at the five temperature treatments, respectively. Based on the species used in this study, results indicate that 26◦C is the optimum temperature to maximize growth of juvenile mussels in downweller bucket systems. The ability to grow endangered juveniles to larger sizes will improve survival in captivity and upon release into the wild and will reduce time spent in hatcheries. As a result, hatcheries can increase their overall production and enhance the likelihood of success of mussel population recovery efforts by federal and state agencies, and other partners.