An Evaluation of Adult Freshwater Mussels Held in Captivity at the White Sulphur Springs National Fish Hatchery, West Virginia
Boyles, Julie L.
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Due to the increasing need to provide refugia for freshwater mussels impacted by anthropogenic activities and exotic species, facilities should be identified and protocols developed for holding mussels in captivity. White Sulphur Springs National Fish Hatchery (WSSNFH), White Sulphur Springs, WV, has held freshwater mussels for nearly eight years, and has the potential to become an important refugium and propagation facility for conservation of mussels in the Ohio River Basin and elsewhere. The goal of this study was to determine the feasibility of holding adult freshwater mussels in long-term captivity at WSSNFH by evaluating survival, energy reserves, and gametogenesis of captive mussels in a recirculating pond system. I relocated three mussel species in the summer of 2001 and 10 mussel species in the summer of 2002 to a recirculating pond system (reservoir and raceway) at the hatchery. Water quality parameters of pH, alkalinity, hardness, temperature, and dissolved oxygen; and algal concentrations were measured periodically from summer 2001 to summer 2003. Annual survival rates of 10 species were estimated (August 2002 to August 2003) using the program MARK. Glycogen, protein, and lipid concentrations in mantle tissue of three captive species (Actinonaias ligamentina, Cyclonaias tuberculata, and Tritogonia verrucosa) were compared to those of wild mussels in the New River. Gametogenic activity and synchrony in A. ligamentina and C. tuberculata were compared between captive and wild mussels. Water quality parameters, with the exception of temperature, were within desirable ranges for most of the study. Temperatures of > 28Â° C were observed for several days during summers 2002 and 2003. Algal concentrations averaged 1903 cells ml-1 in the raceway (range: 300 to 4658 cells ml-1), which is comparable to algal concentrations reported for nearby rivers. The overall survival rate for 10 freshwater mussel species held in the raceway for one year was 77%. Villosa vanuxemensis had the highest survival rate (96%), and Lampsilis cardium had the lowest survival rate (31%). Although there were fluctuations in glycogen, protein, and lipid levels over 2 yr, there were no overall differences in energy substrates between captive and wild mussels at the end of the study. Captivity did not appear to have a negative affect on gametogenesis. Captive C. tuberculata spawned within the expected time frame between January and June, but slightly earlier than their wild counterparts in the New River. Due to the infestation of the gonads of both captive and wild A. ligamentina by digenean trematodes, little gametogenesis was observed. However, captive holding did not appear to have an effect on trematode infestation rates. From these results, I conclude that captive holding conditions in the recirculating pond system at WSSNFH were adequate for long-term holding of a wide range of mussel taxa. I recommend that WSSNFH continue to be used as an adult holding facility. Further research should be conducted to determine food and habitat preferences of freshwater mussel species in captivity so that optimal holding conditions can be provided for each species.
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