Meeting Abstract
Freshwater mussels (family Unionidae) are long-lived filter-feeding bivalves that are important in maintaining ecosystem function by filtering particulate matter and sequestering nutrients in our waterways. Unfortunately, native freshwater mussels are the most imperiled group of animals in North America with more than 2/3 of nearly 300 identified species considered threatened, endangered, or extinct. Threats to these species include habitat degradation due to waterway manipulation, pollution, erosion and sedimentation, and invasive species. While translocation and captive propagation are widely supported as appropriate conservation measures, a high proportion of unionids die within the first year of relocation, reducing the effectiveness of such efforts. Historically, our ability to evaluate the health of freshwater mussels has been limited primarily to behavioral changes, mortality rates, and non-survival assays. New research is utilizing metabolic profiling to evaluate the effects of environmental changes. A study was designed to characterize the metabolic profile of Amblema plicata, the Threeridge mussel, subjected to low nutrient availability. Eight mussels brought into captivity from the wild were isolated for 18 days without a food source. Hemolymph samples were taken prior to, and 9 and 18 days after the start of the study. Samples were analyzed on GC/MS and LC/MS/MS platforms, and 71 metabolites of known identity were detected. Captivity and fasting resulted in changes in energy metabolism, free amino acids, fatty acids, nucleic acids, and proliferation pathways. While fasting resulted in severe metabolite depletion, changes were also evident in many captive fed mussels, indicating that mussels may be experiencing nutritional deficiency and other metabolic stressors under common captive conditions.
