The Clam Exam: Clinical Pathology of Freshwater Mussels
American Association of Zoo Veterinarians Conference 2008
Barbara A. Wolfe1, DVM, PhD; Mary Jo Burkhard2,3, DVM, PhD; Sarah Leavell2; Rachael B. Weiss1, DVM; Kody Kuehnl4, PhD; Hope Valentine1, DVM; G. Thomas Watters4, PhD; Brian Bergstrom5, PhD
1Department of Wildlife and Conservation Medicine, The Wilds, Cumberland, OH, USA; 2Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA; 3Center for Microbial Interface Biology, The Ohio State University, Columbus, OH, USA; 4Department of Ecology, Evolution, and Organismal Biology, The Ohio State University, Columbus, OH, USA; 5Department of Biology, Muskingum College, New Concord, OH, USA
Freshwater mussels are the most imperiled taxon of animals in North America with more than two-thirds of nearly 300 identified species considered endangered, threatened, or extinct.2 These bivalves are important in maintaining our waterway health and species diversity and serve as valuable indicators of environmental quality. While captive propagation and translocation of freshwater mussels are widely supported as conservation measures, a high proportion of these normally long-lived animals die within the first year of translocation.1 Furthermore, the ability to evaluate the health of freshwater mussels has been limited and has relied primarily on behavioral changes, mortality rates, histopathology, and non-survival assays.
Our goal is to develop better biomarkers of health and disease in wild, captive, and translocated freshwater mussels, specifically to: 1) develop techniques for identification of hemocyte cell types in freshwater mussel hemolymph; 2) identify hemolymph chemistries of value in health assessment; and 3) identify catecholamines and monoamines present in hemolymph and assess their response to stressors. We compared six hemolymph collection and processing strategies in Quadrula sp. and assessed the effects on cell yield and morphology, characterizing key morphologic features for the development of a mussel hemogram. We have assessed hemolymph chemistries and hemocyte cell function in control wild mussels and those brought into captivity and monitored closely. Finally, using pericardial catheterization, we have evaluated five hemolymph catecholamine and monoamine reactions to specific stressors in an attempt to identify the mechanisms of the captive stress response in these species.
1. Cope WG, Hove MC, Waller DL, Hornbackh DJ, Bartsch MR, Cunningham LA, et al. Evaluation of relocation of unionid mussels to in situ refugia. J Molluscan Stud. 2003;69:27–34.
2. Williams JD, Warren ML, Cummings KS, Harris JL, Neves RJ. Conservation status of freshwater mussels of the United States and Canada. Fisheries. 1993;18(9):6–22.