Investigating the Role of Contaminants and Parasite Prevalence in the Observed Mortality of Smallmouth Bass in the Susquehanna River Basin
The causes of the decline of smallmouth bass populations observed in some Pennsylvania rivers are unclear. However, it is hypothesized that declines are related to environmental stressors, including pesticides and endocrine-disrupting substances and disease. Thus, additional work is needed to understand the role that contaminants and disease (specifically parasite infection) may be playing in disease and mortality and how chemical concentrations and parasite load vary throughout critical periods for smallmouth bass development. The objectives of this study are to (1) investigate the role and relationships of contaminants in river sediment, adult female smallmouth bass gonads, and YOY tissue as it relates to risk factors for mortality, (2) link contaminant data with ongoing telemetry work to understand risks for exposure, and (3) identify the intermediate host(s) for various myxozoan parasites that are potential threats to YOY and adult smallmouth bass. In this context, the proposed project will substantially build upon our ongoing multi-agency, multi-university collaborative research effort where existing data on the biological condition of smallmouth bass (e.g., external lesions, microscopic pathology, plasma analyses), fish movement, and thermal habitat conditions have been (and are currently being) collected. Publications: Massie, D.L., Smith, G.D., Bonvechio, T.F., Bunch, A.J., Lucchesi, D.O., and T. Wagner. 2018. Spatial and temporal variability of myxozoan parasite. Transactions of the American Fisheries Society 147: 554-565.