Orth, Donald J.Alexander, Kathleen A.Ciparis, SerenaFrimpong, Emmanuel A.Henley, WilliamVoshell, J. Reese2023-03-302023-03-302009-10http://hdl.handle.net/10919/114232Episodic fish mortality began within the Shenandoah basin in 2004 and has since spread to upper James River basin. The reasons for this are unknown although water-borne contaminants, stormwater runoff, levels of parasitism, and intersex are considered important factors in these outbreaks. Utilizing an integrated research approach, we identified the principal factors associated with the fish kills and used this information to begin to identify mitigation, monitoring, and management options for securing the health of these waterways and the fish communities that live there. Our study design for 2008 included four sites that have experienced chronic spring-time fish kills and three sites that have not experienced fish kills. We have collected data on spatial and temporal dynamics of fish kills and examined invertebrate host species for trematode parasites, fish health metrics and parasitism, and land use and contaminant loads in a broad-scale study design in order to identify important variables associated with outbreaks of spring-time fish mortality and potiential long-term monitoring approaches. We collected over 20 smallmouth bass at each of seven sites during pre-kill period and repeated this during typical kill periods. Our primary objective was to investigate the spatial and temporal dynamics of fish kills in relation to select contaminants, fish health metrics, fish parasitism, land use, and population characteristics of snails in order to identify important variables associated with outbreaks of fish mortality in the system and candidate monitoring approaches. Our specific aims were to: 1. Classify watersheds to design a stratified random sampling procedure for examining land use, effect of suspected contaminants including suspended solids, dissolved nutrients, benthic chlorophyll a, periphyton biomass, estrogenic activity, and other organic contaminants. 2. Assess the health of wild, free-living smallmouth bass populations in sample sites based upon physiological markers of stress, key chemical stressors, macroparasite prevalence, diversity and intensity of infection; gross and histological assessment of tissue and organ pathology including pathogenic bacterial infection. 3. Using the data collected in (2) develop a novel health assessment index (HAI) to allow assessment of fish health by watershed classification and other key variables.4. Measure snail population density, sex ratios, and measure trematode prevalence, diversity and intensity of infection. 5. Develop detailed maps of land use and stressor sources and statistically assess land use and stressor relationships to items (2)-(4) above. 6. Provide preliminary identification and ranking of primary variables associated with fish kills in the Shenandoah basin and rank watersheds by levels of risk.21 page(s)application/pdfenIn CopyrightReport2023-03-30Orth, Donald [0000-0002-9236-0147]