Water-quality monitoring in response to young-of-the-year smallmouth bass (Micropterus dolomieu) mortality in the Susquehanna River and major tributaries, Pennsylvania: 2008

Abstract

Mortalities of young-of-the-year (YOY) smallmouth bass (Micropterus dolomieu) recently have occurred in the Susquehanna River due to Flavobacterium columnare, a bacterium that typically infects stressed fish. Stress factors include but are not limited to elevated water temperature and low dissolved oxygen during times critical for survival and development of smallmouth bass (May 1 through July 31). The infections were first discovered in the Susquehanna River and major tributaries in the summer months of 2005 but also were prevalent in 2007. The U.S. Geological Survey, Pennsylvania Fish and Boat Commission, Pennsylvania Department of Environmental Protection, and PPL Corporation worked together to monitor dissolved oxygen, water temperature, pH, and specific conductance on a continuous basis at seven locations from May through mid October 2008. In addition, nutrient concentrations, which may affect dissolved-oxygen concentrations, were measured once in water and streambed sediment at 25 locations. Data from water-quality meters (sondes) deployed as pairs showed daily minimum dissolved-oxygen concentration at YOY smallmouth-bass microhabitats in the Susquehanna River at Clemson Island and the Juniata River at Howe Township Park were significantly lower (p-value < 0.0001) than nearby main-channel habitats. The average daily minimum dissolved-oxygen concentration during the critical period (May 1-July 31) was 1.1 mg/L lower in the Susquehanna River microhabitat and 0.3 mg/L lower in the Juniata River. Daily minimum dissolved-oxygen concentrations were lower than the applicable national criterion (5.0 mg/L) in microhabitat in the Susquehanna River at Clemson Island on 31 days (of 92 days in the critical period) compared to no days in the corresponding main-channel habitat. In the Juniata River, daily minimum dissolved-oxygen concentration in the microhabitat was lower than 5.0 mg/L on 20 days compared to only 5 days in the main-channel habitat. The maximum time periods that dissolved oxygen was less than 5.0 mg/L in microhabitats of PPL Corporation (PPL), conducted a study from May through October 2008 to assess water quality in selected reaches of the Susquehanna River and major tributaries where mortalities of smallmouth bass were documented. The results of the study are presented in this report. The data and interpretations within this report document conditions in 2008 and could be used as a foundation for development of a long-term network of data collection and interpretation.

Development of a Multiplex Fluorescence in Situ Hybridization Assay to Identify Coinfections in Young‐of‐the‐Year Smallmouth Bass

“…The pathogenic effects of myxozoans vary and are dependent upon environmental factors (such as temperature and water quality), host immunocompetence, the species of myxozoan, and the target organ of infection (Gόmez et al 2014). Age-0 Smallmouth Bass in the Susquehanna River drainage are periodically exposed to low dissolved oxygen and elevated temperatures, especially in the summer during low flow (Chaplin et al 2009). Additionally, complex mixtures of surface water contaminants (Reif et al 2012;McClure et al 2020) and tissue contaminants (Walsh et al 2018) have been documented.…”

“…Age‐0 Smallmouth Bass in the Susquehanna River drainage are periodically exposed to low dissolved oxygen and elevated temperatures, especially in the summer during low flow (Chaplin et al. 2009 ). Additionally, complex mixtures of surface water contaminants (Reif et al.…”

“…The magnitude of reoccurring disease in age-0 Smallmouth Bass has been observed at the population level, with a significant decrease in age-1 Smallmouth Bass and a shift to larger and older fish (Smith et al 2015). Initial observations from randomly sampled and/or moribund fish with visible skin lesions included the myxozoan parasite Myxobolus inornatus (Walsh et al 2012a) as well as Flavobacterium columnare (Chaplin et al 2009). Subsequently, Largemouth Bass virus (LMBV), other parasites, and multiple Aeromonas spp.…”

“… 2012a ) as well as Flavobacterium columnare (Chaplin et al. 2009 ). Subsequently, Largemouth Bass virus (LMBV), other parasites, and multiple Aeromonas spp.…”

Spatial and temporal variability of myxozoan parasite, Myxobolus inornatus, prevalence in young of the year smallmouth bass in the Susquehanna River Basin, Pennsylvania

“…Multiple pathogens and parasites have been identified including bacteria (e.g., multiple aeromonads, Flavobacterium columnare (Bernardet and Grimont); Starliper, Blazer, Iwanowicz, & Walsh, ), largemouth bass virus (Boonthai et al., ; Smith et al., ; Starliper et al., ), trematodes (Smith et al., ) and cestodes (Walsh et al., ). In addition to pathogens and parasites, water quality concerns including elevated water temperatures, suboptimal dissolved oxygen concentrations and contaminants have also been investigated in regard to the overall health of YOY smallmouth bass in the Susquehanna River Basin (Blazer et al., ; Chaplin, Crawford, & Brightbill, ; Smith et al., ; Walsh et al., ).…”