Physiological and molecular endpoints observed in juvenile largemouth bass in response to an estrogen (17α-ethinylestradiol) and subsequently a bacterial challenge (Edwardsiella piscicida) exposure under laboratory conditions. Also included are water quality and chemical concentration data.

Largemouth base histological development and transcriptomic changes in gonad tissue after early life stage exposure to Atrazine (1-Chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine) or the model estrogen 17α-ethinylestradiol.

The data was gathered to document the extent and severity of biomarkers of exposure to estrogenic chemicals in smallmouth and largemouth bass. Samples were collected from 2004 through 2010 at sites in five watersheds within the Chesapeake Bay watershed. A total of 281 largemouth bass were collected from the Potomac, Susquehanna, Patuxent and Rappahannock rivers and 1,384 smallmouth bass from the Potomac, Susquehanna and James. Fish were collected by boat electroshocking, euthanized in the field, weighed, measured, a blood samples collected and a necropsy completed that included documenting any visible abnormalities and collecting tissues for histopathology. Plasma obtained from blood samples was analyzed for vitellogenin, a yolk precursor widely used as an indicator of estrogenic exposure in immature and male fishes. Five to seven sections of testes were processed for microscopic analyses, embedded in paraffin, sectioned at 5 µm, stained with hematoxylin and eosin. The presence of testicular oocytes was noted and the severity rated from 1 to 4 based on number and arrangement of oocytes.

Alternative complement pathway assay data observed in adult largemouth bass plasma in response to an EE2 (17alpha-ethinylestradiol) or mixture of estrone and atrazine exposure under laboratory pond conditions, with associated fish identification information.

Adult largemouth bass have been shown to be sensitive to induction of intersex in response to chronic estrogen exposures over a complete reproductive cycle. Late summer to fall is the period of early gonad recrudescence when spermatogenesis is beginning in preparation for the spawning season in the spring. Our objective was to assess in 2018 whether early gonad recrudescence was a period of sensitivity for induction of intersex and/or alterations in reproductive condition or function. Adult male largemouth bass were exposed in outdoor pond mesocosms from post-spawning to early gonad recrudescence to either 17alpha-ethinylestradiol or to a mixture of endocrine-active substances commonly detected in the Chesapeake Bay watershed (atrazine and estrone). Gonad samples were sent overnight to Wetland and Aquatic Research Center laboratories and sperm motility was measured by computer assisted sperm motion analysis. Overall, male reproductive condition, sperm count, and sperm motility were analyzed.

Physiological endpoints observed in adult largemouth bass in response to an EE2 (17 alpha-ethinylestradiol) or mixture of estrone and atrazine exposure under laboratory pond conditions. Also included are water quality and chemical concentration data. Adult LMB were exposed in outdoor pond mesocosms from post-spawning to early gonad recrudescence to either EE2 (2.4 nanograms per liter), or a mixture of endocrine-active substances commonly detected in the Chesapeake Bay watershed, atrazine (5.4 micrograms per liter) and estrone (47.9 nanograms per liter). Male reproductive condition, sperm count, and sperm motility were assessed.

Supporting information for "Kadlec, S.M., Blackwell, B.R., Blanksma, C.A., Johnson, R.D., Olker, J.H., Schoff, P.K. and Mount, D.R. (2022), Gonadal Development in Smallmouth Bass (Micropterus Dolomieu) Reared in the Absence and Presence of 17-α-Ethinylestradiol. Environ Toxicol Chem, 41: 1416-1428. https://doi.org/10.1002/etc.5320". This dataset is associated with the following publication: Kadlec, S., B. Blackwell, C. Blanksma, R. Johnson, J. Olker, P. Schoff, and D. Mount. Gonadal Development in Smallmouth Bass (Micropterus Dolomieu) Reared in the Absence and Presence of 17-α-Ethinylestradiol. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY. Society of Environmental Toxicology and Chemistry, Pensacola, FL, USA, 41(6): 1416-1428, (2022).

In 2016, smallmouth bass were collected from three sites in the Lake Erie drainage in Erie County, Pennsylvania and an out-of-basin site in the Allegheny River drainage in order to assess reproductive health and identify endocrine disruption responses. Pieces of liver and gonad were taken in Z-Fix and RNALater for histology and transcript abundance analysis. A landscape analysis was conducted for the immediate and upstream catchments with 2016 land cover data. Correlations between biological variables and transcripts were made in addition to differences between sites. The results showed that males had biological variables that correlated with transcripts associated with endocrine disruption and a high rate of testicular oocytes and plasma vitellogenin (biomarkers of estrogenic contaminant exposure).

The data were gathered as a preliminary assessment of estrogenicity under base-flow conditions at over 100 sites (lakes and streams) throughout New Jersey followed by more targeted sampling of smallmouth bass at nine sites with varying levels of estrogenicity. In 2016, 102 sites (lakes and streams) for the preliminary estrogenicity assessment were selected utilizing compiled results of previous monitoring studies (chemical and biological), current sampling networks, and other areas of concern based on input from stakeholders. Discrete grab surface water samples were collected under base-flow conditions in the fall of 2016 and analyzed for levels of estrogenicity using a bioluminescent yeast screen. Water samples for estrogenicity were also collected from the nine health sites in April/May of 2017 in combination with fish sampling and again in November 2017 under base flow conditions. In the spring of 2017, 20 adult smallmouth bass were collected from each of the nine sites (two river and seven reservoir sites). Fish were collected by boat electroshocking, euthanized in the field, weighed, measured, a blood sample collected and a necropsy completed that included documenting any visible abnormalities and collecting tissues for histopathology. Plasma obtained from blood samples was analyzed for vitellogenin, a yolk precursor widely used as an indicator of estrogenic exposure in immature and male fishes. Five to seven sections of testes were processed for microscopic analyses, embedded in paraffin, sectioned at 5 µm, stained with hematoxylin and eosin. The presence of testicular oocytes was noted and the severity rated from 1 to 4 based on number and arrangement of oocytes.

Adult and young of the year smallmouth bass from the Chesapeake Bay watershed have faced health issues (mortality events, disease by a variety of pathogens, endocrine disruption in male fish, evidence of oxidative damage to tissues, and signs of exposure to chemical contaminants) at multiple sites within the Susquehanna and Potomac River basins. Functional immune assays were added to long-term comprehensive monitoring assessments to determine if immunosuppression was playing a role in observed disease and mortalities because no one single or consistent cause could be identified. The functional immune assays measured bactericidal activity, respiratory burst activity, and lymphocyte mitogenesis using leukocytes isolated from anterior kidney tissue. From 2016-2021, a total of 740 smallmouth bass were sampled among eight (8) sites. Twenty adults were sampled from each site in spring (pre-spawn; April – May) and fall (recrudescence; October – November) at different points in the study. Ancillary data, including biometrics of the fish and parasite/macrophage aggregate counts in multiple tissue types, were collected in conjunction with the immune data. The functional immune assays serve as part of an integrated assessment to determine environmental stressors and infectious agents that may modulate the immune response in wild smallmouth bass, ultimately making them more susceptible to disease and death. Therefore, it is important to consider the functional immune data alongside other aspects of host and environmental health.