Decades of poor reproductive success and young-of-the-year recruitment, in addition to adult mortality, has led to a decline in the smallmouth bass (SMB) population in subwatersheds of the Potomac River. Previous studies have identified numerous biologic and environmental stressors associated with negative effects on SMB health. To better understand the impact of these stressors, the current study was conducted from 2013-2019 to identify temporal changes associated with SMB reproductive health. Grab surface water samples were collected and analyzed for over 300 organic contaminants, including pesticides, phytoestrogens, pharmaceuticals, hormones and total estrogenicity (E2Eq). Adult SMB were collected and sampled for multiple endpoints, including gene transcripts associated with reproduction (molecular), histopathology (cellular), and organosomatic indices (tissue). In males, biomarkers of estrogenic endocrine disruption, including testicular oocytes (TO) and plasma vitellogenin (Vtg) were assessed. The results identified numerous agriculture-related contaminants or land use associated with gene transcripts in males and females and a positive association of pesticides in the immediate catchment with TO severity and E2Eq with plasma Vtg in males. Prevalence of TO and detectable levels of plasma Vtg, liver vitellogenin transcripts (vtg) and testis vtg were high throughout the study. Peaks of complex mixtures of numerous contaminants occurred during the spring/early summer when early development occurs and to a lesser extent in fall/winter during recrudescence. Management practices to reduce exposure during these critical and sensitive periods may enhance reproductive health of economically important sportfishes.

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.

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.

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.

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.

Intersex in small- and largemouth bass has been observed in the upper Chesapeake Bay Watershed since 2003. This observation is indicative of exposure to estrogenic endocrine disrupting chemicals. In order to complement biological data sets and better identify the spatial and temporal nature of this end-point, discrete grab water samples were collected throughout the upper Chesapeake Bay Watershed for the evaluation of estrogenic activity. Data reported here are estrogenicity values derived from bioassay screening of OASIS-HLB extracts discrete grab water samples. Estrogenicity was determined using a bioluminescent yeast estrogen screen. Here we report estrogenicity data for selected sites in the Chesapeake Bay water shed collected between 2008 and 2011.

Intersex in small- and largemouth bass has been observed in the upper Chesapeake Bay Watershed since 2003. This observation is indicative of exposure to estrogenic endocrine disrupting chemicals. In order to complement biological data sets and better identify the spatial and temporal nature of this end-point, discrete grab water samples were collected throughout the upper Chesapeake Bay Watershed for the evaluation of estrogenic activity. Data reported here are estrogenicity values derived from bioassay screening of OASIS-HLB extracts discrete grab water samples. Estrogenicity was determined using a bioluminescent yeast estrogen screen. Here we report estrogenicity data for selected sites in the Chesapeake Bay water shed collected between 2008 and 2011.

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.

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.