Microscopic appearance of normal and melanistic skin in fish from Chesapeake Bay watershed.
Vicki S. Blazer
Vicki started with the National Fish Health Research Laboratory, Leetown Science Center (now the Eastern Ecological Science Center - Leetown Research Laboratory), Kearneysville, WV in1992. She was previously employed as the Assistant Leader of the Georgia Cooperative Fish and Wildlife Research Unit. She was also on the graduate faculty in the School of Forest Resources, University of Georgia, teac
She is active in numerous research projects within the Northeast as well as nationally and internationally. She is active in the American Fisheries Society Fish Health Section and a member of other scientific societies. She is an adjunct faculty member at West Virginia University and Penn State and serves on graduate student committees. Research areas include development of microscopic and molecular markers for understanding changes in the health and populations of wild fishes. Areas of focus include endocrine disruption, emerging diseases, fish tumor pathology and assessment at Great Lakes Areas of Concern, land use influences on fish health, reproduction and immunomodulation.
Science and Products
Filter Total Items: 20
PFAS Transport, Exposure, and Effects
The team is determining the movement and behavior of per- and poly-fluoroalkyl substances (PFAS) from their sources in the environment, as they move through exposure pathways in ecosystems including watersheds and aquifers, their incorporation into food webs, and molecular to population scale effects on fish and wildlife. These studies are accomplished at a variety of spatial scales from regional...
USGS Integrates Findings about Endocrine-Disrupting Compounds in the Chesapeake Watershed
Issue: Studies in the Chesapeake Bay Watershed have documented the exposure of fish to toxic contaminants including endocrine-disrupting compounds (EDCs) - compounds which can alter normal hormonal function in organisms. Given the importance of fisheries to the economic and environmental health of the Watershed, observed endocrine disruption and fish kills in the Watershed have raised public and...
Groundwater Discharge is a Pathway for Phytoestrogen and Herbicide Entry to Streams in the Chesapeake Bay Watershed
Groundwater discharge zones are important spawning areas for fish because they provide a thermally stable habitat. Research at three streams in the Chesapeake Bay Watershed with areas of focused groundwater discharge revealed that groundwater also is a source of phytoestrogens and herbicides that could result in fish exposure during sensitive life stages.
Bioaccumulation of Mercury in Fish Varied by Species and Location in the Chesapeake Bay Watershed—Summary of Existing Data and a Roadmap for Integrated Monitoring
Fish mercury data from State monitoring programs and research studies within the Chesapeake Bay were compiled and summarized to provide a comprehensive overview of the variation in fish mercury concentrations among species and habitats within the watershed. These data are put into context with existing health benchmarks for humans, birds, and fish. Scientists also provide a roadmap for an...
New Virus Identified in Melanistic Skin Lesions on Smallmouth Bass from the Chesapeake Bay Watershed
Scientists determined the risk factors associated with smallmouth bass melanistic skin lesions on smallmouth bass in the Susquehanna and Potomac Rivers, in the Chesapeake Bay watershed. A new virus, which appears to be a member of an emerging viral family, the Adomaviridae, was identified in the lesions. Questions remain about the full characterization of the virus and the role of environmental...
Land-use influences on estrogenic-endocrine disruption in fish within the Chesapeake Bay watershed
Issue: Effects of exposure to estrogenic-chemical contaminants have been observed in many fish species worldwide. One effect is described as “intersex” because fish will take on characteristics of the other sex, such as immature eggs forming in male fish. Studies in the Chesapeake Bay watershed have also identified the exposure of fish to endocrine-disrupting compounds. The estrogenic-endocrine...
Prevalence of Malignant Melanoma in Brown Bullhead from Lake Memphremagog Greater than Expected—Linkages to Contaminant Exposure and Implications for Fish Population Health are Currently Unknown
Raised black lesions observed in 30 percent of the brown bullhead collected from two sites in Lake Memphremagog from 2014 through 2017 were identified microscopically as malignant melanoma. Malignant melanoma in freshwater fishes has been reported before, but this cancer occurrence cluster is raising questions about the cause of the tumors and the implications for the long-term health of fish...
Point and Non-Point Sources of Endocrine Disrupting Compounds and the Potential Effects on Fish and Frogs in the New Jersey Pinelands
This project, in collaboration with the NJ Pinelands Commission and the USGS NJ Water Center, is evaluating potential effects of endocrine-disrupting chemicals from point and nonpoint sources in the Pinelands Area, a research cluster as part of the Delaware River Watershed Initiative.
Fishing and Hunting Integrated Science Team
The Fishing and Hunting integrated science team focuses on contaminant and pathogen exposures in the environment that could impact the presence and vitality of fish and wildlife populations that drive commercial, recreational and subsistence activities such as hunting and fishing. If actual risks are identified this project will inform how to economically and effectively minimize risk by providing...
Point and Nonpoint Sources of Endocrine Disrupting Compounds and the Potential effects on Fish and Frogs in the New Jersey Pinelands
Scientists from the NJ WSC, Leetown Science Center and New Jersey Pinelands Commission recently initiated a 4 year study designed to characterize the point and non-point sources of endocrine disrupting compound (EDCs) and their potential effects on fish and frogs in the NJ Pinelands.
Rainbow trout with bacterial lesions
This rainbow trout is displaying clinical signs of enteric redmouth disease caused by a systemic bacterial infection.
Striped bass with mycobacteriosis
Striped bass ( Morone saxatilis ) displaying ulcerative skin lesions and chronic wasting, both typical clinical signs of mycobacteriosis, a bacterial disease that is problematic among many types of fishes around the world.
Melanistic and normal areas of fish skin
Microscopic appearance of normal and melanistic skin in fish from Chesapeake Bay watershed.
Necropsy of a young of the year smallmouth bass
As part of a fish health assessment, Heather Walsh is performing a necropsy on a young of the year smallmouth bass from the Susquehanna River. Previously, young of the year smallmouth bass from the Susquehanna River drainage experienced fish kills and lesions. This work was conducted to follow-up on the health status of these bass populations.
As part of a fish health assessment, Heather Walsh is performing a necropsy on a young of the year smallmouth bass from the Susquehanna River. Previously, young of the year smallmouth bass from the Susquehanna River drainage experienced fish kills and lesions. This work was conducted to follow-up on the health status of these bass populations.
Intersex or testicular oocytes in smallmouth bass testes
Immature oocytes within the testicular tissue of a smallmouth bass. The histological or cellular appearance of an intersex smallmouth bass. Immature oocytes (white arrows) are present within the testicular tissue which also contains mature sperm (yellow arrows).
Immature oocytes within the testicular tissue of a smallmouth bass. The histological or cellular appearance of an intersex smallmouth bass. Immature oocytes (white arrows) are present within the testicular tissue which also contains mature sperm (yellow arrows).
Skin lesion on smallmouth bass from Chesapeake Bay watershed.
A hyperpigmented melanistic skin lesion on a Smallmouth Bass from the Chesapeake Bay Watershed.
A hyperpigmented melanistic skin lesion on a Smallmouth Bass from the Chesapeake Bay Watershed.
Raised Black External Tumors on an Adult Brown Bullhead Fish
Raised black external tumors on adult brown bullhead (Ameiurus nebulosus) collected from Lake Memphremagog (Vermont and Canadian Border) were identified as malignant melanoma in a 2014–17 study.
Raised black external tumors on adult brown bullhead (Ameiurus nebulosus) collected from Lake Memphremagog (Vermont and Canadian Border) were identified as malignant melanoma in a 2014–17 study.
Smallmouth bass
Smallmouth bass skin with melanistic lesions.
Smallmouth bass skin with melanistic lesions.
Malignant melanoma in brown bullhead
Melanoma in brown bullhead from Lake Memphremagog, Vermont
Melanoma in brown bullhead from Lake Memphremagog, Vermont
Lip tumor diagnosed as a papilloma on a white sucker
A lip tumor diagnosed as a papilloma on a white sucker (Catostomus commersonii) collected from the Milwaukee River.
A lip tumor diagnosed as a papilloma on a white sucker (Catostomus commersonii) collected from the Milwaukee River.
Surface Tumor on White Sucker
Body surface tumor diagnosed as a squamous cell carcinoma on a white sucker fish
Body surface tumor diagnosed as a squamous cell carcinoma on a white sucker fish
Dissecting a Fish to Determine Possible Endocrine Disruption Effects
USGS scientist dissecting a fish to determine possible effects from exposure to endocrine disrupting contaminants.
USGS scientist dissecting a fish to determine possible effects from exposure to endocrine disrupting contaminants.
Science and Products
Filter Total Items: 20
PFAS Transport, Exposure, and Effects
The team is determining the movement and behavior of per- and poly-fluoroalkyl substances (PFAS) from their sources in the environment, as they move through exposure pathways in ecosystems including watersheds and aquifers, their incorporation into food webs, and molecular to population scale effects on fish and wildlife. These studies are accomplished at a variety of spatial scales from regional...
USGS Integrates Findings about Endocrine-Disrupting Compounds in the Chesapeake Watershed
Issue: Studies in the Chesapeake Bay Watershed have documented the exposure of fish to toxic contaminants including endocrine-disrupting compounds (EDCs) - compounds which can alter normal hormonal function in organisms. Given the importance of fisheries to the economic and environmental health of the Watershed, observed endocrine disruption and fish kills in the Watershed have raised public and...
Groundwater Discharge is a Pathway for Phytoestrogen and Herbicide Entry to Streams in the Chesapeake Bay Watershed
Groundwater discharge zones are important spawning areas for fish because they provide a thermally stable habitat. Research at three streams in the Chesapeake Bay Watershed with areas of focused groundwater discharge revealed that groundwater also is a source of phytoestrogens and herbicides that could result in fish exposure during sensitive life stages.
Bioaccumulation of Mercury in Fish Varied by Species and Location in the Chesapeake Bay Watershed—Summary of Existing Data and a Roadmap for Integrated Monitoring
Fish mercury data from State monitoring programs and research studies within the Chesapeake Bay were compiled and summarized to provide a comprehensive overview of the variation in fish mercury concentrations among species and habitats within the watershed. These data are put into context with existing health benchmarks for humans, birds, and fish. Scientists also provide a roadmap for an...
New Virus Identified in Melanistic Skin Lesions on Smallmouth Bass from the Chesapeake Bay Watershed
Scientists determined the risk factors associated with smallmouth bass melanistic skin lesions on smallmouth bass in the Susquehanna and Potomac Rivers, in the Chesapeake Bay watershed. A new virus, which appears to be a member of an emerging viral family, the Adomaviridae, was identified in the lesions. Questions remain about the full characterization of the virus and the role of environmental...
Land-use influences on estrogenic-endocrine disruption in fish within the Chesapeake Bay watershed
Issue: Effects of exposure to estrogenic-chemical contaminants have been observed in many fish species worldwide. One effect is described as “intersex” because fish will take on characteristics of the other sex, such as immature eggs forming in male fish. Studies in the Chesapeake Bay watershed have also identified the exposure of fish to endocrine-disrupting compounds. The estrogenic-endocrine...
Prevalence of Malignant Melanoma in Brown Bullhead from Lake Memphremagog Greater than Expected—Linkages to Contaminant Exposure and Implications for Fish Population Health are Currently Unknown
Raised black lesions observed in 30 percent of the brown bullhead collected from two sites in Lake Memphremagog from 2014 through 2017 were identified microscopically as malignant melanoma. Malignant melanoma in freshwater fishes has been reported before, but this cancer occurrence cluster is raising questions about the cause of the tumors and the implications for the long-term health of fish...
Point and Non-Point Sources of Endocrine Disrupting Compounds and the Potential Effects on Fish and Frogs in the New Jersey Pinelands
This project, in collaboration with the NJ Pinelands Commission and the USGS NJ Water Center, is evaluating potential effects of endocrine-disrupting chemicals from point and nonpoint sources in the Pinelands Area, a research cluster as part of the Delaware River Watershed Initiative.
Fishing and Hunting Integrated Science Team
The Fishing and Hunting integrated science team focuses on contaminant and pathogen exposures in the environment that could impact the presence and vitality of fish and wildlife populations that drive commercial, recreational and subsistence activities such as hunting and fishing. If actual risks are identified this project will inform how to economically and effectively minimize risk by providing...
Point and Nonpoint Sources of Endocrine Disrupting Compounds and the Potential effects on Fish and Frogs in the New Jersey Pinelands
Scientists from the NJ WSC, Leetown Science Center and New Jersey Pinelands Commission recently initiated a 4 year study designed to characterize the point and non-point sources of endocrine disrupting compound (EDCs) and their potential effects on fish and frogs in the NJ Pinelands.
Rainbow trout with bacterial lesions
This rainbow trout is displaying clinical signs of enteric redmouth disease caused by a systemic bacterial infection.
Striped bass with mycobacteriosis
Striped bass ( Morone saxatilis ) displaying ulcerative skin lesions and chronic wasting, both typical clinical signs of mycobacteriosis, a bacterial disease that is problematic among many types of fishes around the world.
Melanistic and normal areas of fish skin
Microscopic appearance of normal and melanistic skin in fish from Chesapeake Bay watershed.
Microscopic appearance of normal and melanistic skin in fish from Chesapeake Bay watershed.
Necropsy of a young of the year smallmouth bass
As part of a fish health assessment, Heather Walsh is performing a necropsy on a young of the year smallmouth bass from the Susquehanna River. Previously, young of the year smallmouth bass from the Susquehanna River drainage experienced fish kills and lesions. This work was conducted to follow-up on the health status of these bass populations.
As part of a fish health assessment, Heather Walsh is performing a necropsy on a young of the year smallmouth bass from the Susquehanna River. Previously, young of the year smallmouth bass from the Susquehanna River drainage experienced fish kills and lesions. This work was conducted to follow-up on the health status of these bass populations.
Intersex or testicular oocytes in smallmouth bass testes
Immature oocytes within the testicular tissue of a smallmouth bass. The histological or cellular appearance of an intersex smallmouth bass. Immature oocytes (white arrows) are present within the testicular tissue which also contains mature sperm (yellow arrows).
Immature oocytes within the testicular tissue of a smallmouth bass. The histological or cellular appearance of an intersex smallmouth bass. Immature oocytes (white arrows) are present within the testicular tissue which also contains mature sperm (yellow arrows).
Skin lesion on smallmouth bass from Chesapeake Bay watershed.
A hyperpigmented melanistic skin lesion on a Smallmouth Bass from the Chesapeake Bay Watershed.
A hyperpigmented melanistic skin lesion on a Smallmouth Bass from the Chesapeake Bay Watershed.
Raised Black External Tumors on an Adult Brown Bullhead Fish
Raised black external tumors on adult brown bullhead (Ameiurus nebulosus) collected from Lake Memphremagog (Vermont and Canadian Border) were identified as malignant melanoma in a 2014–17 study.
Raised black external tumors on adult brown bullhead (Ameiurus nebulosus) collected from Lake Memphremagog (Vermont and Canadian Border) were identified as malignant melanoma in a 2014–17 study.
Smallmouth bass
Smallmouth bass skin with melanistic lesions.
Smallmouth bass skin with melanistic lesions.
Malignant melanoma in brown bullhead
Melanoma in brown bullhead from Lake Memphremagog, Vermont
Melanoma in brown bullhead from Lake Memphremagog, Vermont
Lip tumor diagnosed as a papilloma on a white sucker
A lip tumor diagnosed as a papilloma on a white sucker (Catostomus commersonii) collected from the Milwaukee River.
A lip tumor diagnosed as a papilloma on a white sucker (Catostomus commersonii) collected from the Milwaukee River.
Surface Tumor on White Sucker
Body surface tumor diagnosed as a squamous cell carcinoma on a white sucker fish
Body surface tumor diagnosed as a squamous cell carcinoma on a white sucker fish
Dissecting a Fish to Determine Possible Endocrine Disruption Effects
USGS scientist dissecting a fish to determine possible effects from exposure to endocrine disrupting contaminants.
USGS scientist dissecting a fish to determine possible effects from exposure to endocrine disrupting contaminants.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government