Unit Leader - West Virginia Cooperative Fish and Wildlife Research Unit
Research Interests
Pat's research emphasis is stress physiology and the effects of contaminants on fish.
Teaching Interests
Pat teaches classes in Fish Physiology and Aquatic Toxicology.
Professional Experience
Unit Leader, West Virginia Cooperative Fish and Wildlife Research Unit, 1998-
Education and Certifications
Ph D University of Memphis 1989
MS Texas State University - San Marcos 1985
BS University of Mount Union 1983
Science and Products
Immune Function of Wild Smallmouth Bass Collected from Sites within the Chesapeake Bay Watershed, 2016-2021
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 com
Morphometric, Age, Visible Abnormalities, Skin and Liver Neoplasms, and Stable Isotopes in White Sucker Collected in the St. Louis River and Estuary, Minnesota/Wisconsin, 2011-2015
The dataset provides length, weight, age, observations of visible external abnormalities, liver and skin histopathology and stable isotopes of white sucker captured within the St. Louis river and associated bays.
Filter Total Items: 22
Application of a lipopolysaccharide (LPS)-stimulated mitogenesis assay in smallmouth bass (Micropterus dolomieu) to augment wild fish health studies
The utility of a functional immune assay for smallmouth bass (Micropterus dolomieu) lymphocyte mitogenesis was evaluated. Wild populations in the Potomac River have faced disease and mortality with immunosuppression from exposure to chemical contaminants a suspected component. However, a validated set of immune parameters to screen for immunosuppression in wild fish populations is not available. P
Authors
Cheyenne R. Smith, Christopher A. Ottinger, Heather L. Walsh, Patricia M. Mazik, Vicki S. Blazer
Development of a multiplex fluorescence in situ hybridization assay to identify coinfections in young-of-the-year smallmouth bass
Histopathological assessments of young-of-the-year (age-0) Smallmouth Bass Micropterus dolomieu in the Susquehanna River drainage identified a high prevalence of the myxozoan Myxobolus inornatus. This myxozoan infects the connective tissue of the muscle below the skin but is sometimes observed in the esophagus and buccal cavity. In some instances, shallow infections cause breaks in the skin, which
Authors
Heather L. Walsh, Vicki S. Blazer, Patricia M. Mazik
Identification of Aphanomyces invadans, the cause of epizootic ulcerative syndrome, in smallmouth bass (Micropterus dolomieu) from the Cheat River, West Virginia, USA
The oomycete Aphanomyces invadans (Saprolegniales, Oomycetes), the cause of epizootic ulcerative syndrome (EUS), is an OIE (World Organization for Animal Health) reportable pathogen, capable of infecting many fish species worldwide in both freshwater and estuarine environments (Iberahim et al. 2018). Since the discovery of EUS in Japan in 1971 (Egusa and Masuda 1971), it has spread globally and ca
Authors
Heather L. Walsh, Vicki S. Blazer, Patricia M. Mazik
Biological and anthropogenic influences on macrophage aggregates in white perch Morone americana from Chesapeake Bay, USA
The response of macrophage aggregates in fish to a variety of environmental stressors has been useful as a biomarker of exposure to habitat degradation. Total volume of macrophage aggregates (MAV) was estimated in the liver and spleen of white perch Morone americana from Chesapeake Bay using stereological approaches. Hepatic and splenic MAV were compared between fish populations from the rural Cho
Authors
Mark A Matsche, Vicki S. Blazer, Erin Pulster, Patricia M. Mazik
High prevalence of biliary neoplasia in white perch Morone americana: Potential roles of bile duct parasites and environmental contaminants
Recent surveys of white perch Morone americana from Chesapeake Bay, USA, revealed a high prevalence of hepatic and biliary lesions, including neoplasia, and bile duct parasites. Here, we describe lesions in the liver and gallbladder and evaluate for statistical associations among lesions, parasites, and biomarkers of chemical exposure in fish from 2 tributaries of Chesapeake Bay. Fish were collect
Authors
Mark A Matsche, Vicki S. Blazer, Erin Pulster, Patricia M. Mazik
Assessment of microscopic pathology in fishes collected at sites impacted by wood tar in Pennsylvania
In an effort to determine whether fish populations in an area affected by wood tar waste exhibited health effects, fish were collected and analyzed with histopathology. Multiple species, including Mottled Sculpin (Cottus bairdii), Creek Chub (Semotilus atromaculatus), White Sucker (Catostumus commersonii), Redside Dace (Clinostomus elongatus), Common Shiner (Luxilus cornutus), and Western Blacknos
Authors
Heather L. Walsh, Vicki S. Blazer, Patricia M. Mazik, Adam J. Sperry, Diana Pavlick
The effects of swimming exercise and dissolved oxygen on growth performance, fin condition and survival of rainbow trout Oncorhynchus mykiss
Swimming exercise and dissolved oxygen (DO) are important parameters to consider when operating intensive salmonid aquaculture facilities. While previous research has focused on each of these two variables in rainbow trout Oncorhynchus mykiss, studies examining both variables in combination, and their potential interaction, are absent from the scientific literature. Both swimming exercise (usually
Authors
Thomas Waldrop, Steven Summerfelt, Patricia M. Mazik, P. Brett Kenney, Christopher Good
Comparisons of stereological and other approaches for quantifying macrophage aggregates in piscine spleens
Macrophage aggregates (MA s) are focal accumulations of pigmented macrophages in the spleen and other tissues of fish. A central role of MA s is the clearance and destruction of degenerating cells and recycling of some cellular components. Macrophage aggregates also respond to chemical contaminants and infectious agents and may play a role in the adaptive immune response. Tissue damage or physiolo
Authors
Mark A Matsche, Vicki S. Blazer, Patricia M. Mazik
Seasonal development of the coccidian parasite Goussia bayae and hepatobiliary histopathology in white perch Morone americana from Chesapeake Bay
The coccidium Goussia bayae infects the gallbladder and bile ducts of white perch Morone americana from Chesapeake Bay, USA. Seasonal changes in coccidian infections were analyzed from bile specimens of 1588 fish from the Choptank River during 2016-2018 using wet mount preparations with a Sedgwick-Rafter counting chamber. Histopathology of the gallbladder and liver was analyzed from a subset (n =
Authors
Mark A Matsche, Vicki S. Blazer, Patricia M. Mazik
Assessment of skin and liver neoplasms in white sucker (Catostomus commersonii) collected in the Sheboygan River Area of Concern, Wisconsin, in 2017
Two hundred adult white sucker (Catostomus commersonii), age 3 years and older, were collected from the lower Sheboygan River Area of Concern in 2017, during the spring spawning run. Fish were euthanized, weighed, and measured, and any visible abnormalities were documented. Pieces of raised skin lesions as well as five to eight pieces of liver were removed and preserved for histopathological analy
Authors
Vicki S. Blazer, Heather L. Walsh, Ryan P. Braham, Patricia M. Mazik
The effects of swimming exercise and dissolved oxygen on growth performance, fin condition and precocious maturation of early-rearing Atlantic salmon Salmo salar
Swimming exercise, typically measured in body-lengths per second (BL/s), and dissolved oxygen (DO), are important environmental variables in fish culture. While there is an obvious physiological association between these two parameters, their interaction has not been adequately studied in Atlantic salmon Salmo salar. Because exercise and DO are variables that can be easily manipulated in modern aq
Authors
Thomas Waldrop, Steven T. Summerfelt, Patricia M. Mazik, Christopher Good
Micronuclei and other erythrocyte nuclear abnormalities in fishes from the Great Lakes Basin, USA
Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumer
Authors
Ryan P. Braham, Vicki S. Blazer, Cassidy H. Shaw, Patricia M. Mazik
Non-USGS Publications**
Mazik, P.M., R. P. Braham, C. M. Hahn, and V.S. Blazer. 2015. Assessment of general and reproductive health of fishes at selected sites in the Great Lakes Basin in 2012. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/CSS-112-2015, Washington, D.C.
Aunins, A.W., J.T. Petty, T.L. King, M. Schilz and P.M Mazik, River mainstem thermal regimes influence population structuring within an appalachian brook trout population. Conserv Genet (2015) 16: 15. doi:10.1007/s10592-014-0636-6
Drew R. Ekman, Gerald T. Ankley, Vicki S. Blazer, Timothy W. Collette, Natàlia Garcia-Reyero, Luke R. Iwanowicz, Zachary G. Jorgenson, Kathy E. Lee, Pat M. Mazik, David H. Miller, Edward J. Perkins, Edwin T. Smith, Joseph E. Tietge and Daniel L. Villeneuve (2013). ENVIRONMENTAL REVIEWS AND CASE STUDIES: Biological Effects–Based Tools for Monitoring Impacted Surface Waters in the Great Lakes: A Multiagency Program in Support of the Great Lakes Restoration Initiative. Environmental Practice, 15, pp 409-426. doi:10.1017/S1466046613000458.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Data
Immune Function of Wild Smallmouth Bass Collected from Sites within the Chesapeake Bay Watershed, 2016-2021
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 comMorphometric, Age, Visible Abnormalities, Skin and Liver Neoplasms, and Stable Isotopes in White Sucker Collected in the St. Louis River and Estuary, Minnesota/Wisconsin, 2011-2015
The dataset provides length, weight, age, observations of visible external abnormalities, liver and skin histopathology and stable isotopes of white sucker captured within the St. Louis river and associated bays. - Multimedia
- Publications
Filter Total Items: 22
Application of a lipopolysaccharide (LPS)-stimulated mitogenesis assay in smallmouth bass (Micropterus dolomieu) to augment wild fish health studies
The utility of a functional immune assay for smallmouth bass (Micropterus dolomieu) lymphocyte mitogenesis was evaluated. Wild populations in the Potomac River have faced disease and mortality with immunosuppression from exposure to chemical contaminants a suspected component. However, a validated set of immune parameters to screen for immunosuppression in wild fish populations is not available. PAuthorsCheyenne R. Smith, Christopher A. Ottinger, Heather L. Walsh, Patricia M. Mazik, Vicki S. BlazerDevelopment of a multiplex fluorescence in situ hybridization assay to identify coinfections in young-of-the-year smallmouth bass
Histopathological assessments of young-of-the-year (age-0) Smallmouth Bass Micropterus dolomieu in the Susquehanna River drainage identified a high prevalence of the myxozoan Myxobolus inornatus. This myxozoan infects the connective tissue of the muscle below the skin but is sometimes observed in the esophagus and buccal cavity. In some instances, shallow infections cause breaks in the skin, whichAuthorsHeather L. Walsh, Vicki S. Blazer, Patricia M. MazikIdentification of Aphanomyces invadans, the cause of epizootic ulcerative syndrome, in smallmouth bass (Micropterus dolomieu) from the Cheat River, West Virginia, USA
The oomycete Aphanomyces invadans (Saprolegniales, Oomycetes), the cause of epizootic ulcerative syndrome (EUS), is an OIE (World Organization for Animal Health) reportable pathogen, capable of infecting many fish species worldwide in both freshwater and estuarine environments (Iberahim et al. 2018). Since the discovery of EUS in Japan in 1971 (Egusa and Masuda 1971), it has spread globally and caAuthorsHeather L. Walsh, Vicki S. Blazer, Patricia M. MazikBiological and anthropogenic influences on macrophage aggregates in white perch Morone americana from Chesapeake Bay, USA
The response of macrophage aggregates in fish to a variety of environmental stressors has been useful as a biomarker of exposure to habitat degradation. Total volume of macrophage aggregates (MAV) was estimated in the liver and spleen of white perch Morone americana from Chesapeake Bay using stereological approaches. Hepatic and splenic MAV were compared between fish populations from the rural ChoAuthorsMark A Matsche, Vicki S. Blazer, Erin Pulster, Patricia M. MazikHigh prevalence of biliary neoplasia in white perch Morone americana: Potential roles of bile duct parasites and environmental contaminants
Recent surveys of white perch Morone americana from Chesapeake Bay, USA, revealed a high prevalence of hepatic and biliary lesions, including neoplasia, and bile duct parasites. Here, we describe lesions in the liver and gallbladder and evaluate for statistical associations among lesions, parasites, and biomarkers of chemical exposure in fish from 2 tributaries of Chesapeake Bay. Fish were collectAuthorsMark A Matsche, Vicki S. Blazer, Erin Pulster, Patricia M. MazikAssessment of microscopic pathology in fishes collected at sites impacted by wood tar in Pennsylvania
In an effort to determine whether fish populations in an area affected by wood tar waste exhibited health effects, fish were collected and analyzed with histopathology. Multiple species, including Mottled Sculpin (Cottus bairdii), Creek Chub (Semotilus atromaculatus), White Sucker (Catostumus commersonii), Redside Dace (Clinostomus elongatus), Common Shiner (Luxilus cornutus), and Western BlacknosAuthorsHeather L. Walsh, Vicki S. Blazer, Patricia M. Mazik, Adam J. Sperry, Diana PavlickThe effects of swimming exercise and dissolved oxygen on growth performance, fin condition and survival of rainbow trout Oncorhynchus mykiss
Swimming exercise and dissolved oxygen (DO) are important parameters to consider when operating intensive salmonid aquaculture facilities. While previous research has focused on each of these two variables in rainbow trout Oncorhynchus mykiss, studies examining both variables in combination, and their potential interaction, are absent from the scientific literature. Both swimming exercise (usuallyAuthorsThomas Waldrop, Steven Summerfelt, Patricia M. Mazik, P. Brett Kenney, Christopher GoodComparisons of stereological and other approaches for quantifying macrophage aggregates in piscine spleens
Macrophage aggregates (MA s) are focal accumulations of pigmented macrophages in the spleen and other tissues of fish. A central role of MA s is the clearance and destruction of degenerating cells and recycling of some cellular components. Macrophage aggregates also respond to chemical contaminants and infectious agents and may play a role in the adaptive immune response. Tissue damage or physioloAuthorsMark A Matsche, Vicki S. Blazer, Patricia M. MazikSeasonal development of the coccidian parasite Goussia bayae and hepatobiliary histopathology in white perch Morone americana from Chesapeake Bay
The coccidium Goussia bayae infects the gallbladder and bile ducts of white perch Morone americana from Chesapeake Bay, USA. Seasonal changes in coccidian infections were analyzed from bile specimens of 1588 fish from the Choptank River during 2016-2018 using wet mount preparations with a Sedgwick-Rafter counting chamber. Histopathology of the gallbladder and liver was analyzed from a subset (n =AuthorsMark A Matsche, Vicki S. Blazer, Patricia M. MazikAssessment of skin and liver neoplasms in white sucker (Catostomus commersonii) collected in the Sheboygan River Area of Concern, Wisconsin, in 2017
Two hundred adult white sucker (Catostomus commersonii), age 3 years and older, were collected from the lower Sheboygan River Area of Concern in 2017, during the spring spawning run. Fish were euthanized, weighed, and measured, and any visible abnormalities were documented. Pieces of raised skin lesions as well as five to eight pieces of liver were removed and preserved for histopathological analyAuthorsVicki S. Blazer, Heather L. Walsh, Ryan P. Braham, Patricia M. MazikThe effects of swimming exercise and dissolved oxygen on growth performance, fin condition and precocious maturation of early-rearing Atlantic salmon Salmo salar
Swimming exercise, typically measured in body-lengths per second (BL/s), and dissolved oxygen (DO), are important environmental variables in fish culture. While there is an obvious physiological association between these two parameters, their interaction has not been adequately studied in Atlantic salmon Salmo salar. Because exercise and DO are variables that can be easily manipulated in modern aqAuthorsThomas Waldrop, Steven T. Summerfelt, Patricia M. Mazik, Christopher GoodMicronuclei and other erythrocyte nuclear abnormalities in fishes from the Great Lakes Basin, USA
Biological markers (biomarkers) sensitive to genotoxic and mutagenic contamination in fishes are widely used to identify exposure effects in aquatic environments. The micronucleus assay was incorporated into a suite of indicators to assess exposure to genotoxic and mutagenic contamination at five Great Lakes Areas of Concern (AOCs), as well as one non-AOC (reference) site. The assay allowed enumerAuthorsRyan P. Braham, Vicki S. Blazer, Cassidy H. Shaw, Patricia M. MazikNon-USGS Publications**
Mazik, P.M., R. P. Braham, C. M. Hahn, and V.S. Blazer. 2015. Assessment of general and reproductive health of fishes at selected sites in the Great Lakes Basin in 2012. Department of Interior, Fish and Wildlife Service, Cooperator Science Series FWS/CSS-112-2015, Washington, D.C.Aunins, A.W., J.T. Petty, T.L. King, M. Schilz and P.M Mazik, River mainstem thermal regimes influence population structuring within an appalachian brook trout population. Conserv Genet (2015) 16: 15. doi:10.1007/s10592-014-0636-6Drew R. Ekman, Gerald T. Ankley, Vicki S. Blazer, Timothy W. Collette, Natàlia Garcia-Reyero, Luke R. Iwanowicz, Zachary G. Jorgenson, Kathy E. Lee, Pat M. Mazik, David H. Miller, Edward J. Perkins, Edwin T. Smith, Joseph E. Tietge and Daniel L. Villeneuve (2013). ENVIRONMENTAL REVIEWS AND CASE STUDIES: Biological Effects–Based Tools for Monitoring Impacted Surface Waters in the Great Lakes: A Multiagency Program in Support of the Great Lakes Restoration Initiative. Environmental Practice, 15, pp 409-426. doi:10.1017/S1466046613000458.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.