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Pat Mazik, PhD

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

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delta waters with a significant amount of floating vegetation

Projecting the Distribution of Aquatic Species of Greatest Conservation Need Throughout the Mid-Atlantic Region

Climate and land use change are affecting many aquatic species throughout Maryland, Pennsylvania, Virginia, and West Virginia. The objective of this project is to understand and plan for the changes in distribution of aquatic species considered “Regional Species of Greatest Conservation Need” (RSGCN) in the mid-Atlantic region. Working with state and federal partners, this project will identify
By
Climate Adaptation Science Centers
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Projecting the Distribution of Aquatic Species of Greatest Conservation Need Throughout the Mid-Atlantic Region

Climate and land use change are affecting many aquatic species throughout Maryland, Pennsylvania, Virginia, and West Virginia. The objective of this project is to understand and plan for the changes in distribution of aquatic species considered “Regional Species of Greatest Conservation Need” (RSGCN) in the mid-Atlantic region. Working with state and federal partners, this project will identify
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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
By
Chesapeake Bay Activities, Eastern Ecological Science Center

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.
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Eastern Ecological Science Center
USGS scientist collecting a liver tissue sample from a wild-caught white sucker
USGS Scientist Collecting a Liver Tissue Sample from a Wild-Caught Whi
USGS Scientist Collecting a Liver Tissue Sample from a Wild-Caught Whi
USGS scientist collecting a liver tissue sample from a wild-caught white sucker

USGS Scientist Collecting a Liver Tissue Sample from a Wild-Caught Whi

USGS Scientist Collecting a Liver Tissue Sample from a Wild-Caught Whi

A U.S. Geological Survey (USGS) scientist collecting a liver tissue sample from a wild-caught white sucker (Catostomus commersonii) from a river in the Great Lakes area.

By
Contaminant Biology, Toxic Substances Hydrology, Environmental Health Program
USGS scientist collecting a liver tissue sample from a wild-caught white sucker

USGS Scientist Collecting a Liver Tissue Sample from a Wild-Caught Whi

USGS Scientist Collecting a Liver Tissue Sample from a Wild-Caught Whi

A U.S. Geological Survey (USGS) scientist collecting a liver tissue sample from a wild-caught white sucker (Catostomus commersonii) from a river in the Great Lakes area.

By
Contaminant Biology, Toxic Substances Hydrology, Environmental Health Program
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
By
Eastern Ecological Science Center

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
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Eastern Ecological Science Center

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
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Eastern Ecological Science Center

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
By
Ecosystems Mission Area, Contaminant Biology, Environmental Health Program, Toxic Substances Hydrology, Eastern Ecological Science Center

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
By
Ecosystems Mission Area, Eastern Ecological Science Center, Chesapeake Bay Activities

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
By
Ecosystems Mission Area, Eastern Ecological Science Center, Pennsylvania Water Science Center

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
By
Cooperative Research Units

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
By
Ecosystems Mission Area, Eastern Ecological Science Center

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
By
Ecosystems Mission Area, Eastern Ecological Science Center

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
By
Ecosystems Mission Area, Eastern Ecological Science Center

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
By
Cooperative Research Units

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
By
Ecosystems Mission Area, Eastern Ecological Science Center

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.

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