Dr. Heather Walsh is a Post Doc Researcher that has been involved in research at the Leetown Science Center Fish Health Research Lab since 2006.
She has focused her research on developing molecular techniques to better understand mechanisms associated with disease in wild fish. To serve this purpose, she has developed her skills in histopathology, in situ hybridization techniques, and laser capture microdissection. The use of these techniques has helped to understand disease observed during fish health assessments conducted in the Great Lakes and Chesapeake Bay (including the Susquehanna and Potomac River drainage). Much of the research she has been involved in has been with fish species used as indicators of environmental contamination, including smallmouth bass, brown bullhead catfish, white suckers, and yellow perch. She also uses PCR, Sanger sequencing, Nanostring technology, and RNA-Seq to help identify parasites or pathogens, for transcript abundance analyses, and de novo transcriptome development.
Professional Experience
B.S., Environmental Studies with a Concentration in Aquatic Science, Shepherd University, Shepherdstown, WV, 2008
B.S., Environmental Studies with a Concentration in Aquatic Science, Shepherd University, Shepherdstown, WV, 2008
M.S., Wildlife and Fisheries Management, West Virginia University, Morgantown, WV, 2011
Ph.D., Forest Resource Science Program, Wildlife and Fisheries Management Major, West Virginia University, 2018
Science and Products
Biological variables and liver and testes transcript abundance from smallmouth bass sampled in the Lake Erie drainage, Pennsylvania (2016)
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
Presence/Absence of Myxobolus inornatus, Aeromonas spp., and Flavobacterium spp. in Young-of-the-Year Smallmouth Bass with Fluorescence In Situ Hybridization
Histopathological assessments of young-of-the-year smallmouth bass (YOY SMB) 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 could increase the
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.
Morphometric, Age and Concentrations of Perfluoroalkyl Substances in Smallmouth Bass Plasma from Four Sites in the Chesapeake Bay Watershed
Archived plasma from fish health monitoring sites within the Chesapeake Bay watershed was analyzed for 13 perfluoroalkyl compounds. Smallmouth bass were collected from two sites in the Potomac River drainage (Antietam Creek, Maryland and South Branch Potomac, West Virginia) and two in the Susquehanna River drainage (West Branch Mahantango Creek, Pennsylvania and Pine Creek, Pennsylvania). Site and
2004-2010 Chesapeake Bay Smallmouth and Largemouth Bass Estrogenic Biomarker Data
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 P
Abundance of 50 transcripts from microdissected liver samples of smallmouth bass
There is an increasing emphasis on effects-based monitoring to document responses associated with exposure to complex mixtures of chemicals, climate change, pathogens, parasites and other environmental stressors in fish populations. For decades aquatic monitoring programs have included the collection of tissues preserved for microscopic pathology. Consequently, formalin-fixed, paraffin-embedded (F
Filter Total Items: 26
Reproductive health and endocrine disruption in smallmouth bass (Micropterus dolomieu) from the Lake Erie drainage, Pennsylvania, USA
Smallmouth bass Micropterus dolomieu were sampled from three sites within the Lake Erie drainage (Elk Creek, Twentymile Creek, and Misery Bay, an embayment in Presque Isle Bay). Plasma, tissues for histopathological analyses, and liver and testes preserved in RNALater® were sampled from 30 smallmouth bass (of both sexes) at each site. Liver and testes samples were analyzed for transcript abundance
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
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
Perfluoroalkyl substances in plasma of smallmouth bass from the Chesapeake Bay Watershed
Smallmouth bass Micropterus dolomieu is an economically important sportfish and within the Chesapeake Bay watershed has experienced a high prevalence of external lesions, infectious disease, mortality events, reproductive endocrine disruption and population declines. To date, no clear or consistent associations with contaminants measured in fish tissue or surface water have been found. Therefore,
Assessing native fish restoration potential in Catoctin Mountain Park
Biological conservation is a fundamental purpose of the National Park system, and Catoctin Mountain Park (CATO) supports high-quality habitat for native fishes in the headwaters of the Chesapeake Bay watershed in eastern North America. However, native Blue Ridge sculpin (Cottus caeruleomentum) have been extirpated in Big Hunting Creek above Cunningham Falls in CATO. Prior research indicates that i
Retrospective analysis of estrogenic endocrine disruption and land-use influences in the Chesapeake Bay watershed
The Chesapeake Bay is the largest estuary in the United States and its watershed includes river drainages in six states and the District of Columbia. Sportfishing is of major economic interest, however, the rivers within the watershed provide numerous other ecological, recreational, cultural and economic benefits, as well as serving as a drinking water source for millions of people. Consequently,
Development of a suite of functional immune assays and initial assessment of their utility in wild smallmouth bass health assessments
Methods were developed for measuring immune function in Micropterus dolomieu (smallmouth bass). The ultimate objective is to monitor and evaluate changes over time in immune status and disease resistance in conjunction with other characteristics of fish health and environmental stressors. To test these methods for utility in ecotoxicological studies, 192 smallmouth bass, age 2 years and older, wer
The effects of tissue fixation on sequencing and transcript abundance of nucleic acids from microdissected liver samples of smallmouth bass (Micropterus dolomieu)
There is an increasing emphasis on effects-based monitoring to document responses associated with exposure to complex mixtures of chemicals, climate change, pathogens, parasites and other environmental stressors in fish populations. For decades aquatic monitoring programs have included the collection of tissues preserved for microscopic pathology. Consequently, formalin-fixed, paraffin-embedded
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
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
Necropsy-based wild fish health assessment
Anthropogenic influences from increased nutrients and chemical contaminants, to habitat alterations and climate change, can have significant effects on fish populations. Adverse effects monitoring, utilizing biomarkers from the organismal to the molecular level, can be used to assess the cumulative effects on fishes and other organisms. Fish health has been used worldwide as an indicator of aquati
Indicators of exposure to estrogenic compounds at Great Lakes Areas of Concern: Species and site comparisons
Adverse effects resulting from potential exposure of wild fishes to estrogenic endocrine disruptors was assessed at seven United States Great Lakes Areas of Concern using biomarkers ranging from organismal (gonadosomatic indices) to tissue/plasma (histology, plasma vitellogenin) and molecular (hepatic gene transcripts) levels. Biomonitoring was conducted on pelagic, top predator species, largemout
Science and Products
- Data
Biological variables and liver and testes transcript abundance from smallmouth bass sampled in the Lake Erie drainage, Pennsylvania (2016)
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 forPresence/Absence of Myxobolus inornatus, Aeromonas spp., and Flavobacterium spp. in Young-of-the-Year Smallmouth Bass with Fluorescence In Situ Hybridization
Histopathological assessments of young-of-the-year smallmouth bass (YOY SMB) 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 could increase theMorphometric, 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.Morphometric, Age and Concentrations of Perfluoroalkyl Substances in Smallmouth Bass Plasma from Four Sites in the Chesapeake Bay Watershed
Archived plasma from fish health monitoring sites within the Chesapeake Bay watershed was analyzed for 13 perfluoroalkyl compounds. Smallmouth bass were collected from two sites in the Potomac River drainage (Antietam Creek, Maryland and South Branch Potomac, West Virginia) and two in the Susquehanna River drainage (West Branch Mahantango Creek, Pennsylvania and Pine Creek, Pennsylvania). Site and2004-2010 Chesapeake Bay Smallmouth and Largemouth Bass Estrogenic Biomarker Data
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 PAbundance of 50 transcripts from microdissected liver samples of smallmouth bass
There is an increasing emphasis on effects-based monitoring to document responses associated with exposure to complex mixtures of chemicals, climate change, pathogens, parasites and other environmental stressors in fish populations. For decades aquatic monitoring programs have included the collection of tissues preserved for microscopic pathology. Consequently, formalin-fixed, paraffin-embedded (F - Publications
Filter Total Items: 26
Reproductive health and endocrine disruption in smallmouth bass (Micropterus dolomieu) from the Lake Erie drainage, Pennsylvania, USA
Smallmouth bass Micropterus dolomieu were sampled from three sites within the Lake Erie drainage (Elk Creek, Twentymile Creek, and Misery Bay, an embayment in Presque Isle Bay). Plasma, tissues for histopathological analyses, and liver and testes preserved in RNALater® were sampled from 30 smallmouth bass (of both sexes) at each site. Liver and testes samples were analyzed for transcript abundanceDevelopment 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, whichIdentification 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 caPerfluoroalkyl substances in plasma of smallmouth bass from the Chesapeake Bay Watershed
Smallmouth bass Micropterus dolomieu is an economically important sportfish and within the Chesapeake Bay watershed has experienced a high prevalence of external lesions, infectious disease, mortality events, reproductive endocrine disruption and population declines. To date, no clear or consistent associations with contaminants measured in fish tissue or surface water have been found. Therefore,Assessing native fish restoration potential in Catoctin Mountain Park
Biological conservation is a fundamental purpose of the National Park system, and Catoctin Mountain Park (CATO) supports high-quality habitat for native fishes in the headwaters of the Chesapeake Bay watershed in eastern North America. However, native Blue Ridge sculpin (Cottus caeruleomentum) have been extirpated in Big Hunting Creek above Cunningham Falls in CATO. Prior research indicates that iRetrospective analysis of estrogenic endocrine disruption and land-use influences in the Chesapeake Bay watershed
The Chesapeake Bay is the largest estuary in the United States and its watershed includes river drainages in six states and the District of Columbia. Sportfishing is of major economic interest, however, the rivers within the watershed provide numerous other ecological, recreational, cultural and economic benefits, as well as serving as a drinking water source for millions of people. Consequently,Development of a suite of functional immune assays and initial assessment of their utility in wild smallmouth bass health assessments
Methods were developed for measuring immune function in Micropterus dolomieu (smallmouth bass). The ultimate objective is to monitor and evaluate changes over time in immune status and disease resistance in conjunction with other characteristics of fish health and environmental stressors. To test these methods for utility in ecotoxicological studies, 192 smallmouth bass, age 2 years and older, werThe effects of tissue fixation on sequencing and transcript abundance of nucleic acids from microdissected liver samples of smallmouth bass (Micropterus dolomieu)
There is an increasing emphasis on effects-based monitoring to document responses associated with exposure to complex mixtures of chemicals, climate change, pathogens, parasites and other environmental stressors in fish populations. For decades aquatic monitoring programs have included the collection of tissues preserved for microscopic pathology. Consequently, formalin-fixed, paraffin-embeddedAssessment 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 BlacknosAssessment 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 analyNecropsy-based wild fish health assessment
Anthropogenic influences from increased nutrients and chemical contaminants, to habitat alterations and climate change, can have significant effects on fish populations. Adverse effects monitoring, utilizing biomarkers from the organismal to the molecular level, can be used to assess the cumulative effects on fishes and other organisms. Fish health has been used worldwide as an indicator of aquatiIndicators of exposure to estrogenic compounds at Great Lakes Areas of Concern: Species and site comparisons
Adverse effects resulting from potential exposure of wild fishes to estrogenic endocrine disruptors was assessed at seven United States Great Lakes Areas of Concern using biomarkers ranging from organismal (gonadosomatic indices) to tissue/plasma (histology, plasma vitellogenin) and molecular (hepatic gene transcripts) levels. Biomonitoring was conducted on pelagic, top predator species, largemout