Paul Hershberger is the Chief of the Fish Heath Section at the U. S. Geological Survey - Western Fisheries Research Center (Seattle, WA) and the Station Leader at the Marrowstone Marine Field Station (Nordland, WA). He is an Affiliate Professor at the University of Washington – School of Aquatic and Fishery Sciences, and former President of the Fish Health Section - American Fisheries Society.
Paul has the pleasure of leading a team of fish health professionals who are experts in their respective fields of fish virology, immunology, toxicology, histopathology, parasitology, and disease ecology. Specific components of the Fish Health Section focus on:
- the development of immune-related tools for fishes and the impact(s) of environmental stressors (e.g. contaminants, pathogens, temperature) on the fish immune response.
- the use of gene knock outs in zebrafish and other model species to assess pathogen virulence and host immune response mechanisms.
- the evolution of virulence and other phenotypes in fish viruses using landscape-scale genotyping to identify patterns of virus occurrence, transmission, and disease impacts across borad temporal and geographic scales.
- the discovery and identification of new and emerging fish viruses in the Pacific Northwest and throughout North America.
- the integration of novel quantitative techniques to understand stochasticity of pathogen transmission and other mechanisms of basic and applied disease ecology.
- the use of histopathology and electron microscopy to assess pathogen / disease monitoring and research needs in populations of wild and hatchery-raised fishes.
- the effects of environmental contaminants, including PAH’s, PCB’s, and emerging contaminants like PFAS and 6-PPD quinone on fish health, survival, and immunological pathways.
- the range expansion of invasive amphibians and their susceptibility to native and exotic pathogens.
In addition, Paul’s personal research employs a combination of laboratory and field approaches to understand, forecast, and mitigate the impacts of infectious and parasitic diseases on populations of wild marine and anadromous fishes.
Professional Experience
2022 to Present: Fish Health Section Chief, U.S. Geological Survey, Western Fisheries Research Center, Seattle, WA
2003 to Present – Station Leader, U.S. Geological Survey, Western Fisheries Research Center, Marrowstone Marine Field Station, Nordland, WA
2004 to Present – Member of the Affiliate Faculty, School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA
Education and Certifications
Ph.D. Fisheries, School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA
M.S. Fisheries, School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA
B.S. Chemistry and Biology, Northland College, Ashland, WI
Science and Products
AquaDePTH-Aquatic Disease and Pathogen Repository
Partners - FHP
Fish Health Program Lead Scientists and Areas of Expertise
Species Studied by the Fish Health Program
Tribal Collaboration - Fish Health Program (FHP)
Phylogenetics of Ichthyophonus parasites
PCB Exposure and Disease Susceptibility
PAH Exposure and Disease Susceptibility
Species Studied at the Marrowstone Marine Field Station
Effects of Nanophyetus salmincola on the Health and Survival of Puget Sound Steelhead
Genomic Mechanisms that Underlie Lack of Recovery of Prince William Sound Herring Following the 1990s Collapse
Herring Disease Program
Caligus Clemensi prevalence and counts on Clupea pallasii from Port Angeles Harbor, WA and from a controlled laboratory experiment conducted at USGS Marrowstone Marine Field Station, WA
Histological and molecular testing of nuclear inclusion X in Pacific Razor clams from select locations in Washington, USA
Survey of viral hemorrhagic septicemia virus in Pacific herring throughout the North Pacific Ocean
Laboratory challenge of Pacific herring Clupea pallasii to Vibrio anguillarum and V. ordallii
Biological responses of Pacific herring embryos to crude oil are quantifiable at exposure levels below conventional limits of quantitation for PAHs in water and tissues
Temporal, environmental, and demographic correlates of Ichthyophonus sp. infections in mature Pacific herring populations
Characteristics of a sea louse (Caligus clemensi) epizootic in wild Pacific herring (Clupea pallasii)
Evaluating the effect of nuclear inclusion X (NIX) infections on Pacific razor clam populations
A phylogeny based on cytochrome-c oxidase gene sequences identifies sympatric Ichthyophonus genotypes in the NE Pacific Ocean
A novel approach for directly incorporating disease into fish stock assessment: A case study with seroprevalence data
Annual recurrences of viral hemorrhagic septicemia epizootics in age 0 Pacific herring Clupea pallasii Valenciennes, 1847
Herring Disease Program - Annual Project Report 2012011-E, February 1, 2010-January 31, 2021
Long-term shedding from fully convalesced individuals indicates that Pacific herring are a reservoir for viral hemorrhagic septicemia virus
Differential susceptibility of Yukon River and Salish Sea stocks of Chinook salmon Oncorhynchus tshawytscha to ichthyophoniasis
Novel diagnostic tests for the putative agent of bacterial gill disease in Pacific razor clams (Siliqua patula)
Anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii as a host for Argulus pugettensis (Crustacea, Branchiura): Parasite prevalence, intensity and distribution
Science and Products
- Science
Filter Total Items: 29
AquaDePTH-Aquatic Disease and Pathogen Repository
The Aquatic Disease and Pathogen Repository (AquaDePTH) will be a public-facing national repository to support biosurveillance of aquatic animal diseases and pathogens. By collating historically published data, plus new aquatic pathogen and disease information, stakeholders will be able monitor fish kill and aquatic pathogen trends spatially and temporally in freshwater and marine environments...Partners - FHP
For more than five decades the WFRC Fish Health Program has worked with partners to provide research findings to managers of aquatic resources. Those partners form a network of colleagues, co-investigators, and customers. Our partners include Department of the Interior bureaus, tribal and state fisheries agencies, other federal partners and the private sector.Fish Health Program Lead Scientists and Areas of Expertise
Lead Scientists - ExpertiseSpecies Studied by the Fish Health Program
List of species studied by the Fish Health Program. These species include bacteria, fish, parasites, and viruses. The list contains both common and scientific names. Descriptions of species and studies can be found under the "Related Science" tab.Tribal Collaboration - Fish Health Program (FHP)
The Fish Health Program has a strong commitment to respond to requests for research and technical support from Tribal fisheries agencies.Phylogenetics of Ichthyophonus parasites
Ichthyophonus spp. are perhaps the most economically and ecologically important parasites of wild marine fish in the world.PCB Exposure and Disease Susceptibility
Researchers at that MMFS are experimentally determining the impacts of high PCB body burdens on the immunocompetency and disease susceptibility of Pacific herring.PAH Exposure and Disease Susceptibility
Researchers at the MMFS are studying the immediate and delayed effects of petroleum hydrocarbon exposures to Pacific herring.Species Studied at the Marrowstone Marine Field Station
The Disease Ecology Research Program at the Marrowstone Marine Field Station addresses fundamental disease processes that impact wild marine and anadromous fishes. The program is not designed around particular host or pathogen species; rather we investigate diseases processes that involve numerous species of marine hosts and pathogens. Please follow the links for more information about some of the...Effects of Nanophyetus salmincola on the Health and Survival of Puget Sound Steelhead
Low early marine survival rates of Puget Sound steelhead (Oncorhynchus mykiss), the state fish of Washington, have contributed to its dramatic population decline and current listing as a “Threatened Species” under the Endangered Species Act. Determining the cause(s) of this elevated mortality remains a primary objective of the Salish Sea Marine Survival Project, a large US / Canada effort...Genomic Mechanisms that Underlie Lack of Recovery of Prince William Sound Herring Following the 1990s Collapse
In the decades following the Exxon Valdez Oil Spill (EVOS), it has become increasingly apparent that oil can be toxic at extremely low concentrations to developing fish embryos including herring, where some toxic phenotypes may be apparent during embryogenesis, but some are delayed until later in life. Therefore, acute and lingering oil may act as an insidious selective force within populations...Herring Disease Program
Using an approach that involves a combination of field- and laboratory-based studies, we are investigating fish health factors that may be contributing to the failed recovery of Pacific herring populations in Prince William Sound, AK. Field studies are providing infection and disease prevalence data to inform the population models, serological data that indicate the prior exposure history and... - Data
Caligus Clemensi prevalence and counts on Clupea pallasii from Port Angeles Harbor, WA and from a controlled laboratory experiment conducted at USGS Marrowstone Marine Field Station, WA
We characterized a natural sea louse epizootic of Caligus clemensi and the effects of parasitism on Pacific herring Clupea pallasii in Port Angeles Harbor, WA, USA. Infestation prevalence on newly metamorphosed age0 Pacific herring reached 100% prevalence by mid-August. At this time, the mean louse intensity was 4.6 lice and a positive correlation occurred between louse intensity and Pacific herriHistological and molecular testing of nuclear inclusion X in Pacific Razor clams from select locations in Washington, USA
Nuclear inclusion X (NIX), the etiological agent of bacterial gill disease in Pacific razor clams (Siliqua patula) was associated with host mortality events in coastal Washington, USA during the mid-1980s. Ongoing observations of truncated razor clam size distributions in Kalaloch Beach, Washington raised concerns that NIX continues to impact populations. We conducted a series of spatial and longiSurvey of viral hemorrhagic septicemia virus in Pacific herring throughout the North Pacific Ocean
Throughout a 20-year biosurveillance period, viral hemorrhagic septicemia virus was isolated in low titers from only 6 / 7,355 opportunistically sampled adult Pacific herring, reflecting the typical endemic phase of the disease when the virus persists covertly. However, more focused surveillance efforts identified the presence of disease hot spots occurring among juvenile life history stages fromLaboratory challenge of Pacific herring Clupea pallasii to Vibrio anguillarum and V. ordallii
Controlled waterborne exposures of Pacific herring (Clupea pallasii) to Vibrio anguillarum and V. ordalii failed to result in overt signs of disease or mortality from vibriosis. Cumulative mortalities among Vibrio - exposed Pacific herring (3.3 - 5.0 percent) were similar to those of saline-exposed negative controls (10 percent) and significantly less (P less than 0.001) than those of Vibrio - exp - Multimedia
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Biological responses of Pacific herring embryos to crude oil are quantifiable at exposure levels below conventional limits of quantitation for PAHs in water and tissues
Pacific herring (Clupea pallasii), a cornerstone of marine food webs, generally spawn on marine macroalgae in shallow nearshore areas that are disproportionately at risk from oil spills. Herring embryos are also highly susceptible to toxicity from chemicals leaching from oil stranded in intertidal and subtidal zones. The water-soluble components of crude oil trigger an adverse outcome pathway thatAuthorsJohn P. Incardona, Tiffany L. Linbo, James R. Cameron, Barbara L. French, Jennie L. Bolton, Jacob L. Gregg, Carey E. Donald, Paul Hershberger, Nathaniel L. ScholzTemporal, environmental, and demographic correlates of Ichthyophonus sp. infections in mature Pacific herring populations
Causes of population collapse and failed recovery often remain enigmatic in marine forage fish like Pacific herring (Clupea pallasii) that experience dramatic population oscillations. Diseases such as ichthyophoniasis are hypothesized to contribute to these declines, but lack of long-term datasets frequently prevents inference. Analysis of pathogen surveillance and population assessment datasets sAuthorsMaya Groner, Eliana D. Bravo-Mendosa, Ashley MacKenzie, Jacob L. Gregg, Carla M. Conway, John T. Trochta, Paul HershbergerCharacteristics of a sea louse (Caligus clemensi) epizootic in wild Pacific herring (Clupea pallasii)
We characterized a natural sea louse epizootic of Caligus clemensi and the effects of parasitism on Pacific herring Clupea pallasii in Port Angeles Harbor, WA, USA. Infestation prevalence on newly metamorphosed age 0 Pacific herring reached 100% prevalence by mid-August. At this time, the mean louse intensity was 4.6 lice/fish, and a positive correlation occurred between louse intensity and herrinAuthorsDavid James Páez, Jacob L. Gregg, Ashley MacKenzie, Sophie Amanda Hall, Paul HershbergerEvaluating the effect of nuclear inclusion X (NIX) infections on Pacific razor clam populations
ABSTRACT: Nuclear inclusion X (NIX), the etiological agent of bacterial gill disease in Pacific razor clams Siliqua patula, was associated with host mortality events in coastal Washington State, USA, during the mid-1980s. Ongoing observations of truncated razor clam size distributions in Kalaloch Beach, Washington, raised concerns that NIX continues to impact populations. We conducted a series ofAuthorsMaya Groner, Paul Hershberger, Steven C. Fradkin, Carla M. Conway, Aine Marie Alice Campbell Hawthorn, Maureen K. PurcellA phylogeny based on cytochrome-c oxidase gene sequences identifies sympatric Ichthyophonus genotypes in the NE Pacific Ocean
ABSTRACT: In recent decades, evidence has accumulated to suggest that the widespread and highly variable parasite Ichthyophonus hoferi is actually a species complex. Highly plastic morphology and a general lack of defining structures has contributed to the likely underestimate of biodiversity within this group. Molecular methods are a logical next step in the description of these parasites, but maAuthorsJacob L. Gregg, Paul Hershberger, Abigail S. Neat, Hiruni T. Jayasekera, Jayde A. Ferguson, Rachel L. Powers, Maureen K. PurcellA novel approach for directly incorporating disease into fish stock assessment: A case study with seroprevalence data
When estimating mortality from disease with fish population models, common disease surveillance data such as infection prevalence are not always informative, especially for fast-acting diseases that may go unobserved in infrequently sampled populations. In these cases, seroprevalence — the proportion of fish with measurable antibody levels in their blood — may be more informative. In cases of lifeAuthorsJohn T. Trochta, Maya Groner, Paul Hershberger, Trevor A. BranchAnnual recurrences of viral hemorrhagic septicemia epizootics in age 0 Pacific herring Clupea pallasii Valenciennes, 1847
Throughout a 20 year biosurveillance period, viral hemorrhagic septicemia virus was isolated in low titers from only 6/7355 opportunistically sampled adult Pacific herring, reflecting the typical endemic phase of the disease when the virus persists covertly. However, more focused surveillance efforts identified the presence of disease hot spots occurring among juvenile life history stages from cerAuthorsPaul Hershberger, Theodore R. Meyers, Jacob L. Gregg, Maya Groner, Sophie Amanda Hall, Hiruni T. Jayasekera, Ashley MacKenzie, Abigail S. Neat, Ella N. Piatt, Kyle A. GarverHerring Disease Program - Annual Project Report 2012011-E, February 1, 2010-January 31, 2021
We will investigate fish health factors that may be contributing to the failed recovery of Pacific herring populations in Prince William Sound. Field samples will provide infection and disease prevalence data from Prince William Sound and Sitka Sound to inform the age structured assessment (ASA) model, serological data will indicate the prior exposure history and future susceptibility of herring tAuthorsPaul Hershberger, Maureen K. PurcellLong-term shedding from fully convalesced individuals indicates that Pacific herring are a reservoir for viral hemorrhagic septicemia virus
Processes that allow viral hemorrhagic septicemia (VHS) virus to persist in the marine environment remain enigmatic, owing largely to the presence of covert and cryptic infections in marine fishes during typical sub-epizootic periods. As such, marine host reservoirs for VHS virus have not been fully demonstrated, nor have the mechanism(s) by which infected hosts contribute to virus perpetuation anAuthorsPaul Hershberger, Ashley MacKenzie, Jacob L. Gregg, M. D. Wilmot, Rachel L. Powers, Maureen K. PurcellDifferential susceptibility of Yukon River and Salish Sea stocks of Chinook salmon Oncorhynchus tshawytscha to ichthyophoniasis
Preliminary evidence suggests that Chinook salmon Oncorhynchus tshawytscha from the Yukon River may be more susceptible to Ichthyophonus sp. infections than Chinook from stocks further south. To investigate this hypothesis in a controlled environment, we experimentally challenged juvenile Chinook from the Yukon River and from the Salish Sea with Ichthyophonus sp. and evaluated mortality, infectionAuthorsDiane G. Elliott, Carla M. Conway, Constance L. McKibben, Ashley MacKenzie, Lucas M. Hart, Maya Groner, Maureen K. Purcell, Jacob L. Gregg, Paul HershbergerNovel diagnostic tests for the putative agent of bacterial gill disease in Pacific razor clams (Siliqua patula)
Nuclear inclusion X (NIX) is a gamma proteobacteria that infects the nuclei of gill epithelial cells in Pacific razor clams. NIX has been associated with clam die-offs in coastal Washington. A quantitative PCR (qPCR) assay was developed to detect NIX in Pacific razor clams, and assay specificity was confirmed by chromogenic in situ hybridization (CISH). Both tests were applied to evaluate NIX infeAuthorsBrooke A Travis, William N. Batts, Maya Groner, Paul Hershberger, Steven C. Fradkin, Carla M. Conway, Linda Park, Maureen K. PurcellAnadromous coastal cutthroat trout Oncorhynchus clarkii clarkii as a host for Argulus pugettensis (Crustacea, Branchiura): Parasite prevalence, intensity and distribution
Coastal cutthroat trout [Oncorhynchus clarkii clarkii (Richardson, 1836)] from the marine waters of Puget Sound, WA, was documented as a new host for the ectoparasite Argulus pugettensis (Dana, 1852). The prevalence of A. pugettensis was 66% (49 of 74) on cutthroat trout and 0% (0 of 55) on coho salmon [O. kisutch (Walbaum, 1792)] collected during the winter of 2017/2018. Infestations occurred mosAuthorsJames P Losee, Simon R M Jones, Caitlin A E McKinstry, William N. Batts, Paul Hershberger - News