About

Paul Bowser, PhD, is a Professor Emeritus of Aquatic Animal Medicine and a Graduate School Professor of Comparative Biomedical Sciences at Cornell University College of Veterinary Medicine in Ithaca, NY. He has a long-standing career focused on infectious and non-infectious diseases of fishes and strategies for fish health management. His recent major research efforts include studying the pathogenesis of walleye dermal sarcoma retrovirus, understanding the seasonality of tumor viruses in fish, and developing therapeutants for cultured food fishes, particularly in aquaculture. Dr. Bowser operates the Fish Disease Diagnostic Laboratory, providing disease diagnostic assistance to the aquaculture community, research community, and fish hobbyists, and collaborates on investigations of fish kills and emerging fish health issues such as Viral Hemorrhagic Septicemia Virus in the Great Lakes Basin. He received his BS from Cornell University in 1970, MS from Iowa State University in 1972, and PhD from Auburn University in 1978. His professional experience includes positions at Mississippi State University and the University of California, Davis, prior to his tenure at Cornell. Dr. Bowser has been continuously funded for his research and has received numerous awards, including the State University of New York Chancellor’s Award for Faculty Service, the S. F. Snieszko Distinguished Service Award from the American Fisheries Society, the National Sea Grant Program Research to Application Award, the Christensen Award for Excellence in Fish Health, and others. He has been recognized as a Distinguished Friend of the Eastern Fish Health Workshop and has received life and honorary memberships in professional organizations. His work has significantly contributed to the field of aquatic animal medicine through research, education, and service.

Research topics

• Biology
• Genetics
• Fishery
• Molecular biology
• Cell biology
• Evolutionary biology
• Zoology
• Virology

Selected publications

• Fish Retroviruses (Retroviridae)

  Elsevier eBooks · 2021 · 1 citations

  • Biology
  • Genetics
  • Evolutionary biology
  PublisherDOI

• Cytochrome oxidase gene sequencing reveals channel catfish ovary cell line is contaminated with brown bullhead cells

  Journal of Fish Diseases · 2020 · 12 citations

  • Biology
  • Molecular biology
  • Fishery

  The channel catfish (Ictalurus punctatus, Rafinesque) ovary (CCO) cell line is the standard cell line used for channel catfish diagnostics. Next-gen sequencing studies of a virus cultured in the CCO cells revealed mitochondrial sequences matching those of brown bullhead (Ameiurus nebulosus, Lesueur). Therefore, we systematically performed partial cytochrome oxidase 1 gene sequencing of several sources of the CCO cell line and all matched the brown bullhead and not the channel catfish.

  PublisherDOI

• Biochemical, Histopathologic, Physiologic, and Behavioral Effects of Nonsteroidal Antiinflammatory Drugs in Rainbow Trout (

  PubMed Central · 2017-03-01 · 6 citations

  articleOpen access

  Because the number of fish being used in research is increasing rapidly, evaluating the analgesic and pathologic effects of NSAID in fish is essential. To determine the biochemical, histopathologic, physiologic and behavioral effects of 3 NSAID, 48 rainbow trout underwent anesthesia with tricaine methanesulfonate and exploratory celiotomy and were randomly assigned to receive flunixin (0.5 mg/kg IM), ketorolac (0.5 mg/kg IM), ketoprofen (2 mg/kg IM), or saline. Clinical pathologic variables were assessed 1 wk before surgery and 48 h after surgery. Histopathology was performed to evaluate the healing of the incision, tissue reaction at the injection site, and potential organ toxicity. Physiologic and behavioral parameters, including weight, feeding, opercular rate, and vertical position in the water, were measured to establish parameters for identifying pain in fish. The difference between the pre- and postoperative phosphorus concentrations was greater in the flunixin group than the saline group and was the only pathologic difference between treatment groups. Histopathology of incision site, injection site, and internal organs appeared normal, and healing did not appear to be inhibited by the drugs used. The physiologic parameters of opercular rate and weight were consistent and may be helpful in identifying pain in fish in future studies, whereas feeding and vertical position in the water were unhelpful as indicators of pain in this rainbow trout surgical model. Overall, according to clinical pathology and histopathology, the use of ketoprofen, ketorolac, and flunixin at the dosages used in this study lack negative effects in rainbow trout undergoing surgery.

  Publisher

• Pathogenesis of experimental viral hemorrhagic septicemia virus IVb infection in adult sea lamprey (Petromyzon marinus)

  Journal of Great Lakes Research · 2017-04-01 · 8 citations

  articleSenior author
  PublisherDOI

• Safety of Strontium Chloride as a Skeletal Marking Agent for Pacific Salmon

  Journal of Aquatic Animal Health · 2017-08-08 · 3 citations

  article

  The purpose of this study was to evaluate the biological effects associated with administering strontium chloride as a marking agent to age-0 Chinook Salmon Oncorhynchus tshawytscha fry. Fish were held in a 0× (0 mg/L), 1× (3,000 mg/L; current standard dosage), 3× (9,000 mg/L), or 5× (15,000 mg/L) solution of strontium chloride for 72 h (three times the standard duration of 24 h). The mortality among fish in the 5× strontium chloride exposure group was significantly higher than that observed in the other groups. A dose-related effect on general fish behavior and on feeding behavior was observed. Fish in all test tanks appeared to feed to satiation, except for fish in the 5× tanks during days 2 and 3. Fish in all other test tanks behaved normally. No dose-related effect on fish growth was detected. Histopathological evaluations showed that fish in the 5× exposure group had a significantly higher number of gill lesions than the 0× group. Our mortality, behavioral, and histological assessments suggested that juvenile Chinook Salmon could be safely immersed for three consecutive days in a 9,000-mg/L solution of strontium chloride. This finding potentially expands the present 1,000-3,000-mg/L dosage and 24-h holding period that can be used to mark juvenile fish with strontium chloride solutions. The research also provides necessary target animal safety data for U.S. Food and Drug Administration approval of strontium chloride as an alternative marking method that is suitable for fish with a short holding time. Received February 19, 2017; accepted July 16, 2017.

  PublisherDOI

• Complete sequences of 4 viral hemorrhagic septicemia virus IVb isolates and their virulence in northern pike fry

  Diseases of Aquatic Organisms · 2017-09-06 · 8 citations

  articleSenior author

  Four viral hemorrhagic septicemia virus (VHSV) genotype IVb isolates were sequenced, their genetic variation explored, and comparative virulence assayed with experimental infections of northern pike Esox lucius fry. In addition to the type strain MI03, the complete 11183 bp genome of the first round goby Neogobius melanostomus isolate from the St. Lawrence River, and the 2013 and 2014 isolates from gizzard shad Dorosoma cepedianum die-offs in Irondequoit Bay, Lake Ontario and Dunkirk Harbor, Lake Erie were all deep sequenced on an Illumina platform. Mutations documented in the 11 yr since the MI03 index case from Lake St. Clair muskellunge Esox masquinongy showed 87 polymorphisms among the 4 isolates. Twenty-six mutations were non-synonymous and located at 18 different positions within the matrix protein, glycoprotein, non-virion protein, and RNA polymerase genes. The same 4 isolates were used to infect northern pike fry by a single 1 h bath exposure. Cumulative percent mortality varied from 42.5 to 62.5%. VHSV was detected in 57% (41/72) of the survivors at the end of the 21-d trial, suggesting that the virus was not rapidly cleared. Lesions were observed in many of the moribund and dead northern pike, such as hemorrhaging in the skin and fins, as well as hydrocephalus. Mean viral load measured from the trunk and visceral tissues of MI03-infected pike was significantly higher than the quantities detected in fish infected with the most recent isolates of genotype IVb, but there were no differences in cumulative mortality observed.

  PublisherDOI

• Histologic and molecular characterization of <i>Edwardsiella piscicida</i> infection in largemouth bass ( <i>Micropterus salmoides</i> )

  Journal of Veterinary Diagnostic Investigation · 2016-03-07 · 74 citations

  articleOpen access

  The genus Edwardsiella is composed of a diverse group of facultative anaerobic, gram-negative bacteria that can produce disease in a wide variety of hosts, including birds, reptiles, mammals, and fish. Our report describes the isolation and identification of Edwardsiella piscicida associated with chronic mortality events in 2 separate captive largemouth bass (Micropterus salmoides) populations in New York and Florida. Wet-mount biopsies of skin mucus, gill, kidney, and spleen from several affected largemouth bass contained significant numbers of motile bacteria. Histologic examination revealed multifocal areas of necrosis scattered throughout the heart, liver, anterior kidney, posterior kidney, and spleen. Many of the necrotic foci were encapsulated or replaced by discrete granulomas and associated with colonies of gram-negative bacteria. Initial phenotypic and matrix-assisted laser desorption ionization-time of flight mass spectrometric analysis against existing spectral databases of recovered isolates identified these bacteria as Edwardsiella tarda Subsequent molecular analysis using repetitive sequence mediated and species-specific PCR, as well as 16S rRNA, rpoB, and gyrB sequences, classified these isolates as E. piscicida As a newly designated taxon, E. piscicida should be considered as a differential for multiorgan necrosis and granulomas in largemouth bass.

  PublisherOA PDFDOI

• Applying multi-scale occupancy models to infer host and site occupancy of an emerging viral fish pathogen in the Great Lakes

  Journal of Great Lakes Research · 2015-01-24 · 11 citations

  articleSenior author
  PublisherDOI

• Efficacy of an Extract from Garlic, <i>Allium sativum</i>, Against Infection with the Furunculosis Bacterium, <i>Aeromonas salmonicida</i>, in Rainbow Trout, <i>Oncorhynchus mykiss</i>

  Journal of the World Aquaculture Society · 2015-06-01 · 26 citations

  articleSenior author

  Abstract Juvenile rainbow trout, Oncorhynchus mykiss , were fed diets containing 0, 0.5, 1.0, and 2.0% of a garlic extract, challenged with a modified 50% lethal dose of Aeromonas salmonicida and monitored for 28 d. There were significant increases in survival of trout fed 0.5 and 1.0% garlic extract as compared to the control and 2.0% garlic extract groups. A target animal safety study was performed at varying increments using the target dose of 0.5% garlic extract at 0× (0% garlic extract), 1× (0.5% garlic extract), 3× (1.5% garlic extract), and 5× (2.5% garlic extract) for 3× (6 wk) the duration of the original study. There was a significant increase in the level of circulating lymphocytes and a significant decrease in the level of circulating monocytes. The latter correlated to an increased level of pigment‐containing macrophage centers within the renal tissue as garlic extract dosing increased, denoting a potential deleterious inflammatory effect as macrophage infiltration became severe at the highest dose. These studies suggest that feeding low‐dose (0.5% or 1.0%) garlic extract improves survivability in rainbow trout when challenged with A. salmonicida and appears safe; however, higher levels do not appear to be effective and may cause deleterious effects on health.

  PublisherDOI

• In vivo and in vitro phenotypic differences between Great Lakes VHSV genotype IVb isolates with sequence types vcG001 and vcG002

  Journal of Great Lakes Research · 2014-09-18 · 7 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

Frequent coauthors

• Rodman G. Getchell

  164 shared

• G. A. Wooster

  Cornell University

  107 shared

• Gregory A. Wooster

  Cornell University

  86 shared

• James W. Casey

  Cornell University

  55 shared

• Geoffrey H. Groocock

  New York State College of Veterinary Medicine

  48 shared

• Emily R. Cornwell

  Food and Drug Administration

  44 shared

• Chun‐Yao Chen

  Tzu Chi University

  29 shared

• Hélène Marquis

  Cornell University

  29 shared

Awards & honors

• State University of New York Chancellor’s Award for Faculty…
• S. F. Snieszko Distinguished Service Award from the Fish Hea…
• National Sea Grant Program -- Research to Application Award…
• Christensen Award for Excellence in Fish Health from the Int…
• New York Sea Grant Award of Excellence (2014)