Jacob Gregg
Jacob is a Fish Biologist at the Marrowstone Marine Field Station, Nordland, WA.
Science and Products
Filter Total Items: 43
Ichthyophonus parasite phylogeny based on ITS rDNA structure prediction and alignment identifies six clades, with a single dominant marine type
Despite their widespread, global impact in both wild and cultured fishes, little is known of the diversity, transmission patterns, and phylogeography of parasites generally identified as Ichthyophonus. This study constructed a phylogeny based on the structural alignment of internal transcribed spacer (ITS) rDNA sequences to compare Ichthyophonus isolates from fish hosts in the Atlantic and Pacific
Authors
Jacob Gregg, Rachel L. Thompson, Maureen K. Purcell, Carolyn S. Friedman, Paul Hershberger
The parasite Ichthyophonus sp. in Pacific herring from the coastal NE Pacific
The protistan parasite Ichthyophonus occurred in populations of Pacific herring Clupea pallasii Valenciennes throughout coastal areas of the NE Pacific, ranging from Puget Sound, WA north to the Gulf of Alaska, AK. Infection prevalence in local Pacific herring stocks varied seasonally and annually, and a general pattern of increasing prevalence with host size and/or age persisted throughout the NE
Authors
Paul K. Hershberger, Jacob L. Gregg, Lucas M. Hart, Steve Moffitt, Richard L. Brenner, K. Stick, Eric Coonradt, E. O. Otis, Johanna J. Vollenweider, Kyle A. Garver, Jan Lovy, T.R. Meyers
Molecular identification of erythrocytic necrosis virus (ENV) from the blood of Pacific herring (Clupea pallasii)
Viral erythrocytic necrosis (VEN) is a condition affecting the red blood cells of more than 20 species of marine and anadromous fishes in the North Atlantic and North Pacific Oceans. Among populations of Pacific herring (Clupea pallasii) on the west coast of North America the disease causes anemia and elevated mortality in periodic epizootics. Presently, VEN is diagnosed by observation of typical
Authors
Eveline J. Emmenegger, Jolene A. Glenn, James R. Winton, William N. Batts, Jacob L. Gregg, Paul K. Hershberger
Distribution and transmission of the highly pathogenic parasite Ichthyophonus in marine fishes of Alaska
A combination of field surveys, molecular typing, and laboratory experiments were used to improve our understanding of the distribution and transmission mechanisms of fish parasites in the genus Ichthyophonus. Ichthyophonus spp. infections were detected from the Bering Sea to the coast of Oregon in 10 of 13 host species surveyed. Sequences of rDNA extracted from these isolates indicate that a ubiq
Authors
Jacob L. Gregg, Courtney A. Grady, Rachel L. Thompson, Maureen K. Purcell, Carolyn S. Friedman, Paul K. Hershberger
Influence of temperature on viral hemorrhagic septicemia (Genogroup IVa) in Pacific herring, Clupea pallasii Valenciennes
An inverse relationship between water temperature and susceptibility of Pacific herring (Clupea pallasii) to viral hemorrhagic septicemia, genogroup IVa (VHS) was indicated by controlled exposure studies where cumulative mortalities, viral shedding rates, and viral persistence in survivors were greatest at the coolest exposure temperatures. Among groups of specific pathogen-free (SPF) Pacific herr
Authors
P.K. Hershberger, M. K. Purcell, L.M. Hart, J.L. Gregg, R.L. Thompson, K.A. Garver, J. R. Winton
Survival and growth of juvenile Pacific lampreys tagged with passive integrated transponders (PIT) in freshwater and seawater
Tagging methods are needed for both adult and juvenile life stages of Pacific lampreys Lampetra tridentata to better understand their biology and factors contributing to their decline. We developed a safe and efficient technique for tagging juvenile Pacific lampreys with passive integrated transponder (PIT) tags. We tested the short-term survival of PIT-tagged juvenile lampreys in freshwater at fo
Authors
Matthew G. Mesa, Elizabeth S. Copeland, Helena E. Christiansen, Jacob L. Gregg, Sean R. Roon, Paul K. Hershberger
Susceptibility of Pacific herring to viral hemorrhagic septicemia is influenced by diet
Groups of specific-pathogen-free Pacific herring Clupea pallasii were highly susceptible to infection by viral hemorrhagic septicemia virus (VHSV); however, the level of mortality was influenced by diet during the 40–71 d before, during, and after the first exposure to the virus. Cumulative mortality was highest among the herring maintained on an experimental soy-based pellet, intermediate among t
Authors
Joshua Beaulaurier, N. Bickford, J.L. Gregg, C.A. Grady, A.L. Gannam, J. R. Winton, P.K. Hershberger
Kinetics of viral load and erythrocytic inclusion body formation in pacific herring artificially infected with erythrocytic necrosis virus
Viral erythrocytic necrosis (VEN) is a condition that affects marine and anadromous fish species, including herrings and salmonids, in the Atlantic and Pacific oceans. Infection is frequently associated with severe anemia and causes episodic mortality among wild and hatchery fish when accompanied by additional stressors; VEN can be presumptively diagnosed by (1) light microscopic identification of
Authors
Jolene A. Glenn, Eveline J. Emmenegger, Courtney A. Grady, Sean R. Roon, Jacob L. Gregg, Carla M. Conway, James R. Winton, Paul K. Hershberger
Inability to demonstrate fish-to-fish transmission of Ichthyophonus from laboratory infected Pacific herring Clupea pallasii to naïve conspecifics
The parasite Ichthyophonus is enzootic in many marine fish populations of the northern Atlantic and Pacific Oceans. Forage fishes are a likely source of infection for higher trophic level predators; however, the processes that maintain Ichthyophonus in forage fish populations (primarily clupeids) are not well understood. Lack of an identified intermediate host has led to the convenient hypothesis
Authors
J.L. Gregg, C.A. Grady, C.S. Friedman, P.K. Hershberger
Efficacy of a glycoprotein DNA vaccine against viral haemorrhagic septicaemia (VHS) in Pacific herring, Clupea pallasii Valenciennes
Viral haemorrhagic septicaemia virus (VHSV) and its associated disease state, viral haemorrhagic septicaemia (VHS), is hypothesized to be a proximate factor accounting for the decline and failed recovery of Pacific herring populations in Prince William Sound, AK (Marty et al. 1998, 2003, 2010). Survivors of laboratory-induced VHSV epizootics develop resistance to subsequent viral exposure (Kocan e
Authors
L.M. Hart, Niels Lorenzen, S. E. LaPatra, C.A. Grady, S.E. Roon, J. O’Reilly, J.L. Gregg, P.K. Hershberger
Induction of anti-viral genes during acute infection with Viral hemorrhagic septicemia virus (VHSV) genogroup IVa in Pacific herring (Clupea pallasii)
Infection with the aquatic rhabdovirus Viral hemorrhagic septicemia virus (VHSV) genogroup IVa results in high mortality in Pacific herring (Clupea pallasii) and is hypothesized to be a potential limiting factor for herring recovery. To investigate anti-viral immunity in the Pacific herring, four immune response genes were identified: the myxovirus resistance (Clpa-Mx), a major histocompatibility
Authors
John D. Hansen, James C. Woodson, Paul K. Hershberger, Courtney Grady, Jacob L. Gregg, Maureen K. Purcell
Energetic cost of ichthyophonus infection in Juvenile Pacific Herring (Clupea pallasii)
The energetic costs of fasting and Ichthyophonus infection were measured in juvenile Pacific herring (Clupea pallasii) in a lab setting at three temperatures. Infected herring incurred significant energetic costs, the magnitude of which depended on fish condition at the time of infection (fat versus lean). Herring that were fed continually and were in relatively good condition at the time of infec
Authors
Johanna J. Vollenweider, J.L. Gregg, R.A. Heintz, P.K. Hershberger
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Filter Total Items: 43
Ichthyophonus parasite phylogeny based on ITS rDNA structure prediction and alignment identifies six clades, with a single dominant marine type
Despite their widespread, global impact in both wild and cultured fishes, little is known of the diversity, transmission patterns, and phylogeography of parasites generally identified as Ichthyophonus. This study constructed a phylogeny based on the structural alignment of internal transcribed spacer (ITS) rDNA sequences to compare Ichthyophonus isolates from fish hosts in the Atlantic and PacificAuthorsJacob Gregg, Rachel L. Thompson, Maureen K. Purcell, Carolyn S. Friedman, Paul HershbergerThe parasite Ichthyophonus sp. in Pacific herring from the coastal NE Pacific
The protistan parasite Ichthyophonus occurred in populations of Pacific herring Clupea pallasii Valenciennes throughout coastal areas of the NE Pacific, ranging from Puget Sound, WA north to the Gulf of Alaska, AK. Infection prevalence in local Pacific herring stocks varied seasonally and annually, and a general pattern of increasing prevalence with host size and/or age persisted throughout the NEAuthorsPaul K. Hershberger, Jacob L. Gregg, Lucas M. Hart, Steve Moffitt, Richard L. Brenner, K. Stick, Eric Coonradt, E. O. Otis, Johanna J. Vollenweider, Kyle A. Garver, Jan Lovy, T.R. MeyersMolecular identification of erythrocytic necrosis virus (ENV) from the blood of Pacific herring (Clupea pallasii)
Viral erythrocytic necrosis (VEN) is a condition affecting the red blood cells of more than 20 species of marine and anadromous fishes in the North Atlantic and North Pacific Oceans. Among populations of Pacific herring (Clupea pallasii) on the west coast of North America the disease causes anemia and elevated mortality in periodic epizootics. Presently, VEN is diagnosed by observation of typicalAuthorsEveline J. Emmenegger, Jolene A. Glenn, James R. Winton, William N. Batts, Jacob L. Gregg, Paul K. HershbergerDistribution and transmission of the highly pathogenic parasite Ichthyophonus in marine fishes of Alaska
A combination of field surveys, molecular typing, and laboratory experiments were used to improve our understanding of the distribution and transmission mechanisms of fish parasites in the genus Ichthyophonus. Ichthyophonus spp. infections were detected from the Bering Sea to the coast of Oregon in 10 of 13 host species surveyed. Sequences of rDNA extracted from these isolates indicate that a ubiqAuthorsJacob L. Gregg, Courtney A. Grady, Rachel L. Thompson, Maureen K. Purcell, Carolyn S. Friedman, Paul K. HershbergerInfluence of temperature on viral hemorrhagic septicemia (Genogroup IVa) in Pacific herring, Clupea pallasii Valenciennes
An inverse relationship between water temperature and susceptibility of Pacific herring (Clupea pallasii) to viral hemorrhagic septicemia, genogroup IVa (VHS) was indicated by controlled exposure studies where cumulative mortalities, viral shedding rates, and viral persistence in survivors were greatest at the coolest exposure temperatures. Among groups of specific pathogen-free (SPF) Pacific herrAuthorsP.K. Hershberger, M. K. Purcell, L.M. Hart, J.L. Gregg, R.L. Thompson, K.A. Garver, J. R. WintonSurvival and growth of juvenile Pacific lampreys tagged with passive integrated transponders (PIT) in freshwater and seawater
Tagging methods are needed for both adult and juvenile life stages of Pacific lampreys Lampetra tridentata to better understand their biology and factors contributing to their decline. We developed a safe and efficient technique for tagging juvenile Pacific lampreys with passive integrated transponder (PIT) tags. We tested the short-term survival of PIT-tagged juvenile lampreys in freshwater at foAuthorsMatthew G. Mesa, Elizabeth S. Copeland, Helena E. Christiansen, Jacob L. Gregg, Sean R. Roon, Paul K. HershbergerSusceptibility of Pacific herring to viral hemorrhagic septicemia is influenced by diet
Groups of specific-pathogen-free Pacific herring Clupea pallasii were highly susceptible to infection by viral hemorrhagic septicemia virus (VHSV); however, the level of mortality was influenced by diet during the 40–71 d before, during, and after the first exposure to the virus. Cumulative mortality was highest among the herring maintained on an experimental soy-based pellet, intermediate among tAuthorsJoshua Beaulaurier, N. Bickford, J.L. Gregg, C.A. Grady, A.L. Gannam, J. R. Winton, P.K. HershbergerKinetics of viral load and erythrocytic inclusion body formation in pacific herring artificially infected with erythrocytic necrosis virus
Viral erythrocytic necrosis (VEN) is a condition that affects marine and anadromous fish species, including herrings and salmonids, in the Atlantic and Pacific oceans. Infection is frequently associated with severe anemia and causes episodic mortality among wild and hatchery fish when accompanied by additional stressors; VEN can be presumptively diagnosed by (1) light microscopic identification ofAuthorsJolene A. Glenn, Eveline J. Emmenegger, Courtney A. Grady, Sean R. Roon, Jacob L. Gregg, Carla M. Conway, James R. Winton, Paul K. HershbergerInability to demonstrate fish-to-fish transmission of Ichthyophonus from laboratory infected Pacific herring Clupea pallasii to naïve conspecifics
The parasite Ichthyophonus is enzootic in many marine fish populations of the northern Atlantic and Pacific Oceans. Forage fishes are a likely source of infection for higher trophic level predators; however, the processes that maintain Ichthyophonus in forage fish populations (primarily clupeids) are not well understood. Lack of an identified intermediate host has led to the convenient hypothesisAuthorsJ.L. Gregg, C.A. Grady, C.S. Friedman, P.K. HershbergerEfficacy of a glycoprotein DNA vaccine against viral haemorrhagic septicaemia (VHS) in Pacific herring, Clupea pallasii Valenciennes
Viral haemorrhagic septicaemia virus (VHSV) and its associated disease state, viral haemorrhagic septicaemia (VHS), is hypothesized to be a proximate factor accounting for the decline and failed recovery of Pacific herring populations in Prince William Sound, AK (Marty et al. 1998, 2003, 2010). Survivors of laboratory-induced VHSV epizootics develop resistance to subsequent viral exposure (Kocan eAuthorsL.M. Hart, Niels Lorenzen, S. E. LaPatra, C.A. Grady, S.E. Roon, J. O’Reilly, J.L. Gregg, P.K. HershbergerInduction of anti-viral genes during acute infection with Viral hemorrhagic septicemia virus (VHSV) genogroup IVa in Pacific herring (Clupea pallasii)
Infection with the aquatic rhabdovirus Viral hemorrhagic septicemia virus (VHSV) genogroup IVa results in high mortality in Pacific herring (Clupea pallasii) and is hypothesized to be a potential limiting factor for herring recovery. To investigate anti-viral immunity in the Pacific herring, four immune response genes were identified: the myxovirus resistance (Clpa-Mx), a major histocompatibilityAuthorsJohn D. Hansen, James C. Woodson, Paul K. Hershberger, Courtney Grady, Jacob L. Gregg, Maureen K. PurcellEnergetic cost of ichthyophonus infection in Juvenile Pacific Herring (Clupea pallasii)
The energetic costs of fasting and Ichthyophonus infection were measured in juvenile Pacific herring (Clupea pallasii) in a lab setting at three temperatures. Infected herring incurred significant energetic costs, the magnitude of which depended on fish condition at the time of infection (fat versus lean). Herring that were fed continually and were in relatively good condition at the time of infecAuthorsJohanna J. Vollenweider, J.L. Gregg, R.A. Heintz, P.K. Hershberger