Epizootiology of viral hemorrhagic septicemia virus in Pacific herring from the spawn-on-kelp fishery in Prince William Sound, Alaska, Usa

• Published in: Diseases of aquatic organisms 1999-06, Vol.37 (1), p.23-31
• Main Authors: HERSHBERGER, P. K, KOCAN, R. M, ELDER, N. E, MEYERS, T. R, WINTON, J. R
• Format: Article
• Language: English
• Subjects: Alaska - epidemiology; Animal aquaculture; Animal productions; Animals; Biological and medical sciences; Clupea harengus pallasi; Clupea pallasi; Disease Outbreaks - veterinary; DNA Primers - chemistry; DNA, Viral - chemistry; Fish Diseases - epidemiology; Fish Diseases - virology; Fisheries; Fishes; Fundamental and applied biological sciences. Psychology; Kidney - virology; Pacific Ocean; Pisciculture; Polymerase Chain Reaction - veterinary; Prevalence; Rhabdoviridae - isolation & purification; Rhabdoviridae Infections - epidemiology; Rhabdoviridae Infections - veterinary; Spleen - virology; Vertebrate aquaculture; Viral hemorrhagic septicemia virus; Viral Plaque Assay - veterinary; Water Microbiology
• ISSN: 0177-5103; 1616-1580
• DOI: 10.3354/dao037023

Both the prevalence and tissue titer of viral hemorrhagic septicemia virus (VHSV) increased in Pacific herring Clupea pallasi following their introduction into net pens (pounds) used in the closed pound spawn-on-kelp (SOK) fishery in Prince William Sound, Alaska. VHSV was also found in water samples from inside and outside the SOK pounds after herring had been confined for several days; however, water samples taken near wild free-ranging, spawning herring either failed to test positive or tested weakly positive for virus. Little or no virus was found in tissue samples from free-ranging, spawning herring captured from the vicinity of the pounds, nor did the prevalence of VHSV increase following spawning as it did in impounded herring. The data indicated that increased prevalences of VHSV were correlated with confinement of herring for the closed pound SOK fishery and that infection was spread within the pounds through waterborne exposure to virus particles originating from impounded fish. In addition, pounds containing predominantly young fish had higher prevalences of VHSV, suggesting that older fish may be partially immune, perhaps as a result of previous infection with the virus. Operation of SOK pounds during spawning seasons in which young herring predominate may amplify the disease and possibly exacerbate the population fluctuations observed in wild herring stocks.