Incidence of<i>Ichthyophonus hoferi</i>in Puget Sound Fishes and Its Increase with Age of Pacific Herring

Hershberger, Paul K.; Stick, Kurt C.; Bui, Ba Trung; Carroll, C. Ronald; Fall, B.; Mork, C.; Perry, James A.; Sweeney, Emma Claire; Wittouck, J.; Winton, James R.; Kocan, Richard M.

doi:10.1577/1548-8667(2002)014<0050:ioihip>2.0.co;2

Cited by 56 publications

(53 citation statements)

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“…Fishery collapse is often attributed to overfishing, pollution, and habitat destruction (Holmlund & Hammer 1999, Jackson et al 2001, Worm et al 2006), but disease is only rarely investigated as a possible cause. Documented cases include the impact of sea lamprey Petromyzon marinus on lake trout Salvelinus namaycush in the North American Great Lakes (Coble et al 1990), Ichthyophonus hoferi on decreased survival of reproductively important mature female Pacific herring near Cherry Point, Washington, USA (Hershberger et al 2002), and Gyrodactlyus salaris on young Atlantic salmon Salmo salar in Norwegian rivers (Heggberget & Johnsen 1982). For Pacific herring in Prince William Sound, Alaska, neither toxin exposure nor overfishing is limiting recovery , Hulson et al 2008.…”

Section: Possible Causes Of Recovery Failurementioning

confidence: 99%

Failure of population recovery in relation to disease in Pacific herring

Marty

Hulson²,

Miller³

et al. 2010

Dis. Aquat. Org.

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Following an estimated 60% decline in population abundance in early 1993, recovery of the Pacific herring Clupea pallasii population of Prince William Sound, Alaska, USA, has been impaired by disease. Comprehensive epidemiological study from 1994 through 2002 validated an age-structured assessment (ASA) model of disease and population abundance; from 2003 to 2006, the impact of disease was modeled by analyzing only 2 lesions: ulcers and white foci in the heart. The ASA model identified increased natural mortality since 1993 that can be explained by (1) epidemics associated with ulcers (prevalence about 3%) and the North American strain of viral hemorrhagic septicemia virus (VHSV Type IVa; prevalence up to 14%) in 1994 and 1998 and (2) relatively high prevalence of the mesomycetozoean Ichthyophonus hoferi from 1994 through 2006, including epidemics with the greatest sample prevalence in 2001 (38%, by histopathology) and 2005 (51%, estimated histopathology prevalence). Fourteen other parasites occurred at prevalence >10%, but none were considered significant contributors to fish mortality. We predict that if natural mortality after 1994 had returned to background levels that best fit the model from 1980 to 1992 (0.25 yr -1 ), population biomass in 2006 would have been 3 times the best estimate, despite relatively poor recruitment since 1994. In conclusion, disease information can be used to explain and predict changes in populations that have confounded traditional fisheries assessment.KEY WORDS: Pacific herring · Clupea pallasii · Viral hemorrhagic septicemia virus · VHSV Type IVa · Ulcers · Ichthyophonus hoferi · Age-structured assessment model · Population-level response Resale or republication not permitted without written consent of the publisherDis Aquat Org 90: [1][2][3][4][5][6][7][8][9][10][11][12][13][14] 2010 are 3 to 5 yr old, live for about 12 yr, and weigh up to about 250 g. Mature fish spawn every year, but for reasons probably related to environmental conditions (Williams & Quinn 2000), strong year-classes recruit into the adult population only about once every 4 yr. The most accurate biomass estimates are made in early spring, when fish aggregations move to shallow waters to spawn. After spawning, fish disperse and do not reaggregate near spawning areas until late fall. Feeding is minimal during the winter (Foy & Norcross 2001).Four years after the March 1989 'Exxon Valdez' oil spill in Prince William Sound, about 60% of the Pacific herring population died during the winter of 1992/1993. Death was attributed to poor food availability in 1992, which resulted in poor fish condition the following winter (Pearson et al. 1999, Elston & Meyers 2009). The weakened fish had 2 types of lesions or pathogens that are commonly associated with population stress: (1) cutaneous ulcers and (2) the North American strain of viral hemorrhagic septicemia virus (VHSV Type IVa) (Meyers et al. 1994, Pearson et al. 1999, Carls et al. 2002). An alternative hypothesis attributes a greater proportion of th...

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Section: Possible Causes Of Recovery Failurementioning

confidence: 99%

Failure of population recovery in relation to disease in Pacific herring

Marty

Hulson²,

Miller³

et al. 2010

Dis. Aquat. Org.

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show abstract

“…The disease caused by Ichthyophonus hoferi is of economic significance, because epizootics have resulted in mass mortality of commercial fish species such as Atlantic herring Clupea harengus Linnaeus, 1758(McVicar 1999 and Pacific herring C. pallasi Valenciennes, 1847 off the coast of Alaska (Marty et al 1998) and Washington (Hershberger et al 2002). Salmonids are also susceptible to this parasite (Jones & Dawe 2002, Schmidt-Posthaus & Wahli 2002.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Assessing the accuracy of a polymerase chain reaction test for Ichthyophonus hoferi in Yukon River Chinook salmon Oncorhynchus tshawytscha

Whipps¹,

Burton²,

Watral³

et al. 2006

Dis. Aquat. Org.

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“…The observed prevalence patterns of I. hoferi in PWS herring through 2006 (Table 5) suggest that the pathogen could be limiting survival of herring, particularly in the older year classes (Hershberger et al 2002). Given the poorly understood relationship between infection intensity and prevalence on population mortality risk, we conclude that these factors need to be more fully understood before accurate conclusions and predictions relating I. hoferi infection to population effect can be made.…”

Section: Recoverymentioning

confidence: 95%

“…Ichthyophonus hoferi is a pathogen producing chronic disease that progressively affects older age classes of herring more severely Hershberger et al 2002). I. hoferi is associated with adult Atlantic herring mortality, in some cases on a massive scale (Tibbo and Graham 1963;Patterson 1996).…”

Section: Pathogen Ichthyophonus Hoferimentioning

confidence: 99%

Hypotheses concerning the decline and poor recovery of Pacific herring in Prince William Sound, Alaska

Pearson¹,

Deriso

Elston³

et al. 2011

Rev Fish Biol Fisheries

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This paper updates previous reviews of the 1993 stock decline of Pacific herring (Clupea pallasi) in Prince William Sound, Alaska, and focuses on hypotheses about subsequent poor recovery. Recent age structured assessment modeling with covariate analysis indicates that the population dynamics of the sound's herring are influenced by oceanic factors, nutrition, and, most substantially, hatchery releases of juvenile pink salmon. For the 1993 decline, poor nutrition remains the most probable cause with disease a secondary response. Concerning poor recovery, we examined 16 potential factors and found three to be causal: oceanic factors, poor nutrition, and hatchery releases of juvenile pink salmon. Absences of strong year classes at both Sitka and Prince William Sound after 1993 indicate the action of large-scale ocean processes. Beyond regional-scale environmental factors, two factors specific to the sound influence the population dynamics of herring and are likely impeding recovery. First, pink salmon fry releases have increased to about 600 million annually and may disrupt feeding in young herring, which require adequate nutrition for growth and overwintering survival. Juvenile pink salmon and age-1 herring co-occur in nearshore areas of bays in late spring and summer, and available data on dietary overlap indicates potential competition between the age-1 juvenile herring and juvenile pink salmon. Field studies demonstrate that juvenile herring reduce food intake substantially in the presence of juvenile pink salmon. Second, overwintering humpback whales may consume potentially large amounts of adult herring, but further studies must confirm to what extent whale predation reduces herring biomass.

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Incidence ofIchthyophonus hoferiin Puget Sound Fishes and Its Increase with Age of Pacific Herring

Cited by 56 publications

References 14 publications

Failure of population recovery in relation to disease in Pacific herring

Failure of population recovery in relation to disease in Pacific herring

Assessing the accuracy of a polymerase chain reaction test for Ichthyophonus hoferi in Yukon River Chinook salmon Oncorhynchus tshawytscha

Hypotheses concerning the decline and poor recovery of Pacific herring in Prince William Sound, Alaska

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