SW Descaling horizontal

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The Influence of Hatcheries and their Products on
the Health and Physiology of Naturally Rearing
Fish

Matthew G. Mesa and Diane G. Elliott
Western Fisheries Research Center Biological
Resources Discipline U.S. Geological Survey
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Project Collaborators
USGS Matthew G. Mesa Diane G.
Elliott WDFW Todd N. Pearsons Yakama
Nation David E. Fast USFWS Ray D. Brunson
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Project Goal
Evaluate the influence of salmonid hatchery
effluents and hatchery-reared fish on
transmission of disease to naturally rearing
salmonids. Focus will be on transmission of
Renibacterium salmoninarum (Rs), the
causative agent of bacterial kidney disease
(BKD).
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Rationale and Significance

• BKD is a serious disease of hatchery salmonids in
  the Columbia River basin.
• Hatcheries rearing Rs-infected fish may influence
  Rs levels in river water and naturally rearing
  fish via several pathways
• Release of Rs in hatchery effluents
• Release of Rs-infected hatchery fish
• Stocking of Rs-infected carcasses

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Rationale and Significance

• Proposed research is relevant to several future
  needs included in the Artificial Production
  Program Summary prepared for the
  mainstem/systemwide RFP, including studies on
• Interactions of hatchery and wild fish such as
  physiological responses, disease transmission.
• Nature and extent of ecological risk to wild
  salmonids associated with the release of hatchery
  fish.
• Infectious diseases.

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Rationale and Significance

• Proposed research addresses actions toward RPA
  184 in the 2000 Biological Opinion
• Develop a hatchery research, monitoring, and
  evaluation program to determine whether hatchery
  reforms reduce the risk of extinction for
  salmonids.
• Research is intended to evaluate certain hatchery
  procedures and products, and to identify reforms
  to minimize health impacts on wild fish.

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Objective 1
Determine if salmonid hatcheries amplify Rs
concentrations in effluent water or outfalls and
subsequently influence the health of fish
residing below the hatchery.
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Objective 2
Determine if the release of juvenile spring
chinook salmon that are the progeny of females
with high Rs antigen levels can result in the
infection of fish in the natural environment, and
ultimately influence the health of those fish.
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Objective 3
Determine the influence of natural or artificial
stocking of adult spring chinook salmon carcasses
on Rs concentrations in natural waters and
resident fish.
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Objective 1 Study Design

• Optimize methods for detection and quantification
  of Rs in water.
• Conduct Rs analysis of water samples collected
  from effluents of 3 hatcheries, and from selected
  sites upstream and downstream for 1 year.
• Determine potential for Rs in hatchery effluents
  to infect juvenile salmonids rearing in simulated
  natural environments.

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Treatment Groups (Replicated) for Test of
Hatchery Effluents
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Objective 2 Study Design

• Stock groups of wild and hatchery-reared
  subyearling spring chinook salmon into artificial
  streams for Rs transmission studies.
• Sample fish from the streams at selected time
  intervals during the 1-year rearing period, and
  analyze for prevalence and levels of Rs,
  nutritional status, and physiological condition.

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Treatment Groups (Replicated) for Hatchery/Wild
Fish Cohabitation Studies
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Objective 3 Study Design

• Evaluate survival of Rs in adult salmon carcasses
  stored in a hatchery freezer for up to 4 months.
• Analyze presence and levels of Rs in water and
  resident fish in stream artificially stocked with
  hatchery salmon carcasses.
• Analyze presence and levels of Rs in water of
  stream naturally stocked with salmon carcasses by
  spawning wild salmon.

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Expected Results

• Improved methods for detection and quantification
  of viable Rs in environmental samples.
• Increased understanding of dynamics of Rs in
  hatchery effluents and associated rivers.
• Increased understanding of influence of hatchery
  practices and rearing cycles on Rs levels in
  hatchery effluents and rivers.

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Expected Results

• Increased understanding of potential effects of
  Rs in hatchery effluents on health and survival
  of naturally rearing salmonids.
• Increased understanding of potential effects of
  Rs-infected hatchery outplants on health and
  survival of naturally rearing salmonids.

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Expected Results

• Determination of effectiveness of hatchery
  freezer storage for destruction of viable Rs in
  adult salmon carcasses before they are stocked
  into streams.
• Increased understanding of potential influence of
  stocked hatchery salmon carcasses on Rs levels in
  rivers and resident salmonids.

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Expected Results

• Recommendations for modifications to hatchery
  practices to minimize potential for Rs
  transmission to naturally rearing fish via
  hatchery effluents or hatchery-reared fish.
• Development of methodology that will be
  applicable to the study of other fish pathogens.